The Black-Hole Hunter Peering Into the Heart of Our Galaxy

T.                            The Black-Hole Hunter Peering Into the Heart of Our Galaxy

If you cast an observational lasso into the center of the Milky Way galaxy and pull it closed, you will find a dense, dark lump: a mass totaling some four million suns, crammed into a space no wider than twice Pluto’s orbit in our solar system.

In recent years, astronomers have come to agree that inside this region is a supermassive black hole, and that similar black holes lurk at the cores of nearly all other galaxies as well. And for those revelations, they give a lot of credit to Andrea Ghez.

Since 1995, Ghez, an astrophysicist at the University of California, Los Angeles, has used the W.M. Keck telescope on Mauna Kea in Hawaii to see fine details at the center of the galaxy. The observations that Ghez has made of stars racing around the Milky Way’s core (alongside those of rival Reinhard Genzel, an astrophysicist at the Max Planck Institute for Astrophysics in Garching, Germany) have proven to most astronomers that the central object can be nothing but a black hole. But to be able to see these fine details, Ghez had to become a pioneering user of adaptive optics, a technology that measures distortions in the atmosphere and then adjusts the telescope in real time to cancel out those fluctuations. The technique produces images that look as if they were taken under the calmest possible skies.

In Ghez’s mind, new discoveries require that scientists take risks. “If you have a new idea, the thing you are going to encounter first and foremost is ‘no, you can’t do it,’” she said. “I can’t tell you how many times in the course of this project I have been told ‘this won’t work.’” Her first proposal to image the galactic center was turned down; two decades later, Ghez, now 52, has received a MacArthur Fellowship, among other awards, and was the first woman to receive a Crafoord Prize from the Royal Swedish Academy of Sciences.

The supermassive black hole has been identified, but her explorations are far from over. Theories of galactic evolution suggest that the Milky Way’s center should have lots of old stars and almost no young stars. Observations show the opposite. Ghez’s group is also tracking a mysterious, glowing infrared blob called G2 that skimmed past the black hole in 2014. And now, using their decades-long data set, her team has begun testing whether the stars orbiting the black hole move according to the rules of Einstein’s general relativity or are subject to exotic deviations from theory.

Quanta caught up with Ghez to hear about these projects and her plans. The interview has been edited and condensed for clarity.

Joshua Sokol: You use new telescope technology to address deep theoretical questions. Which one comes first for you: observation or theory?

Andrea Ghez: I think that’s a great question about creativity and discovery. Like, how do you figure out your next project? For me, what floats my boat the most is to figure out new ways of seeing things; to reveal puzzles. What makes me happiest is when observations don’t make sense. And in order for observations to not make sense in a new way—in other words to not be doing incremental work—you need to be looking in a way that’s different.

Sokol: Your team and Reinhard Genzel’s group disagreed about how to interpret the observations of G2. They thought it was a gas cloud; your group suggested it was a star. Can you walk us through what happened when it passed the black hole in 2014?

Ghez: I was pretty convinced that you could explain this object with a model in which you said the object was actually intrinsically a star. One of the key determinants of whether it was a pure gas cloud or a star was whether or not it survived closest approach in 2014. It happily survived.

The interpretation that I am most intrigued by is the idea that you are seeing an object that began its life as a binary star. And if you put very close binaries near a black hole, it turns out to induce what’s known as a three-body interaction, and the binary can merge. So black holes can drive binaries to merge more quickly than they would anywhere else in our galaxy. You end up with an object that has the characteristics of what we are looking at.

It also explains some of the unusual observations of the center of the galaxy. We see many young stars at the center of the galaxy that are hard to explain. It turns out that when binaries merge, it’s like resetting the clock; you get a rebirth of a star, so to speak. So it will create an excess of apparently young stars really close to the black hole, and that’s exactly what we see.

And then after we got very excited about this whole business of binaries, the detection [of gravitational waves from a black-hole merger] happened. In fact, if you take this scenario that we’re developing, where G2 at the galactic center is a binary, it actually gives a mechanism for very naturally explaining these events.

Sokol: You’re referring to the fact that the Laser Interferometer Gravitational-Wave Observatory (LIGO) found black holes of around 30 times the mass of the sun, which is heavier than astronomers expected?

Ghez: If you took two stellar-mass black holes that are the mass that we anticipated, which is 10 times the mass of the sun rather than the 30 that is being observed, and put them near a supermassive black hole, then the two would merge to become a 20 solar mass black hole. And if you do this successively you can work your way up to the 30 solar mass number.

Again, we always start with what’s simple, and then the observations often lay out a more complicated picture. But today, the standard picture is that most if not all galaxies harbor supermassive black holes, so if you think they can play an important role in terms of driving binary stars to merge, then you need to think about that in terms of understanding LIGO. So I think G2 has this really interesting connection—potentially, let me really emphasize potential, as this just an idea we’re playing with—but it has a lot of nice attributes of being very consistent with what we know today about the universe and the center of our galaxy specifically.

Sokol: By which you mean the young stars in the galactic center, and the LIGO observations?

Ghez: Right. There’s a third mystery that may be a bit of a stretch. We anticipate that the population of old stars should be greater near the black hole. And yet we actually don’t see that. There are all sorts of different explanations, from all different camps, but one camp is that the old stars that you are looking at have envelopes that are a little fluffy. If you think that binary stars are being driven to merge, before they merge the binaries might strip these old stars of their outer envelopes. That would make them fainter than you expect them to be, so the lack of old stars might just be an observational outcome of this binary process. Again—when you line up all your mysteries, you have to ask, well, what’s the missing element? What am I not seeing?

Sokol: You have started testing general relativity around the supermassive black hole, and you haven’t found any deviations yet from Einstein’s predictions. What are your plans for this project?

Ghez: In 2018, the star that is the strongest probe of the gravity around the black hole, S02, will make its next closest approach. And it will be the first time we have enough of a handle on its orbit for that closest passage to probe the laws of gravity. In the space of a month or so its velocity will change by more than 6,000 kilometers per second. That’s what will enable us to test general relativity.

Sokol: Speaking of improvements in technology, you were until recently on the science advisory committee of the Thirty Meter Telescope (TMT), which is expected to be the world’s most powerful ground-based telescope. The observatory was planned for Mauna Kea, but the Hawaiian Sovereignty Movement considers that mountain a sacred place and is opposing the project. Spain’s Canary Islands have been chosen as a backup location. If TMT doesn’t go up on Mauna Kea, how does that affect your studies of the galactic center?

Ghez: Oh, you know, that’s such a can of worms. Let me tell you a side story before we get into this more political stuff.

Today, all these weird phenomena that we see—like G2, and the young stars where there should be none, and not enough old stars—you’re really only looking at the brightest stars. So, in order to truly understand the population, you really need to see the typical star, because most stars are low mass or faint. So as we improve our technology both in terms of adaptive optics and going to larger telescopes, it allows you to see a typical star like the sun.

In addition, not only would better resolution let you probe gravity with better measurements of the stellar orbits, but you can increase your understanding of how black holes impact the evolution of a galaxy. And this effect is a key parameter of all cosmological models. You want to be able to see not just the tip of the iceberg in terms of the stellar population.

OK, so then let’s tackle this TMT story. I was on the TMT science advisory committee for, I don’t know, 13 years. The thing that is important is that you get a site where adaptive optics works really well. That means that you want a very smooth airflow over the site where your telescope is at; you want to be on a mountain that is surrounded by a body of water. So you always see observatories near water. Hawaii is surrounded by water, and the Canary Islands are surrounded by water, as opposed to having just water on one side. That makes for much smoother airflows. So I think that the alternative site has some interesting characteristics. Without being—can you tell my angst about talking about this?

Sokol: Yes, sorry to put you on the spot. But I had to, because it’s very interesting.

Ghez: It’s a very interesting story that goes so far beyond science. If it were only a scientific decision, today, Mauna Kea would be my preference. It’s what we chose, so we chose it for a reason. It’s a great site from the point of view of performance of adaptive optics. From my biased perspective, it’s also farther south, so it’s easier to see the center of the galaxy. But one has to be totally respectful of the cultural issues associated with Mauna Kea. It’s one thing to be an astronomer over on the mainland thinking and looking at this, but when you go over there, you understand that it’s a much more complex issue.

I hope for the sake of science, and also for the sake of bringing science and technology to the state of Hawaii, that this project can continue. But it has to continue in a way that works for all the players. And I think the issues have risen far above the issues of astronomy.

Solar eclipse a chance to study life's resilience

Solar eclipse a chance to study life's resilience


On August 21, as North America experiences its first total eclipse of the Sun in 38 years, astrobiologists are taking advantage of this rare celestial event to conduct experiments on life's ability to survive hostile conditions.

Flying at roughly 100,000 feet (30,000 meters), the balloons are expected to make it into the stratosphere, where scientists will gather data on Earth's atmospheric response to the eclipse shadow in an effort to inform atmospheric models. And with the Moon blocking the solar disk, cameras will be able to more clearly capture images of the Sun's normally obscured corona, or atmosphere.

Additionally, the balloons will face extreme conditions similar to the surface of Mars. As such, David J. Smith, a microbiologist at NASA Ames Research Center in Mountain View, California, and his colleagues at NASA's Jet Propulsion Laboratory and Cornell University are piggybacking astrobiology experiments onto the project to test life's ability to survive Mars-like conditions.

The balloons will carry sensors and a thin, lightweight aluminum strip called a "coupon." The rectangular coupons each weigh less than a gram and are about the size of three postage stamps. They are coated with a thin film containing sticky spores of the bacterium Paenibacillus xerothermodurans, originally recovered from the dirt outside NASA's Kennedy Space Center in the 1970s.

"This bacterial strain is harmless to the environment and to humans. Nothing hazardous is going to be hovering over our heads," Smith assured.

The scientists are experimenting with P. xerothermodurans because it is highly resistant to environmental extremes, including high temperatures and ultra-dry conditions. By attaching the microbial coupons onto the balloons, the researchers hope to see life's response to the kinds of extremes seen on the surface of Mars and other distant locales.

"Critics of this work might ask, 'Why not just do this research in an environmental simulation chamber?'" Smith said. "But there is no way to simulate all the complexity and wavelengths of sunlight. We can use our work in Earth's atmosphere to hopefully help verify the findings we get in simulation chambers."

Thirty-four teams from across the United States will fly these bacteria. "All they need to do is mount coupons on the outside of their balloons," Smith said. They can participate in this research without a lot of effort."

The sensors placed on the balloons will vary by teams, but include temperature and humidity we well as radiometers to measure the amount of radiation such as ultraviolet light that they are exposed to, Smith said.

After the balloons land, the researchers will see how many bacteria survived on the coupons. They can then compare survival rates with sensor data to see how the microbes responded to various conditions in the stratosphere.

"I think we'll have bacterial survivors in these experiments," Smith said. "I'm consistently surprised by the resilience of life—the ability of life to linger in conditions we consider extreme is humbling."

Neptune-sized alien moon.

Scientists may have found a Neptune-sized alien moon.

Right now, there's only the Kepler telescope data to work with. It's one of the strongest candidates for an exomoon to date (most candidates fail quickly), but not so bulletproof that you'd stake your life on it. The scientists want to collect measurements from the Hubble telescope before they can make an authoritative statement one way or the other. This is probably an alien moon, but you never want to rule out the possibility of another object.

Of course, a bona fide exomoon wouldn't be shocking. Ask anyone with a passing interest in space and they'll probably argue that moons are common in other star systems, if just through sheer numbers. Rather, it could represent a big milestone in how humanity studies space. Where the focus so far ha been on spotting the largest objects, this suggests that astronomers might have some success looking for the minutiae of a system. And that's more important than you think. Earth's Moon increased the chances for life on its host planet (by stabilizing the rotation and shielding it from asteroids), so it's conceivable that an exomoon might produce a similar effect.

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Nano Laser TECHNOLOGY

Single molecular layer and thin silicon beam enable nanolaser operation at room temperature

For the first time, researchers have built a nanolaser that uses only a single molecular layer, placed on a thin silicon beam, which operates at room temperature. The new device, developed by a team of researchers from Arizona State University and Tsinghua University, Beijing, China, could potentially be used to send information between different points on a single computer chip. The lasers also may be useful for other sensing applications in a compact, integrated format.

