Speed of..................gravity!

[Andrew*]

what or how is a photon moving at the speed of light?

light! A photon is a "particle" or unit of light.

Andrew

[kev 102 42]

how is it traveling at that speed?

[narrowbandpaul]

it has to travel at that speed...its a consequence of maxwells equations

[narrowbandpaul]

the speed is 1/sqrt(e_0*u_0)

[narrowbandpaul]

1 over square root of epsilon nought mu nought

[kev 102 42]

1 over square root of epsilon nought mu nought

cheers butty now i understand easy when you know how

[EA2007]

Kev, your welsh aren't you?

Pauline, stop showing off lol, brenda needs you in the kitchen....your making spag-bol tonight with blackhole meatballs, the spaghetti's already spaghettified!! Astrophysics in the kitchen...i like it!

[kev 102 42]

how could you tell im welsh butt moutain man i am.........kev

[EA2007]

the fact you keep calling people 'butt'

I went to uni in Wales....so the lingo caught on a bit. Which part you from?

[kev 102 42]

i knew the butty bit was a bit of a giveaway :laughing3: im from pontypool live just above the base of a moutain we get a lot of cloud,its about25 miles east of Cardiff as they say in Llandow Hwyl am y tro........kev

[Steve922]

Yes, Gravity does have a finite speed. It is <= the speed of light in vacuo.

No, no-one has ever been able to measure the speed.

Unfortunately, I don't know this, these are just my guess about current beliefs based on the small amount which I've read. Newton claimed that gravity is instant. Einstein claimed that nothing, including Gravity can travel faster than the speed of light. But what the original poster was asking is whether or not there is any proof of this.

Can anyone point us to some empirical proof? If not proof, then perhaps some strong supporting evidence; perhaps similar to the evidence supporting the claim that the speed of light is a ceiling.

GREAT question, EA2007. I would love to know the real answer to this. Anyone?

Steve

[Steve922]

As an aside, I believe there is an experiment just starting to try to detect gravitons/gravity waves which is very similar to the famous Michelson-Morley experiment to detect the ether. But on a larger scale! I would think that if grvitons are ever detected it would be a relatively small step further to measure their speed.

Interesting times.

Steve

[Kaptain Klevtsov]

So this gravity stuff propogates at the speed of light, which actually fits in with the bits of ABHOT that I could understand, so it "travels" at less than the escape velocity of a black hole. Now here's the catch, how does the gravity get out, when nothing can get out of the black hole?

It gets wierder, this universe of ours. Lets go back to a flat earth and have done with it!

Kaptain Klevtsov

[Andrew*]

But the gravitational field - the warping of space-time - is created before it becomes a black hole, so before the escape velocity exceeds c. Or is this old hat?

Andrew

[jgs001]

Is this not at least part of what the LHC was supposed to prove ? before it expired in a mass of overheated components that is. There is an interesting phenomena, quantum entanglement, that seems to indicate that when two quantum entangled components/particles, damnably small things (??) are seperated, any state change in one is reflected instantly to the other, implying the "communication" between them is FTL.

[themos]

how does the gravity get out, when nothing can get out of the black hole?

Gravity doesn't have to "get out". Gravity IS the in and the out.

[narrowbandpaul]

the experiment is called LISA..Laser Interfermoter Space Antenna

its a triangular arrangement of spacecraft, firing high power IR lasers.

Launch data is around 2018, if NASA can be bothered.

We have a research group here IGR (institute for gravitational research), who are building and testing components for use on LISA...in fact they are building the actual flying spacecraft! i think

Ally and I should be working on LISA (perhaps testing flexure in the spacecraft walls down to picometer accuracy), as part of our honours project.

[EA2007]

GREAT question, EA2007. I would love to know the real answer to this. Anyone?

Why thankyou, I excel myself sometimes......haha

i knew the butty bit was a bit of a giveaway :laughing3: im from pontypool live just above the base of a moutain we get a lot of cloud,its about25 miles east of Cardiff as they say in Llandow Hwyl am y tro........kev

Ah Pontypool eh, I know where you mean, have a friend from there, she was on my uni course. You ever noticed that its pretty much always raining in the valleys but once you head down to Cardiff the weathers fine ? Odd that!

There's LISA and LIGO. LIGO is already kinda in operation at two sites in the U.S, basically an L shaped contraption with each arm 1 km or so in length with lasers trying to deduce sideways and lengthways movements caused by incoming gravitational waves, however they are having issues closer to home such as the ocean and traffic along with seismic activity affecting the results................hence LISA, which will be in space and not have any traffic jams messing things up (unless that toolbox flies in the way of the beams hee hee!)

[kev 102 42]

i knew the butty bit was a bit of a giveaway :laughing3: im from pontypool live just above the base of a moutain we get a lot of cloud,its about25 miles east of Cardiff as they say in Llandow Hwyl am y tro........kev

Ah Pontypool eh, I know where you mean, have a friend from there, she was on my uni course. You ever noticed that its pretty much always raining in the valleys but once you head down to Cardiff the weathers fine ? Odd that!

i worked in Cardiff its a couple of degrees warmer than than the valleys,were you in Cardiff uni?

[supernova]

WOT is Gravity & what creates it ??

[EA2007]

The graviton is supposedly whats behind gravity.

Back in the good old days (just a few nanoseconds after the big bang) the forces were created, those being:

the 2 electroweak forces of 'electromagnetic' & 'weak'

the strong force

and gravity

gravity however is the weakest of all four forces!

If your a Jedi or Sith then of course there are many more forces including the 'push', 'pull', 'speed', 'seeing', 'lightening' and 'heal'

[supernova]

I thought the Earth sucked.

[an1mal astronomer]

Hi Ian here is my message..

First begin by knowing what is gravity. Gravity is the mutual attraction of objects about each other and in other words is the force of attraction that exists between all particles with mass in the universe. Well it is true that gravity has a speed but it's all very concerning because changes and masses of particles and energy from stars to planets so. Soon it would be very uniform know the speed of gravity in a black hole for example the speed of escape (320000m / s) exceeds the speed of light (around 300000m / s). For example if you were on Mars the force of gravity was different, the earth and mercury too. The matter black or invisible matter is not explicitly for sure but it has a high density and gravity exerts on other bodies such as the galaxies since this component comprises 90% of the mass of the universe and 23% of the energy that once the gravity is something very Very concerning if you wanted to calculate the value of gravity on earth was very difficult to measure because you approach the core of the planet and the severity will be greater if you throw in a building the speed of gravity is increased as the weight to fall on earth will be something like 20 times your weight when you fall. So to learn the value of gravity is very difficult if not virtually impossible because many factors have been around this. We managed to learn the speed of a black hole because the speed at the core of this and exactly the same as if it were a little further because it is very items. And finally something simple such that we still have strength in space because gravity that we have bodies who exercise power over each other or energy. As we depart from energy to gravity force will become increasingly void as it is close to zero forces. I hope I have helped John Christ.

[Steve922]

Its like a little puzzle, isn't it?

Steve

[acey]

I think we need some help from Mr Rubik.