Friday, May 04, 2012

Could black holes a few dozen light years from Earth cause mass extinctions?


When reading a book by Lewis Darnell “Life in the Universe” (April 17, 2012 Books Blog) I encountered some speculation that earlier extinctions (over 1 billion years ago, not the dinosaur wipe-out 65 million years ago from the asteroid hit) could have been prompted by encounters with moderate or small black holes as the Sun revolves around the galactic center.  Not close enough to suck up the solar system, but maybe close enough to unleash destructive gamma radiation on Earth.  A supernova 30 light years away could unleash destructive radiation within a few thousand years.  There are some speculations that supernovae as far away as 1000 light years, enough to form black holes, could result in extinguishing advanced life on Earth.

I looked up a few videos on YouTube in the subject. 

I found one by Thomas Lucas and “space.com”, 18 min,  “The Largest Black Holes in the Universe.”  He notes that some black holes formed very early in the history of the Universe, and that some coalesced to form quasars.

But a more interesting short, 10 min, narrated by Michael, produced by Numberphile, is  “Travel Inside a Black Hole”.

If you approached a black hole, you would experience time dilation, so it could seem like a long time before the tidal forces started to “hurt”.

An outside observer would see you approach the Schwarzchild Radius, and seem to stay there, because of time dilation.  Your image would be “red-shifted” out of sight, gradually.  He also explains the “Cosmological Principle”, that the Universe has no “center”, but that from any point, everything seems to be moving away from you at the same rate.

He also discusses “acoustic black holes” or “dumb holes”.  He also says that if the Universe got big enough through expansion, there is a good statistical chance of “Another Earth” (as in the sci-fi movie by Brit Marling) actually existing.


You can also try this 1 hour video, “The Greatest Unsolved Mysteries of the Universe”, by Dr. Paul Francis at ANU (Australia).   There is some mathematical theory that says that all the information in a galaxy will be stored on the surface of black holes in the galaxy.  When people die, their “information” will be stored there forever (as a kind of afterlife).  But there is a problem that the surface area may not be large enough to house all the information (because of the way volume and surface area work out in high school solid geometry!)

There is also the controversial idea of “Micro Black Holes”, which, in theory, could wreak havoc by “hacking” information in bizarre ways if they really existed, Wikipedia reference here



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