Business

Imagining a camera-shy black hole

super massive black holes they are greedy gravitational monsters weighing millions to billions of times the mass of our Sun. In fact, astronomers now propose that perhaps every large galaxy in the observable Universe harbors one of these strange objects in its secret dark heart, and our own barred spiral Milky Way is no exception. Our Galaxy is haunted by its own dark-hungry heart, cloaked in mystery, and has managed to keep its myriad secrets well hidden from the prying eyes of curious astronomers. But despite their enormous mass and enormous numbers, supermassive black holes are notoriously camera-shy and have managed to escape being photographed…until now. On April 10, 2019, the Event Horizon Telescope (EHT) released the first historical image of a supermassive black hole event horizon, which is the region beyond which not even light can escape the powerful and merciless gravitational grip of the ravenous dark-hearted beast. Although black holes have been theorized for more than two centuries, they were generally thought to be impossible to observe directly. Tea EHT is an international collaboration whose support in the US includes the National Science Foundation (NSF).

The recently presented supermassive black hole weighs 6.5 trillions times the mass of our Sun. By contrast, the dark core of our own galaxy is relatively light, at least by the standards of supermassive black holes, weighing barely million (Opposite to trillions) times the solar mass. Our Milky Way’s resident gravity beast has been named Sagittarius A* (pronounced Sagittarius – A star ), and is now a quiet, ancient gravitational beast, only occasionally awakening from its peaceful slumber to nibble on a doomed rogue star or unlucky gas cloud that has managed to travel too close to its jaws. When the Universe, our Galaxy and Sagittarius A* were young, our resident beast glowed like a quasar (the accretion disk surrounding a black hole), while feeding greedily and carelessly on whatever managed to travel too close to where it lay in wait. The ill-fated banquet swirled down, down, into the waiting gravitational clutches of the then young black hole, falling to its inevitable doom from the dazzling accretion disk that surrounded it. Sagittarius A* considers himself asleep now, but every now and then he wakes up for dinner with the same avidity he once did, long ago, when he was a brilliant quasar illuminating the ancient Universe during its flaming youth. Sagittarius A* he is old and quiet now, but he can still remember.

The camera-shy black hole, pictured recently, is located in the elliptical galaxy. Messier 87 (M87). An earlier image obtained from NASA Spitzer Space Telescope show the whole M87 galaxy in infrared light. On the contrary, the EHT The image relied on radio wavelengths to reveal the black hole’s secret shadow against the background of high-energy material swirling around it.

The nature of the gravitational beast

Black holes come in different sizes. Some are of the supermassive type, residing in the center of galaxies, while those of “only” stellar mass they are much smaller. ON stellar mass A black hole is born when a very massive star shatters in a supernova conflagration, thus ending its life as a main stream (which burns hydrogen) star in the Hertzsprung-Russell diagram of stellar evolution there’s also intermediate mass black holes which are much heavier than their stellar-mass siblings, but much less massive than their supermassive relatives. The gravitational collapse of a very massive star is a natural process. It is inevitable that when a heavy star reaches the end of that long stellar path, meaning all its energy sources have been exhausted, it will collapse under the merciless crushing of its own powerful gravity. This catastrophic event is heralded by the bright and resplendent Grand finale of a supernova explosion. The most massive stars in the Universe perish in this way and eventually collapse into a stellar-mass black hole.

Intermediate-mass objects weigh hundreds of solar masses. Some astronomers have proposed that intermediate-mass black holes collided and merged in the early Universe, thus creating the huge supermassive array that lurks at the heart of galaxies.

our milky way Sagittarius A* has a lot of smaller company. Theoretical studies suggest that a large population of stellar-mass black holes, perhaps as many as 20,000, could be dancing around the resident dark heart of our own galaxy. A 2018 study, using data collected by NASA Chandra X-ray Observatoryindicates the existence of such a group of fascinating stellar-mass black holes at the heart of our Milky Way.

Despite their name, black holes are not just empty spaces. Squeeze enough matter into a small enough area, and a black hole will always be born. However, black holes are really simple objects. A black hole of any mass has only three properties: electric charge, mass, and spin (angular momentum).

