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Supermassive Black Holes Can Abort Star Formation
cremeglace writes "Astrophysicists have found that when a supermassive black hole quickly devours gas and dust, it can generate enough radiation to abort all the embryonic stars in the surrounding galaxy. It's not clear what this means for life's ability to take hold in such a bleak environment, but the research shows that the process might have determined the fates of many of the large galaxies in the universe."
What are these galaxies made of if not stars?
Gas, lots and lots of gas.
It's actually what stars are made of, along with the vast majority of planets. When stars super-nova, then they create dust, which can then become earth-like rocky planets. In baby galaxies and in galaxies with an active super-massive black hole, gas is being sucked in to the black hole so fast that it glows, It's like an ultra-massive star with a super-massive black hole core. The radiation from these black holes comes from the gas surrounding it falling in, not from the black hole itself. This radiation can potentially kick start other stars further out to form.
Basically what the article is saying, is that a black hole can become so large, that if it activates again (new gas is introduced in some way, or it has simply had so much to consume that if finally hit the right size) that it can kill any young stars in the galaxy. That doesn't mean the older stars will be eliminated, because once a star reaches a certain size its own pressure maintains the reaction without external influence. It's the ones that are still collecting gas and are too small to maintain their own reaction that can be snuffed out.
Furthermore, the gravity of a black hole, even a supermassive, has limits. Our solar system, for example, is well outside the range of the Milky Way's supermassive black hole - we are held in orbit by proximity to the mass of stars further from the center of the galaxy. So what you will end up with is not giant, invisible galaxies, but galaxies with a giant hole in the middle (like all galaxies with a non-active supermassive) and zero new star formation. It would take close to the heat death of the universe for them to become dark, and most galaxies will be nearly dark by then anyway.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
The point of the article is that if they suck hard enough, then they also blow.
If you were blocking sigs, you wouldn't have to read this.