It is proven. Gravity expands at speed of light

[Zero]

Originally posted by Azazel

With my humble knowledge I see a problem to describe the wavelike features of a graviton according to the de-broglie equation, because the wave's frequency is a function of the particle's mass. But do gravitons have mass? I don't think so.

Alva you're not alone. I am clearly not the one with most knowledge...

Anyway I'd like to humbly refute this with my humble knowledge as well. What about light?

[Zero]

Originally posted by Azazel
I find it cool. I would have done physics if I had a chance to work in cosmology or as a nuclear physicist. sadly I didn't. I wanted to go to biochemistry to cure cancer, and stop aging. The army didn't let me. Now I am in Chemistry, to make better Shampoos. I envy you, Richard. ( OMG, I don't believe I've just said it.... j/k )

So thats where all chem majors go. Working for herbal essence.... Nooooooo!~~~~~

[Az]

good question, one second.

[Az]

ok, Guess what? It appears that photons have mass after all.
a quick googlesearch has came up with the following link:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html

Now, being scientists, we do not just accept theories like general relativity or conclusions like photons have no mass. We constantly test them, trying to definitively prove or disprove. So far, general relativity has withstood every test. And try as we might, we can measure no mass for the photon. We can just put upper limits on what mass it can have. These upper limits are determined by the sensitivity of the experiment we are using to try to "weigh the photon". The last number I saw was that a photon, if it has any mass at all, must be less than 4 x 10-48 grams. For comparison, the electron has a mass of 9 x 10-28 grams.

well, what do you know....

[Zero]

you learn something new everyday.

Btw. Thats awfully small~ wow...

[Az]

I just have to take quantum physics.

IIRC, btw, they've actually managed to freeze a light beam a couple of days ago. I really want to read about that.

back on topic.....

[reds4ever]

Originally posted by Lars-E
The stuff I read (sorry no link) talks about huge differences in the speed of light. Much faster before. It might have declined gradually.

i saw a docu on this about three years ago, it was some young scandanavian (i think) physicist who was working in the UK. Sorry can't remember much more, i'll try and be a bit more vague next time

[Az]

Calc II: I keep looking for sources, and all they say is 'no it doesn't have mass, probably'.

[TCO]

Re: It is proven. Gravity expands at speed of light

Originally posted by Tripledoc
Gravity expands at speed of light

It was proven today that gravity expands at the speed of light. This proves Einsteains theory. newton was convinced that the speed of gravity was infinite. The speed of gravity has until now been an unknown constant.

It was discovered that the planet Jupiter would pass by (as seen from earth) the quasar JO842+1835 on september 8 2002. This meant that radiowaves from the quasar would be slightly bent as they passed the gravitational pull of Jupiter on their way to earth. the signal was picked up by the Very Long Baseline Array, a collection of large radio recievers on Earth placed in Hawaii, United States and Germany.
The accuracy of the experiment compares to measuring the thickness of a human hair as seen from a distance of 400 kilometres.

Until know gravity has been the great unknown and it is thus a step forwards towards a total and collective understanding of laws of the universe.

Are you sure that this experiment proves the speed of propogation of gravity. Or does it just prove that light is bent by gravity. (something shown in other experiments).

If it does prove what you are saying, could you explain a little more how? Thanks.

[Provost Harrison]

Yes, I was not sure how this was supposed to relate to the speed of propagation of gravity...

[TCO]

Originally posted by Azazel
the de-broglie equation says that all things have wavelike properties. The smaller the particle is, the more it is relevant. For example, contrary to what many people think, you can't see the electrons mooving around the nucleus in nice circular patterns. The electron is actually a cloud around the nucleus. That cloud takes different forms, for different atoms ( long story to explain ). for hydrogen for example, there single electron forms a cloud of probability, with the highest probability to find him being near the nucleus. That cloud never ends, though, so there is an infinetly small chance that electrons from your body are now actually in the alpha centauri system (!)

With my humble knowledge I see a problem to describe the wavelike features of a graviton according to the de-broglie equation, because the wave's frequency is a function of the particle's mass. But do gravitons have mass? I don't think so.

There is a certain place where these things get metaphysical, but I think you can think of the electron not as a cloud but as a particle with indeterminate location. The "cloud" that you draw is a representation of the probability function across space. But not necessarily a smear of electron. (but this mayjust be a descriptional difference...)

[TCO]

Originally posted by Azazel
ok, Guess what? It appears that photons have mass after all.
a quick googlesearch has came up with the following link:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html

well, what do you know....

Shouldn't it have a mass by relativity? e=mc^2

E =hnu


m = hnu/c^2

[Dauphin]

I very much doubt that gravitons exist.

[Dauphin]

Originally posted by GP


Shouldn't it have a mass by relativity? e=mc^2

E =hnu


m = hnu/c^2

E^2 = p^2c^2 + m^2c^4

[Graag]

*head explodes*