things without mass

[sooey]

By way of light relief from all the cr*pola on here lately :
I heard a prof on the radio today saying that the "c" in E=MC ² Doesn't really stand for the speed of light, but the speed of things with no mass. This got me wondering why things with no mass should all go shooting around at a zillion miles an hour. What propels them in the first place?

 

[joinerjohn]

The C in Einstein's famous equation really does stand for the speed of light though. Albeit, the speed of light in a vaccum (light slows down when passing through different mediums eg glass,air,water etc

 

[imamartian]

excellent question.... but what i don't get is how can anything not have mass? eg a photon? how can it exist without any mass?

And surely what propels these things is the energy from nuclear fusion or fission reactions?

 

[PrenticeBoyofDerry]

I thought it was a song by Big Audio Dynamite
If you read the lyrics to it, I don't know which is the easiest to understand
Einsteins theory or
the song

 

[imamartian]

hmmmm interesting post and partial post deletion here!!!

 

[Blasphemous]

That time our priest was arrested we had no mass.

 

[^woody^]

Whenever I try and get E to equal mc2, it always comes out as E=mc^3 instead.

Have a go and see what you come up with

 

[PrenticeBoyofDerry]

Surely the correct formula would be
N=PC²

 

[noseall]

A beam of light has no mass.

 

[WabbitPoo]

Begs the question - what is mass, or what gives rise to it? IIRC they reckon some sort of uber-tiny fundamental particle gives rise to mass. Read a book on it ages ago, but instantly forgot it as soon as the book was finished!

 

[sooey]

The C in Einstein's famous equation really does stand for the speed of light though.

Yes, but the point is, it stands for the speed of anything without mass, not just light. Gravity waves are another example I think.

Begs the question - what is mass, or what gives rise to it? IIRC they reckon some sort of uber-tiny fundamental particle gives rise to mass. Read a book on it ages ago, but instantly forgot it as soon as the book was finished!

It's the higgs boson or something, that's what they are trying to detect at cern.

 

[joinerjohn]

A beam of light has no mass.

All depends whether you treat "Light" as a waveform or a particle.
Scientists have shown that light does exert pressure on the objects it shines on to, therefore, if it has no mass at all, it can't exert any pressure on anything. All Einstein has shown by his famous equation is that light has an equivalent mass.

 

[sooey]

Scientists have shown that light does exert pressure on the objects it shines on to

Are you sure they're talking about light, and not the solar wind? Charged particles given off by the sun.

 

[geraint]

That time our priest was arrested we had no mass.

i bet he did,,,,

 

[geraint]

A beam of light has no mass.

but it has energy.. so is that a mass