The Theory of Everything

[Micilin]

The "light" that one views things by is imagined anyway. So Your argument is spurious.

The reflected light is real but our interpretation of it is different .

 

[Brigadier]

But the sun is not losing mass through emitting light, I believe......

Light is just a small part of the energy released in nuclear fusion, but it is part of it.
Put simplistically, two hydrogen atoms fuse to create one helium atom, which weighs slightly less than the two hydrogen atoms. The missing mass is converted into energy right across the spectrum from radio waves to gamma waves in accordance with E=MC2, visible light is part of that so I reckon the sun is losing mass through emitting light.

...but the light itself doesn't have any mass (photons are massless, but have momentum - as per one of the links I posted earlier)

 

[noseall]

So if a ball bounces off a wall the ball has zero mass???

No, in the same way it can't have mass one minute and not the next.

The ball always has mass.

The light never had mass.

 

[sooey]

The light never had mass.

Are you sure about that?

Ever heard of solar sails?

 

[noseall]

The light never had mass.

Are you sure about that?

Positive. Anything that travels at that speed can not and does not have any mass.

 

[Dextraneous]

Solar sails work by them being of energy. They don't necessitate mass

 

[sooey]

The light never had mass.

Are you sure about that?

Positive. Anything that travels at that speed can not and does not have any mass.

How do you know?

 

[sooey]

Solar sails work by them being of energy.

What does that mean?

 

[noseall]

Positive. Anything that travels at that speed can not and does not have any mass.

How do you know?[/quote]Because we would all be dead.

At light speed mass becomes infinite.

 

[Brigadier]

The light never had mass.

Are you sure about that?

Ever heard of solar sails?

...but the light itself doesn't have any mass (photons are massless, but have momentum - as per one of the links I posted earlier)


Counterintuitive, but the photons create a driving force on the sail (transfer of momentum?), but without the photons having any mass.

 

[sooey]

As far as I understand it, you can't have momentum without mass.

 

[Brigadier]

http://science.howstuffworks.com/solar-sail2.htm

The reflective nature of the sails is key. As photons (light particles) bounce off the reflective material, they gently push the sail along by transferring momentum to the sail.

 

[sooey]

The reflective nature of the sails is key. As photons (light particles) bounce off the reflective material, they gently push the sail along by transferring momentum to the sail.

But momentum is a product of mass times velocity, so for light to have momentum to transfer it must have a little mass.

 

[peterchichester]

They have mass as in energy, essentially the same thing, but they have no mass if not moving. Not that they can not move.

 

[sooey]

So you're saying that they have mass when moving? They being photons.