Slashdot Mirror
Hundreds of Black Holes Roam Loose In Milky Way
sciencehabit writes "From Science: 'Astronomers suspect that hundreds of medium-sized black holes are roaming loose in the Milky Way. These rogues, according to a new study, are the orphaned central black holes of the many smaller galaxies that the Milky Way has swallowed over its billions of years of existence.'"
Anything else we need to be worrying about?
I wonder if black holes could account for either of these things? Gamma rays would be released if a large mass hits a black hole. A cosmic ray could be accelerated if it passes too close to a black hole.
http://michaelsmith.id.au
My kind of galaxy!
If I found hundreds of "black holes" in my "Milky Way", surely that would mean it's an Aero?
I'll grab my coat ...
'If Christ had tweeted the sermon on the mount, it might have lasted until nightfall.' - John Perry Barlow
Scenario. The Milky Way swallows a galaxy, and by extension, all the stars around the central black hole. Yet, the same gravity that causes the stars to amalgamate completely misses the biggest mass in that swallowed galaxy? Why would that make sense?
The only bit which I think is strange is that the black hole from the swallowed galaxy hangs around in our galaxy. It should have enough velocity to pass right through our galaxy and never come back. Most likely the captured stars would die of old age before they passed though our galaxy. Only red dwarfs would keep going because of their long life. Gas clouds in the captured galaxy would interact with our gas clouds. I think that is the only component which would really get captured.
http://michaelsmith.id.au
And how can the news networks use it to induce fear?
And more importantly, how we can we use it to sell stuff?
"Black hole protective face-masks" just don't seem like a seller, to me.
Because the galaxy is not a point mass. Most ordinary star/planet modelling is based on viewing each object as a sphere, which behaves as a point mass at the centre. But when you penetrate inside another body, as two galaxies do when they collide, this simplification no longer applies. Some of the mass of the "other" galaxy moves behind the penetrating galaxy, slowing it down rather than, as the point mass model would suggest, continuing to accelerate into the centre. In the simplest model, of inter-penetrating spheres, gravity no longer has an inverse square law but an inverse linear law. Of course, galaxies are not uniform spheres, and the modelling is much harder. However, it is widely accepted that when two galaxies collide, they merge and the vast majority of the mass forms a single galaxy - though clusters may be flung out. If the galaxies are of broadly similar masses, the distinctive spiral structure is wiped out and the merged result becomes an elliptical galaxy for a few hundred million years before the spiral structure re-establishes.
Google "andromeda collisions" for simulations of the collision between our galaxy and the Andromeda galaxy in about 3 billion years.
Consciousness is an illusion caused by an excess of self consciousness.
Take this wise lesson from Red Dwarf:
"Well, the thing about a Black Hole, its main distinguishing feature, is it's black. And the thing about space, your basic space colour is black. So how are you supposed to see them?"
*later on*
"They weren't Black Holes."
"What were they?"
"Grit. Five specks of grit on the scanner-scope. See, the thing about grit is, it's black, and the thing about scanner-scopes..."
"Oh shut up!"
To do something right, you often have to roll up your sleeves and get busy.
What happens when two black holes actually intersect at their event horizons? Inquiring non-astrophysicists would like to know.
They merge into one bigger hole. The final hole mass will be (almost) the sum of the two masses, and will likely have a significant spin, even if the pre-merger holes don't.
Disclaimer: this is actually my area of research.