Chandra's view of Sagittarius A*, the Milky Way's central black hole, in 2005. (AFP/NASA-HO/File)
Posted on 04/15/2008 12:33:38 PM PDT by NormsRevenge
PARIS (AFP) - A black hole slumbering at the centre of our galaxy went into a "feeding frenzy" three centuries ago, the European Space Agency (ESA) said on Tuesday.
Located around 26,000 light years from Earth, the black hole, known as Sagittarius A-star (Sgr A*), is a monster with a mass four million times that of the Sun.
Japanese astronomers, using ESA's XMM-Newton orbital telescope and US and Japanese X-ray satellites, discovered that clouds of gas brightened and faded in X-ray light when they passed near Sgr A*'s maw, ESA said in a press release.
The phenomenon is due to X-ray pulses that are believed to be residual bursts from a flare that happened 300 years ago.
"We have wondered why the Milky Way's black hole appears to be a slumbering giant," team leader Tatsuya Inui of Kyoto University said.
"But now we realise that the black hole was far more active in the past. Perhaps it's just resting after a major outburst."
One theory is that a few centuries ago, the powerful gravitational pull of the black hole engulfed clouds of gas from an exploding star called a supernova, ESA said.
The "temporary feeding frenzy" caused X-ray energy to leap from its mouth in a giant flare.
Chandra's view of Sagittarius A*, the Milky Way's central black hole, in 2005. (AFP/NASA-HO/File)
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=42587
X-ray Echoes of a Past Outburst of Sgr A*
15 Apr 2008
In a forthcoming paper, the history of the X-ray brightness of Sgr A*, the massive black hole at the heart of our Galaxy, is derived from observations made over a 11-year period by four X-ray observatories. The results are based on X-ray line emission from molecular clouds, considered to be reflecting Sgr A*’s X-ray emission with a delay time of 300 years.
Sgr A* is a compact radio source located at the dynamical centre of our Galaxy as confirmed by, for example, its apparent motion (solely due to our own motion around the Galactic centre) and the orbits of stars close to the Galactic centre. It is generally believed to be a massive black hole of several million solar masses.
Currently, Sgr A* is observed to be in a quiescent state. Its X-ray luminosity is several orders of magnitude below that of active galactic nuclei with a comparable sized black hole. This is the case even during the known frequent flaring events of Sgr A* when the flux increases by a factor of ~10. Observed events in our Galaxy’s central region actually occurred ~26 000 years ago as we are at a distance of about 8 kpc from the Galactic centre.
—snip—
Does this mean that we will begin to detect evidence of the feeding frenzy 25,700 years from now?
Bush’s fault!
Wake me up 25,999 years from now to be concerned.
Wow, 26,000 light years away and we know what happened 300 years ago. Time travel is here!!!
Yes... the Milky Way’s largest belch!
This is my galaxie. There are many like it, but this one is mine.
(You may use it, but bus your own trays.)
What has ME concerned are the remarks that the galaxy center is 26,000 years away.... and they are talking about xrays originating 300 years ago???
Ummm xrays are the same as light or other radio frequency energy, thus travel at the speed of light... Which means, we didn’t detect it YET if it just started “300 years” ago.
Someone has their head firmly planted somewhere other than in the stars, or in astrophysics (Astrophysics doesn’t change the math, sorry)
No, it means it happened ~26,000 years ago, and we’re just now seeing it.
Yet another example of a “journalist” reporting on something way outside their depth.
If the gases illuminated when they passed near the black hole, and
If the black hole is 26,000 light years away, and
If the black hole awoke only 300 years ago, THEN
How could the brighter light from the illuminated gas have reached us by now to figure this out?
What do I know . . .I’m a only a banker.
Don’t we need to wait another 25,700 years to know what it was doing 300 years ago?
Yes. lol
Monster black hole? 300 years ago?
I had no idea Michael Moore was that old.
Whoever wrote this is an idiot. Here’s better explanation.
The black hole is 26,000 light years away. 300 years ago plus 26,000 years, a major supernova flare occured. It ejected massive clouds of gas. Those gases took 300 years to reach the vicinity of the black hole, and the effect the black hole had on that gas is just now reaching us. All the excitement happened back when humans were still duking it out with each other over who got the best mammoth steaks.
Or Helen Thomas!.............
I am confused. If it is 26,000 light years away, how do we know what happened 300 years ago????
John Wheeler not available for comment.
Wouldn’t that really be 26,300 years ago?
Man, I was late to the party.
Further evidence leading to their decision:
bump
I guess the part about going on a “feedling frenzy” made me think of Michael Moore.
oops.
FEEDING frenzy, not “feedling”
I’ll blame the journo for this blooper: It is impossible to determine what took place 300 years ago on an object that is 26,000 light years away.
It can't be quite that simple or the gas cloud would be behind the black hole.
The X-rays from the 'feeding frenzy' are long gone. Humans were too busy killing each other to notice. If we had we might be able to use this pulse as a fine calibration tool on distances at the galactic center. We still can, it will just take many years and additional gas clouds lighting up.
In any case I'm inclined to give the journalist a pass on this one. If the journalist had actually understood he or she would have been unable to convey it to the public without resorting to some lame metaphor (cosmic echo) that would only serve to get the mouth breathers to think they understand.
They should include a diagram. Language is a really blunt instrument.
Hehe! I think they need a new science editor.
Karl Schwarzschild could have supplied an equation to explain it.
A flare affecting something 26,000 light years away?
WOW! News travels fast.
Impossible?
Maybe this was a very resourceful reporter who knew some trade secrets about how to get the scoop first ;-)
I notice they also had to tell us there was an exploding star, called a supernova. Everyone I know, and pretty much everyone who is going to bother reading this article, already knows what a supernova is. Except the guy who wrote the article, I guess.
Carl Sagan was only half right. We need to be a two universe species not a two planet species.
What is the chance that clouds of gas exist between us and the supernova, with a 300-light-year added path difference compared to straight line-of-sight with the supernova? As seen by us, those clouds would be lighting up right now in the reflected light of the supernova, which may be detectable. If the clouds were large, we should see a spherical shell of illumination traversing them (at the speed of light). Parts would light up or disappear as the supernova’s light hit new patches, or traversed beyond the spatial extent of patches previously illuminated.
Remind me in 26,699 years.
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
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