Casper Badenhorst asked:
I was wondering how Relativistic jets can be shot out from a black hole even though light which has no mass can't escape one?
Sutton - London
Nothing can escape once it has passed the event horizon, so the jets originate outside the event horizon.
It might be worth considering relativistic effects in the structure of a fast spinning black hole, i.e. material at the equator may be less entropically active than material at a core more or less beween the poles. This would be due to the spin. Material at the equater would be affected by gravity plus speed while the core material would be affected by gravity only.
when gravitational collapse occurs angular momentum is conserved and any residual rotation speeds up. This will continue until the rotation become so rapid that it prevents further collapse.
As long as it happens outside a event horizon there is nothing stopping radiation from leaving a black hole. If Earth became a black hole today it would do nothing to the stability of the solar system. They would generally speaking move as usual. The compression that creates a black hole doesn't change its mass (ignoring what gets lost before it becomes a black hole), yor_on, Mon, 17th Jun 2013
Do you realise that a black hole with a mass equal to that of the earth is just under 2cm in diameter. Soul Surfer, Mon, 17th Jun 2013
It's pretty weird, and yeah. Haven't used that one in a while though :) yor_on, Mon, 17th Jun 2013
I accept the text book explanations but I think a point is missed when there is a concentration on size (diameter) rather than the criticallity of a borderline structure. Perhaps it was a bit misleading to say 'black hole' when I really meant a structure heading to become a black hole.
There are two types of black holes. The Schwarzschild solution describing a non rotating black hole. That type we haven't found yet, as far as I know. The other type is rotating black holes, some of them spinning close to the speed of light. Those we have found, indirectly evidenced. And Soulsurfers explanation to why they spin so fast, is a analogue to what you can see when a skater spin, pulling in her arms to rotate faster. As the mass 'shrinks' into a black hole, its angular momentum must increase.
Bracewell; The non rotating or "Schwarzschild" black hole is essentially a theoretical entity devised by modellers because it is the simplest sort possible and for many years it was the only one for which the space time equations could be solved.
Soul Surfer - good stuff. However, I would value your opinion on the following scenario.
Another way you could end up with (almost) non-spinning black holes is if two black holes with similar mass but opposite spin directions merged together.
A random thought: If the relativistic jets were turned so they fired in or near the plane of the galaxy, could this produce the burst of star formation seen in barred spiral galaxies? evan_au, Sun, 23rd Jun 2013
Some recent discoveries show a different way that matter can escape from the vicinity of a black hole.
evan - very interesting about the rejection of matter from very large objects.