By: Heidi DuPuis
Most of us have heard of black holes; a few may have even watched the 1979 movie by Disney. They have appeared in fiction since the early 1900s, though the term “Black Hole” was not invented until the 1960s. Authors have invented many uses for them, including warping through space and traveling through time, but there’s still a lot we don’t know about the real thing.
There are 3 types of black holes that astronomers know about. Primordial black holes are the smallest, and scientists think they formed just after the big bang. They contain about the mass of a large mountain, compressed into the space of just one atom.
The second type are stellar black holes, which squeeze the mass of about 20 times our sun into a sphere about 10 miles across. These form when massive stars no longer burn enough fuel to keep their shape, and they collapse in on themselves. The collapse triggers a explosion known as a supernova, and a black hole may form from what remains of the star.
Supermassive black holes are enormous, containing the mass of more than a million of our suns. Some scientists think every large galaxy has one of these at its center, formed at the same time as the galaxy.
Objects in space have gravity that increases in proportion to their mass; the larger the object, the stronger the gravitational field. In the case of a black hole, a lot of mass is squeezed into a tiny area, creating a gravitational field that nothing can escape, even light. Because of this, black holes are invisible. Scientists can find them mainly by examining the behavior of the things around them. When matter gets too close to a black hole, it is pulled in, adding to the mass there. The point where not even light can escape is called the event horizon.
“Black Hole Week” was first celebrated by NASA in 2019, following the release of the very first image ever made of a black hole. It has become an opportunity to flood the news with information, images, and discoveries about black holes. That first image was created by an international research team known as the Event Horizon Telescope (EHT) Collaboration. A year ago, in May 2022, the same group released an image of a second black hole, this time of the one at the center of our own Milky Way Galaxy, about 27,000 light-years from Earth.
There is still much to learn about these mysterious, invisible objects in our universe. Watch for Black Hole news from NASA next week & prepare to be fascinated!
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