Time and Space

[evman150]

Really it just went from one nerdy topic to another nerdy topic.

As for your original question, google or wiki "Lorentz contraction". The Lorentz contraction is the mathematical basis/result for/of special relativity.

[troutman]

Originally Posted by Azure

So....had a discussion on this with someone else.

Still not sure how exactly it works.

Say, if I traveled to Pluto and back at the speed of light, and it took 'x' amount of days, how would that be relative to the amount of 'time' it took to come back for someone here on earth who was keeping track?

....in the simplest words possible of course.

Pluto is 30.993 AU from earth today

1 AU = 149,597,870.691 km

speed of light = 299,792,458 m/s

by my math, I think it takes light 4.3 hours to travel from Earth to Pluto (at other times it is 5.5 hours).

x = 0.36 days (round trip)

[photon]

Originally Posted by evman150

As for special relativity, it's not that hard once you wrap your mind around it. When you go fast, time slows down, length gets contracted.

Talking about (massive objects) going the speed of light is not very productive. It just ends in infinities and singularities, nothing substantive.

I've got a question that I'm almost afraid to ask, I think it really shows I don't truly get the implications of no absolute frames of reference.

Basically they were saying that the whole idea that the universe is expanding was just one way put things that helped put things in a context and introduce the concept to people, but really it was equally valid to say the length of everything was contracting, and in reality neither is really "real". Then they started talking about co-moving coordinates I think and I was totally lost.

What the heck were they talking about. I'll dig out the thread if I can find it, it was on a pretty big physics forum (I can't remember if I saw it on BA's forum, or if it was linked from there).

[Ford Prefect]

Originally Posted by photon

Simplest words, you can't. Traveling at the speed of light would take infinite energy and you'd weight an infinite amount.

If you could for you the trip would be instant because at the speed of light there'd be no time passing, and for an external observer the trip would take 10 to 20 hours or so, depending of course where earth and pluto were in their respective orbits.

The faster you go, the slower time passes for you.

Well, that explains what 4x4 is doing out there in the Deerfoot left lane. He's just trying to be immortal.

[Blaster86]

Originally Posted by DementedReality

my head hurts

I think he called your mom fat =|

[4X4]

Originally Posted by Ford Prefect

Well, that explains what 4x4 is doing out there in the Deerfoot left lane. He's just trying to be immortal.

Finally someone who understands.

[ricosuave]

I thought that this thread was about simpson talking about regher and his taking the thread title away...

[BlackEleven]

The relationship between time and space is mostly easily explained as the two things your girlfriend tell you she needs from you when she is sleeping with someone else.

[REDVAN]

Originally Posted by 4X4

Finally someone who understands.

I'm 47 going on 24. Why do you think I drive so fast?

But on topic: yeah, it is theoretically true that you can never go the speed of light because as your speed increases, you need more energy. I also heard somewhere that the faster you go, the larger you get... so as matter approaches the speed of light it gets infinitely large. Not sure about that one.

If humans are ever going to travel across the universe, there are IMO two possible ways: 1) transform into light... weird? or 2) Create wormholes and bend space-time. Neither of which are very likely in anyone's lifetime.

[flylock shox]

Originally Posted by worth

As Photon said, you can't travel at 100% the speed of light. You can only approach the speed of light, meaning 99.9% (repeating).

If you read "Relativity: The Special and General Theory" it explains it all pretty simply.

Again, as photon said, the faster you go, the slower time passes for you.

This has been proven by synchronizing an atomic clock on a very fast jet with one on the ground. Fly the jet around at high speeds for a long period of time and eventually you will see a difference between the two clocks because time has slowed down for the clock on the jet relative to the time for the clock on the ground.

The same is true for astronauts because the orbit the earth at 17,000mph for months at a time. They have basically time traveled a fraction of a second into the future because their clocks slow down relative to time on earth.

Actually, this "experiment" was a marketing ploy devised by Sears in 1953 to promote the sale of Atomic Clocks - something Sears hoped would be a fad product to follow in the success of microwave ovens. An atomic clock kept on public display outside Sears Tower in Chicago was synchronized with the watch of a supersonic aircraft pilot, who flew three runs, each of 2 hours duration. When the watch and clock were compared after the third flight, the pilot's watch was found to be 17 minutes behind the atomic clock. Unfortunately for Sears, this expensive promotion backfired, as very few people bought the atomic clocks (which were valued at thousands of dollars even then), and Sears also saw a precipitous drop in wristwatch sales.