In addition to Ning, key authors of the article, "Room-temperature Continuous-wave Lasing from Monolayer Molybdenum Ditelluride Integrated with a Silicon Nanobeam Cavity," include Yongzhuo Li, Jianxing Zhang, Dandan Huang from Tsinghua University.

Ning said pivotal to the new development is use of materials that can be laid down in single layers and efficiently amplify light (lasing action). Single layer nanolasers have been developed before, but they all had to be cooled to low temperatures using a cryogen like liquid nitrogen or liquid helium. Being able to operate at room temperatures (~77 F) opens up many possibilities for uses of these new lasers," Ning said.

The joint ASU-Tsinghua research team used a monolayer of molybdenum ditelluride integrated with a silicon nanobeam cavity for their device. By combining molybdenum ditelluride with silicon, which is the bedrock in semiconductor manufacturing and one of the best waveguide materials, the researchers were able to achieve lasing action without cooling, Ning said.

A laser needs two key pieces – a gain medium that produces and amplifies photons, and a cavity that confines or traps photons. While such materials choices are easy for large lasers, they become more difficult at nanometer scales for nanolasers. Nanolasers are smaller than 100th of the thickness of the human hair and are expected to play important roles in future computer chips and a variety of light detection and sensing devices.

Because silicon is already used in electronics, especially in computer chips, its use in this application is significant in future applications.

"A laser technology that can also be made on Silicon has been a dream for researchers for decades," said Ning. "This technology will eventually allow people to put both electronics and photonics on the same silicon platform, greatly simplifying manufacture."

Silicon does not emit light efficiently and therefore must be combined with other light emitting materials. Currently, other semiconductors are used, such as Indium phosphide or Indium Garlium Arsenide which are hundreds of times thicker, to bond with silicon for such applications.

Looking forward, the team is working on powering their laser with electrical voltage to make the system more compact and easy to use, especially for its intended use on computer chips.

HOWRAH BRIDGE

Howrah Bridge
For the film, see Howrah Bridge (film).

Howrah Bridge is a bridge with a suspended span over the Hooghly River in West Bengal, India. Commissioned in 1943,[8][10] the bridge was originally named the New Howrah Bridge, because it replaced a pontoon bridge at the same location linking the two cities of Howrah and Kolkata (Calcutta). On 14 June 1965 it was renamed Rabindra Setu after the great Bengali poet Rabindranath Tagore, who was the first Indian and Asian Nobel laureate.[10] It is still popularly known as the Howrah Bridge.
Howrah Bridge

Howrah Bridge, Kolkota.jpg
The Howrah Bridge
Coordinates     22.5851°N 88.3469°E
Carries     4 lanes] of Strand Road, pedestrians and bicycles
Crosses     Hooghly River
Locale     Howrah and Kolkata
Official name     Rabindra Setu
Maintained by     Kolkata Port Trust[3]
Characteristics
Design     Suspension type Balanced Cantilever and truss arch
Material     Steel
Total length     705 m (2,313.0 ft)
Width     71 ft (21.6 m) with two footpaths of 15 ft (4.6 m) on either side[4]
Height     82 m (269.0 ft)[5]
Longest span     1,500 ft (457.2 m)[4]
Clearance above     5.8 m (19.0 ft)
Clearance below     8.8 m (28.9 ft)
History
Designer     Rendel, Palmer and Tritton[8]
Constructed by     The Braithwaite Burn and Jessop Construction Company Limited
Construction start     1936[8]
Construction end     1942[8]
Opened     3 Feb 1943; 74 years ago[7]
Statistics
Daily traffic     100,000 vehicles and 150,000 pedestrians[9]
Toll     Free both ways
Howrah Bridge is located in West Bengal
Howrah Bridge

The bridge is one of four on the Hooghly River and is a famous symbol of Kolkata and West Bengal. The other bridges are the Vidyasagar Setu (popularly called the Second Hooghly Bridge), the Vivekananda Setu, and the newly built Nivedita Setu. It weathers the storms of the Bay of Bengal region, carrying a daily traffic of approximately 100,000 vehicles[11] and possibly more than 150,000 pedestrians,[9] easily making it the busiest cantilever bridge in the world.[12] The third-longest cantilever bridge at the time of its construction,[13] the Howrah Bridge is currently the sixth-longest bridge of its type in the world.[14]

History
1862 proposal by Turnbull

In 1862, the Government of Bengal asked George Turnbull, Chief Engineer of the East India Railway Company to study the feasibility of bridging the Hooghly River — he had recently established the company's rail terminus in Howrah. He reported on 19 March with large-scale drawings and estimates that:[15]

    The foundations for a bridge at Calcutta would be at a considerable depth and cost because of the depth of the mud there.
    The impediment to shipping would be considerable.
    A good place for the bridge was at Pulta Ghat "about a dozen miles north of Calcutta" where a "bed of stiff clay existed at no great depth under the river bed".
    A suspended-girder bridge of five spans of 400 feet and two spans of 200 feet would be ideal.

The bridge was not built.
Pontoon bridgeEdit
A photo of the old pontoon bridge that was later replaced by the Howrah Bridge

In view of the increasing traffic across the Hooghly river, a committee was appointed in 1855-56 to review alternatives for constructing a bridge across it.[16] The plan was shelved in 1859-60, to be revived in 1868, when it was decided that a bridge should be constructed and a newly appointed trust vested to manage it. The Calcutta Port Trust was founded in 1870,[8] and the Legislative department of the then Government of Bengal passed the Howrah Bridge Act in the year 1871 under the Bengal Act IX of 1871,[8][16] empowering the Lieutenant-Governor to have the bridge constructed with Government capital under the aegis of the Port Commissioners.

Eventually a contract was signed with Sir Bradford Leslie to construct a pontoon bridge. Different parts were constructed in England and shipped to Calcutta, where they were assembled. The assembling period was fraught with problems. The bridge was considerably damaged by the great cyclone on 20 March 1874.[7] A steamer named Egeria broke from her moorings and collided head-on with the bridge, sinking three pontoons and damaging nearly 200 feet of the bridge.[7] The bridge was completed in 1874,[8] at a total cost of ₹2.2 million,[16] and opened to traffic on 17 October of that year.[7] The bridge was then 1528 ft. long and 62 ft. wide, with 7-foot wide pavements on either side.[8] Initially the bridge was periodically unfastened to allow steamers and other marine vehicles to pass through. Before 1906, the bridge used to be undone for the passage of vessels during daytime only. Since June of that year it started opening at night for all vessels except ocean steamers, which were required to pass through during daytime.[16] From 19 August 1879, the bridge was illuminated by electric lamp-posts, powered by the dynamo at the Mullick Ghat Pumping Station.[8] As the bridge could not handle the rapidly increasing load, the Port Commissioners started planning in 1905 for a new improved bridge.
Plans for a new bridge

In 1906[7] the Port Commission appointed a committee headed by R.S. Highet, Chief Engineer, East Indian Railway and W.B. MacCabe, Chief Engineer, Calcutta Corporation. They submitted a report stating that

    Bullock carts formed the eight - thirteenths of the vehicular traffic (as observed on 27 August 1906, the heaviest day's traffic observed in the port of Commissioners 16 days' Census of the vehicular traffic across the existing bridge). The roadway on the existing bridge is 48 feet wide except at the shore spans where it is only 43 feet in roadways, each 21 feet 6 inches wide. The roadway on the new bridge would be wide enough to take at least two lines of vehicular traffic and one line of trams in each direction and two roadways each 30 feet wide, giving a total width of 60 feet of road way which are quite sufficient for this purpose.................... The traffic across the existing floating bridge Calcutta & Howrah is very heavy and it is obvious if the new bridge is to be on the same site as the existing bridge, then unless a temporary bridge is provided, there will be serious interruptions to the traffic while existing bridge is being moved to one side to allow the new bridge to be erected on the same site as the present bridge.

The committee considered six options:

    Large ferry steamers capable of carrying vehicular load (set up cost ₹900,000, annual cost ₹437,000)
    A transporters bridge (set up cost ₹2 million)
    A tunnel (set up cost ₹338.2 million, annual maintenance cost ₹1779,000)
    A bridge on piers (set up cost ₹22.5 million)
    A floating bridge (set up cost ₹2140,000, annual maintenance cost ₹200,000)
    An arched bridge

The committee eventually decided on a floating bridge. It extended tenders to 23 firms for its design and construction. Prize money of £ 3,000 (₹45,000, at the then exchange rate) was declared for the firm whose design would be accepted.[8]
Planning and estimation

The initial construction process of the bridge was stalled due to the World War I, although the bridge was partially renewed in 1917 and 1927. In 1921 a committee of engineers named the 'Mukherjee Committee' was formed, headed by Sir R.N. Mukherjee, Sir Clement Hindley, Chairman of Calcutta Port Trust and J. McGlashan, Chief Engineer. They referred the matter to Sir Basil Mott, who proposed a single span arch bridge.[8] Charles Alfred O"Grady one of the Engineers

In 1922 the New Howrah Bridge Commission was set up, to which the Mukherjee Committee submitted its report. In 1926 the New Howrah Bridge Act passed. In 1930 the Goode Committee was formed, comprising S.W. Goode as President, S.N. Mallick, and W.H. Thompson, to investigate and report on the advisability of constructing a pier bridge between Calcutta and Howrah. Based on their recommendation, M/s. Rendel, Palmer and Tritton were asked to consider the construction of a suspension bridge of a particular design prepared by their chief draftsman Mr. Walton.[8] On basis of the report, a global tender was floated. The lowest bid came from a German company, but due to increasing political tensions between Germany and Great Britain in 1935, it was not given the contract.[7] The Braithwaite Burn and Jessop Construction Company Limited was awarded the construction contract that year. The New Howrah Bridge Act was amended in 1935 to reflect this, and construction of the bridge started the next year.[8]
Construction

The bridge does not have nuts and bolts,[10][17] but was formed by riveting the whole structure. It consumed 26,500 tons of steel, out of which 23,000 tons of high-tensile alloy steel, known as Tiscrom, were supplied by Tata Steel.[7][18] The main tower was constructed with single monolith caissons of dimensions 55.31 x 24.8 m[4][19] with 21 shafts, each 6.25 metre square.[20] The Chief Engineer of the Port Trust, Mr. J. McGlashan, wanted to replace the pontoon bridge, with a permanent structure, as the present bridge interfered with North/South river traffic. Work could not be started as World War I (1914-1918) broke out. Then in 1926 a commission under the Chairmanship of Sir R. N. Mukherjee recommended a suspension bridge of a particular type to be built across the River Hoogly. The bridge was designed by one Mr.Walton of M/s Rendel, Palmer & Triton. The order for construction and erection was placed on M/s.Cleveland Bridge & Engineering Company in 1939. Again World War II (1939-1945 ) intervened. All the steel that was to come from England were diverted for war effort in Europe. Out of 26,000 tons of steel, that was required for the bridge, only 3000 tons were supplied from England. In spite of the Japanese threat the then ( British ) Government of India pressed on with the construction. Tata Steel were asked to supply the remaining 23,000 tons of high tension steel. The Tatas developed the quality of steel required for the bridge and called it Tiscom. The entire 23,000 tons was supplied in time. The fabrication and erection work was awarded to a local engineering firm of Howrah - The Braithwaite Burn & Jessop Construction Company. The two anchorage caissons were each 16.4 m by 8.2 m, with two wells 4.9 m square. The caissons were so designed that the working chambers within the shafts could be temporarily enclosed by steel diaphragms to allow work under compressed air if required.[20] The caisson at Kolkata side was set at 31.41 m and that at Howrah side at 26.53 m below ground level.[4]

One night, during the process of grabbing out the muck to enable the caisson to move, the ground below it yielded, and the entire mass plunged two feet, shaking the ground. The impact of this was so intense that the seismograph at Kidderpore registered it as an earthquake and a Hindu temple on the shore was destroyed, although it was subsequently rebuilt.[21] While muck was being cleared, numerous varieties of objects were brought up, including anchors, grappling irons, cannons, cannonballs, brass vessels, and coins dating back to the East India Company. The job of sinking the caissons was carried out round-the-clock at a rate of a foot or more per day.[21] The caissons were sunk through soft river deposits to a stiff yellow clay 26.5 m below ground level. The accuracy of sinking the huge caissons was exceptionally precise, within 50–75 mm of the true position. After penetrating 2.1 m into clay, all shafts were plugged with concrete after individual dewatering, with some 5 m of backfilling in adjacent shafts.[20] The main piers on the Howrah side were sunk by open wheel dredging, while those on the Kolkata side required compressed air to counter running sand. The air pressure maintained was about 40 lbs per square inch (2.8 bar), which required about 500 workers to be employed.[12] Whenever excessively soft soil was encountered, the shafts symmetrical to the caisson axes were left unexcavated to allow strict control. In very stiff clays, a large number of the internal wells were completely undercut, allowing the whole weight of the caisson to be carried by the outside skin friction and the bearing under the external wall. Skin friction on the outside of the monolith walls was estimated at 29 kN/m2 while loads on the cutting edge in clay overlying the founding stratum reached 100 tonnes/m.[20] The work on the foundation was completed on November 1938.

