Reply for the question of Mr. Cool.
About gravity travelling faster than light.
Hi,
Let me clearly explain two points first.
We call something a particle only if it has some mass. (Photon is a energy particle with zero mass as per Eienstein Physics of energy-matter interconvertibility.)
Gravity is a cause and effect phenomena. it is not a information or particle. earth is a rocky object that doesnt not have any intelligence to interpret information. for example, its like stone stays in our hand as long as we hold it. It is a cause that is acting against gravity. if we leave it it will fall down because there is nothing against gravity. this is effect.
A similar thing happens in the solar system or Universe. all the planets are there in the free space is because the huge gravitational force of Sun holding it. and why it is not falling into the sun... This is because the earth is revoving around the sun at a certain velocity countinously so as to not to fall in the sun. Its like sun pulling the earth into itself (F=mg) and earth trying to stop it by its centrifugal force (F=mrw^2). Combinimng this two, sun 's pull g will be compensated by rw^2.
that is g=rw^2.
It is like a plane will stay in the air as long as it is flying (moving). think of the case where all engines of the plane stops in the mid air, the planes suddenly drop down and crashes right !!! This is a similar phenomena..
If the sun/star explodes (supernova), the gravitational pull of the sun suddenly decreases (Explosion decreases density in the body, and density directly proportional to gravity, hence gravity decreases.), but at that time the earth countinously revolves around the sun with a certain velocity and in a particular orbit so as to compensate the sun's pull. the moment the suns gravity decreases, the centrifugal force generated to compensate suns's 'g' while earth revolves will have obviously more force than the present gravitational force and it dominates the suns gravity and pull off the earth out of its orbit (by shear difference in force). that is spilling out.
I hope I answered your question.
PS: According to the chandrasekhar's limit, the sun will never explode. It just shrinks in itself.