Many astronomers think that supermassive black holes already existed when the Universe was very young. During that ancient epoch, clouds of gas and unlucky stars swirled in the fatal gravitational embrace of the black hole, never to return from the churning vortex that surrounded this ravenous entity. As the captured material swirled to its doom, it created a bright and violent storm of dazzling material around the black hole: the accretion disk (quasar). As the material got hotter and hotter, it released a violent storm of radiation, particularly as it traveled closer to the event horizon–The point of no return.

In the 18th century, John Michell and Pierre-Simon Laplace considered the possibility that there might be Really be strange black holes in the Universe. In 1915, Albert Einstein, in his General Relativity Theory (1915) predicted the existence of objects with such strong gravitational fields that any unlucky trip too close to the hungry beast would be consumed. However, the idea that such strange objects could actually exist in the Cosmos seemed so outlandish at the time that Einstein rejected the idea, even though his own calculations suggested otherwise.

In 1916, physicist Karl Schwarzschild formulated the first modern solution to the General Relativity Theory which described a black hole. However, the interpretation of it as a region of space from which absolutely nothing could escape, as a result of the object’s powerful gravitational grip, was not properly understood until almost 50 years later. Until then, black holes were thought to be mere mathematical oddities. It was not until the middle of the 20th century that theoretical work demonstrated that these strange objects are a generic prediction of General relativity.

The dark heart of M87

Astronomers have been observing M87 for more than a century, and has been imaged by numerous NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory, and NuSTAR. In 1918, the American astronomer Heber Curtis (1872-1942) was the first to detect “a curious straight ray” coming from the center of the galaxy. This dazzling jet of high-energy material formed a rapidly spinning disk surrounding the black hole, which could be seen in multiple wavelengths of light, from radio waves to X-rays. When the particles in the jet hit the interstellar medium, they formed a shock wave that radiated in the infrared and radio wavelengths of the electromagnetic spectrum, but not in visible light. The Spitzer images show a shock wave that is more prominent than the plane itself.

The brightest jet is located to the right of the galaxy’s center and travels almost directly toward Earth. The brightness of the jet is intensified due to both its high speed in our direction and its “relativistic effects” that arise because the jet is traveling near the speed of light. The jet’s path is slightly outside our line of sight to the galaxy. This means that astronomers can observe part of the length of the jet. The shock wave begins around the point where the jet appears to curve downward, thus highlighting regions where fast-moving particles collide with gas in the galaxy and thus slow it down.

In contrast, the second jet is moving away from Earth so quickly that relativistic effects make it invisible at all wavelengths of the electromagnetic spectrum. However, the shock wave it creates in the interstellar medium can be seen from here.

The shock wave is located on the left side of M87 center, and looks like an inverted letter “C”. Although it cannot be seen in optical images, the lobe can be seen in radio waves, as seen in an image obtained from the Very Large Array of the National Radio Astronomy Observatory.

By combining observations obtained in the infrared, radio waves, visible light, X-rays, and extremely energetic gamma rays, astronomers can study the physics of these powerful jets. Astronomers are still trying to gain a solid theoretical understanding of how the gas that black holes consume forms outward jets.

Infrared light at wavelengths of 3.6 and 4.5 microns is depicted in blue and green in the camera’s revealing image of the shy dark heart. M87–thus revealing the all-star cast. Dust features glowing at 8.0 microns are shown in red in the image. The image was obtained during by Spitzer “cold” initial mission.

Tea Event Horizon Telescope, which captured the historic image of a black hole, is a planet-scale array made up of eight ground-based radio telescopes that were designed to image a camera-shy black hole. EHT project director Dr. Shepherd S. Doelman of the Harvard-Smithsonian Center for Astrophysics (CfA)noted on April 10, 2019 EHT press release that “We have taken the first photograph of a black hole. This is an extraordinary scientific feat achieved by a team of more than 200 researchers.”

This landmark scientific breakthrough was announced in a series of six articles published on April 10, 2019 in a special edition of The Astrophysical Journal Letters.

Dr. Doelman went on to comment that “We have achieved something that was supposed to be impossible just a generation ago. Technological advances, connections between the world’s best radio observatories, and innovative algorithms have come together to open a whole new window on black holes.” and the event horizon.