By the end of 1940, the erection of the cantilevered arms was commenced and was completed in mid-summer of 1941. The two halves of the suspended span, each 282 feet (86 m) long and weighing 2,000 tons, were built in December 1941. The bridge was erected by commencing at the two anchor spans and advancing towards the center, with the use of creeper cranes moving along the upper chord. 16 hydraulic jacks, each of which had an 800-ton capacity, were pressed into service to join the two halves of the suspended span.[13]

The entire project cost ₹25 million (£2,463,887).[8] The project was a pioneer in bridge construction, particularly in India, but the government did not have a formal opening of the bridge due to fears of attacks by Japanese planes fighting the Allied Powers. Japan had attacked the United States at Pearl Harbor on December 7, 1941. The first vehicle to use the bridge was a solitary tram.[7]

The bridge is regarded "the gateway to Kolkata, as it connects the city to the Howrah Station".[22]
Description

When commissioned in 1943, Howrah was the 3rd-longest cantilever bridge in the world,[13] behind Pont de Québec (549 metres (1,801 ft)) in Canada and Forth Bridge (521 metres (1,709 ft)) in Scotland. It has since been surpassed by three bridges, making it the sixth-longest cantilever bridge in the world in 2013. It is a suspension type balanced cantilever[4] bridge, with a central span 1,500 feet (460 m) between centers of main towers and a suspended span of 564 feet (172 m). The main towers are 280 feet (85 m) high above the monoliths and 76 feet (23 m) apart at the top. The anchor arms are 325 feet (99 m) each, while the cantilever arms are 468 feet (143 m) each.[6] The bridge deck hangs from panel points in the lower chord of the main trusses with 39 pairs of hangers.[4] The roadways beyond the towers are supported from ground, leaving the anchor arms free from deck load. The deck system includes cross girders suspended between the pairs of hangers by a pinned connection.[6] Six rows of longitudinal stringer girders are arranged between cross girders. Floor beams are supported transversally on top of the stringers,[6] while themselves supporting a continuous pressed steel troughing system surfaced with concrete.[4]

The longitudinal expansion and lateral sway movement of the deck are taken care of by expansion and articulation joints. There are two main expansion joints, one at each interface between the suspended span and the cantilever arms, and there are others at the towers and at the interface of the steel and concrete structures at both approach.[4] There are total 8 articulation joints, 3 at each of the cantilever arms and 1 each in the suspended portion. These joints divide the bridge into segments with vertical pin connection between them to facilitate rotational movements of the deck.[4] The bridge deck has longitudinal ruling gradient of 1 in 40 from either end, joined by a vertical curve of radius 4,000 feet (1,200 m). The cross gradient of deck is 1 in 48 between kerbs.[4]
TrafficEdit
Howrah Bridge Traffic
Traffic Flow for fast moving heavy vehicles[11]
Year     Trams     Buses/Vans     Trucks
1959     13%     41%     46%
1986     4%     80%     16%
1990     3%     82%     15%
1992     2%     80%     18%
1999     -     89%     11%
Traffic Flow for fast moving light vehicles[11]
Year     Two-wheelers/Autos     Cars/Taxis
1959     2.47%     97.53%
1986     24%     76%
1990     27%     73%
1992     26%     74%
1999     20%     80%

The bridge serves as the gateway to Kolkata, connecting it to the Howrah Station, which is one of the four intercity train stations serving Howrah and Kolkata. As such, it carries the near entirety of the traffic to and from the station, taking its average daily traffic close to nearly 150,000 pedestrians and 100,000 vehicles.[9] In 1946 a census was taken to take a count of the daily traffic, it amounted to 27,400 vehicles, 121,100 pedestrians and 2,997 cattle.[12] The bulk of the vehicular traffic comes from buses and cars. Prior to 1993 the bridge used to carry trams also. So much traffic! Trams departed from the terminus at Howrah station towards Rajabazar, Sealdah, High Court, Dalhousie Square, Park Circus and Shyambazar. From 1993 the tram services on the bridge were discontinued due to increasing load on the bridge. However the bridge still continues to carry much more than the expected load. A 2007 report revealed that nearly 90,000 vehicles were plying on the bridge daily (15,000 of which were goods-carrying), though its load-bearing capacity is only 60,000.[23] One of the main reasons of overloading was that although vehicles carrying up to 15 tonnes are allowed on the structure, vehicles with 12-18 wheels and carrying load up to 25 tonnes often plied on it. 31 May 2007 onwards, overloaded trucks were banned from plying on the bridge, and were redirected to the Vidyasagar Setu instead.[24] The road is flanked by footpaths of width 15 feet, and they swarm with pedestrians.[4]
Maintenance

The Kolkata Port Trust (KoPT) is vested with the maintenance of the bridge. The bridge has been subject to damage from vehicles due to rash driving, and corrosion due to atmospheric conditions and biological wastes. On October 2008, 6 high-tech surveillance cameras were placed to monitor the entire 705 metres (2,313 ft) long and 30 metres (98 ft) wide structure from the control room. Two of the cameras were placed under the floor of the bridge to track the movement of barges, steamers and boats on the river, while the other four were fixed to the first layer of beams — one at each end and two in the middle — to monitor vehicle movements. This was in response to substantial damage caused to the bridge from collisions with vehicles, so that compensation could be claimed from the miscreants.[25]

Corrosion has been caused by bird droppings and human spitting. An investigation in 2003 revealed that as a result of prolonged chemical reaction caused by continuous collection of bird excreta, several joints and parts of the bridge were damaged.[9] As an immediate measure, the Kolkata Port Trust engaged contractors to regularly clean the bird droppings, at an annual expense of ₹500,000 (US$7,800). In 2004, KoPT spent ₹6.5 million (US$100,000) to paint the entirety of 2.2 million square metres (24 million square feet) of the bridge. Two coats of aluminium paint, with a primer of zinc chromate before that, was applied on the bridge, requiring a total of 26,500 litres of paint.[26]
The illuminated Howrah Bridge at night

The bridge is also considerably damaged by human spitting.[27] A technical inspection by Port Trust officials in 2011 revealed that spitting had reduced the thickness of the steel hoods protecting the pillars from six to less than three millimeters since 2007.[28][29] The hangers need those hoods at the base to prevent water seeping into the junction of the cross-girders and hangers, and damage to the hoods can jeopardize the safety of the bridge. KoPT announced that it will spend ₹2 million (US$31,000) on covering the base of the steel pillars with fibreglass casing to prevent spit from corroding them.[30]

On 24 June 2005, a private cargo vessel M V Mani, belonging to the Ganges Water Transport Pvt. Ltd, while trying to pass under the bridge during high tide, had its funnel stuck underneath for three hours, causing substantial damage worth about ₹15 million to the stringer and longitudinal girder of the bridge.[31] Some of the 40 cross-girders were also broken. Two of four trolley guides, bolted and welded with the girders, were extensively damaged. Nearly 350 metres (1,150 ft) of 700 metres (2,300 ft) of the track were twisted beyond repair.[32] The damage was so severe that KoPT requested help from Rendall-Palmer & Tritton Limited, the original consultant on the bridge from UK. KoPT also contacted SAIL to provide 'matching steel' used during its construction in 1943, for the repairs.[33] For the repair costing around ₹5 million (US$78,000), about 8 tonnes of steel was used. The repairs were completed in early 2006.[34]
Cultural significance

Pedestrians on the bridge

The bridge has been shown in numerous films, such as Bimal Roy's 1953 film Do Bigha Zamin, Ritwik Ghatak's Bari Theke Paliye in 1958, Satyajit Ray's Parash Pathar in the same year, Mrinal Sen's Neel Akasher Neechey in 1959, Shakti Samanta's Howrah Bridge (1958), that featured the famous song Mera Naam Chin Chin Chu and China Town (1962) and Amar Prem (1971), Amar Jeet's 1965 Teen Devian in 1965, Mrinal Sen's 1972 National Award winning Bengali film Calcutta 71 and Sen's Calcutta Trilogy its sequel in 1973, Padatik, Richard Attenborough's 1982 Academy Award winning film Gandhi, Goutam Ghose's 1984 Hindi film Paar, Raj Kapoor's Ram Teri Ganga Maili in 1985, Nicolas Klotz's The Bengali Night in 1988, Roland Joffé's English language film City of Joy in 1992, Florian Gallenberger's Bengali film Shadows of Time in 2004, Mani Ratnam's Bollywood film Yuva in 2004, Pradeep Sarkar's 2005 Bollywood film Parineeta, Subhrajit Mitra's 2008 Bengali film Mon Amour: Shesher Kobita Revisited, Mira Nair's 2006 film The Namesake, Blessy's 2008 Malayalam Film Calcutta News, Surya Sivakumar's 2009 Tamil film Aadhavan, Imtiaz Ali's 2009 Hindi film Love Aaj Kal, Abhik Mukhopadhyay's 2010 Bengali film Ekti Tarar Khonje, Sujoy Ghosh's 2012 Bollywood film Kahaani, Anurag Basu's 2012 Hindi film Barfi!, Riingo Banerjee's 2012 Bengali film Na Hannyate, Rana Basu's 2013 Bengali film Namte Namte, and Ali Abbas Zafar's 2014 Hindi film Gunday and the 2015 YRF release from director Dibakar Banerjee's Detective Byomkesh Bakshy! "Shoojit sircar's"Piku"also features some scenes on this iconic bridge. The bridge was also featured in Garth Davis' Academy Award-nominated 2016 film Lion.

Raksha Bandhan(festival of relationship between sister & brother)

                                                                      Raksha Bandhan

Raksha Bandhan, or simply Rakhi is a Hindu festival, celebrated in many parts of the Indian subcontinent, notably India and Nepal.[2] Raksha bandhan means "bond of protection". It is observed on the full moon day of the Hindu luni-solar calendar month of Shravana, which typically falls in Gregorian calendar month of August.[3][4]
Raksha Bandhan

Examples of rakhi
Official name     Raksha Bandhan.
Also called     Rakhi, Rakhri, Nepali: रक्ष्या बन्धन; Marathi: रक्षा बंधन; Hindi: रक्षा बन्धन, also called as Raksha Bandhana (Kannada: ರಕ್ಷಾ ಬಂಧನ), Rakhi Purnima , (Punjabi: ਰੱਖੜੀ)
Observed by     Hindus
Type     Religious, cultural, secular
Celebrations     sister and brother get together, tie rakhi on wrist, perform aarti,[1] mark tilak, brother promises to protect sister, sister feeds brother, brother gives gift, hugs
Date     Purnima (full moon) of Shrawan
2017 date     Monday, 7 August
Related to     Bhai Duj, Bhai Tika, Sama Chakeva

The festival celebrates the love and duty between brothers and sisters.[5] It is also popularly used to celebrate any brother-sister type of relationship between men and women who may or may not be biologically related. On Raksha Bandhan, a sister ties a rakhi (sacred thread) on her brother's wrist with a prayer for his prosperity and happiness.[5][6] This symbolizes the sister's love. The brother gives her a token gift and a promise to protect her.[5][7]

Raksha Bandhan is primarily observed on the Indian subcontinent.[8] It is also celebrated by some Jains and Sikhs, and by Hindu communities in other parts of the world.[9][10] The festival is also observed by Jains as a religious festival, wherein Jain priests give threads to devotees.[11][12] Raksha Bandhan has been an important tradition in the history of Sikhism as well,[13][14] sometimes referred to as Rakhardi or Rakhari.[15][16]

Description
A formal Aarti plate for Raksha Bandhan

Raksha Bandhan as a religious festival focuses on performing the aarti and saying prayers prior to tying the rakhi. The prayers draw inspiration from the Hindu scriptures.
Significance

