Are you sure M87 * is a black hole? We all remember the great astronomical milestone of April 2019 in which science managed to obtain a direct image of a supermassive black hole at the center of the galaxy M87. The fruit of years of work with enormous human collaboration and technical ingenuity . It was the first time in human history that we were able to see first-hand what the actual appearance of a black hole looked like. However, a team of European astrophysicists now suggests that the universe could be full of “boson stars”, which are invisible, theoretical and transparent objects made of boson particles and that, precisely, M87 * could be, then, a invisible boson star.
If they were real, boson stars would share many characteristics with supermassive black holes, including the fact that “boson stars are predicted by general relativity and can grow to millions of solar masses and reach very high compactness,” he explains. Héctor Olivares from Radboud University in the Netherlands, Goethe University in Germany and leader of the research collected in the Monthly Notices of the Royal Astronomical Society magazine.
The scientists set out to calculate whether boson stars would end up looking like the shadow of M87 *, the first photographed black hole 55 million light-years from Earth, with a mass equivalent to 7 billion suns.
Boson stars are among the many strange theoretical objects in our cosmos. They don’t look like standard stars, plus they appear to be a mass of matter. However, where stars are composed primarily of particles known as fermions – protons, neutrons, electrons – boson stars could be composed entirely of … bosons. These particles, along with photons, gluons, and the well-known Higgs boson, do not follow the same body patterns as fermions.
For example, they can overlap, something that does not happen with fermions. Fermions are subject to the Pauli exclusion precept, which suggests that you cannot have two identical particles occupying the same place; instead, there can be two bosons occupying the same space, forming a “matter wave”. These structures may end up forming an even larger structure, such as the Bose-Einstein condensate, achieved in a laboratory on the International Space Station in June 2020: the fifth state of matter.
While certain types of bosons have been observed here on Earth, the types of extremely small mass bosons required to form these boson stars have yet to be observed. These theoretical particles are incredibly difficult to detect but, according to experts, observing an object that looks like a boson star (M87 *) could indicate their existence.
Because these boson stars would be mostly transparent , except for a possible spinning plasma ring surrounding some of them, such as the accretion disk that surrounds black space, they think that M87 * probably couldn’t have been a bosonic star. , since the theoretical shadow would be too small. Boson stars do not fuse nuclei and may not emit radiation.
Future observations of the Event Horizon Telescope will confirm whether or not the supermassive black hole in question is really what it appears to be.
And if it’s not that way?
If M87 * were not a black hole it would not imply that supermassive black holes do not exist; But it will determine that boson stars are real , and in turn, this can have enormous effects on astronomy, from the inflation of the early universe to the search for dark matter.
Referencia: How to tell an accreting boson star from a black hole. Hector Olivares, Ziri Younsi, Christian M Fromm, Mariafelicia De Laurentis, Oliver Porth, Yosuke Mizuno, Heino Falcke, Michael Kramer, Luciano Rezzolla. Monthly Notices of the Royal Astronomical Society, Volume 497, Issue 1, September 2020, Pages 521–535, https://doi.org/10.1093/mnras/staa1878
