We’ve never observed a black hole directly, but that could change soon.
How To Get Rid Of A Black Hole
How does a galaxy get rid of a supermassive black hole?
Huge Black Hole In A Cosmic Backwater
Inside the galaxy known as NGC 1600 there is a black hole 17 billion times more massive than our Sun.
Hiding in Plain Sight
An ultracompact dwarf galaxy has only about 100 million stars, but they are packed into a region only 200 light years across. In such a galaxy you might see a million stars with the naked eye.
No Makeup Selfie
For Interstellar, scientists created an accurate view of a black hole. How much the science reached the screen?
Little Bang
In the center of our galaxy there is a supermassive black hole known as Sgr A*. Through observations of stars orbiting the black hole, we know it has a mass of about 4 million Suns. Normally this black hole is pretty quiet, but in 2013 there was an unexpected x-ray burst.
Holding It Together
In the center of our Milky Way galaxy is a supermassive black hole. We can’t see this black hole directly because there is too much dust in the direction of galactic center, but radio waves can penetrate that dust, so we can observe the radio signals of hot stars and gas near galactic center. We’ve been observing these signals over several years, and we’ve noticed how the stars near galactic center orbit the region very quickly. From their orbital motion and a simple use of Kepler’s laws we can get a pretty good idea of the mass of the black hole. It turns out to be about 4 million solar masses. While this is a huge black hole, most of the stars orbiting it aren’t too terribly close. So for the time being they aren’t at risk of being ripped apart by the intense forces near the black hole. But there was one object recently that did make a very close approach.
Recoil Effect
Most galaxies have a supermassive black hole in their centers, but some don’t. The Triangulum galaxy (also known as M33) doesn’t have one, despite being a pretty standard looking spiral galaxy. The general thought is that such galaxies did have a supermassive black hole at one time, but it was ejected by some mechanism. One mechanism is through collisions with …
Star Seed
One of the big mysteries in cosmology is how supermassive black holes formed in the centers of galaxies. Did they form directly from large concentrations of matter and dark matter, or did they form when early stars collided and accreted into massive black holes? Another idea is that they may have formed from the collapse of supermassive stars. In this idea stars with masses of 10,000 Suns or more could have lived short, violent lives before their core collapsed into a massive black hole. It’s an interesting idea, but new research shows that such supermassive stars might have a different fate.
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