Slashdot Mirror
The Milky Way's Black Hole Is Not So Quiescent
esocid writes in with a followup to the recent discussion about the possibility that our galaxy's central black hole could reignite. "Using NASA, Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that Sagittarius A* let loose a powerful flare three centuries before the time at which we are observing it (i.e., 26,000 years in the past). X-ray pulses emanating from just outside the black hole take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier. 'By observing how this cloud lit up and faded over 10 years, we could trace back the black hole's activity 300 years ago,' says team member Katsuji Koyama of Kyoto University. 'The black hole was a million times brighter three centuries ago.'"
has discovered that Sagittarius A* let loose a powerful flare three centuries before the time at which we are observing it (i.e., 26,000 years in the past)
That's a bit of a confusing sentence but I think I understand. What they really meant to say is that if Sagittarius A's flare produces a 26,000 Hz tone, it
will interfere with GT&T's subspace carrier signal and allow you to send free messages to the gamma quadrant.
Damn global warming!
It does not 'ignite' by any sense of the word. It does get very hot through friction, and emits black body radiation. But it does not burn.
Burning requires oxygen, but everyone knows there is no oxygen in space!
Why else would the space-men wear those funny hats?
QED
You may refer to it as "the hole who so recently was known as black".
Ni.
Yeah? Well I think you're overrated too.
Sadly it extends way beyond just physics
Pogo said it best: Nuclear physics ain't so new, and it ain't so clear.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
We Didn't Start the Fire...
It's not thought likely. Supernovae are triggered by the collapse of a star's core; external phenomena don't have a great deal to do with it. However, active galactic nuclei have been known about for quite some time. Perhaps when Niven was writing, the idea that active galaxies were powered by chained supernova swarms was current in the literature.
The contemporary model for such phenomena is that the gas swirling around the black hole is heated by friction and by compression as it moves inward. Consider: you're dropping thousands of solar masses through the deepest gravity well in the universe. That releases an awful lot of energy. It makes little difference to Niven's nightmare scenario: it's entirely possible that our Galaxy was active in this way in the past, may become so again in the future, and may even be a little bit active right now. If anyone were to go to the galactic core today in a General Products #3 hull with a quantum-II hyperdrive and discover that the X-ray flux was way, way higher than it ought to be... then we'd better start making plans to run to Andromeda, now.
Real Daleks don't climb stairs - they level the building.
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
The term black is offensive to some, We say African American Holes
"let loose a powerful flare"...
"26,000 Hz tone"...
Sounds like the Brown Note...
Move all sig!
That's one of my favorite movies.
It isn't an issue of stupidity no matter how much you wish it was, just an issue of posting too fast. Besides, I do have a signature but my post didn't, that is all. Anyway, here it is: Failure to question fundamental statements, even when made by eminent authorities, is a key feature of poor science. - Simon Singh