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.'"

Comments

Re:"300 years ago"

[Barryke]

"The weird effects that relativity is famous for come into play when you're comparing clocks between two reference frames that are moving relative to each other at relativistic speeds."

No offense intended, but i am amazed at something sounding really profound to me in a scientific way actually more resembles the average political speach. I beleive to fully understand what you meant, and wonder if my "plain english" interpretation be a correct translation by your standards;

"Comparing the whole situation on moment A, would work. It would also work on any moment B. When one wants to compare the comparisons of moments A and B, it gets more complicated."

Well that sounds pretty straight forward, if not stupid. Its like saying "Slicing a bread on more than one unique axis is more difficult."