Science type people (not you Aster) read this!!

[Czar]

I never quite got relativity. I do understand how you can overtake light that left Earth a hundred years ago and then look back at it to see what it reflected off of. That's the same principle as overtaking a car that left five minutes before you. Easy.

I know why it might look like you travel in time. I just don't get why you actually do.

- Joel Fagin

Of course, you can't actually overtake light that left Earth a hundred years ago to look at what was reflected off of it, since you can't travel faster than light (according to our current understandings of the laws of physics).

There is also causality.
Which I definitely don't understand.
(What I've got so far, which quite possibly is wrong, is that some times, due to relativity, an independent observer may see the effect occuring before the cause. A big no-no in any physical context. Causality is complex because it needs to explain why this occurs/cannot occur. Or something.)

[Risky]

I always liked the theory that relativity "works" because, as you get close to the speed of light, since the passage of time is just the movement of particles, those particles suddenly have the inability to move "upstream". So everything moves slower than it would. Your flashlight only works in one direction. Stuff like that. You can't walk forward in a vehicle going at the speed of light. Neither can the atoms move forward, neither can their particulates.

So stuff "slows down" since it is bumping against the theoretical limit of how fast it can go.

[AsterAzul]

This is a spacetime graph like the ones we use to explain causality.



Really, all it says is that if an event can't reach you at light-speed then as far as you're concerned it doesn't happen until it does get to you.
So stuff in the past that's light years away in space doesn't affect you, and you can't affect the next five minutes of the future of an alien race in Alpha Centauri.

[Wp]

The experiment was indeed done. However, for a more conclusive look, it was redone on the Space Shuttle. It's also been done in race cars, jets, sattelites (GPS systems have to regularly correct for differences in time due to dialation), etcetera. Every single mission we have sent outside earth's orbit has had to account for this effect. Every communications sattelite in orbit has to account for this effect. Supercolliders have to account for this effect. Every GPS system has to account for this effect.

Even at small differences in speeds (500mph, 2000mph, 20,000mph...) there will be a real difference (albeit tiny) between two clocks. When that difference becomes important is when the timing is critical.

The effect is entirely, unquestionably real and verified.

Hey, rkolter. I heard about another experiment trying to confirm one of Einstein's calculations. It had something to do with the precession of objects in rotation and in orbit. Do you have any idea what I'm talking about? I can't remember quite clearly, but scientists made a perfectly (almost) spherical ball and sent it in orbit around the sun or something, and it precessed the exact amount as calculated by his equations.

[Czar]

Helpful explanation.

That actually makes sense.

I think. I wouldn't ask me to explain it to someone though (which is how I measure my ability to grasp a concept. If I can explain it, I've got it).

[Rkolter]

The experiment was indeed done. However, for a more conclusive look, it was redone on the Space Shuttle. It's also been done in race cars, jets, sattelites (GPS systems have to regularly correct for differences in time due to dialation), etcetera. Every single mission we have sent outside earth's orbit has had to account for this effect. Every communications sattelite in orbit has to account for this effect. Supercolliders have to account for this effect. Every GPS system has to account for this effect.

Even at small differences in speeds (500mph, 2000mph, 20,000mph...) there will be a real difference (albeit tiny) between two clocks. When that difference becomes important is when the timing is critical.

The effect is entirely, unquestionably real and verified.

Hey, rkolter. I heard about another experiment trying to confirm one of Einstein's calculations. It had something to do with the precession of objects in rotation and in orbit. Do you have any idea what I'm talking about? I can't remember quite clearly, but scientists made a perfectly (almost) spherical ball and sent it in orbit around the sun or something, and it precessed the exact amount as calculated by his equations.

Frame dragging; another reprecussion of Einstein's. In the most basic of terms, any rotating object in space should pull space along with it to some degree. Imagine pushing a rotating drill into a sheet of cloth. The cloth spins up with the drill.

Now, the Earth's effect should be amazingly small, but still present. And that sattelite is attempting to detect it.

[Rkolter]

Well, you can study relativity all you want, but to have it make intuitive sense to you is really, really hard.

Not if you're a real, real geek. It made sense to me from the start. I still don't understand all the math behind it though.

I'm posting again to point out that Aster's chart and description is accurate and insightful. Which sucks eggs, because it's far more appealing to me to poke fun at him. But, what can ya do? *sigh*

I went out to find Einstein's original thought experiment on relativity, and the first dozen sites are all pretty poor examples. It comes down to this:

Imagine you are chasing a beam of light, and that you are moving just as fast as it is. Then you would expect to see the light stable in front of you, with it neither retreating from you, nor you advancing on it. That's essentially the same as saying the light is not moving at all.

