In mid-October of 2017, the whole world was hotly discussing an important scientific event. Scientists announced the first ever detection of gravitational wave burst from the merger of two neutron stars. This was done with the assistance of the LIGO interferometer, with which we observed the first gravitational bursts from merging black holes, for which three famous physicists were awarded the Nobel prize.
A feature of the October opening was the fact that after the gravitational signal has been received in the electromagnetic range, gamma, optical, radio and x-ray. One of the important findings is the confirmation of the hypothesis that in such processes in the Universe is born most of the elements heavier than iron — gold, lanthanides, uranium and others. A discovery made by LIGO was the topic of the interview, which the famous astrophysicist Stephen Hawking gave a BBC journalist Pallab gosh. This interview, as the author notes, was the last one for Hawking. Scientist died March 14.
Tell us, how the important detection of the merger of two neutron stars?
This is a real achievement. This is the first detection of a gravitational wave source with an electromagnetic response. It confirms that short gamma-ray bursts occur when neutron stars merge. It gives a new possibility of determining distances in cosmology and talks about the behavior of matter with extremely high density.
What will tell us the electromagnetic waves from the merger?
Electromagnetic radiation tells us the exact position of the source on the sky. In addition, it tells us about the redshift of the object (the shift of spectral lines in the wavelength direction). Gravitational waves show us the photometric distance. Together these measurements give us a new way of measuring distances in cosmology. This is the first example of what will become a new cosmological distance scale. The matter inside neutron stars is much denser than what we can produce in the laboratory. The electromagnetic signal from merging neutron stars can tell us about the behavior of matter with such high density.
Tell us whether this discovery, the structure of black holes?
The fact that black holes can be formed by the merger of two neutron stars, were known from the theory. But this event was the first test of the first observation. The merger probably leads to the formation of a rotating, supermassive neutron star that then collapses into a black hole.
This is quite different from other ways of black hole formation, such as supernova explosion or during the accretion of matter normal star to the neutron star. Careful data analysis and theoretical modeling on supercomputers will provide ample opportunity to understand the dynamics of black hole formation and gamma ray bursts.
Will measure gravitational waves deeper understanding of how space-time and gravity, and hence will change our view of the Universe?
Yes, without a shadow of a doubt. Independent of the cosmological distance scale can give an independent test of cosmological observations, and can conceal many surprises. Gravitational-wave observations allow us to test General relativity in cases when the gravitational field is strong and very dynamic. Some believe that General relativity requires revision to avoid the introduction of dark energy and dark matter. Gravitational waves provide new way to search for signs of possible deviations from General relativity. The emergence of a new observational window to the Universe usually leads to surprises that cannot be predicted. And we all three our eyes, or rather ears, since only woke up to hear the sound of gravitational waves.
Can the merger of neutron stars to be one of the few ways, or only way through which the Universe is formed of gold? If it can explain why gold is so little on Earth?
Yes, the collision of neutron stars is one of the ways of making gold. It can also come with the rapid captures of neutrons in supernova explosions. A little gold everywhere, not just on Earth. The reason for its rarity is that the maximum energy of the nucleus falls on the iron, which hinders the formation of elements heavier than him. In addition, for the formation of such stable heavy nuclei, like gold, is required to overcome the strong electromagnetic repulsion.
A recent interview of Stephen Hawking
Nikolai Khizhnyak