This experiment also led to the now widely accepted theory that Casios are sh*t.

[/bs]

[RougeUnderoos]

Originally Posted by flylock shox

Actually, this "experiment" was a marketing ploy devised by Sears in 1953 to promote the sale of Atomic Clocks - something Sears hoped would be a fad product to follow in the success of microwave ovens. An atomic clock kept on public display outside Sears Tower in Chicago was synchronized with the watch of a supersonic aircraft pilot, who flew three runs, each of 2 hours duration. When the watch and clock were compared after the third flight, the pilot's watch was found to be 17 minutes behind the atomic clock. Unfortunately for Sears, this expensive promotion backfired, as very few people bought the atomic clocks (which were valued at thousands of dollars even then), and Sears also saw a precipitous drop in wristwatch sales.

This experiment also led to the now widely accepted theory that Casios are sh*t.

[/bs]

That was pretty slick. Well done.

[Hack&Lube]

LOL, good one. I was buying it into the 2nd line, successful microwave ovens from Sears in 1953 which was still military technology.

Also, if the supersonic aircraft pilot's watch was behind 17 minutes after 6 hours of flight, Sears should get the nobel prize for debunking of Einstein. That's a lot of time dilation for only mach speeds!

[worth]

Originally Posted by flylock shox

Actually, this "experiment" was a marketing ploy devised by Sears in 1953 to promote the sale of Atomic Clocks - something Sears hoped would be a fad product to follow in the success of microwave ovens. An atomic clock kept on public display outside Sears Tower in Chicago was synchronized with the watch of a supersonic aircraft pilot, who flew three runs, each of 2 hours duration. When the watch and clock were compared after the third flight, the pilot's watch was found to be 17 minutes behind the atomic clock. Unfortunately for Sears, this expensive promotion backfired, as very few people bought the atomic clocks (which were valued at thousands of dollars even then), and Sears also saw a precipitous drop in wristwatch sales.

This experiment also led to the now widely accepted theory that Casios are sh*t.

[/bs]

LOL, I was getting ready to refute, then I saw the /bs tag. Nice one.

[Teh_Bandwagoner]

Homer: NNNNEEERRRDDDD... *looks at jock* Hey! Did you see that nerd?
Jock: Pardon me?

[GoinAllTheWay]

Originally Posted by photon

Simplest words, you can't. Traveling at the speed of light would take infinite energy and you'd weight an infinite amount.

I thought that applied to accelerating to the speed of light, not traveling at it. A rocket scientist I am not though.

[photon]

You are correct! Though if you know of a way to reach a speed without accelerating to that speed you win a cookie!

[GoinAllTheWay]

Originally Posted by photon

You are correct! Though if you know of a way to reach a speed without accelerating to that speed you win a cookie!

Warping space? I really don't know. I guess that wouldn't really be traveling at the speed of light then, would it?

[photon]

Actually you'd win more than a cookie, probably a nobel prize at the least, I don't know either.

[evman150]

Originally Posted by photon

I've got a question that I'm almost afraid to ask, I think it really shows I don't truly get the implications of no absolute frames of reference.

Basically they were saying that the whole idea that the universe is expanding was just one way put things that helped put things in a context and introduce the concept to people, but really it was equally valid to say the length of everything was contracting, and in reality neither is really "real". Then they started talking about co-moving coordinates I think and I was totally lost.

What the heck were they talking about. I'll dig out the thread if I can find it, it was on a pretty big physics forum (I can't remember if I saw it on BA's forum, or if it was linked from there).

Ignoring co-moving coordinates is one way one can "go faster" than the speed of light. We had a thread a couple months ago where I posted a funny little diagram illustrating co-moving coordinates which I thought was pretty instructive.

Basically what they are saying is that saying "the universe is expanding" is too hand-wavy, that by saying that we are missing a lot of the cosmology behind it, namely co-moving coordinates.

I'm going to try and dig up that post.

[photon]

I remember that you did post a diagram, I'll check it out.