Raksha Bandhan in Sanskrit literally means "the tie or knot of protection".[17] The word Raksha means protection, while Bandhan is the verb to tie. It is an ancient Hindu festival that ritually celebrates the love and duty between brothers and their sisters.[4][18] The sister performs a rakhi ceremony, then prays to express her love and her wish for the well being of her brother; in return, the brother ritually pledges to protect and take care of his sister under all circumstances. It is one of the several occasions in which family ties are affirmed in India.[6]

The festival is also an occasion to celebrate brother-sister like family ties between cousins or distant family members,[19] sometimes between biologically unrelated men and women.[20] To many, the festival transcends biological family, brings together men and women across religions, diverse ethnic groups and ritually emphasizes harmony and love. It is observed in the Hindu calendar month of Śrāvaṇa, and typically falls in August every year.[6][4][21]
Practices

The festival is marked by the several rituals, which vary regionally within India. Typical rituals include:
Women shopping for rakhi, the ceremonial thread marking brother-sister love, before the Raksha Bandhan festival
Prepare for Raksha Bandhan'

Days or weeks before Raksha Bandhan, women shop for rakhi, the ceremonial thread to tie around her brother's (or brother-like friend's) wrist. Some women make their own rakhi.[22] A rakhi may be a simple thread, woven and colorful, or may be intricate with amulets and decorations. Sometimes, a rakhi may be a fancy watch or men's wrist accessory in the form of bracelet or jewelry. Rakhi in the form of a colorful woven thread is most common. Typically the brother also shops for gifts for his sister, ahead of Raksha Bandhan. The gift from the brother can be a simple thoughtful token of love, and may be more elaborate.[6][23]
Rakhi ritual

On the morning of Raksha Bandhan the brothers and sisters get together, often in nice dress in the presence of surviving parents, grandparents and other family members. If the sister and brother are geographically separated, the sister may mail the rakhi ahead of the Raksha Bandhan day, along with a greeting card or letter wishing her brother well. The ritual typically begins in front of a lighted lamp (diya) or candle, which signifies fire deity. The sister and brother face each other. The sister ties the rakhi on her brother's wrist.[6]
Prayer, aarti, promise and food

Once the rakhi has been tied, the sister says a prayer for the well being of her brother – good health, prosperity and happiness. This ritual sometimes involves an aarti, where a tray with lighted lamp or candle is ritually rotated around the brother's face, along with the prayer and well wishes.
The rituals of Raksha Bandhan (from top left): 1. Tie the rakhi, 2. tilak (prayer and promise), 3. She feeds him with her hands, 4. Hugs and gifts.

The prayer is a self composed note, or one of many published Rakhi poems and prose.[24] One of the earliest examples of a Rakhi prayer is found in Book V, Chapter V of Vishnu Purana; it is the prayer that Yasoda says while tying a Raksha Bandhan amulet on Krishna's wrist.[25][26] An abridged form of this prayer is:

    May the lord of all beings protect you,
    May the one who creates, preserves and dissolves life protect thee,

    May Govinda guard thy head; Kesava, thy neck; Vishnu, thy belly;
    the eternal Narayana, thy face, thine arms, thy mind, and faculties of sense;

    May all negativity and fears, spirits malignant and unfriendly, flee thee;
    May Rishikesa keep you safe in the sky; and Mahidhara, upon earth.

After the prayer, the sister applies a tilak (tikka), a colorful mark on the forehead of the brother. After the tilak, the brother pledges to protect her and take care of his sister under all circumstances.[6][17]

The sister then feeds the brother, with her hands, one or more bites of sweets (desserts), dry fruits and other seasonal delicacies.[17][27]
Gifts and hugs

The brother gives his sister(s) gifts such as cards, clothes, money or something thoughtful. The brother may also feed his sister, with his hands, one or more bites of sweets, dry fruits and other seasonal delicacies. They hug, and the larger family ritually congratulate the festive celebration of brother-sister love and protection.[6][23]

The brothers wear the rakhi for the entire day, at school or work, as a reminder of their sisters and to mark the festival of Raksha Bandhan.[28]
Myths and legends
A rakhi band

The scriptures, epics of Hinduism is peppered with stories of rakhi and Raksha Bandhan. Some of these include:
Indra Dev

According to Bhavishya Purana, in the war between Gods and demons, Indra – the deity of sky, rains and thunderbolts – was disgraced by the powerful demon King Bali. Indra’s wife Sachi consulted Vishnu, who gave her a bracelet made of cotton thread, calling it holy.[3] Sachi tied the holy thread around Indra wrist, blessed with her prayers for his well being and success. Indra successfully defeated the evil and recovered Amaravati. This story inspired the protective power of holy thread.[17][23][29] The story also suggests that the Raksha Bandhan thread in ancient India were amulets, used by women as prayers and to guard men going to war, and that these threads were not limited to sister-brother like relationships.[3]
King Bali and Goddess Laxmi

According to Bhagavata Purana and Vishnu Purana, after Vishnu won the three worlds from the demon King Bali, Bali asked Vishnu to stay with him in his palace, a request Vishnu granted. Vishnu's wife, Goddess Lakshmi did not like the palace or his new found friendship with Bali, and preferred that her husband and she return to Vaikuntha. So she went to Bali, tied a rakhi and made him a brother to her. Bali asked her what gift she desired. Lakshmi asked that Vishnu be freed from the request that he live in Bali's palace. Bali consented, as well accepted her as his sister.[30]
Santoshi MaaEdit

Ganesh had two sons, Shubh and Labh. The two boys become frustrated that they have no sister to celebrate Raksha Bandhan with. They ask their father Ganesh for a sister, but to no avail. Finally, saint Narada appears who persuades Ganesh that a daughter will enrich him as well as his sons. Ganesh agreed, and created a daughter named Santoshi Maa by divine flames that emerged from Ganesh's wives, Ruddhi (Amazing) and Siddhi (Perfection). Thereafter, Shubh Labh (literally "Holy Profit") had a sister named Santoshi Maa (literally "Goddess of Satisfaction"), for Raksha Bandhan.[31]
Krishna and Draupadi

In the epic Mahabharat, Draupadi tied a rakhi on Krishna, while Kunti tied her rakhi on her grandson Abhimanyu, before the great war.[29]
Yama and the Yamuna

According to another legend, Yama, the god of Death, had not visited his sister Yamuna for 12 years. Yamuna was sad and consulted Ganga. Ganga reminded Yama of his sister, upon which Yama visits her. Yamuna was overjoyed to see her brother, and prepared a bounty of food for Yama. The god Yama was delighted, and asked Yamuna what she wanted for a gift. She wished that he, her brother should return and see her again soon. Yama was moved by his sister's love, agreed and to be able to see her again, made river Yamuna immortal. This legend is the basis for a Raksha Bandhan-like festival called Bhai Duj in some parts of India, which also celebrates brother-sister love, but near Diwali.[32][33]
History
Rakhi threads for sale in India

Raksha Bandhan is an ancient festival of the Indian subcontinent, and its history dates back thousands of years.
Alexander the Great and King Puru

According to one legendary narrative, when Alexander the Great invaded India in 326 BCE, Roxana (or Roshanak, his wife) sent a sacred thread to Porus, asking him not to harm her husband in battle. In accordance with tradition, Porus, the king of Kaikeya kingdom, gave full respect to the rakhi. In the Battle of the Hydaspes, when Porus saw the rakhi on his own wrist and restrained himself from attacking Alexander personally.[34]
Rani Karnavati and Emperor Humayun

Another controversial historical account is that of Rani Karnavati of Chittor and Mughal Emperor Humayun, which dates to 1535 CE. When Rani Karnavati, the widowed queen of the king of Chittor, realised that she could not defend against the invasion by the Sultan of Gujarat, Bahadur Shah, she sent a rakhi to Emperor Humayun. The Emperor, according to one version of the story, set off with his troops to defend Chittor. He arrived too late, and Bahadur Shah had already captured the Rani's fortress. Alternative accounts from the period, including those by historians in Humayun's Mughal court, do not mention the rakhi episode and some historians have expressed skepticism whether it ever happened.[35] Humayun's own memoirs never mention this, and give different reasons for his war with Sultan Bahadur Shah of Gujarat in 1535.[36]

Muslim commentators in modern era publications mention this story as evidence of Muslim-Hindu communal ties in the past.[37][38]
Rabindranath Tagore and the Bengal partition of 1905

Rabindranath Tagore, the Indian Nobel Laureate for literature, invoked Raksha Bandhan and rakhi as concepts to inspire love, respect and a vow of mutual protection between Hindus and Muslims during India's colonial era.[39] In 1905, the British empire divided Bengal, a province of British India on the basis of religion. Rabindra Nath Tagore arranged a ceremony to celebrate Raksha Bandhan to strengthen the bond of love and togetherness between Hindus and Muslims of Bengal, and urge them to together protest the British empire. He used the idea of Raksha Bandhan to spread the feeling of brotherhood. In 1911, British colonial empire reversed the partition and unified Bengal, a unification that was opposed by Muslims of Bengal. Ultimately, Tagore's Raksha Bandhan-based appeals were unsuccessful. Bengal not only was split during the colonial era, one part became modern Bangladesh and predominantly Muslim country, the other a largely Hindu Indian state of West Bengal. Rabindranath Tagore started Rakhi Mahotsavas as a symbol of Bengal unity, and as a larger community festival of harmony.[40] In parts of West Bengal, his tradition continues as people tie rakhis to their neighbors and close friends.[41]

One of Tagore's poem invoking rakhi is:[42]

    The love in my body and heart
    For the earth's shadow and light
    Has stayed over years.

    With its cares and its hope it has thrown
    A language of its own
    Into blue skies.

    It lives in my joys and glooms
    In the spring night's buds and blooms
    Like a Rakhi-band
    On the Future's hand.

Sikh history

In the 18th century, states Arvind-Pal Singh Mandair, Sikh Khalsa armies introduced the term Rakhi (Raksha Bandhan) as a promise of protection to farmers from Muslim armies such as those of the Mughals and Afghans, in exchange for sharing a small cut of their produce.[43][44]

Maharaja Ranjit Singh was the founder and ruler of the Sikh Empire, and he observed Raksha Bandhan festival.[45] His wife Maharani Jindan sent a Rakhi to the ruler of Nepal, who accepted her as sister and gave her refuge in the Hindu kingdom of Nepal in 1849 after the collapse of the Sikh Empire and annexation of its territories by the British.[46][47]

Sikhs have observed Raksha Bandhan festival, and has sometimes been referred to as Rakhardi (literally, wristband)[15] or Rakhari in historic Sikh texts.[48][49][50] Like the Hindu tradition, the festival has involved the tying of the rakhi and giving of gifts.[51][52]
Multi-culturalism and activism

Some Muslims in India view it a secular, multicultural festival.[37] Raksha bandhan has also been adopted by the Christian community in India who view it as a festival of historical and social importance.[53]

In 2015, men tied rakhis on women seeking protection from the ‘misuse’ of section 498A of the Indian Penal Code. "Society has gone through massive changes in the last few decades and men are now considered on the same platform with women. Why should laws show a discrimination against them?" asked Amartya Talukdar, founder member of Hridaya, an NGO working for gender neutrality.[54]
Regional variations
Rakhi tied to a man's wrist in Mauritius.

While Raksha Bandhan is celebrated in various parts of South Asia, different regions mark the day in different ways.
West Bengal and Odisha (Orissa)

In the state of West Bengal and Odisha, this day is also called Jhulan Purnima. Prayers and puja of Lord Krishna and Radha are performed there. Sisters tie rakhi to brothers and wish immortality. Political parties, offices, friends, schools to colleges, street to palace celebrate this day with a new hope for a good relationship.[citation needed]
Maharashtra
Gujarat Chief Minister Anandiben Patel ties a rakhi on Narendra Modi.

