I'm a retard and what is light?

>>8449808
Great thread! This will help me brush up on my meme understanding of general relativity. If you asked me over the Summer I would have been able to answer you probably because I was reading Kip Thorne's book: Black Holes and Time Warps.

>>8449808
Electromagnetic radiation. Gravity affects it because gravity is the curvature of spacetime and light travels through spacetime.

>>8449808
this should clear things up for you
[math]R_{\mu \nu} - \tfrac{1}{2}R \, g_{\mu \nu} + \Lambda g_{\mu \nu} = \frac{8 \pi G }{c^4} T_{\mu \nu}[/math]

Not a physicist so hopefully an anon can come in and fix my autistic answer, but here is my reason:

A photon's trajectory with a black hole is related to Einstein's proposal of space-time.

Now back to space-time. Space-time is determined by matter distribution in the universe, and blackholes are a SINGULAR point in space time that leaves a massive dent. It effectively curves space time around the singularity. Light travels along space-time and when it approaches a blackhole, its trajectory is warped due to the warping of space-time.

Why light cannot escape the attraction of a black hole, I do not know. But I guess it has something to do with Einstein's theory of Relativity, which states there is a exchange between mass and Energy (E=mc^2), or that mass and energy are related.

>>8449828
>well-intentioned half-truths: the post

>>8449808
You don't need no mass to follow geodesics!
And geodesics are the same for anyone, no preferences.

That's why the mass (almost) doesn't affect your free fall here on earth

>>8449828
basically
0. light travels in 'straight' lines in space-time (actually a geodesic)
1. mass warps space-time
2. a lot of mass warps space-time a lot
3. black holes warp it enough and are small enough that within the event horizon all paths in space-time lead to the singularity, ergo nothing (including light) with the event horizon may escape

>>8449837
*if you're not familiar with this principle, I'll attach a remainder here: when no external force applied, things go in geodesics (locally shortest paths on your pseudo-manifold. Reminder, it's a space-time, not only space)

>>8449825
I already said I'm a retard you don't have to rub it in.

>>8449843
Things with internal energy have mass, right? Such that if you lower the thing's internal energy, its mass is also lowered. In this case, why does light not have mass if it has energy?

>>8449884
>Things with internal energy have mass, right?
No. light doesn't have mass, but it does have energy.
in terms of E = mc^2 you'd think that the photon energy hf = mc^2, so light has some mass, right?
not really, because E=mc^2 is just a special case of [math]E^2 = \frac{m c^2}{\sqrt{1-v^2/c^2}} [/math] if you take v = c then you have 0 mass multiplied by 1/0 which is sort of undetermined. in this case you have to refer to [math] E^2 = c^2 p^2 + m^2 c^4[/math], and you see that for a photon m=0, but p is not equal to 0 because the momentum of a photon is given by [math]p = h/\lambda[/math]

>>8449900
whoops, that was meant to be [math]E = \frac{m c^2}{\sqrt{1-v^2/c^2}}[/math], not [math]E^2[/math]

>>8449900
Oh, thank you. I also found this http://i.imgur.com/LccUj2K.png

This seems to be a symptom of where high school teaches you babby physics instead of real physics so as to increment the difficulty rather than the logicality so that they can trick normies into thinking they can go become physics majors 2 years into uni and get their shekels.

>>8449900
I just realized though. This means that mass is relativistic? Say you increase the internal energy of a ball, its mass increases, right? How does that work as the ball approaches the speed of light, given that the general case of E=mc^2 is relativistic?

>>8449808
Its a frequency of electromagnetic radiation that is good enough or our organic cells to translate into visual information, the other frequencies are either too low or too high meaning they destroy our retinas. Visible light is produced by anything that is white hot meaning energetic stuff creates visible light.

>>8449940 this is one of the reasons why you can't travel at or past the speed of light. well done.

>>8449940
>Energy increases
>Mass increases

Who wrote the rules in this universe?

>>8449940
as the ball gets closer to the speed of light more energy adds to the mass instead of the speed

>>8449940
'relativistic mass' is given by [math]\gamma m[/math] where [math]\gamma = \frac{1}{\sqrt{1 - v^2/c^2}}[/math] but it's more common to think of mass as rest mass (ie mass measured in the v=0 reference frame) which is invariant in all reference frames. in a moving reference frame then it will appear that inertial mass increases with velocity, yes.

>>8449972
>>8449976
Thanks for the answers everyone.

File: Yt1m0.jpg (92KB, 500x663px) Image search: [Google]

92KB, 500x663px

>>8449825
>OP asked for help understanding something
>Better pretend to not be faggot by being faggot

>>8450013
Wut? This thread didn't enlighten me at all and why I came here. I'll go back to thinking of it as a wave and a particle and leave it at that. Waves of particles.

>>8450127
Same here. e=mc^2 is a SHIT. I HATE MASS. I HATE ENERGY. I HATE MOMENTUM. I HATE FORCES. Those fucking non-existent bullshit notions. fuck they're awful. curvature is nice. geodesics are fine.

>>8450159
> non-existent bullshit notions.

You mean like anything any human has ever described anything as then?

What makes energy any more of a bullshit concept than curvature\?

>>8450199
Because it's a part of geometry, the most undoubted part, and it's derived from metric, which is most undoubted thing after topology. If anything is real, it's this.

While others are artificial human bullshit. Just like gravity """force""" bullshit back then, wrong in its very essence.