Today at 16:00 Minsk time in different parts of the world will begin the press conference, which will be shown the first image of a black hole. More precisely, not itself a black hole and its accretion disk and the “shadow”. A live webcast of the press conference will be conducted on the YouTube channel of the European Commission.
- What is a black hole?
- How to photograph a black hole?
- What black holes we photograph?
Before the release of the first ever direct image of a black hole (or “shadow”) it is worth remembering that all the images you have seen before a fantasy artist. The real photo is unlikely to be like at least something colorful in the Google SERP. Most likely, we can expect something similar to one of the computer simulations team EHT. Also do not forget that these telescopes allow you to create only a monochrome image. If the final picture will be present the colour is artificial toning, applied to the photo exclusively for aesthetic reasons.
Simulation possible image. EHT
What is a black hole?
Black holes often arise as a result of the death of stars. When the fuel reserves in the major stars are exhausted, the dying fusion reaction can no longer resist the gravitational collapse of a star. And she begins to collapse to a critically small size. The mass of such objects is pretty large. Because of this, the force of gravity such an object does not allow even light to escape from the gravitational radius, and it falls into a black hole.
Artists usually depict a black hole as a black circle surrounded by a glowing sphere. The border between shadow and light is called the event horizon. This feature, from beyond which it can not escape, no object, no matter how high its speed. But the glowing sphere is the accretion disc of a compressible substance, falling into the black hole, heated by friction.
The existence of black holes predicted by General relativity and indirectly proven by a gravitational wave was in September 2015 the two LIGO detectors. Form of the received signal gravitational waves coincide with those predicted by the General theory of relativity form of the signal from the merger of two black holes.
Today, scientists have discovered thousands of objects, the properties of which it is possible to assume that they are black holes. But direct observation has not yet been reported, since the radius of these objects is so small that they are extremely difficult to detect with modern telescopes.
How to make a black hole?
For the current shooting responsible project Event Horizon Telescope (EHT) is a collaboration of scientists and several radio telescopes located in different corners of the Earth. In particular, in France, the USA, Mexico, Chile, Spain, Antarctica and Hawaii. These radio-telescopes over a period of time monitored the incoming radiation from the two supermassive black holes. One placed in the center of our milky Way galaxy, and is called Sagittarius A* and the other is in the supermassive galaxy Messier 87.
Due to the huge number of radio telescopes in different parts of the world EHT managed to create an interferometer — a virtual telescope with an effective diameter as the Earth, with high sensitivity and high angular resolution. The main problem was to synchronize the data from all telescopes at the time. But because each of them relies on the reference time of atomic clock.
It is one thing to collect data and quite another task to process them. During the observation of black holes has collected huge amount of data from each telescope. So great, that it was impossible to convey over the Internet. And because hard disks these data are transported by aircraft to the Haystack Observatory (USA), owned by the Massachusetts Institute of technology, and radio astronomy max Planck Institute (Germany). There, the data was cross-correlated and analyzed on a supercomputer.
What black holes we look?
Sagittarius A* is located in the center of the milky Way at a distance of about 26,000 light years from Earth. Estimated mass of this radio source more than 4 million solar masses.
Strong gravity around a black hole distorts the region of space-time, and heats the gases falling into the black hole, to extreme temperatures. Due to the radiation of heated gases.
The supergiant elliptical galaxy Messier 87 (M 87) is at a distance of 53.5 million light years from Earth. Located in the center of this galaxy is a supermassive black hole gives rise to the emission of energetic plasma at a distance of 4900 light years. According to the latest data, the mass of the black hole can range from 3.5 to 6.6 billion solar masses. This black hole is supposedly surrounded by a disk of ionized gas which rotates with a speed of 1000 km/s.
A black hole in the representation of the artist. NASA/JPL-Caltech
(to be completed by the end of the press conference)
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