A Conversation for Time Dilation
Uncle Ghengis Started conversation Aug 28, 2002
One idea, that is rarely discussed is 'what is the speed of Gravity' ?
Apparently, the speed of gravity is much FASTER than light.
But what does it mean to say 'the speed of gravity' ?
If you look at the sun (not a good idea in practice, you would blind
yourself!) then you see where it was 8 minutes ago. (Taking Earth as
our frame of reference.) The light has taken 8 minutes to get from
the sun to Earth. However, the gravitation pull on the Earth is not
in the same direction as the light. Apparently, the pull of gravity
from the Sun is in the direction of where the Sun is "NOW"...
Uncle Ghengis Posted Sep 6, 2002
Or is it ??
Apparently Einstein reckons the speed of gravity to be equal to the speed of light, but an experiment is planned to find out for sure...
b9nr515 Posted Jan 21, 2003
Assuming, say an asteroid is falling towards the moon. Wouldn't it be traveling at the speed of gravity. If so than gravity cannot be equal to light.
Researcher 218837 Posted Feb 10, 2003
Well usually I close my eyes, or at least squint when I look at the sun. Sometimes I have my shades on.
But, isnt light a waveform and gravity a force. The force can be with you much sooner than the wave. Ask a surfer.
Cefpret Posted Feb 10, 2003
> Assuming, say an asteroid is falling towards the
> moon. Wouldn't it be traveling at the speed of
> gravity. If so than gravity cannot be equal to
No, it doesn't travel at the speed of gravity. Gravitation simply accelerates it. The gravitational field is there, and the asteroid cruises through it.
> But, isnt light a waveform and gravity a
Light consists of electromagnetic forces only.
> The force can be with you much sooner than the
> wave. Ask a surfer.
No, it can't. As long as light or gravitation haven't arrived, they can't cause action.
Gravity propagates at the speed of light in current physical model.
b9nr515 Posted Feb 11, 2003
Got it. Until the
>Gravity propagates at the speed of light
Wouldn't that mean that gravity is traveling at the speed of light?
Researcher 224872 Posted Apr 13, 2003
The graviational force travels at the speed of light, but it depends on the mass of the object exerting that force, i.e. the moon, that decides the speed of the object moving towrds it. If you two large mass objects, stars, they would move towards each other much faster than two lesser mass objects. What i'm trying to say is that the force travels to the object at the speed of light, but the object travels towards the force at a speed depending on the mass of the initial object.
Researcher 247536 Posted Sep 24, 2003
Gravity is just a warping of 4D space time. You can think of space-time as like a trampoline, any object dents space-time. The effect of gravity is just any object falling into this "valley". Rather than being pulled towards the sun the Earth is "rolling" around the rim of this valley. Therefore the effect of gravity is always being felt because it doesn't have to travel anywhere. Also the acceleration due to gravity depends on the mass of the object "excerting" the force
Mort - a middle aged Girl Interrupted Posted Sep 24, 2003
Hi researcher 247536
Welcome to h2g2,
You need to do is activate your personal space (that’s your ‘homepage’) and you can do this by using the 'edit page' button on the rhs of the page or by clicking on this shortcut >> <./>UserEdit?masthead=1</.>. Just type anything – even just hello to start off will do, and click update. Once that is done a friendly ACE, like myself will drop by your page and leave a welcome message with some tips and hints to get you started!
b9nr515 Posted Sep 24, 2003
Let's back up here people:
Post 1: the speed of gravity is much faster than the speed of light
Post 7: gravity propagates at the speed of light
Can we make up our minds here?
224872-One of the variables of the speed of an object accelerated by gravity include the mass and not just the gravity produced thereof. Meaning that two objects with large mass will travel towards eachother at the same speed as two smaller objects that are perportional.
Cefpret Posted Sep 26, 2003
Researcher 247536: Please forget the image with the trampoline. I know that it's very popular, but is is equally misguiding.
b9nr515: See http://www.astronomy.net/forums/blackholes/messages/4156.shtml for a clear statement which I can only underline. You can google for more.
b9nr515 Posted Sep 26, 2003
O.k. then, we'll go with gravity travels at the speed of light, no more no less.
Researcher 241371 Posted Sep 27, 2003
Gravity does not travel at the speed of light because it does not travel at all.Gravity is the effect of the fourth dimension.
b9nr515 Posted Sep 27, 2003
The present theory is that gravity effects time, not time gravity and I do have a tendency to agree.
Cefpret Posted Sep 27, 2003
> Gravity does not travel at the speed of light
> because it does not travel at all.Gravity is the
> effect of the fourth dimension.
Well, if you define it this way, there is no travelling in this universe at all. The point is this:
If, somewhere in spacetime, a new, fresh mass came into existence (the how is insignificant here), then it will have effect (=force) on another mass which is one lightyear away after one year.
Gavitational waves (disturbances of the spacetime continuum) propagates at light speed, too.
Key: Complain about this post
- 1: Uncle Ghengis (Aug 28, 2002)
- 2: Uncle Ghengis (Sep 6, 2002)
- 3: Cefpret (Sep 6, 2002)
- 4: b9nr515 (Jan 21, 2003)
- 5: Researcher 218837 (Feb 10, 2003)
- 6: b9nr515 (Feb 10, 2003)
- 7: Cefpret (Feb 10, 2003)
- 8: b9nr515 (Feb 11, 2003)
- 9: Cefpret (Feb 11, 2003)
- 10: b9nr515 (Feb 12, 2003)
- 11: Researcher 224872 (Apr 13, 2003)
- 12: Cefpret (Apr 13, 2003)
- 13: Researcher 247536 (Sep 24, 2003)
- 14: Mort - a middle aged Girl Interrupted (Sep 24, 2003)
- 15: b9nr515 (Sep 24, 2003)
- 16: Cefpret (Sep 26, 2003)
- 17: b9nr515 (Sep 26, 2003)
- 18: Researcher 241371 (Sep 27, 2003)
- 19: b9nr515 (Sep 27, 2003)
- 20: Cefpret (Sep 27, 2003)