A team of astronomers from the University of Texas at Austin and Harvard University (USA) have tested a basic principle of black holes, showing that matter disappears completely when it collides with the last frontier of the black hole: the event horizon. Their results constitute another successful test for Albert Einstein’s General Theory of Relativity.
Most scientists agree that black holes are surrounded by an event horizon. O nce matter or energy is close enough to the black hole, he can not escape. However, despite being so widely believed, the existence of the event horizon has remained in theory, it has not been demonstrated. Up to now.
“Our goal here is to turn this idea of an event horizon into an experimental science, and find out whether or not event horizons around black holes really exist ,” says Pawan Kumar, co-author of the paper that has been published in the journal. Monthly Notices of the Royal Astronomical Society.
To do this, the scientists performed a computer simulation in the case that the black holes had a hard and solid surface. If a star were to collide with it, the gas from the star would probably envelope the black hole for years, emitting large amounts of energy. Taking into account that almost in every galaxy there is a supermassive black hole at its center, we should be able to find concrete evidence about the presence of this energy.
“We estimate the rate of stars that fall on supermassive black holes. Almost all galaxies have one, the most massive, weighing about 100 million solar masses or more, and there are a million of them within a few billion light years. of the Earth “, clarifies Wenbin Lu, co-author of the work.
So they searched a recent archive of observations from the Pan-STARRS observatory, a 1.8-meter telescope in Hawaii, to see if these collisions were occurring in space. Its lenses observed a large area of the sky over a period of 3.5 years looking for phenomena that glow for a short time and eventually fade.
By his calculations, Pan-STATRRS would have had to have observed more than 10 of them, if the hard surface theory was correct.
How many did they find? None.
This conclusion confirms that some, or perhaps all, black holes have event horizons and that the material that collides with these exotic objects actually disappears from the observable universe. “General Relativity has passed another critical test,” concludes Ramesh Narayan, co-author of the study.
Reference: Stellar disruption events support the existence of the black hole event horizon “by Wenbin Lu, Pawan Kumar, and Naresh Narayan in the June 2017 issue of Monthly Notices of the Royal Astronomical Society. Doi.org/10.1093/mnras/stx542
