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Milky Way's Black Hole Wasn't Always Such a Wimp
scibri writes "Sagittarius A*, the dormant supermassive black hole that lies at the center of our galaxy, was much more active not that long ago. Astronomers using the Fermi Gamma-ray Space Telescope have picked up some faint gamma-ray signals that suggest Sagittarius A* was emitting a pair of powerful gamma-ray jets like other galactic black holes as recently as 20,000 years ago (arXiv paper). If our black hole was more active in the past, it could explain why Sagittarius A* seems to be growing about 1,000 times too slowly for it to have reached its current mass of about four million solar masses since the Galaxy formed about 13.2 billion years ago."
What makes a black hole dormant? Lack of gamma ray jets... ?
Just more evidence that eating turkey makes you sleepy. It would appear that our galaxy's super massive black hole ate too much space turkey, and now it is having a nice long nap.
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so at 4 million solar masses how much would a teaspoon of that stuff weigh?
It wasn't always such a wimp, but then it got caught doing steroids, so it had to have an asterisk after its name.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
Oh sure, it's easy to call it a wimp from way out here on the outskirts of the galaxy. But I bet you wouldn't call it a wimp if it were right in your face!
Is anyone else disturbed that such an incredibly major change happened only 20,000 years ago?
This could be worse than an ice age.
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
Is anyone else disturbed that such an incredibly major change happened only 20,000 years ago?
This could be worse than an ice age.
No. If, 20,000 years ago, it was much more active, it proves living in a galaxy with an active nucleus is not a problem. What it means is, if it becomes more active again, we don't really have anything to worry about -- we've been living with the "problem" for most of five billion years and gotten along just fine...
"Convictions are more dangerous enemies of truth than lies."
well, since the gamma rays are practically pointing directly perpendicular to the rotation of the galaxy, they wont come anywhere near us. Even if it were pointing directly at us, it would take them at least 26,000 years to reach us. Granted, we wouldn't know they were coming until we were fried.
The jets should be perpendicular to the accretion disk which should mostly be co-planar with the disk of the galaxy. So, the jets will not point at us. If some oddball star or mass or whatever that is in a highly out of galactic plane orbit gets sucked in, we should still be ok as there is quite a lot of dust between us and Sag A*.
Al Gore went back in time 20,000 years (and you thought he only invented the Internet) to begin the process of Galactic Cooling so counteract the effects of Global Warming.
Now that would be interesting: http://en.wikipedia.org/wiki/File:EPICA_delta_D_plot.svg
it's in my head
It means exactly what it always does. 20,000 years ago. You're trying to be too clever with the speed of light thing, when we observed it is when it happened as far as we're concerned.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn.
In the land of the blind, the one-eyed man is king.
http://www.google.com/search?q=galactic+superwave+theory
One example:
http://www.etheric.com/LaViolette/Predict.html
"Subsequent concurrence (1998): In 1988, when presented with Dr. LaViolette's Galactic explosion hypothesis, astronomer Mark Morris dismissed the idea as having no merit. However, in 1998 after ten years of observation, Morris was quoted as saying that the center of our Galaxy explodes about every 10,000 years with these events each lasting 100 years or so."
Imagine if you were to go outside one night and the sky suddenly lit up as bright as day and stayed that way for 100 years!
Maybe matter falls towards the galactic core, but interacts with the core to produce shock waves that push it away again, to form some sort of resonant process that happens every 10,000 years?
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
It was explained in my astrophysics class that when a black hole reaches a certain mass that whole stars pass inside the event horizon before being torn up by tidal force. Then the singularity no longer has a big accretion disk and the radiation emitted by infalling matter is trapped within the event horizon. So it goes quiet.
We now have evidence that gamma rays influence climate
Speaking of incomplete data - No, we have evidence that gamma rays leave a vapour trail in a cloud chamber since that's how we detect them in an atom smasher. A few people have taken this fact and speculated that gamma rays affect the climate by seeding clouds, there are even a couple of books about the idea. Only problem is, their speculation does not not fit everyone else's observations. However you will find the 'Iris theory' presented as fact in the opinion pages of the wall street journal. Why? - Because on top of their complete lack of evidence, the people pushing this idea just happen to think it 'proves' Earth's climate is self regulating so we don't have to worry about regulating our emmissions.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Surely he would have un-invented chads while he was there?
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
If two black holes happens to be near each others, will they collide?
Or will one of the black hole swallow the other?
Will the bigger black hole swallowing up the smaller one, or will it be the reverse, the little guy biting chunks out of its bigger counterpart?
And when two black holes interact with each others, what will happen to the dimensions?
Will it create enough disruptions to the dimensions in the vicinity that temporary additional dimensions pop up here and there?
Muchas Gracias, Señor Edward Snowden !
From the view of an outside observer, the larger (greater mass) black hole will appear to draw the smaller one in. In reality, they're drawn to each other, and eventually merge, like two drops of water meeting on a window pane. The singularities become one. Simulations suggest that the merger will radiate massive quantities of energy in the form of gravity waves, a major ringing of the bell.
The ringing quickly dies down, and the only evidence of the merger being 1) the changed direction of movement relative to other nearby objects and 2) major disruptions of whatever was orbiting the two holes, from stars down to the accreation disc gas.
I haven't read Susskind yet, but I have read General Relativity by Dirac.
According to Dirac's, the singularity will never actually occur because of time and space dilation. The stellar matter will accelerate towards the singularity but never actually reach it. And never is an appropriate term since according to Hawking the black holes have a finite lifetime and will eventually evaporate according to Quantum Mechanics.
Will get to Susskind as soon as I finish a couple of Penrose books.
If someone is passing you on the right, you are an asshole for driving in the wrong lane.
Unless there is some unknown thing about the radiation stopping that allowed civilization to develop.
Like a lower rate of mutations allowing humanity to become genetically stable.
Sounds like a good Sci-Fi premise.
so would it be a good or bad thing if it lit up again?
The oscillation of our solar system's orbit brings us above and below the plane of the galactic ecliptic every 200,000 years or so and that's when massive speciation seems to happen.
So, hang on for that long and you won't need Red Bull to give you wings.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)