Recent content by virgil1612

Thanks.

Thanks Perok, that's definitely useful. So we shouldn't even talk about relativistic mass, it's a wrong concept that leads us astray.

Massless as per rest mass, but why couldn't I talk about that "relativistic" mass?

Photons have 0 rest mass. But could I talk about relativistic, or dynamic photon mass, that would be the solution of hf = mc^2 ? The relativistic mass would be m = m0/sqrt(1-v^2/c^2), where m0 is the rest mass, so 0, and v = c, so the denominator is also 0. The previous equations would give 0/0...

Hello, Could someone explain or post some links for the current status-quo of the mechanisms that make a massive star explode?I know that the prompt mechanism doesn't work, that the shock stalls and must be revived by something (neutrinos, presumably), but where are they (the researchers) as...

Great, thank you.

If an astronaut travels to a 10 ly distant star with a speed very close to light speed, then he will measure a distance to his star much smaller than 10 ly (length contraction) so his time for reaching the star will be smaller than 10 years, let's say 1 year. Then, without delay, he returns back...

Yes, but I meant... is that luminous ring the accretion disk, or it's just light coming from there and orbiting the black hole (the photon sphere, that's how it's called?), giving us a sense of the shape of the horizon of the black hole? Virgil.

Does the light come from the accretion disk?

I was thinking about red dwarfs possibly favouring rocky planet formation because of the recent discovery of the Trappist system... A red dwarf surrounded by 7 (!) rocky planets... seems quite extraordinary.

Hello, 1. Does the star type influence the type of planets forming around it? Specifically, could a red dwarf favour the formation of rocky planets around them, compared to gas giants? 2. Planets would be much closer to a red dwarf star than they are for a solar type star. Consequently, the...

Thanks phyzguy, I guess I should have checked the net myself before asking.

I'm merely speculating here, but I guess a galactic collision between a big galaxy like ours and a much smaller galaxy (so that the big galaxy does not lose it's individuality) could produce retrograde motions of stars.

Hello, I'm curious about the origin of the nebulosity that can be seen around the main stars in the open cluster Pleiades (M45). Is it a residual of the huge cloud from which these stars were born not so long ago (astronomically), or it just happens that these stars pass through an interstellar...

I know that you can only define a temperature in a system in equilibrium. Could it be that when electrons go degenerate you can no longer talk about thermal equilibrium between them and the ions?