Speed of light isn't a certain speed is it?

It's said that as something approaches the speed of light, that it's mass increases to infinity. So they say that the photons of light themselves have no mass, to explain why they can move at the speed of light without having gravity themselves; but here's my question. If they don't have mass, how does gravity affect them as it often does. Pictures of deep space show what I think is called a gravity lense, where gravity from a supermassive object bends light around the object. Wouldn't that imply that photons have mass? And since gravity obviously effects light, then shouldn't the speed of light vary constantly? If light leaves a relativly low-mass star, the gravity of the star pulls on the photons as they leave (slowing them down slowly). But should the light head directly towards a super-massive star, shouldn't it pull the light in, eventually pulling the light to faster than the 'speed of light'?

[edit on 23-1-2005 by mdcclxxvi]

The Photon-Mass Relationship

As for gravity affecting light, that's where the idea of gravity simply being a 'bending' of space comes in.

There have been several light/mass/photon topics on here. I would suggest those interested read this thread:
www.scienceforums.net...

It covers everything I've seen posted, including why things actually don't obtain mass as they reach the speed of light (rather it is impossible to reach the speed of light if you have mass), and that the only way to reach the speed of light is to have no mass (at rest - like a photon!)

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A gravity lens works because the light around the edges of the warp in space [that would otherwise miss Earth] are focused at the Earth. A ring of light is more than the theoretical standard point of light. [doughnut is more than the doughnut hole]

Your question does make me wonder about light. Maybe one can think of it as [semi?] rigid lateral struts of the Universe. Forcing the stretch of space down into gravity wells. Maybe that is what gives space its surface tension.

Also since time slows somewhat in gravity wells, it might imply the the flow of time is perpendicular to the flat [low-zero gravity] regions of space. And where the stretch of the Universe is more parallel to that flow [streamlining on an oblique angle] the passage/flow of time is somewhat evaded.

If light is indeed a [semi?] rigid strut of the Universe, I wonder if you focus light from all points of a sphere at the central/mass-less point in flat space if you could create somekind of inverse warp that went the opposite direction from gravity warps. ie. create a 'white hole' in space and see what it's properties were.

edit spelling

[edit on 24-1-2005 by slank]