13th May 2007 - 05:43 AM
The teams led by Smith and Ofek propose that SN 2006gy marks the death of a star that was between 150 and 240 times as heavy as the sun. In such a star, energetic gamma rays push out from the core and resist gravity's pull. Instability sets in when gamma rays annihilate each other and become pairs of electrons and positrons. As the rays vanish, the entire star collapses and then blows up, leaving behind no black hole or neutron star. This type of explosion, known as a pair-instability supernova, can produce an outburst as bright as SN 2006gy, the two teams suggest. http://www.sciencenews.org/articles/20070512/fob5.asp
13th May 2007 - 10:59 AM
If huge stars cannot become black holes then how is it we have super-massive black holes of billions of solar masses in the relatively short time the universe has existed? They are not going to form just because a large cloud of hydrogen is subjected to a nearby super-nova. Such super-massive black holes need a large original hole to form around.
If we are receiving massive amounts of gamma rays from the site of that explosion, what do you get when material falls into a black hole in large amounts? Gamma rays!
13th May 2007 - 02:23 PM
We are i the zone of stellar black hole.A stellar black hole is still stellar black hole on ly ,it is not supermassive black hole.The formation of supermassive black hole is of different mechanism.
13th May 2007 - 02:51 PM
If the Big Bang theory is true, then a super-massive black hole could only exist if it was there from the beginning of the universe, or created from the direct collision of the hubs of two galaxies, which would still be extremely early in time.
There is no other known mechanism to get that concentration of mass back in the same place after it has already been expanding out ward. The gravitational acceleration between andromeda and the milkyway is negligible, for example,at
~ 4.5E-14 m/s^2, assuming each has a mass of 400billion solar masses.
A "super massive" black hole could never form from a mere star or group of stars.
14th May 2007 - 10:31 AM
So there isqualitative difference between stellar blackhole and supermassive blackhole.
14th May 2007 - 11:07 AM
Quantum Conundrum. The big bang idea talks of matter expanding outwards at great speed so it is debatable if anything would coagulate and form even something as large as a fist sized lump of rock. This especially so since the material created was supposed to be hydrogen and helium which does not naturally clump.
The idea is that super-massive black holes formed over time, normally at the centre of galaxies where there was plenty of material to fall into them. Other black holes can merge with them and form ever larger black holes.
I would guess that super-massive black holes were the seeds around which galaxies formed.
17th May 2007 - 10:30 AM
Intermediate black holes dicovered.