Does Light Mass Increase a Black Hole?

[PerenialQuest]

I'm just curious, when light enters a black hole, does the black hole gain a little bit of mass? We think of photons as massless particles, but they do have energy, and energy has a mass equivalent, e=mc² Would the mass gained perhaps be, = hν / c² ?

 

[Pengwuino]

It's better to realize that black holes don't just have mass, they have energy in all forms (mass, e/m field energy, angular momentum). So in reality, you could have a bunch of mass that barely doesn't have enough mass to form a black hole, bombard it with a high powered light source, and it will collapse into a black hole because energy, not just mass, gravitates.

 

[Aaronvan]

It's better to realize that black holes don't just have mass, they have energy in all forms (mass, e/m field energy, angular momentum). So in reality, you could have a bunch of mass that barely doesn't have enough mass to form a black hole, bombard it with a high powered light source, and it will collapse into a black hole because energy, not just mass, gravitates.

Don't black hole have mass and spin only?

 

[Pengwuino]

Don't black hole have mass and spin only?

They also have charge.

 

[kenrocks]

It's better to realize that black holes don't just have mass, they have energy in all forms (mass, e/m field energy, angular momentum). So in reality, you could have a bunch of mass that barely doesn't have enough mass to form a black hole, bombard it with a high powered light source, and it will collapse into a black hole because energy, not just mass, gravitates.

Generally black holes are of how much mass?

 

[phyzguy]

I'm just curious, when light enters a black hole, does the black hole gain a little bit of mass? We think of photons as massless particles, but they do have energy, and energy has a mass equivalent, e=mc² Would the mass gained perhaps be, = hν / c² ?

I don't think you got an answer to your question. The answer is yes, if a photon of frequency nu falls into a black hole, the black hole gains an amount of mass equal to h*nu/c^2.

 

[phyzguy]

Generally black holes are of how much mass?

Black holes that we know about (or think we know about) range in mass from a few solar masses to a few billion solar masses.

 

[Aaronvan]

They also have charge.

Ah yes, spin, mass and charge.

 

[harcel]

Black holes that we know about (or think we know about) range in mass from a few solar masses to a few billion solar masses.

With a large gap in between a few tens of solar masses (the most massive stellar balck holes) and a few tens of thousands of solar masses (the lowest observed masses for black holes in the center of galaxies). Although some people have evidence for the so-called intermediate mass black holes ( roughly 100-10.000 solar masses), the evidence is far from compelling.