/sci/ - Science & Math

>>3549999

Quad 9's say yes.

>Could then, the mass of a galaxy also influence light?
yes
>Because the mass of a galaxy is the sum of all the mass within, might its gravitational force influence the light that escapes it exaggerate (or perhaps explain) the redshift effect astronomers observe?
exaggerate only, not fully explain. expansion of universe explains it

>>3549999
>photon has mass

WTF?

>>3550022
But isn't the expansion of the universe explained by the redshift?

So, if something else explains the observed redshift, is the universe still expanding?

>sky very blue
>must be moving away at terrific speed.

Photons have no mass.

But they are influenced by gravity regardless. They even produce gravity. All energy density warps spacetime.

>>3550034
>>3550049
Right, my bad, light has no mass. Still, the question bothers me. Looking to see if anyone can tell me why I may be wrong.

>>3550034

You ARE a fucking retard. I mean fuck I'm not even a Physics major, I'm Chemical Engineering, and I know a photon may be assigned a relativistic mass given by E=mc^2 --> E/(c^2)=m

Get lost chump.

>>3550032
expansion explains part of redshift, gravity the rest. the proportions depend on how much gravity and how far away the galaxy.

gravity alone cannot explain why a far away galaxy has more red shift than an equally massive nearby galaxy

> A photon has just enough mass for gravity to influence it.
Nope.

>An object as massive as our Sun can bend light (gravitational lensing)
Happens, but very very minimally for something the mass of our sun.

>Could then, the...etc etc...(or perhaps explain) the redshift effect astronomers observe?
No because they already take that into account when they are calculating it. It would also have to be a colossal coincidence(see impossible) that the galaxies farthest from us are also uniformly in mass with regards to distance(regardless of their size).

>Photon has just enough mass for gravity to influence it

That is incorrect. Photons have no mass, the bending of light due to gravity occurs because massive objects distort space-time into a higher dimension.

>>3550076
Op, here. Thank you. Sounds legit to me.

>>3550067
Your concept isn't really wrong. But it's a known effect.
http://en.wikipedia.org/wiki/Gravitational_redshift

>>3550086
Aw sweet, thanks!

>>3550073
>trying to use E=mc² on a massless particle that travels at light speed

>>3550073
i seriously hope you guys dont do this

>>3550067
> Looking to see if anyone can tell me why I may be wrong.

This is how science is supposed to work. gg

>>3550101
>>3550097

NO. You guys are wrong. If you know anything at all you would know photons have momentum.

What the fuck do you think linear momentum is? Mass times velocity.

Photons don't have a real mass, but mass is a fuzzy word with 2 common definitions, and by using E=mc^2 you can assign a mass.

>>3550081
That's not quite correct either. Space-time isn't bent "into another dimension". It is simply bent - bent in regards to a flat, constant (pseudo-)metric.

>>3550073
>relativistic mass

How is life in the 1910's working for you? Why the fuck would you use such an outdated concept?

>>3550133
0/10

And if you're NOT trolling, take this as feedback. You have no clue what you're talking about. I'll prove it if you like.

>>3550193
prove it.

>>3550133
No one uses the concept of relativistic mass anymore, it is terribly outdated, just flat out wrong. It is not taught, nor even fucking mentioned (besides in a history of physics course) in the modern physics community.

It is confusing, and inconsistant with the rest of physics. Even Einstien said it was fucking retarded concept.

When we talk about a photon we talk about its mometum, frequency, wavelength, energy, etc. NO ONE FUCKING TALKS ABOUT ITS MASS, CAUSE AS A PHOTON DOESNT HAVE FUCKING MASS.

Please stop reading such fucking outdated material.

>>3550193
also read this you dumb piece of shit.

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

i got the link by typing "mass of a photon" into google and clicking the first link, just so you know i'm not trying to pull something on you. comes from a .edu

>>3550217
what should i be calling it then?

photons have no stationary mass but they have a relativistic mass so m0=0 but m is not

>>3550219
>highschooler who doesn't know how to research properly

Just stop talking kid, you are only proving your ignorance.

>>3550238
I've looked this concept up on 5 webpages now, which all come it "relavistic mass". Give me a more widely used term, also, whats in a name? WHATS IN A NAME? DO YOU THINK DISPLACEMENT CURRENT OR ELECTROMOTIVE FORCE ARE GOOD NAMES? NO. BUT THEY'RE NAMES.

i just wawnt to interjec here and say the following ... while you can use E=mc^2, u really should use quantum mechanics when refering to photons not relativity ... that's my opinion

waw my post has a too may spelling errors .. please excuse that.

>>3550034
m*c^2 = h*f

You find that pseudo-mass in every good physics book.
umad?

>>3550219
Ah, good, the equation I wanted to point to you is right there. See that "p"? THAT is the photon momentum. And it has absolutely nothing to do with mass. The rest mass for photons is 0, and the relativistic mass is not a very useful concept, especially for photons. In GR, it's not even well-defined.

a ... no no you do not ... i'm not saying it's good .. just possible

>>3550227
The point is, the whole concept of relativistic mass is not fucking needed in any shape or form. All physics is simplier and neater, without such a fucking retarded concept.

A photon has mometum, momentum bends space-time. Hence a photon with mometum (all photons have mometum) fucking bends space-time. It is that fucking simple. All the talk of relativitic mass is not needed to explain anything. Rel. Mass is a fucking useless concept, which leads you to shitty and wrong conclusions (like only massive objects bend space-time).

>>3550290
>relativistic mass
>good physics book

LMFAO. The highschool shit you read are not "good physics books".

>>3550300
fine instead of calling it relativistic mass (which is only a term), i'll call it the "proportionality constant" between momentum and velocity.

as you can see calling something... the "proportionality constant" between momentum and velocity... is somewhat longer

does this work for /sci/?

>>3550386
The proportionality constant for photons is undefined, because the momentum depends on the wavelength, but the velocity is always c.

>>3550386
I don't think you understand the point.
THERE IS NO FUCKING USE FOR THE CONCEPT OF RELATIVISTIC MASS.

No matter what the fuck you call it, you would never need to use it when doing any sort of physics. The information you seek is already fucking encoded in the photons mometum. So, Why make up a superfluous varible? THERE IS NO FUCKING NEED! JUST FUCKING TALK ABOUT THE MOMENTUM!

There is no situation where you would need your "proportionallity constant/relativitisc mass", instead of just using the mometum information. In fact the physics would be much easier if you just used mometum from the fucking get-go (what physicist do!).