The strange behavior of Sagittarius A-Star
Weighing millions to billions of times more than our Sun, supermassive black holes likely lurk in the dark, secret hearts of most, if not all, galaxies floating in our observable Universe. Our resident Beast, who resides in the mysterious center of our Milky Way galaxy, is called Sagittarius A-Stargold Sgr A-starfor short (pronounced Saj-a-star), and it’s a relatively light weight like these strong and hungry supermassive gravitational beasts, weighing “merely” millions, rather than billions, of solar masses. Black holes, as the name implies, are pretty black! However, in the August 30, 2013 issue of the magazine Science, Astronomers present new findings that shed light on the strange behavior of our own resident Beast and, by inference, the other supermassive black holes lurking in the dark hearts of other galaxies dancing in our Cosmos.
Over the last twenty years, astronomers have assembled strong evidence to support the concept that a supermassive Beast lurks secretly at the heart of our vast, barred-spiral Milky Way. Because this mysterious entity inhabits relatively close to our own planet, it provides valuable insight into current theories about the strange and little-understood workings of extreme gravity, and General Relativity as well. Because black holes are extremely black, astronomers must try to understand their properties by looking at the light emanating from the hot gas immediately surrounding them.
Such Supermassive Beasts are without a doubt some of the strangest entities lurking in the Cosmos. These strange and bewitching objects grow by devouring their surroundings, and are very Hungry, greedily dining on gasoline and star stuff with incredibly voracious appetites! They also have no table manners and are very messy, greedily gobbling down unfortunate stars and gas blobs, attempting to bite off considerably more than they can chew. Sgr A-star now he is a quiet old Beast; it was much more active, bright and hungry in its glory days billions of years ago when our ancient galaxy was young.
Smaller black holes, of “only” stellar mass, also strut around the Cosmos. These relatively tiny gravitational monsters are born from the funeral pyre of a very massive star that has “died”, having collapsed in the incandescent fires of a supernova explosion that has torn the doomed star to pieces. The supernova explosion heralds the end of the furiously incandescent life of a massive star as a main sequence (which burns hydrogen) star. After a black hole has risen like a phoenix from the fiery ashes of the supernova, it can continue to gain more and more weight while feeding on any unfortunate object unfortunate enough to wander too close to its gravitational embrace.
The matter of the doomed stars and the blobs of unfortunate gas spin in the turbulent vortex of the gigantic supermassive beasts, and this falling banquet spins and spins and descends, creating a huge disc, called a disk. accretion disk. This doomed dinner party is getting hotter and hotter, emitting an astonishing amount of radiation, as it gets closer and closer to that dreaded hellish point where it must abandon all hope, entering that infamous region of no return called the event horizon Tea event horizon is located in the innermost part of the accretion disk.
albert einstein General Theory of Relativity predicts the existence of black holes, which he intended to be entities with gravitational wells so deep that they absolutely nothing, not even light, could fly to freedom and escape its devilishly strong gravitational grip. Anything unfortunate enough to wander too close to one of these insatiably hungry Beasts will inevitably, invariably be eaten. However, the actual existence in Nature of these gravitational monstrosities seemed so bizarre at the time that even Einstein doubted his own prediction. Eventually, however, he went on to characterize them this way: “Black holes are where God divides by zero.”
Black holes can be big or small. Such a strange entity can be defined as a region in space-time where the pull of gravity is so unimaginably powerful that not even light can escape its pull. The pull of gravity is so powerful because matter has been squeezed into a very small space. Pack enough matter into a small enough space, and you always get a black hole!
Most supermassive black holes, such as Sgr A-starthey accumulate very slowly and are difficult to distinguish from the dark galactic hearts they inhabit. Sgr A-star provides a valuable and instructive exception to the rule, because astronomers can get an up close and personal view of its soft X-ray emission. August 30, 2013 Science titled paper Dissection of X-ray emitting gas around the center of our galaxy by Dr QD Wang et al. writes: “The core of our galaxy offers a multitude of opportunities to observe the interaction between a supermassive black hole… and its immediate surroundings… It is believed that Sgr A-star it is fed by winds from surrounding massive stars.” Dr. Wang is from the University of Cambridge in the UK and the University of Massachusetts at Amherst.
