[XMark]

Okay, it's fairly widely accepted that the speed of light is the maximum speed that anything can travel, so when the human race expands across the galaxy they're going to have to wait thousands of years for communication to go between stars and stuff (unless some faster-than-light hyperspacey kinda thingy gets discovered)

But what about gravity? Does the effect of gravity (or magnetism) have a speed limit? Like if a massive gravitational anomaly were to suddenly appear a light year away would we feel it instantaneously or would gravity itself have to obey the speed limit?

If it's instantaneous, some kind of high-power gravitational generator thing could be used for instantaneous communications across large distances. Of course, it would require a ridiculous amount of energy but it's a thought. (though a totally random one at that)

Anyway, return to your daily routines. Nothing to see here.
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Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!

[Ninkazu]

I'm sure that attractive forces have nothing in common with the restrictive properties of projectile motion. I'll talk to my physics teacher about it tomorrow, but ya.

t = sqrt(1 - v/c)

So if velocity is over the speed of light, then you have a square root of a negative and that's impossible. You'll notice that you need to go insanely fast to just get a little bit off the relative timeline.

[tcaudilllg]

How to say it: gravity has a speed limit, and it doesn't.

It has an "interval range", because gravity is inertia is matter is energy, says relativity. The earth's gravity has a range of lightspeed 'c' (186,000mps as you may know) because whatever energy that is affected by its gravity can only move at that rate, so the only way to measure gravity is by the energy it effects. Experimentally then, gravity can only be shown to "travel" at 'c'.

The interesting thing is, you can't isolate the path of a gravitational force. You can determine its location, certainly, but not its path because as general relativity shows, spacetime fabric is distorted by the matter in it. Spacetime distortion (called by Einstein the general relativity "metric") draws material objects together and bends lightwaves, or, if the distortion is broader than 186,000 miles, it can trap them in a "black hole".

I've tried to model the universe in terms of the propagation of light and the force of gravity being the same force from different angles. Maybe it may make things clearer to see it in the macro, as opposed to a "local" example like you'd see in a textbook.

http://unitedinfinity.atspace.com/Projects/JS/Physics/SimpleCosmosJS.html

[Ninkazu]

Wow... I guess I need to take some college physics courses o_O

[bay]

see science and physics are a bunch of bs, because they are based on these ideas of numbers that dont change or can't change.

such as many problems in physics are "this and this when in a closed system with no outside forces, yada yada" which is completely useless. its to make the problems actually fit in nice equations, which for the most part may be exhibited as correct on earth.

the main thing is that light might be able to be slowed... (doesn't travel at a constant speed or rather, it can be slowed down.) i wish i had the reference onhand, but it was a cool read.

i won't argue vehemontly for this point because i dont have the reference backing, but don't take everything you read in books anywhere as complete truth.

just remember, before science came around to this idea of what we consider the environment we live in, there was something called the "ether" that surrounded us..

not to mention until it was proven otherwise, the earth was flat and the sun revolved around the earth.

we're just in between changes in what science tells us.

.02$

[tcaudilllg]

Right now there seems to be a debate going on about what light "is": a wave, or a particle? General relativity only works with the wave version, and with the particle you don't need general relativity at all.

[Adam]

It's all strings baby!
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https://numbatlogic.com

[biggerUniverse]

Oh, you're one of THOSE people... Anyway, QM and String Theory both work, just at different scales.

When I look at Quantum Physics, I have the sinking feeling that it is too simple... Light, Mass, Energy, Gravity. Why does that seem like Air, Earth, Fire, and Water to me? They aren't directly synonymous, but the point is that perhaps the model is too simple. This is of course only philosophical, and has no mathematical basis- it's really just instinct.

Here's a curve for you: what is the speed of time? If time were to go slower or faster, how would we know? When you're on a moving train with the windows shut, you can't tell how fast you are going- you need a reference point that is outside the train. In time, we have no reference point, and therefore, we can't know if time itself is any faster or slower at any given point.
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We are on the outer reaches of someone else's universe.

[Joakim]

It's old news that you can slow light down. c is just defined as the speed of light in complete vacuum.

And if you do not isolate the subject of your theory, it's impossible to make a equation or formula that can be used in more complex systems later on.

Anyways, we do have reference points in time. For example, Earth travels faster through space than the sun, which means that time is a tiny bit faster on the sun in relation to on the earth. And for a proven example, time is proven to be slower in satelites orbiting Earth than time is on the earth.

But of course, if time in general became faster, we would have no idea because of the lack of reference points as you stated.

[XMark]

Yeah, I read a bunch of stuff about light speed at the back of my highschool physics textbook. Apparently the closer you get to the speed of light, the slower time goes for everything around you. But at the relatively low speed that satellites go the time difference would be something like 1 second in a year.

Now, I know I read the answer to this question but I forgot what it was: how do you deal with the question of two flashlights facing away from each other. In relative terms, isn't one beam traveling at twice the speed of light compared to the other?
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Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!

[Verious]

[BadMrBox]

...
I know I shouldn't but...
'Beam me up Scotty!'

Well, that was a mature add to this discussion.
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[LeoDraco]

[XMark]

Beam me up Uhura.
_________________
Mark Hall
Abstract Productions
I PLAYS THE MUSIC THAT MAKES THE PEOPLES FALL DOWN!

[tcaudilllg]

I have a sort of skepticism over anything that goes faster than 'c'....

Now I can imagine a system in which information can be inferred, because in a generally relative universe, like the one Einstein implies in Relativity: The Special and General Theory, starting at one point and traveling the length of the cosmos brings you back to your starting point. So by treating the universe like a matrix that loops back onto itself (like writing more than 65536 bytes to a single RAM segment, or going over the limit on an odometer) one can infer how changing something at one end can change something on the other. (on an astronomical scale, at least)

However, it seems to me, that if you look at light as a series of photon transmissions between atoms (and why not, when you need an atom to detect its existence) then it stands to reason that cold temperatures, like those that have been demonstrated to slow light propagation, may not actually slow the velocity of photons in space at all, but rather may have a bearing on their rate of absorbtion and release by the atoms they come into contact with. If there is a tangible delay period between the instant that a photon is absorbed by an atom and the instant in which it is released by it, then it seems to me that the bottom falls out from under modern physics.