In Maharashtra, the festival of Raksha Bandhan is celebrated along with Narali Poornima (coconut day festival). Kolis are the fishermen community of the coastal state. The fishermen offer prayers to Lord Varuna, the Hindu god of Sea, to invoke his blessings. As part of the rituals, coconuts were thrown into the sea as offerings to Lord Varuna. The girls and women tie rakhi on their brother's wrist, as elsewhere.[55][56]
Jammu (Kashmir)

In the regions of North India, mostly Jammu, it is a common practice to fly kites on the nearby occasions of Janamashtami and Raksha Bandhan. It's not unusual to see the sky filled with kites of all shapes and sizes, on and around these two dates. The locals buy kilometres of strong kite string, commonly called as "gattu door" in the local language, along with a multitude of kites.[citation needed]
Haryana

In Haryana, in addition to celebrating Raksha Bandhan, people observe the festival of Salono.[57] Salono is celebrated by priests solemnly tying amulets against evil on people's wrists.[58] As elsewhere, sisters tie threads on brothers with prayers for their well being, and the brothers give her gifts promising to safeguard her.[59]
Nepal

In Nepal, Raksha Bandhan is referred to as Janai Purnima or Rishitarpani, and involves a sacred thread ceremony. It is observed by both Hindus and Buddhists of Nepal.[60] The Hindu men change the thread they wear around their chests (janai), while in some parts of Nepal girls and women tie rakhi on their brother's wrists. The Raksha Bandhan-like brother sister festival is observed by other Hindus of Nepal during one of the days of the Tihar (or Diwali) festival.[61]bcg

what is smoking--!!!!!!!!!(IN HINDI)

धूम्रपान

. इसे एक रिवाज के एक भाग के रूप में, समाधि में जाने के लिए प्रेरित करने और आध्यात्मिक ज्ञान को उत्पन्न करने में भी किया जा सकता है। वर्तमान में धूम्रपान की सबसे प्रचलित विधि सिगरेट है, जो मुख्य रूप से उद्योगों द्वारा निर्मित होती है किन्तु खुले तम्बाकू तथा कागज़ को हाथ से गोल करके भी बनाई जाती है। धूम्रपान के अन्य साधनों में पाइप, सिगार, हुक्का एवं बॉन्ग शामिल हैं। ऐसा बताया जाता है कि धूम्रपान से संबंधित बीमारियां सभी दीर्घकालिक धूम्रपान करने वालों में से आधों की जान ले लेती हैं किन्तु ये बीमारियां धूम्रपान न करने वालों को भी लग सकती हैं। 2007 की एक रिपोर्ट के अनुसार प्रत्येक वर्ष दुनिया भर में 4.9 मिलियन लोग धूम्रपान की वजह से मरते हैं।[1]

धूम्रपान मनोरंजक दवा का एक सबसे सामान्य रूप है। तंबाकू धूम्रपान वर्तमान धूम्रपान का सबसे लोकप्रिय प्रकार है और अधिकतर सभी मानव समाजों में एक बिलियन लोगों द्वारा किया जाता है। धूम्रपान के लिए कम प्रचलित नशीली दवाओं में भांग तथा अफीम शामिल है। कुछ पदार्थों को हानिकारक मादक पदार्थों के रूप में वर्गीकृत किया गया है जैसे कि हेरोइन, किन्तु इनका प्रयोग अत्यंत सीमित है क्योंकि अक्सर ये व्यवसायिक रूप से उपलब्ध नहीं होते.

धूम्रपान का इतिहास लगभग 5000 ई.पू. पुराना हो सकता है और दुनिया भर की कई संस्कृतियों में इसका जिक्र किया गया है। शुरूआती धूम्रपान धार्मिक अनुष्ठानों जैसे देवताओं को प्रसाद, सफाई के रिवाजों के तौर पर, या फिर आध्यात्मिक ज्ञान के लिए ओझाओं/0} या पुजारियों द्वारा अनुमान लगाने के लिए अपने मस्तिष्क के विचार बदलने के प्रयोजन से किया जाता था। यूरोपीय अन्वेषण और अमेरिका की विजय के बाद, तम्बाकू धूम्रपान की आदत दुनिया भर में तेज़ी से फैली. भारत तथा अफ्रीका के उप सहारा में, यह धूम्रपान के समकालीन तरीकों (अधिकतर भांग) के साथ मिल गई। यूरोप में, यह नए प्रकार की सामाजिक गतिविधि और नशीली दवाओं के सेवन के रूप में शुरू हुई, जो पहले अज्ञात थी।

धूम्रपान संबंधित धारणाएं; पवित्र और पापी, परिष्कृत और गलत, रामबाण दवा और स्वास्थ्य के लिए घातक खतरा, समय तथा स्थान के साथ बदलती रही हैं। केवल अपेक्षाकृत हाल ही में और औद्योगिक पश्चिमी देशों में मुख्य रूप से, धूम्रपान को नकारात्मक रूप से देखा जाने लगा है। आज चिकित्सा अध्ययनों ने यह प्रमाणित कर दिया है है कि तम्बाकू धूम्रपान कई रोगों जैसे फेफड़े का कैंसर, दिल का दौरा, नपुंसकता और जन्मजात विकारों को बढ़ावा देने वाले प्रमुख कारणों में से एक है। धूम्रपान के स्वास्थ्य निहित खतरों के कारण, कई देशों ने तम्बाकू पदार्थों पर उच्च कर लगा दिए हैं और तम्बाकू धूम्रपान को रोकने के प्रयासों के रूप में धूम्रपान विरोधी अभियान प्रत्येक वर्ष शुरू किए जाते हैं।

एज़्टेक महिलाओं को बैंकट में खाने के पहले फुल और स्मोकिंग ट्यूब्स पकड़ा दी जाते हैं, फ्लोरेंटाइन कोडेक्स, 1500

धूम्रपान का इतिहास लगभग 5000 ई.पू. शामानी वाद के समय का है।[2] कई प्राचीन सभ्यताओं जैसे बेबीलोनियन, भारतीय और चीनी, धार्मिक अनुष्ठानों में धूप जलाते थे, जिस प्रकार इज़राइली और बाद में कैथोलिक और रूढ़िवादी ईसाई चर्च भी करने लगे थे। अमेरिका में धूम्रपान की शुरुआत संभवतः झाड़फूंक के समारोहों में धूप जलाने से शुरू हुई किन्तु बाद में इसे आनंद के लिए या सामजिक रस्म के रूप में स्वीकार कर लिया गया।[3] तम्बाकू और अन्य कई अन्य नशीली दवाओं का प्रयोग समाधि में जाने तथा आत्माओं की दुनिया से संपर्क करने के लिए किया जाता था।

लगभग 2000 साल पहले भांग, मक्खन (घी), मछली के मांस, सांप की सूखी खाल और कई प्रकार के लेप अगरबत्तियों के चारों ओर मले जाते थे। धूनी (धूप) और हवन (होम) का वर्णन आयुर्वेद में चिकित्सा के प्रयोजन के लिए किया गया है और कम से कम 3000 साल पहले से इनका प्रयोग होता रहा है, जबकि धूम्रपान (अर्थात धुंआ पीना), कम से कम 2000 साल पहले से चला आ रहा है। आधुनिक समय से पहले ये पदार्थ विभिन्न लम्बाईयों के पाइपों या चिल्मों द्वारा ग्रहण किए जाते थे।[4]

तम्बाकू के आगमन से पहले, मध्य पूर्व में भांग का धूम्रपान आम था तथा यह एक सामान्य सामाजिक गतिविधि थी जो एक पानी के पाइप के इर्द गिर्द केन्द्रित थी, जिसे हुक्का कहते थे। तंबाकू की शुरुआत के बाद विशेष रूप से, धूम्रपान, मुस्लिम समाज और संस्कृति का एक महत्त्वपूर्ण अंग बन गया और यह कई महत्त्वपूर्ण रस्मों जैसी शादियों, ज़नाज़े के साथ जुड़ गया और इसकी अभिव्यक्ति वास्तुकला, कपड़ों, साहित्य तथा कविता द्वारा की जाने लगी.[5]

अफ्रीका के उप सहारा में भांग का धूम्रपान इथियोपिया और पूर्वी अफ्रीकी तट पर भारतीय या अरब व्यापारियों द्वारा 1200 के दशक में या इससे पहले शुरू हुआ और यह उन मार्गों पर फ़ैल गया जिनके द्वारा कॉफ़ी का व्यापार किया जाता था, जो इथियोपिया के पहाड़ी इलाकों में उगाई जाती थी।[6] यह धूम्रपान मिट्टी के कटोरे के साथ जुड़े कालाबाश पानी के पाइपों द्वारा किया जाता था, जो कि निश्चित तौर एक इथियोपियाई आविष्कार था जो बाद में पूर्वी, दक्षिणी तथा मध्य अफ्रीका में प्रचलित हुआ।

अमेरिका तक पहुँचने वाले पहले खोजकर्ताओं और विजेताओं द्वारा दी गई सूचनाओं, जिसमे निवासी पादरी स्वयं खुमारी की उच्च दर तक धूम्रपान करते थे, से ऐसी संभावनाओं का पता चलता है कि रिवाज़ केवल तम्बाकू तक ही सीमित नहीं थे।[7]
लोकप्रियता

{तम्बाकू के प्रभाव और विकास के बारे में और अधिक जानकारी प्राप्त करने के लिए तम्बाकू का इतिहास देखें। तम्बाकू के वाणिज्यिक विकास के बारे में और अधिक जानकारी प्राप्त करने के लिए संयुक्त राज्य अमेरिका में वाणिज्यिक तम्बाकू का इतिहास देखें।
मुहम्मद कासिम द्वारा एक फारसी लड़की धूम्रपान.इसफाहन, 1600सक

जेम्सटाउन समझौते के छह साल बाद 1612 में, तम्बाकू को सफलतापूर्वक नकदी फसल के रूप में उगाने का श्रेय जॉन राल्फ को दिया गया। मांग तेज़ी से बढ़ी क्योंकि तम्बाकू, जो "सुनहरी फसल" के रूप में प्रसिद्ध हो गया था, ने वर्जीनिया को अपने सोने के अभियान में असफल होने के बाद पुर्नजीवित कर दिया था।[8] दुनिया भर से आने वाली मांगों को पूरा करने के लिए, तम्बाकू लगातार बोया गया जिससे भूमि तेज़ी से बंजर होने लगी. इसने पश्चिम को एक अज्ञात महाद्वीप में बसने के लिए प्रेरक का कार्य किया और इसी तरह तम्बाकू उत्पादन का एक विस्तार हुआ।[9] बेकन के विद्रोह से पहले ठेके पर काम करने वाले मजदूर इसके प्राथमिक श्रमिक बने, जिसके बाद गुलामी पर ध्यान केन्द्रित किया गया।[10] यह प्रवृत्ति अमेरिकी क्रांति के बाद कम हुई क्योंकि दासप्रथा लाभहीन मानी गई। हालांकि 1794 में सूत कातने वाली मशीनों के आविष्कार के साथ यह प्रथा फिर से जीवित हो गई।[11]

1560 में फ्रांस में जीन निकोट नाम के एक फ्रांसीसी (जिनके नाम से निकोटिन शब्द बना है) ने तम्बाकू का प्रयोग शुरू किया। फ्रांस से तम्बाकू इंग्लैंड में फैल गया। धूम्रपान करने वाले पहले अंग्रेज की सूचना 1556 में ब्रिस्टल के एक नाविक के बारे में है, जिसे "अपने नथुनों से धुआं छोड़ते हुए" देखा गया।[12] चाय, कॉफी और अफीम की ही तरह, तम्बाकू कई प्रकार के मादक पदार्थों में से एक था जिनका प्रयोग दवाई के तौर पर किया जाता था।[13] 1600 के आसपास फ्रांसीसी व्यापारियों द्वारा उस जगह पर तम्बाकू की शुरुआत की गई जिसे आज के आधुनिक समय में जाम्बिया और सेनेगल के नाम से जाना जाता है। इसी समय मोरक्को के काफिले टिम्बकटू के आसपास के क्षेत्रों से तथा पुर्तगाली दक्षिणी अफ्रीका में वस्तु (और पौधे) ले कर आये, जिससे 1650 तक पूरे अफ्रीका में तम्बाकू लोकप्रिय हो गया।

प्राचीन दुनिया में शुरुआत के तुरंत बाद ही तम्बाकू की राज्य स्तर पर और धार्मिक नेताओं द्वारा आलोचना होने लगी. तुर्क साम्राज्य, 1623-40, का सुल्तान मुराद चतुर्थ, यह कह कर धूम्रपान पर प्रतिबंध लगाने वाले पहले व्यक्तियों में से एक था कि यह जनता की नैतिकता और स्वास्थ्य के लिए खतरा है। चीनी सम्राट चोंगझेन ने अपनी मृत्यु से दो साल पहले धूम्रपान पर प्रतिबंध लगाने और मिंग राजवंश को समाप्त करने का फतवा जारी किया। बाद में, किंग राजवंश के मांचू, जो खानाबदोश घुड़सवार योद्धाओं का कबीला था, ने धूम्रपान के बारे में दावा किया कि "यह तीरंदाजी की उपेक्षा से अधिक जघन्य अपराध है". जापान में इडो काल के दौरान, सेनाध्यक्षों द्वारा तम्बाकू के कुछ शुरूआती पौधे यह कह कर बेकार घोषित कर दिए गए कि ये सैन्य अर्थ व्यवस्था के लिए खतरा हैं, क्योंकि, मूल्यवान भूमि को फसलों के पौधों की बजाए एक नशीली दवाई के रूप में प्रयुक्त किया जा रहा है।[14]
अमेरिकी पेटेंट के रूपों में दिखाया गया बोंसैक सिगरेट के रोलिंग मशीन 238,640.

