Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: syhprum on 20/09/2007 20:16:23
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An interesting article on primordial black holes things I have often thought ought to exist but I have not seen discussed before.
http://space.newscientist.com/article/dn1617-black-holes-detonating-all-over-our-galaxy.html
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Very interesting. If you look at the theory, the black holes do not get significantly bright until they are in the last few seconds of their life and only radiate significantly powerfully at very high energies.
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Do I need to wear my hard hat? [???]
Interesting article. Black holes fascinate me.
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I don't think we really need to worry because a tiny black hole approaching a relatively dense area like the solar system would probably pick up quite a lot of stray material in the form of gas and dust in its passage through the Oort cloud this would probably make it visible and would also put off the day of its demise. As the article suggests it would have to be quite close to the earth (within the distance from the earth to the sun. before the explosion represented a significant risk to life.
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I don't think we really need to worry because a tiny black hole approaching a relatively dense area like the solar system would probably pick up quite a lot of stray material in the form of gas and dust in its passage through the Oort cloud this would probably make it visible and would also put off the day of its demise. As the article suggests it would have to be quite close to the earth (within the distance from the earth to the sun. before the explosion represented a significant risk to life.
This raises the question in my mind as to why these are appearing in the Orion belt, where I would expect there to be a higher density of matter than in other areas of space. I would understand if they were everywhere, but why specifically there?
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The article says the Orion spiral arm not the Orion belt. The Orion spiral arm runs considerably to the east of the constellation of Orion. It is the closest spiral arm to the sun and is looking outwards away from the centre of the galaxy. This tends to suggest that the events are quite local to the sun ie within a few hundred light years as you would expect for very small weak events like exploding tiny black holes.
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As the mini black hole approached the end of its life how rapidly would the radiation from it rise, could we detect it about to go of and duck down.
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it is quite a steady rise
using http://xaonon.dyndns.org/hawking/
1 year before it goes it's 16 megatons/ second
1 day before it goes its 835 megatons'second
1 hour 7000
1 minute 106,000
1 second 1,633,382 megatons per second or about one hundred thousanth of the brightness of the sun
Its only as bright as the sun for the last seven nanoseconds
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I cannot feel that the description of its final moments as " a steady rise " if it goes from 1/100000 the luminosity of the sun (about as bright as the moon ?) in one second is really appropriate.
is it possible to determine its ultimate power output, I take it it would be in Gamma rays
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There are quite a lot of arguments about what it is likely to be, most of them suggest a lot of the energy will come out in the form of particle anti particle pairs so in the final stages there could be a lot of very high energy exotic particles but most of them would very rapidly break down to the sorts of things that we are familiar with.
This was the source of the argument between Stephen Hawking and another physics expert which Stephen Hawking recently conceded when he agreed that the particles that come out of an evaporating black hole could have somerelation to the ones that went into it.