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turk4037
01-08-07, 03:34 PM
I don't get how it works if Photons don't have mass. Can anyone explain this to me?

DONNIE D
01-08-07, 03:48 PM
Chris LeDoux can explain Gravatational Pull!!! Has something to do with being married and sex.

turk4037
01-08-07, 03:50 PM
Yeah, but how does Gravity exert pull on Photons, when they supposedly don't have MASS.

fubar
01-08-07, 03:51 PM
Chris LeDoux can explain Gravatational Pull!!! Has something to do with being married and sex.
You mean it rarely exists?

DONNIE D
01-08-07, 03:52 PM
Just think SEX. If you don't have mass, gravity won't matter.

turk4037
01-08-07, 03:54 PM
But how does gravity lens photons without MASS?

DONNIE D
01-08-07, 04:02 PM
Like Fubar said, or wanted to say, "it bends"

turk4037
01-08-07, 06:12 PM
But how!? You have to have mass for gravity to bend you.

Starr ChamBear
01-09-07, 12:03 PM
Perhaps the gravity is bending matter that the light rides on?

DONNIE D
01-09-07, 12:11 PM
Perhaps the gravity is bending matter that the light rides on?When I stand up, Gravity bends my matter, and I turn the lights off.

macviolinist
01-09-07, 12:52 PM
Turk, 43 is close. Light isn't commonly thought of as "riding" matter, but gravity bends space that light travels through. From the perspective of the light, it is travelling in a straight line, but from a great enough distance, you can see that it is travelling in an arc.

It's useful to visualize Einstein's description of space as a rubber sheet stretched out and suspended. Mass rests on the sheet and causes it to indent, pulling objects near it closer. The denser the object's mass, the deeper the indention and the stronger the pull. Light travels in a straight line relative to the stretched rubber sheet. Relative to an observer, it's path is bent.

This is why light can't escape from a black whole, not because photons have mass, but because it has to follow the path of the space it exists in.

OsoCoreyell
01-09-07, 01:05 PM
Turk, 43 is close. Light isn't commonly thought of as "riding" matter, but gravity bends space that light travels through. From the perspective of the light, it is travelling in a straight line, but from a great enough distance, you can see that it is travelling in an arc.

It's useful to visualize Einstein's description of space as a rubber sheet stretched out and suspended. Mass rests on the sheet and causes it to indent, pulling objects near it closer. The denser the object's mass, the deeper the indention and the stronger the pull. Light travels in a straight line relative to the stretched rubber sheet. Relative to an observer, it's path is bent.

This is why light can't escape from a black whole, not because photons have mass, but because it has to follow the path of the space it exists in.

What about a 3/5 black? Can light escape from one of those? :)

Sorry. Couldn't resist.

Starr ChamBear
01-09-07, 01:33 PM
Turk, 43 is close. Light isn't commonly thought of as "riding" matter, but gravity bends space that light travels through. From the perspective of the light, it is travelling in a straight line, but from a great enough distance, you can see that it is travelling in an arc.

It's useful to visualize Einstein's description of space as a rubber sheet stretched out and suspended. Mass rests on the sheet and causes it to indent, pulling objects near it closer. The denser the object's mass, the deeper the indention and the stronger the pull. Light travels in a straight line relative to the stretched rubber sheet. Relative to an observer, it's path is bent.

This is why light can't escape from a black whole, not because photons have mass, but because it has to follow the path of the space it exists in.

I was thinking of black holes when I came up with my conceptual explanation. Not too shabby I guess for someone whose highest science was Packard Physics.

Starr ChamBear
01-09-07, 01:34 PM
What about a 3/5 black? Can light escape from one of those? :)



Are you thinking of one of those Dreaded Scott Black Holes?

John Shaft
01-11-07, 02:23 AM
Photons have mass when they are being directly observed (they behave like particles). Else they have zero mass (they behave like waves). At least, that's what the "shoot photons through two slits in the wall" experiment apparently proved. Mother Nature is a MAAAAD SCIENTIST at the quantum level.

(That experiment also seems to beg the question that perhaps what we consider matter is only particle-like because it is being observed and would otherwise decay into non-massive waves.)

I'm thinking that if Hawking et al can't really come up with a good answer then I probably won't understand it either. Maybe once we can visualize ten-dimensional (or twenty-six-dimensional) space then it will become clear.

*edit
DOH. We say Photons and I think electrons for some reason. Disregard the above. Has the existence of photons actually been proven, or are they simply a useful analogy for a particle-educated field (like the theoretical graviton)?

LordByron
01-11-07, 06:55 AM
Like Fubar said, or wanted to say, "it bends"Light from a distant star bends when it passes near Old Sol.

turk4037
01-19-07, 09:33 AM
No reason to disregard your post. It is correct. I am still not entirely sure why photons are bent by light since they don't have mass, however, I understand what everyone has pointed out here too.


Photons have mass when they are being directly observed (they behave like particles). Else they have zero mass (they behave like waves). At least, that's what the "shoot photons through two slits in the wall" experiment apparently proved. Mother Nature is a MAAAAD SCIENTIST at the quantum level.

(That experiment also seems to beg the question that perhaps what we consider matter is only particle-like because it is being observed and would otherwise decay into non-massive waves.)

I'm thinking that if Hawking et al can't really come up with a good answer then I probably won't understand it either. Maybe once we can visualize ten-dimensional (or twenty-six-dimensional) space then it will become clear.

*edit
DOH. We say Photons and I think electrons for some reason. Disregard the above. Has the existence of photons actually been proven, or are they simply a useful analogy for a particle-educated field (like the theoretical graviton)?