धार्मिक नेता अक्सर उन प्रमुख लोगों में से रहे हैं जिन्होनें धूम्रपान को अनैतिक या तिरस्कार के योग्य माना है। 1634 में मास्को के पैट्रिआर्क ने तम्बाकू की बिक्री पर रोक लगा दी और इस प्रतिबंध का उल्लंघन करने वाले स्त्री और पुरुषों के नाक काटने और उनकी चमड़ी उधड़ने तक चाबुक मारने की सज़ा सुनाई. कुछ इसी तरह पश्चिमी चर्च नेता अर्बन VII (सप्तम) ने 1590 के पोप सम्बंधी आदेश में धूम्रपान की निन्दा की. कई ठोस प्रयासों के बावजूद, प्रतिरोध और प्रतिबंध लगभग दुनियाभर में नजरअंदाज कर दिए गये। जब इंग्लैंड के एक कट्टर धूम्रपान विरोधी और ए काउंटरब्लास्ट टू टोबेको (A Counterblaste to Tobacco) के लेखक जेम्स प्रथम ने 1604 में तम्बाकू पर अप्रत्याशित 4000% कर लगा कर एक नई शुरुआत करने की कोशिश की, तो यह एक विफलता साबित हुई, क्योंकि 1600 के दशक की शुरुआत में लंदन में लगभग 7000 तम्बाकू विक्रेता थे। बाद में, होशियार शासकों को धूम्रपान प्रतिबंध की निरर्थकता का एहसास हुआ और तम्बाकू के व्यापार और खेती को आकर्षक सरकारी एकाधिकार में बदल दिया गया।[15]

1600 के दशक के मध्य तक हर प्रमुख सभ्यता तम्बाकू के धूम्रपान से परिचित थी और बहुत से मामलों में इसे पहले ही देशी संस्कृति में शामिल कर लिया गया था, बावजूद इसके कि कई शासकों ने इसे रोकने के लिए सख्त दंड या जुर्माने का प्रावधान किया। तंबाकू, उत्पाद और पौधे, दोनों प्रमुख बंदरगाहों और बाजारों के प्रमुख मार्गों पर और इसके बाद आंतरिक इलाकों में फैले. अंग्रेजी भाषा का शब्द स्मोकिंग 1700 के दशक के अंत में गढ़ा गया था, जिससे पहले यह प्रक्रिया धुंआ पीने (drinking smoke) के नाम से जानी जाती थी।[12]

विश्व में किसी भी स्थान से कहीं ज्यादा अफ्रीका के उप सहारा में तंबाकू और भांग का प्रयोग ना केवल सामाजिक संबंधों की पुष्टि करने अपितु नए संबंध बनाने में भी किया गया। वर्तमान में कांगो के नाम से बुलाई जाने वाली जगह पर 1800 के दशक में लुबुको ("द लैंड ऑफ़ फ्रेंडशिप) में बेना दिएम्बा (Bena Diemba) ("पीपुल ऑफ़ कैनाबिस") नाम से एक संस्था गठित की गई थी। बेना दिएम्बा शांतिप्रिय समुदाय थे जिन्होनें भांग के पक्ष में शराब तथा हर्बल दवाओं को अस्वीकार कर दिया था।[16]

1860 के दशक के अमेरिकी नागरिक युद्ध तक विकास स्थिर रहा, जिसके बाद प्रमुख श्रमिक, दास से फसल के हिस्सेदार बन गए। इससे मांग में एक जटिल परिवर्तन हुआ जिसके कारण सिगरेट के साथ तंबाकू उत्पादन के औद्योगीकरण की शुरुआत हुई. 1881 में एक शिल्पकार जेम्स बोंसेक ने सिगरेट का उत्पादन बढ़ाने के लिए मशीन बनाई.[17]
अफ़ीम
मुख्य लेख : अफ़ीम
ले पेटिट जर्नल के कवर पर एक अफीम गुफा का एक उदाहरण, 5 जुलाई 1903.

1800 के दशक में अफीम का धूम्रपान आम हो गया था। पहले यह केवल खाई जाती थी और वह भी मुख्य रूप से केवल अपने औषधीय गुणों के कारण. चीन में बड़े पैमाने पर अफीम के धूम्रपान में वृद्धि का मुख्य कारण चीनी राजवंश किंग द्वारा ब्रिटिश व्यापार घाटा था। इस समस्या को सुलझाने के लिए, ब्रिटिश लोगों ने भारतीय उपनिवेशों में बड़े पैमाने पर उगाई गई अफीम का निर्यात शुरू कर दिया. सामाजिक समस्याओं और मुद्रा में बड़ी गिरावट के कारण, आयात को रोकने के लिए चीन द्वारा कई प्रयास हुए जो अंततः अफीम युद्ध में बदल गए।[18]

बाद में अफीम का धूम्रपान चीनी प्रवासियों के प्रसार के साथ फैला तथा दक्षिण व दक्षिण पूर्व एशिया और यूरोप के आसपास स्थित चीनी शहरों के अफीम के कुख्यात गुप्त अड्डों तक फैलता चला गया। 1800 के दशक के उत्तरार्द्ध में, अफीम धूम्रपान, यूरोप के कलात्मक समुदाय में लोकप्रिय हो गया था, विशेषकर पेरिस में कलाकारों के इलाके जैसे मोंटपार्नेस तथा मोंटमारट्रे आभासी "अफीम राजधानियां" बन गए थे। जबकि दुनिया भर के चीनी शहरों में स्थित अफीम के गुप्त ठिकानों ने प्रवासी चीनियों को आपूर्ति जारी रखी, प्रथम विश्व युद्ध के फैलने के बाद यूरोपीय कलाकारों में यह प्रवृत्ति बड़े पैमाने पर कम हुई.[18] चीन में अफ़ीम की खपत 1960 और 1970 के दशक में सांस्कृतिक क्रांति के दौरान कम हुई.
सामाजिक कलंक

1930 और 1940 के दशकों में होने वाले आंदोलन के बारे में अधिक जानकारी प्राप्त करने के लिए नाजी जर्मनी में होने वाले तम्बाकू-विरोधी आंदोलन को देखें। आधुनिक आंदोलन के बारे में और अधिक जानकारी प्राप्त करने के लिए धूम्रपान-विरोधी आंदोलन देखें। साँचा:सार्वजनिक पॉलिसी के विकास के लिए टोबैको पॉलिटिक्स देखें
चित्र:German anti-smoking ad.jpeg
एक नाजी विरोधी धूम्रपान विज्ञापन शीर्षक "द चेन-स्मोकर" कहकर "ही डज़ नॉट डिवोर इट [द सिगरेट], इट डिवोर्स हिम"

1920 के दशक में जीवन में वृद्धि की संभावनाओं और सिगरेट निर्माण के आधुनिकीकरण के साथ, स्वास्थ्य के प्रतिकूल प्रभाव और अधिक परिलक्षित होने लगे. जर्मनी में, धूम्रपान विरोधी समूह, जो अक्सर शराब विरोधी समूहों के साथ जुड़े होते थे, ने 1912 और 1932 में देर तबकगेग्नेर (Der Tabakgegner) (तम्बाकू विरोधी) नामक एक पत्रिका में तम्बाकू की खपत के खिलाफ अपना पक्ष प्रकाशित किया।[19] 1929 में, ड्रेस्डेन जर्मनी के फ्रिट्ज लिकिंट ने फेफड़ों के कैंसर-तम्बाकू के संबंध में औपचारिक सांख्यिकीय प्रमाणों के साथ एक पत्र प्रकाशित किया। घनघोर अवसाद के दौरान, एडॉल्फ हिटलर ने धूम्रपान करने की लत को पैसे की बरबादी कहकर इसकी निन्दा की थी और बाद में इस विषय पर उसने दृढ़ वक्तव्य दिये.[20] नाजी प्रजनन नीति के साथ इस आन्दोलन को और अधिक बढ़ावा मिला क्योंकि जर्मन परिवार में धूम्रपान करने वाली महिला पत्नी या मां बनने के लिए अनुपयुक्त मानी जाती थी।[21]

द्वितीय विश्व युद्ध के दौरान नाजी जर्मनी आंदोलन समाप्त हो गया क्योंकि धूम्रपान विरोधी समूहों ने जल्दी ही अपना समर्थन खो दिया था। द्वितीय विश्व युद्ध के अंत तक, अमेरिकी सिगरेट निर्माताओं ने जर्मन काले बाज़ार में फिर से प्रवेश कर लिया। तम्बाकू की अवैध तस्करी प्रचलित हो गई,[22] और धूम्रपान विरोधी अभियान के नेताओं की हत्या कर दी गई।[23] मार्शल योजना के तहत संयुक्त राज्य अमेरिका ने जहाजों द्वारा जर्मनी में मुफ्त में तम्बाकू भेजा जो 1948 में 24,000 टन और 1949 में 69,000 टन था।[22] युद्ध के पश्चात् जर्मनी में प्रति व्यक्ति सिगरेट की वार्षिक खपत 1950 में 460 से बढ़ कर 1963 तक 1,523 हो गई।[24] 1900 के दशक के अंत तक, जर्मनी के धूम्रपान विरोधी अभियान नाजी युग के 1939-1941 के प्रभाव को बढ़ाने में असमर्थ थे और जर्मन तम्बाकू स्वास्थ्य अनुसन्धान संस्थान को रॉबर्ट एन प्रॉक्टर द्वारा "मौन" वर्णित किया गया था।[24]
एक लंबा करने के लिए मजबूत कानूनी कार्रवाई के लिए आवश्यक सहयोग से स्थापित किए गए एक अध्ययन.

1950 में ब्रिटिश मेडिकल जर्नल में प्रकाशित एक शोध द्वारा रिचर्ड डौल ने धूम्रपान और फेफड़ों के कैंसर के बीच में संबंध दिखाया.[25] चार साल बाद, 1954 में ब्रिटिश डॉक्टरों के एक अध्ययन, यह अध्ययन 40 हजार डॉक्टरों द्वारा 20 से भी अधिक वर्षों तक किया गया था, ने इस बात की पुष्टि की जिसके आधार पर सरकार ने सलाह जारी की कि धूम्रपान और फेफड़ों के कैंसर का आपस में संबंध था।[26] कुछ इसी तरह 1964 में धूम्रपान और स्वास्थ्य पर अमेरिकन सर्जन जनरल ने धूम्रपान और कैंसर के बीच संबंध बताया, जिसकी पुष्टि 20 वर्षों बाद 1980 के दशक के बाद के वर्षों में की गई।

जबकि 1980 के दशक में वैज्ञानिक साक्ष्य बढ़ने लगे, तम्बाकू कंपनियों ने आंशिक लापरवाही का दावा किया क्योंकि स्वास्थ्य के प्रतिकूल प्रभाव अज्ञात या अविश्वसनीय थे। 1998 तक स्वास्थ्य अधिकारियों ने इन दावों का साथ दिया, जिसके बाद उन्होनें स्थिति पलट दी. संयुक्त राज्य अमेरिका की चार बड़ी तम्बाकू कंपनियों और 46 राज्यों के अटॉर्नी जनरल के बीच हुए टोबेको मास्टर सेटलमेन्ट एग्रीमेंट (Tobacco Master Settlement Agreement), जो बाद में अमेरिका के इतिहास का सबसे बड़ा नागरिक समझौता बन गया, के तहत तम्बाकू के कई प्रकार के विज्ञापनों पर प्रतिबंध लगा दिया गया और स्वास्थ्य के लिए मुआवजे की मांग रखी गई।[27]

