The study of Japanese scientists has shaken the theory of Stephen Hawking about dark matter
One of the most famous theories of Stephen Hawking about dark matter greatly shaken after the publication of the results of the Japanese team of astrophysicists led by Masahiro Takada of Physics and Mathematics Institute of the universe in the Kavli, reports Live Science. Who left this world in the past year, the famous physicist believed that this mysterious and invisible substance composed of primordial black holes that appeared immediately after the Big Bang. Japanese scientists using the Subaru telescope carried out an experiment, the results of which, though not completely refute the theory of Hawking, but admit that these black holes have to be really tiny, to explain the nature of dark matter.
Dark matter - a term that physics called the mysterious substance which, in their opinion, could explain another interesting fact: in the universe everything moves and rotates as if it contains more mass than we can detect. Other scientists at different times tried to ascribe the properties of so-called dark matter different objects. In the 1970s, Stephen Hawking and his colleagues suggest that the Big Bang could have created a large number of relatively small black holes - each the size of a proton. These tiny celestial bodies are difficult to see, but they will have a strong gravitational influence on other objects - two well-known properties of dark matter. Until now, this theory can be checked only primordial black holes whose mass is more than the moon. But with advances in technology, scientists were able to get more and more clear space pictures. For their new study, a team of Japanese astronomers has used the camera Hyper Suprime-Cam (HSC), mounted on the Subaru telescope located in Hawaii. With it, they took pictures throughout Andromeda, the nearest galaxy to us, trying to find these small objects. The result of their work published in the journal Nature Astronomy.
Black holes do not emit light but super-massive black holes, like the one that is located in the center of the M87 galaxy, the photo which scientists have recently received, surrounded by bright accretion disk of hot matter. But since the primary hole size in billions of times smaller and have no visible luminous matter surrounding them, then you can find them only through observation they create a powerful gravitational fields, causing distortion of the radiation of adjacent objects. This phenomenon called microlensing.
Telescopes capable of detecting microlens black holes with the help of a long shooting stars. When the black gifts passes in front of the point of observation and the star, it distorts light light, causing it to "flash". The smaller the black hole, the faster this outbreak.
"If the object creates a microlens has, for example, one solar mass, the time scale (flash duration) will be from several months to a year," - explains Masahiro Takada of Physics and Mathematics Institute of the universe in the Kavli.
However, the primary holes that looked for the Japanese team, is only part of the weight - it is approximately equal to the mass of our Moon. This means that the observed flare should be much shorter.
Takada calls HSC unique camera because using it at a time, scientists were able to obtain images of the Andromeda galaxy of stars with a minimum delay of about 2 minutes. Altogether astronomers could get about 200 pictures Andromeda for 7 hours clear overnight. As a result, they found only one expected microlensing event. According to Takada, if primordial black holes account for a significant proportion of dark matter, they would have to see about 1,000 microlensing signals.
"microlensing - the gold standard technologies to search for black holes" - he says physicist Simeon Bird of the University of California, has been studying black holes, but was not involved in the latest study.
"The work of Japanese scientists eliminates primordial black holes as the main source of dark matter."
Does this mean that Hawking's theory has been completely refuted? Takada and Bird are in no hurry with final conclusions. According to them, the results still can not completely rule out the existence of primordial black holes, because due to their small mass outbreaks of signals would be too short to have time to fix them. According to researchers, it is necessary to develop new tools that would detect them.
At the same time, scientists have noted that the discovery of even one such signal can be critical for future studies that will test some of the revolutionary theories of Hawking.
"Just spent one observation may not have something to convince. It is necessary to carry out further. If this signal really is a signal of a primordial black hole, we must continue the search for her relatives, "- concludes Takada.
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