ok...blackholes collect matter/data till the like...do whatever...colapse or whatnot

anyway...while they are doing what they do, i havce heard that light cannot escape the gravity...(after a certain point in its life)

so, is that to say that light has mass?

if you had a table in a room, would light eventually "melt" the table as if it were water in the same fashion?
something my classmate sugested is that light is protons...the have no mass....so...i got really confused...somone help me :confused:

yeah. im thinking they're plasma, but i may well be wrong. Anyhow, it does have mass, but the atoms of the table it is hitting may be strongly enough bonded that energy imparted from the photon would have no effect. :m:

Hum,
while i would think that light, (photons) are massless, but has `moving` energy.


Best to have a quick look here:
http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

(theres a bit about nonzero rest mass, at the end)


I also think that a blackhole just bends the `fabric` of space, and the light just follows the geometry, er , like a ball rolls towards the center of a bowl. (the center of the bowl seems to `suck` in the ball).

Light just follows a straight line; in the case of a black hole the `straight line` is drawn on a curved space-time - imagine a straight line drawn on a bit of paper ; now bend the paper...

ok...blackholes collect matter/data till the like...do whatever...colapse or whatnot

anyway...while they are doing what they do, i havce heard that light cannot escape the gravity...(after a certain point in its life)

so, is that to say that light has mass?Light has no mass – the theory of relativity explains how a something without mass (like a photon) can be affected by gravity.

oh...ok

Certainly light and other EM radiation is equivalent to mass in a way, since the two are interchangeable in nuclear reactions. A star has to sacrifice some of its mass in order to shine. Cosmologists talk about the mass-energy density of the Universe as a whole.

In the distant future, of course, black holes will gradually evaporate as their mass is recycled into weak radiation through the Hawking quantum process. The smaller the hole becomes, the higher the frequency of its radiation leakage and the faster mass loss will proceed. So, in theory, light can escape from a black hole - or at least be spontaneously generated along its event horizon.

Starthane:
Since Hawking radiation is due to the instantaneous creation of particle/antiparticle pairs near an event horizon, I don't think any of the radiation would be in the form of light.

I think in most cases the virtual particle/antiparticle pairs will be a pair of photons, which are their own antiparticle; I also understand that the annihilation of virtual particle pairs happens because one particle has negative energy, so that the total energy of the pair equals zero. So most Hawking radiation wil be photons after all.

In fact the way that Hawking radiation is described in popular science articles is quite a bit oversimplified, and having seen a more accurate description of the process once, I think that is probably a good thing.

I have the general impression that the wavelength of said radiation was determined by the diameter of the black hole's event horizon: thus, for a stellar-mass black hole with a diameter measured in kilometers, the radiation would start out as extremely long-wave radio. Only after about 10^60 years, when the hole had shrunk down to microscopic size, would it begin to glow in visible light...

For galactic-mass black holes, this timeframe could be as long as 10^100 years.

Apologies, I stand corrected. However, the Hawking radiation is not sufficient to cause the black hole to evaporate, as the surface temperature of 60nK for a black hole of 1 solar mass (ie. smaller than all known black holes) is less than the cosmic microwave background temperature. Wikipedia quotes a mass of 4.5x10^22 kg (about the mass of the moon) as the equilibrium point.

That is right; black holes don't start to lose energy until the whole universe has cooled off enough to be cooler than they are.