But, this is not what light does. It does move. And it moves at the speed of light away from you, no matter the reference. So, if you're standing still, light moves away from you at the speed of light. And if you're moving at the speed of light, light will move away from you at the speed of light. BUT, if you're standing still and watching someone chase a beam of light at the speed of light, they will appear to chase each other, the gap not growing or diminishing.

Now, Aster's graph shows another feature - that nothing, even (or especially!) information, moves faster than light.

This means that the Sun is several minutes away from us, at the speed of light. If the sun were to suddenly vanish, there is a several minute "queue" of light, headed our direction. Without the sun, there'd be no gravity there either - and gravity propogates at the speed of light. So, there's a several minute "queue" of gravity on it's way towards us. If the sun were to vanish, we'd first know when our closest sattelite recorded the event. Removing the sun does not remove it's presence from the entire universe instantly, but rather at the speed of light.

Which if you think about it makes sense. Ever watch the space shuttle take off? You see it take off and start to rise, and THEN you hear the roar. Light travels faster than sound. So, that doesn't mean there wasn't sound... just that the sound hadn't reached you yet. Light doesn't move instantly, but instead at a tremendously high (but not infinite) rate of speed. So just as sound takes time to get to you, so does light. Ditto lightning - you see the lightning, then feel the thunder.

Since no information can travel faster than the speed of light, no knowledge of an event can travel faster than light. Thus, if Mars decides to attack us, it will take minutes for the knowledge of their ships departure to reach us.. Or to put it another way, when we see their ships launch, they will have ALREADY launched.

... now, quantum entanglement is cool stuff... apparently some things do travel faster than light - such as the change in spin of a particle when the particle's entangled twin has it's spin changed. Currently we haven't been able to transmit data though this means, although up to five particles have been entangled in the lab... if they get to eight, they could do seven bits and a partity bit... but that's something else entirely.

[Risky]

Yay, cesium quantum leap transmitters!

[[AlmightyPyro]]

wow... this all makes since even more now.

Thank you RKolter for you awsome science!

Bill Nie has NOTHING on you! ... well he does have sound effects.

[AsterAzul]

*posts again after Risky and Pyro*

For posterity's sake, of course.

[[AlmightyPyro]]

*posts again after Risky and Pyro*

For posterity's sake, of course.

lol

[Joel Fagin]

Now, Aster's graph shows another feature - that nothing, even (or especially!) information, moves faster than light.

Except monarchy.

(Terry Pratchett reference.)

I still don't understand, by the way, but I wouldn't worry about it.

- Joel Fagin

[Aster Azul]

Now, Aster's graph shows another feature - that nothing, even (or especially!) information, moves faster than light.

Except monarchy.

(Terry Pratchett reference.)

I still don't understand, by the way, but I wouldn't worry about it.

- Joel Fagin

And bad news.

(Douglas Adams reference.)

[Joel Fagin]

Except monarchy.

(Terry Pratchett reference.)

And bad news.

(Douglas Adams reference.)

It's harder to modulate bad news to create data transfer, where as torturing the King modulates a monarchy quite well.

- Joel Fagin

[Aster Azul]

Well, we did try to create a communications system that ran on bad news, but it was unwelcome wherever it went.

Monarchy is more useful as a communications system. You send a bunch of princes to a far off galaxy, and then you can kill their fathers in different combinations in order to send instant messages to the colonists.

[Alschroeder]

Ok my brother was telling me about an experiement 'They' 9the people that do those sort of things) did trying to prove the Einsteins theory that if you travel at the speed of light time stops, or whatever.

Essentially, they got two super fast jets to fly around the world in opposite directions (refueling in air ofcourse) at 500 miles an hour. Each Jet had an atomic clock in them (the ones that never get off) and there was one atomic clock at the starting point in Washington. all in all when the whole deal was over the clocks were off set by a fraction of a millisecond. (which is still quite a bit of time speaking in science type terms. <_< >_>)

Has any one else heard this or is it something some one made up and told my brother?
RKolter, I'm looking your way...

It's true. Guarenteed.---Al

[Rkolter]

wow... this all makes since even more now.

Thank you RKolter for you awsome science!

Bill Nie has NOTHING on you! ... well he does have sound effects.

I'll work on that. Bzzzzap! Fizzdangle! Uhm... POP!

[Noxmeansxno]

wow... this all makes since even more now.

Thank you RKolter for you awsome science!

Bill Nie has NOTHING on you! ... well he does have sound effects.

I'll work on that. Bzzzzap! Fizzdangle! Uhm... POP!

And somebody needs to create an infinitely annoying theme song for ya' too.

[Wp]

Thanks, rkolter. That was bugging me a lot more than it should have.

[Rkolter]

Thanks, rkolter. That was bugging me a lot more than it should have.

Science: It's like that incessant ringing in your ear that you just can't ignore or get rid of.