On the night of November 23, 2014, a powerful telescope on Mauna Kea in Hawaii tried to pick out the enigmatic motions of a black hole moving through space. In the seven hours that the telescope looked at the cosmos, it possibly caught on, because a structure about the size of the earth obscured a star in our nearest galactic neighbor, Andromeda, about 2.5 million light-years away. Amid the 188 relatively faint images taken of the galaxy that night, the candidate black hole event was a moment of literal enlightenment.
‘If it’s right next to the line of sight, the light bends [the black hole]. Not only the rays of light that point to you to be with, but also those that would pass you, bend towards you, ”said Alexander Kusenko, astrophysicist at UCLA and the Kavli Institute for Physics and Mathematics of the Universe , in a video said call. ‘It will make the star look brighter for a moment. It’s a bit counter-intuitive. ”
Kusenko is the lead author of a recent article discussing the event, published in the journal Physical Review Letters In October. The research suggests that the dark matter between some and the whole universe can be explained by primordial black holes – hypothesis small and very old versions of the classical cosmic character that were only directly displayed for the first time in 2019. All black holes, regardless of their size, are celestial objects that exert so much gravitational force that nothing, not even light, can escape from them.
One idea is that at the beginning of the universe slight density fluctuations in the incredibly dense inflatable universe would have been enough to cultivate black holes from the pre-star plasma, especially if it interacts with an unknown force with heavy particles. (Famous black holes are mostly formed by collapsing stars on the course of the mill.)
“If you take a spoonful of primordial plasma, it’s almost a black hole,” Kusenko said, referring to the universe’s initial density. “Push it a little, and the light will not escape.”
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Some of these theoretical black holes would have been of critical size, in line with Einstein’s theory of gravity, to be considered to continuously expand to an observer within the black hole – while remaining a static size for the outside observer. . This idea may evoke the notions of ‘baby universe’ in our own, but keep in mind that the original black holes are only theoretical at the moment.
And that is the immediate concern of Kusenko’s team: to prove their existence. The original black holes would have to be many if they had to account for some of the dark matter of the universe – mysterious things that seem to make up about 27% of the universe – but too small to detect, as their confirmed counterparts were .
Kusenko and his colleagues (the October article involves researchers from UCLA and Kavli IPMU) cast a wide net for black-hole candidates using the Hyper Suprime-Cam, a nearly 6-foot lens attached to the nearly 30-foot mirror . the Subaru telescope on Mauna Kea. The camera can capture the entire Andromeda galaxy every few minutes. Since one candidate was selected for an ancient black hole in the seven-hour tour of the cosmos in 2014, Kusenko hopes future observations can gather more opportunities to unpack.
The 2014 observation was not easy to find in all the data. That team scoured a catalog of more than 15,000 candidate stars to see if they were light and in the process found nearly 50 “fraudsters” events, caused by bright stars, among others. One deceiver was even caused by a passing asteroid. But after sorting out many stars, one candidate looked right.
If more candidate events are identified, there will be more runways for the team’s theory that many miniature black holes are responsible for the excessive gravity measured in many galaxies (this is the extra gravity that drew scientists from the existence of dark matter in the 1970s). To put things in perspective, the smallest known black holes in the kingdom are five solar masses (this is five times the size of the sun). The recent candidate black hole was simply the size of our planet.
If a black hole of the earth is hard to believe, it is not even the smallest black hole. Last year, physicists suggested that a bowls-sized black hole to explain a hypothetical object in our solar system known as Planet Nine.
Kusenko’s team made another round of observations at Mauna Kea at the end of 2020 and they now have to do the careful work of sifting the data. We would know later this year if they found potential black holes—And our fingers are tightly crossed for good news.