These zones of spacetime are created when massive stars collapse as their life ends and continue to expand by pulling in stars and merging with other black holes. This engagement has mesmerized researchers for decades, who use it to detect their presence, as electromagnetic radiation is emitted as visible light across space.
Two Types of Black Holes
Astronomers have detected scores of stellar black holes in binary systems and determined that the radio origin known as Sagittarius A*, which is located at the nucleus of the Milky Way galaxy, hosts a supermassive black hole of around 4.3 million solar masses.
These kinds of space phenomena are greatly different, but Harvard University astrophysicist Fabio Pacucci unveiled, during a recent TedTalk, how they both pose their own unique hazards.
He said: “Most of the black holes that we have found can be thought as two main types – the smaller ones, called stellar-mass black holes, have a mass of up to 100 times larger than that of our Sun. They are formed when a massive star consumes all its nuclear fuel, and its core collapses. We’ve observed several of these objects as close as 3,000 light-years away, and there could be up to 100 million small black holes just in the Milky Way.”
However, Dr. Pacucci said we should not be worried, even though he found a theoretic way in which this kind of black hole could pose a threat to us.
Earth’s Orbit Could be Modified
He further explained that in spite of their large mass, stellar black holes only have a radius of approximately 300 kilometers (186 miles) or even less, which makes the possibility of a direct hit with Earth minuscule. However, because their gravitational fields can impact a planet from a great distance, they could be risky even without a direct clash.
“If a typical stellar-mass black hole were to pass in the region of Neptune, the orbit of the Earth would be considerably modified, with dire results. Still the combination of how small they are and how vast the galaxy means that stellar black holes don’t give us much to worry about,” Dr. Pacucci explained.
Still, the scientist doesn’t believe this is a probable scenario to unfold anytime soon, but he did issue a warning about the other kind of cosmic oddity. According to Dr. Pacucci, we still have to encounter the second type, the supermassive black holes.
These objects have masses millions or billions greater than that of the Sun and also have event horizons that could expand across billions of kilometers, the researcher said. These giant black holes have grown to gigantic proportions by pulling in the matter and merging with other black holes.
However, Dr. Pacucci concluded, the combination of how small they are at the moment and how vast the galaxy is, means that stellar black holes ‘do not give us much to worry about.’