1965 से 2006 तक, संयुक्त राज्य अमेरिका में धूम्रपान की दर 42% से गिर कर 20.8% हुई है।[28] छोड़ने वालों में अधिकतर पेशेवर संपन्न आदमी थे। उपभोग में इस कमी के बावज़ूद, प्रति दिन प्रति व्यक्ति सिगरेट की औसत खपत संख्या 1954 में 22 से बढ़ कर 1978 में 30 हो गई। यह विरोधाभास बताता है कि छोड़ने वाले लोग कम थे, जबकि जारी रखने वाले हलकी सिगरेटों की ओर आकर्षित होने लगे.[29] यह प्रवृत्ति कई औद्योगिक देशों में समानान्तर चलती रही, भले ही उसकी दर बराबर रही या उसमें गिरावट आई. तथापि, विकासशील दुनिया में, 2002 में 3.4% की दर के साथ तम्बाकू की खपत में वृद्धि जारी है।[30] अफ्रीका के कई क्षेत्रों में, धूम्रपान को आधुनिकता से जोड़ कर देखा जाता है और पश्चिम की कई मज़बूत सलाहों पर बहुत कम ध्यान दिया जाता है।[31] आज रूस तम्बाकू का शीर्ष उपभोक्ता है और उसके बाद इंडोनेशिया, लाओस, यूक्रेन, बेलारूस, ग्रीस, जोर्डन और चीन हैं।[32] विकासशील दुनिया में खपत की दर को कम करने के लिए विश्व स्वास्थ्य संगठन ने तम्बाकू मुक्त पहल (Tobacco Free Initiative) (TFI) नामक कार्यक्रम की शुरुआत की है।

साँचा:क्रैक कोकेन के बारे में और जानने के लिए क्रैक एपिडेमिक देखें (संयुक्त राज्य)

1980 के दशक की शुरुआत में, अंतरराष्ट्रीय नशीले पदार्थों की संगठित तस्करी बढ़ी. हालांकि, अत्यधिक उत्पादन और जटिल कानूनों की समस्या से परेशान ड्रग डीलरों ने पाउडर को "क्रैक"-कोकीन का एक ठोस धूम्रपान करने योग्य रूप, में बदलने का निश्चय किया, जिसे कम मात्रा में ज्यादा लोगों को बेचा जा सकता था।[33] 1990 के दशक में पुलिस कार्यवाही के साथ मज़बूत अर्थव्यवस्था से कई संभावित उमीदवारों का माल जब्त होने या उन्हें आदत छोड़ने के लिए मजबूर करने के कारण, इस प्रवत्ति में कमी आई.[34]

हाल के वर्ष वाष्पित हेरोइन, मेथाम्फेटामाइन तथा फेन्सीस्लाइडीन (पीसीपी) (PCP) की खपत में वृद्धि को दर्शाते हैं। इनके साथ कम संख्या में दिमाग पर असर करने वाली दवाएं जैसे कि DMT, 5-Meo-DMT और सल्विया डिविनोरम शामिल हैं।[कृपया उद्धरण जोड़ें]
पदार्थ

धूम्रपान में प्रयुक्त होने वाला सबसे लोकप्रिय पदार्थ तम्बाकू है। तम्बाकू की विभिन्न प्रजातियाँ मौजूद हैं जिन्हें कई प्रकार के मिश्रण और ब्रांडों की विविधता से बनाया जाता है। तंबाकू अक्सर सुगंधित कर के बेचा जाता है, जिसमे अक्सर विभिन्न फलों की खुशबू होती है, कुछ ऐसे रूप में जो पानी के पाइपों जैसे हुक्के के साथ अधिक लोकप्रिय है। धूम्रपान में प्रयुक्त होने वाला दूसरा सबसे आम पदार्थ भांग है, जिसे कैनाबिस सतिवा (Cannabis sativa) के फूलों या पत्तियों से बनाया जाता है। इस पदार्थ को दुनिया के अधिकतर देशों द्वारा अवैध माना जाता है और वे देश जिनमे सार्वजनिक खपत बर्दाश्त की जाती है, यह केवल छद्म तौर पर वैध है। इस के बावजूद, कई देशों में वयस्क जनसंख्या का काफी बड़ा प्रतिशत इसका प्रयोग करने वालों की कोशिश करने वालों में से है जिनमे से एक छोटी संख्या इसका प्रयोग नियमित रूप से करती है। चूंकि तम्बाकू अवैध है या ज्यादातर क्षेत्रों में बर्दाश्त किया जाता है, सिगरेटों में इसका बड़े पैमाने पर उत्पादन नहीं होता है जिसका अर्थ है कि धूम्रपान का सबसे प्रचलित प्रकार हाथ से मोड़ी गई सिगरेट, जिसे अक्सर जॉईंट (joints) कहा जाता है, या पाइप हैं। पानी के पाइप भी काफी आम है और भांग के लिए इस्तेमाल करने पर अक्सर इन्हें बॉन्ग कहा जाता है।

कुछ अन्य मादक दवाओं का प्रयोग छोटे पैमाने पर होता है। इनमे से अधिकतर पदार्थ नियंत्रित हैं और कुछ तम्बाकू या भांग से कहीं अधिक नशीले हैं। इनमे क्रैक कोकीन, हेरोइन, मेथाम्फेटामाइन और पीसीपी (PCP) शामिल हैं। इनके साथ कम संख्या में दिमाग पर असर करने वाली दवाएं जैसे कि DMT, 5-Meo-DMT और सल्विया डिविनोरम शामिल हैं।
एक अलंकृत सजाया हुआ पाइप.

धूम्रपान के सबसे प्राचीन रूप के प्रदर्शन के लिए भी किसी तरह के उपकरण की आवश्यकता है। इसके परिणामस्वरूप दुनिया भर में विभिन्न प्रकार के धूम्रपान उपकरण और सामग्रियां बनी हैं। चाहे तम्बाकू, भांग, अफीम या जड़ी बूटी हो, सभी प्रकारों के मिश्रण को जलाने के लिए आग के एक स्रोत की आवश्यकता होती है। अभी तक सबसे आम सिगरेट है, जो कस कर लपेटी गई कागज़ की ट्यूब से बना होता है, व जिसका निर्माण औद्योगिक रूप से किया जाता है, या फिर कागज़ को मोड़ कर खुले तम्बाकू से बनाया जाता है, जिसमे एक फ़िल्टर हो सकता है। अन्य लोकप्रिय धूम्रपान उपकरणों में विभिन्न प्रकार के पाइप और सिगार हैं। एक कम आम लेकिन तेजी से लोकप्रियता की ओर बढ़ता प्रकार वैपोराईज़र (vaporizer) है, जो गर्म हवा से संचालित होता है और जिसमे पदार्थ का दहन नहीं करना पड़ता, अतः फेफड़ों के स्वास्थ्य के लिए कम खतरनाक होता है।

वास्तविक धूम्रपान उपकरण के अलावा कई अन्य वस्तुएं धूम्रपान के साथ जुड़ी हुई हैं, सिगरेट केस, सिगार बॉक्स, लाईटर, माचिस, सिगरेट होल्डर, सिगार होल्डर, ऐश ट्रे, पाइप क्लीनर, तम्बाकू कटर, माचिस स्टैंड, पाइप टेम्पर, सिगरेट कॉम्पैनीयन तथा कई अन्य. इनमे से कई मूल्यवान संग्राहक वस्तुएं बन गई हैं और विशेषकर अलंकृत और प्राचीन वस्तु बेहतरीन नीलामी घरों में उच्च कीमतों पर बिक सकती है।

इलेक्ट्रॉनिक सिगरेट की शुरुआत के साथ 2004 में धूम्रपान का एक कथित अधिक स्वास्थ्यवर्धक विकल्प प्रदर्शित हुआ। ये बैटरी चालित, सिगरेट जैसे उपकरण, तम्बाकू द्वारा उत्पन्न होने वाले धुएं की नक़ल के रूप में एयरोसोल का उत्पादन करते हैं, जिससे उपयोगकर्ता को तम्बाकू धूम्रपान में उत्पन्न होने वाले हानिकारक पदार्थों के बिना निकोटिन प्राप्त होता है। दावा किया गया है कि इलेक्ट्रॉनिक सिगरेट असली सिगरेटों की तुलना में कम हानिकारक है, हालांकि कई देशों की कानूनी स्थिति के अनुसार यह अभी विवादित है।

नेपालै नरहे (कविता)

यो कविता कवि माधव घिमिरेद्वारा लिखत गिती कविता हो ।

  नेपाली हामी रहौँला कहाँ नेपालै नरहे
उचाइ हाम्रो चुलिन्छ कहाँ हिमालै नरहे
  तराई हाम्रो सुनको टुक्रा हिमाल हिराको
    माटो र पानी पहिलो धन धर्तीका छोराको
  ए कहाँबाट हेरौँला संसार सन्झ्यालै नरहे
    नेपाली हामी रहौँला कहाँ नेपालै नरहे

  दसैँ र तिहार रमाइला हाम्रा चुड्का र ख्यालीले
  हिर्दय हाम्रो जुर्मुराउँछ जितको झ्यालीले
  बैँसको तालमा नाचौँला कहाँ मादलै नरहे
  नेपाली हामी रहौँला कहाँ नेपालै नरहे

  आकाश छुने टाकुरा हाम्रो भेटेर भेटिन्न
  पौरखी हाम्रा पुर्खाको पाइला मेटेर मेटिन्न
  बिम्झौँला कहाँ पुर्वको पैलो उज्यालै नरहे
  नेपाली हामी रहौँला कहाँ नेपालै नरहे  

झ्याउरे लयमा रचना गरिएको यस ‘नेपालै नरहे’ कविता राष्ट्र कवि माधवप्रसाद  घिमिरेको उच्चस्त्रवादि  स्वर घन्किएको कविता हो l नेपाली माटो, नेपाली प्रकृति,  विरता, संस्कृति जस्ता  विषय माथि प्रकाश पार्दै  नेपाल र नेपालीको परिचय  कवितामा प्रस्तुत गरिएको  छ l हिमालको काखमा अवस्थित यस सुन्दर आकर्षक देश नेपाललाई आर्थिक सामाजिक उन्नतिले सजाउनु पर्ने संदेश कवितामा भेटिन्छ l तराईको  उर्वरता, हिमालको स्वच्छता, नेपालीको मौलिकता, नेपाली र नेपालको चिनारी भनि नेपाललाई संसारकै सर्वोत्क्रिस्ट र सर्वोच्च भूमिको रुपमा कविले प्रस्तुत गरेका छन् l

नेपाली संस्कृति, परम्परा, चाडपर्व, भाकामा नेपाली रम्ने राष्ट्रिय भlब ब्यक्त गर्दै हाम्रा पुर्खाको बलिदान, समर्पण, त्याग युग्युगंतर सम्म रहिरहने कवितामा भनिएको छ l चेतना, शिक्षा,सभ्यता धर्तीमा पुर्व बाट सुरु भएकोले र हामी पूर्वका बासिन्दा हुनाले गौरवको अनुभव कवितामा प्रस्तुत भएको छ l राष्ट्र को चिनारी अस्तित्व भए मात्र देशबासी परिचित हुने भावलाइ प्रस्तुत गरिएको छ l देशको भूगोलमा रहेको स्थानको आ आफ्नै महत्व हुने कुरा लाई प्रस्तुत गर्न कबि ले तराई लाइ सुन र हिमाललाइ  हिरा संग तुलना गर्दै राष्ट्र प्रति को सम्मान भाव व्यक्त गरेका छन् l

Milky Way Galaxy

Milky Way Galaxy

The Milky Way's Galactic Center in the night sky above Paranal Observatory (the laser creates a guide-star for the telescope).
Observation data
Type	Sb, Sbc, or SB(rs)bc[1][2] (barred spiral galaxy)
Diameter	100–180 kly (31–55 kpc)[3]
Thickness of thin stellar disk	≈2 kly (0.6 kpc)[4][5]
Number of stars	100–400 billion (2.5 × 1011 ± 1.5 × 1011)[6][7][8]
Oldest known star	≥13.7 Gyr[9]
Mass	0.8–1.5×1012 M☉[10][11][12][13]
Angular momentum	≈1×1067 J s[14]
Sun's distance to Galactic Center	26.4 ± 1.0 kly (8.09 ± 0.31 kpc)[15][16][17]
Sun's Galactic rotation period	240 Myr[18]
Spiral pattern rotation period	220–360 Myr[19]
Bar pattern rotation period	100–120 Myr[19]
Speed relative to CMB rest frame	631 ± 20 km/s[20]
Escape velocity at Sun's position	550 km/s[13]
Dark matter density at Sun's position

