Black Hole and Explosions, Oh My!
By Jimmie on Jan 12, 2009 in Hey, Mr. Science Guy!
Here’s an interesting little science story for you this morning.
Most galaxies our size and larger are a lot quieter than they should be, which puzzles scientists, who like to see their theories borne out by observation. Here’s the problem. These galaxies, the theory goes, have a supermassive black hole at their center. That black hole should be sucking down matter like a Japanese guy sucks down Nathan’s Famous hot dogs and since gravity shld be drawing in huge amounts of gas emitted by other stars and various nebulae, there should be plenty of matter for the black holes to “eat”. The perceptible sign that there’s a black hole absorbing matter is the amount of “noise” it gives off in the form of X-rays (and other cosmic rays).
Except that these galaxies aren’t nearly as noisy as they should be which has led to some scientific consternation. The theory is sound, the math works, but the observable result isn’t there.
So there’s a slightly new theory. The reason there isn’t as much noise as expected is because there isn’t as much matter there to be absorbed as expected. The gas that should be there is being destroyed, the new theory says, by the shockwaves from exploding stars (what we know as a nova or a supernova, depending on the size of the explosion, generally). Normally, the hot gas that we find all over our galaxy and others counteracts the shockwaves from novae – disperses the energy. But the coolergas nearer the center of the galaxy isn’t as good as absorbing the energy from the shockwave and so the gas that should be there gets the brunt of the energy and disappears.
The practical application here is if, for some reason, the Large Hadron Collider does create a black hole that threatens to consume the planet, all we need is a good-sized star to explode near us and it’ll get rid of any nearby gas thus preventing the black hole from growing so it’ll remain a manageable size.
No…wait. That’s not right.
Stumble it!
OK, just to be pedantic–”destroyed” isn’t the word you want there. The black hole should gobble up any gas in the region that gets cool (that is, slow) enough. Supernova shockwaves heat (accelerate) the cooler gas, without as much effect on gas that’s already hot. At least, that seems to be the theory. Thus, the gas gets a chance to leave the area where it’s in danger of being swallowed by the black hole. Left unexplained is where that gas ends up….
From that area, not altogether. Matter is still conserved. (OK, mass-energy, but in this case calling it ‘conservation of matter’ is probably an accurate approximation.)
Mr. Science Guy | Jan 12, 2009 | Reply
I was running the risk of using exactly the same terms as the article in my summation and figured that approxiamtions would work. Really, the gas is being evaporated by the shockwave.
Jimmie | Jan 12, 2009 | Reply
Okay, I do like most of the science stuff you post, but I’m not really all that smart about all this…can you please explain what this means to me? Are we going to die? Should I buy more rice? LOL I’m kind of skeered…
Cheesestick | Jan 12, 2009 | Reply
None of the above.
Like so many pure science stories, the layman’s headline for this one is “Scientist thinks up plausible guess–mystifying, obscure measurement becomes merely obscure.” It’s mildly relevant to interstellar travel, and it will influence other scientists’ theories, but that’s probably about it. (That’s not to say it’s useless–if Aristotle had accurate theories about how hurricanes work, not many of his contemporaries would care much, given how rarely hurricanes affect shipping in the Mediterranian–but a millenium or two later, it might be considered the most important work he ever did.)
Hoping that the science journalist was giving an accurate precis of the facts? In my experience, the odds are not good.
Still trying to approximate what’s going on in terms that your audience can relate to? I’m not sure that’s any better–gases don’t evaporate. “Dissipated” is a better word in this case, I’d say.
Mr. Science Guy | Jan 12, 2009 | Reply
It seems that “blown away” would have been the best approximation I wanted, but I went for something a bit more punchy. Probably shouldn’t have.
Jimmie | Jan 12, 2009 | Reply
It’s an interesting thing that’s not likely to affect you at all. Like Mr. Science Guy explained, though, it could be useful later when we want to do interstellar traveling. Shockwaves that can push around gas like that will definitely have an influence on a spacecraft’s courts (like his hurrical analogy).
It was just a story that caught my eye and made me say “Hmm…neat!”.
Jimmie | Jan 12, 2009 | Reply
LOL – Okay, that’s good to know. Just didn’t know if you meant “interesting” like comets & solar flares could get very interesting….or “interesting” like Pluto’s not really a planet interesting. Basically just needed an indication of if it was “time to move to the bunker” interesting.
Cheesestick | Jan 13, 2009 | Reply