Integral rolls back history of Milky Way's super-massive black hole

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Everything I need to know I learned through Googling.

Only 350 years ago? That's really cool. It just happened, cosmologically!

... I assume by 350 years ago, they mean the gamma rays would have been observed from Earth 350 years ago.

Blast that finite speed of light!

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You can't take the sky from me.

I was thinking that earlier, but you gotta keep your reference frame in mind. 350 years, +1 year per LY between here and the black hole for the actual event. Almost said something, but passed.

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This is very interesting. I wonder if somebody here knows exactly the quantitty of energy released actually by the black hole, I'm starting to play with the idea that 350 years ago, our galaxy was a Seyfert Galaxy

I'm surprised that having such an active black hole at the galactic centre does not seem to have affected us over the centuries. When will that gamma ray burst reach Earth? And what will happen when it does?

Also, I don't think the event would have been witnessed on Earth 350 years ago. The object is 30 thousand light years away, so whatever event happened would take 30 thousand years to reach us. A 350-year head start doesn't amount to much.

And can I say, a bit off topic I know, that the name scientists give this black hole is a strong argument for bringing more poets into physics. This is the black hole at the centre of our galaxy, the infernal cosmic engine, the dark satanic mill at our galaxy's core, and all they can call it is Sgr A*? Surely it deserves a more honourable name than that?

Exactly right. The article is misleading. It's physically impossible to have happened 350 years ago, since our sun is 30,000 light years from the galaxy center where the event was observed.

Anything we observe from that region today happened 30,000 years ago. The event they described happened 30,350 years ago.

However it's common to describe things in earth-centric terms. E.g. the supernova forming Crab Nebula "happened" in 1054 AD. However at 6,300 light years from earth it really happened about 5246 BC.

This is what's wrong: The article describes the event from a LOCAL viewpoint. It describes the 350 year light travel time from Sgr A* to Sgr B2. Yet it never states once the travel time to earth. This makes it more confusing than usual.

Maybe it did. We had the Little Ice Age at about that time.

It gets confusing talking about how long ago something happened when it's light-years away. Accepting your figures, the event actually happened 30,350 years ago. Reading the next post, I can see that joema also noticed this.

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There are ten kinds of people. Those that understand binary, and those that do not.

Exactly right! The names given to these objects, while undoubtedly functional and efficient for cataloguing, are boring and complex. Personally I'm voting for Heart of Emptiness but hey thats me.

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What I meant was that it happened 350 years ago, but wouldn't reach us for 30,000 years minus the 350-year head start.

Scientists have been explaining it by saying we are now seeing an echo from a sort of natural mirror near the galactic centre, Sgr B2 simply and its giant cloud reflects gamma rays emitted by Sgr A* in the past

Galactic Centre Region

http://sci.esa.int/science-e/www/obj...objectid=37890

article to be published in the Astrophysical Journal, Bélanger et al. present the results of a detailed analysis of approximately 1900 hours of observations of the galactic centre

Supernova Rate For Milky Way
http://www.sciencedaily.com/releases...0106003748.htm

http://www.universetoday.com/am/publ...26.html?512006


also check this idea
http://sci.esa.int/science-e/www/obj...objectid=36959
The Gamma Ray Lens
The future of gamma ray astronomy relies on the development of significantly higher sensitivity instrumentation. This suggests the need to develop a gamma ray focuser, an optic capable of concentrating gamma rays onto a small detector, thus minimising the background and maximising sensitivity. The Gamma Ray Lens TRS investigates the potential technologies and architecture of such a mission

Integral looks at Earth to seek source of cosmic radiation
http://www.esa.int/esaSC/SEM8EVLVGJE_index_0.html
10 February 2006