The Milky  Way is the galaxy that contains our Solar System.The descriptive "milky" is derived from the appearance from Earth of the galaxy – a band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle").[25][26][27] From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe.[28] Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis,[29] observations by Edwin Hubble showed that the Milky Way is just one of many galaxies. The Milky Way is a barred spiral galaxy with a diameter between 100,000[30] and 180,000 light-years.[31] The Milky Way is estimated to contain 100–400 billion stars.[32][33] There are probably at least 100 billion planets in the Milky Way.[34][35] The Solar System is located within the disk, about 26,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole. Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. The constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much of the mass of the Milky Way does not emit or absorb electromagnetic radiation. This mass has been termed "dark matter".[36] The rotational period is about 240 million years at the position of the Sun.[18] The Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference. The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.[9] The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster. Appearance A view of the Milky Way toward the constellation Sagittarius (including the Galactic Center) as seen from an area not polluted by light (the Black Rock Desert, Nevada). The bright object on the right is Jupiter, just above Antares. Play media This time-lapse video captures the Milky Way circling over ALMA. The "Milky Way" can be seen as a hazy band of white light some 30 degrees wide arcing across the sky.[39] Although all the individual naked-eye stars in the entire sky are part of the Milky Way,[40][41] the light in this band originates from the accumulation of unresolved stars and other material located in the direction of the galactic plane. Dark regions within the band, such as the Great Rift and the Coalsack, are areas where light from distant stars is blocked by interstellar dust. The area of the sky obscured by the Milky Way is called the Zone of Avoidance. The Milky Way has a relatively low surface brightness. Its visibility can be greatly reduced by background light such as light pollution or stray light from the Moon. The sky needs to be darker than about 20.2 magnitude per square arcsecond in order for the Milky Way to be seen.[42] It should be visible when the limiting magnitude is approximately +5.1 or better and shows a great deal of detail at +6.1.[43] This makes the Milky Way difficult to see from any brightly lit urban or suburban location, but very prominent when viewed from a rural area when the Moon is below the horizon.[nb 2] The new world atlas of artificial night sky brightness shows that more than one-third of Earth's population cannot see the Milky Way from their homes due to light pollution.[44] As viewed from Earth, the visible region of the Milky Way's Galactic plane occupies an area of the sky that includes 30 constellations.[45] The center of the Galaxy lies in the direction of the constellation Sagittarius; it is here that the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the Galactic anticenter in Auriga. The band then continues the rest of the way around the sky, back to Sagittarius. The band divides the night sky into two roughly equal hemispheres. The Galactic plane is inclined by about 60 degrees to the ecliptic (the plane of Earth's orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic, relative to the Galactic plane. The north Galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near β Comae Berenices, and the south Galactic pole is near α Sculptoris. Because of this high inclination, depending on the time of night and year, the arc of the Milky Way may appear relatively low or relatively high in the sky. For observers from approximately 65 degrees north to 65 degrees south on Earth's surface, the Milky Way passes directly overhead twice a day. The Milky Way arching at a high inclination across the night sky (fish-eye mosaic shot at Paranal, Chile). The bright object is Jupiter in the constellation Sagittarius, and the Magellanic Clouds can be seen on the left. Galactic north is downwards. Size and mass A photograph of galaxy UGC 12158, which is thought to resemble the Milky Way in appearance. The Milky Way is the second-largest galaxy in the Local Group, with its stellar disk approximately 100,000 ly (30 kpc) in diameter, and, on average, approximately 1,000 ly (0.3 kpc) thick.[4][5] As a guide to the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter (24.3 mm (0.955 in)), the Milky Way would be approximately the size of the continental United States.[46] A ring-like filament of stars wrapping around the Milky Way may belong to the Milky Way itself, rippling above and below the relatively flat galactic plane.[31] If so, that would mean a diameter of 150,000–180,000 light-years (46–55 kpc).[47] Schematic profile of the Milky Way. Estimates of the mass of the Milky Way vary, depending upon the method and data used. At the low end of the estimate range, the mass of the Milky Way is 5.8×1011 solar masses (M☉), somewhat less than that of the Andromeda Galaxy.[48][49][50] Measurements using the Very Long Baseline Array in 2009 found velocities as large as 254 km/s (570,000 mph) for stars at the outer edge of the Milky Way.[51] Because the orbital velocity depends on the total mass inside the orbital radius, this suggests that the Milky Way is more massive, roughly equaling the mass of Andromeda Galaxy at 7×1011 M☉ within 160,000 ly (49 kpc) of its center.[52] In 2010, a measurement of the radial velocity of halo stars found that the mass enclosed within 80 kiloparsecs is 7×1011 M☉.[53] According to a study published in 2014, the mass of the entire Milky Way is estimated to be 8.5×1011 M☉,[54] which is about half the mass of the Andromeda Galaxy.[54] Much of the mass of the Milky Way appears to be dark matter, an unknown and invisible form of matter that interacts gravitationally with ordinary matter. A dark matter halo is spread out relatively uniformly to a distance beyond one hundred kiloparsecs from the Galactic Center. Mathematical models of the Milky Way suggest that the mass of dark matter is 1–1.5×1012 M☉.[10][11][55] Recent studies indicate a range in mass, as large as 4.5×1012 M☉ [56] and as small as 8×1011 M☉.[57] The total mass of all the stars in the Milky Way is estimated to be between 4.6×1010 M☉[58] and 6.43×1010 M☉.[10] In addition to the stars, there is also interstellar gas, comprising 90% hydrogen and 10% helium by mass,[59] with two thirds of the hydrogen found in the atomic form and the remaining one-third as molecular hydrogen.[60] The mass of this gas is equal to between 10%[60] and 15%[59] of the total mass of the galaxy's stars. Interstellar dust accounts for an additional 1% of the total mass of the gas.[59] Contents Further information: Exoplanet The Milky Way contains between 200 and 400 billion stars[61][62] and at least 100 billion planets.[63] The exact figure depends on the number of very-low-mass stars, which are hard to detect, especially at distances of more than 300 ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars.[64] Filling the space between the stars is a disk of gas and dust called the interstellar medium. This disk has at least a comparable extent in radius to the stars,[65] whereas the thickness of the gas layer ranges from hundreds of light years for the colder gas to thousands of light years for warmer gas.[66][67] The disk of stars in the Milky Way does not have a sharp edge beyond which there are no stars. Rather, the concentration of stars decreases with distance from the center of the Milky Way. For reasons that are not understood, beyond a radius of roughly 40,000 ly (13 kpc) from the center, the number of stars per cubic parsec drops much faster with radius.[68] Surrounding the galactic disk is a spherical Galactic Halo of stars and globular clusters that extends further outward but is limited in size by the orbits of two Milky Way satellites, the Large and Small Magellanic Clouds, whose closest approach to the Galactic Center is about 180,000 ly (55 kpc).[69] At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds. Hence, such objects would probably be ejected from the vicinity of the Milky Way. The integrated absolute visual magnitude of the Milky Way is estimated to be around −20.9.[70][71][a] Both gravitational microlensing and planetary transit observations indicate that there may be at least as many planets bound to stars as there are stars in the Milky Way,[34][72] and microlensing measurements indicate that there are more rogue planets not bound to host stars than there are stars.[73][74] The Milky Way contains at least one planet per star, resulting in 100–400 billion planets, according to a January 2013 study of the five-planet star system Kepler-32 with the Kepler space observatory.[35] A different January 2013 analysis of Kepler data estimated that at least 17 billion Earth-sized exoplanets reside in the Milky Way.[75] On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way.[76][77][78] 11 billion of these estimated planets may be orbiting Sun-like stars.[79] The nearest such planet may be 4.2 light-years away, according to a 2016 study.[80] Such Earth-sized planets may be more numerous than gas giants.[34] Besides exoplanets, "exocomets", comets beyond the Solar System, have also been detected and may be common in the Milky Way.[81] 360-degree panorama view of the Milky Way (an assembled mosaic of photographs) by ESO. The galactic centre is in the middle of the view, with galactic north up. Structure Play media An artist's impression that shows how the Milky Way would look from very different perspectives than from Earth. From some angles, the central bulge shows up as a peanut-shaped glowing ball of stars, and from above, the central narrow bar appears clearly. The many spiral arms and their associated dust clouds are also clearly seen. Artist's conception of the spiral structure of the Milky Way with two major stellar arms and a bar[82] Spitzer reveals what cannot be seen in visible light: cooler stars (blue), heated dust (reddish hue), and Sgr A* as bright white spot in the middle. Bright X-ray flares from Sagittarius A*, location of the supermassive black hole at the center of the Milky Way.[83] The Milky Way consists of a bar-shaped core region surrounded by a disk of gas, dust and stars. The mass distribution within the Milky Way closely resembles the type Sbc in the Hubble classification, which represents spiral galaxies with relatively loosely wound arms.[1] Astronomers began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s.[84] Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005[85] that showed the Milky Way's central bar to be larger than previously thought. Galactic quadrants Main article: Galactic quadrant A galactic quadrant, or quadrant of the Milky Way, refers to one of four circular sectors in the division of the Milky Way. In actual astronomical practice, the delineation of the galactic quadrants is based upon the galactic coordinate system, which places the Sun as the origin of the mapping system.[86] Quadrants are described using ordinals—for example, "1st galactic quadrant",[87] "second galactic quadrant",[88] or "third quadrant of the Milky Way".[89] Viewing from the north galactic pole with 0 degrees (°) as the ray that runs starting from the Sun and through the Galactic Center, the quadrants are as follows: 1st galactic quadrant – 0° ≤ longitude (ℓ) ≤ 90°[90] 2nd galactic quadrant – 90° ≤ ℓ ≤ 180°[88] 3rd galactic quadrant – 180° ≤ ℓ ≤ 270°[89] 4th galactic quadrant – 270° ≤ ℓ ≤ 360° (0°)[87] Galactic Center Main article: Galactic Center The Sun is 25,000–28,000 ly (7.7–8.6 kpc) from the Galactic Center. This value is estimated using geometric-based methods or by measuring selected astronomical objects that serve as standard candles, with different techniques yielding various values within this approximate range.[15][16][17][91][92][93] In the inner few kpc (around 10,000 light-years radius) is a dense concentration of mostly old stars in a roughly spheroidal shape called the bulge.[94] It has been proposed that the Milky Way lacks a bulge formed due to a collision and merger between previous galaxies, and that instead it has a pseudobulge formed by its central bar.[95] The Galactic Center is marked by an intense radio source named Sagittarius A* (pronounced Sagittarius A-star). The motion of material around the center indicates that Sagittarius A* harbors a massive, compact object.[96] This concentration of mass is best explained as a supermassive black hole[nb 3][15][97] (SMBH) with an estimated mass of 4.1–4.5 million times the mass of the Sun.[97] The rate of accretion of the SMBH is consistent with an inactive galactic nucleus, being estimated at around 1×10−5 M☉ y−1.[98] Observations indicate that there are SMBH located near the center of most normal galaxies.[99][100] The nature of the Milky Way's bar is actively debated, with estimates for its half-length and orientation spanning from 1 to 5 kpc (3,000–16,000 ly) and 10–50 degrees relative to the line of sight from Earth to the Galactic Center.[92][93][101] Certain authors advocate that the Milky Way features two distinct bars, one nestled within the other.[102] However, RR Lyrae variables do not trace a prominent Galactic bar.[93][103][104] The bar may be surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the Milky Way, as well as most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way.[105] X-ray emission from the core is aligned with the massive stars surrounding the central bar[98] and the Galactic ridge.[106] Illustration of the two gigantic X-ray/gamma-ray bubbles (blue-violet) of the Milky Way (center) In 2010, two gigantic spherical bubbles of high energy emission were detected to the north and the south of the Milky Way core, using data from the Fermi Gamma-ray Space Telescope. The diameter of each of the bubbles is about 25,000 light-years (7.7 kpc); they stretch up to Grus and to Virgo on the night-sky of the southern hemisphere.[107][108] Subsequently, observations with the Parkes Telescope at radio frequencies identified polarized emission that is associated with the Fermi bubbles. These observations are best interpreted as a magnetized outflow driven by star formation in the central 640 ly (200 pc) of the Milky Way.[109] Later, on January 5, 2015, NASA reported observing an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*