Dr. Wang and colleagues present X-ray observations of Sgr A-star that help astronomers constrain some of the most important theoretical models that describe the strange behavior of the material that accumulates in the gigantic Hungry Beast.
By tracking the orbits of individual stars revolving around our resident supermassive black hole, using the Telescope, astronomers previously calculated its mass; the best estimate now is about 4 million solar masses, which is pretty light compared to some other beasts of its kind. Tea W. M. Keck Observatory It consists of two 10-meter telescopes, located at an elevation of 13,600 feet near the summit of mauna kea in Hawaii.
Using a global network of radio telescopes, the astronomers were also able to determine the size of the radio source emanating from Sgr A-star, calculating it to sport a diameter of less than 40 million kilometers. Due to additional observations of the very fast X-ray flares flying from Sgr A-starits X-ray-emitting component was determined to be of similar size.
Dr. Jeremy D. Schnittman, in a comment attached to the article published on August 30, 3013 Science, noted that “combined, these vital statistics can only be explained by a massive black hole.” Dr. Schnittman is at NASA Goddard Space Flight Center in Greenbelt, Maryland.
Strange things happen at the galactic center
The observations made by Dr. Wang and his colleagues are important for several reasons. First, the center of our Milky Way is well hidden by a thick and enticing veil of heavy dust. This obscuring veil prevents any visible light from escaping to freedom, and therefore it is not possible to observe the dark heart of the Milky Way with conventional optical telescopes. Infrared telescopes and radio telescopes, while an improvement, also have serious shortcomings. Dr. Schnittman explained on August 30, 2013 Science that “X-rays, by contrast, have extremely short wavelengths, so they should be ideal for taking high-resolution pictures.” He added that “The all-time champion of angular resolution among X-ray telescopes is the Chandra X-ray Observatorythat can resolve images with more than 1 arc second…detail”.
Dr. Wang and his team used the Chandra X-ray space observatory to make important discoveries in their efforts to understand why stellar matter and hot gas revolve around Sgr A-star are surprisingly faint at X-ray wavelengths. The new findings are the result of one of the largest observational efforts by the highly successful Chandra assignment. During the year 2012, Chandra gathered about five weeks of observations to obtain by far the best X-ray images and energy signatures of the multi-million degree gas swirling, in doomed splendor, around our galaxy’s resident Beast. On a “mother” 26,000 light years from our planet, Sgr A-Star it is one of a very small number of black holes, among the billions lurking in the Cosmos, that astronomers can look at to witness the movement of nearby matter. The diffuse emission of X-rays from Sgr A-star it comes from the searing gas it has trapped and gravitationally sucked inward, into its waiting maw. The very hot gas is caused by winds produced by a disk-shaped population of young, massive, bouncy stars seen in infrared observations.
Dr. Wang and his colleagues suggest that less than 1% of the material, which is within the deadly reach of the supermassive Beast, actually reaches the event horizon This is because apparently a large amount of it is expelled. As a result, the X-ray emission emanating from material near Sgr A-star it is very faint, like that of most of the supermassive black holes that lurk in the Universe.
The doomed material must lose some of its heat and angular momentum before it can make the fateful step into the supermassive black hole, never to return. Ejecting material allows this to happen.
The important work of Dr. Wang and his colleagues should help these astronomers, using radio telescopes, to observe and understand the mysterious “shadow” cast in space by the event horizon of Sgr A-star. This strange shadow is cast against the background of the surrounding glowing material. This work should also prove useful in allowing astronomers to understand the impact orbiting stars and gas clouds have on matter traveling to and from the supermassive Beast.
Dr. Schnittman noted in his article that “[t]he future looks bright, literally. In the next few months, a large cloud of gas is on its way to collide with the black hole, which could brighten by a factor of one.” million”. or more, greatly enhancing our ability to observe this unique region where gravity rules supreme.”