The Scale of the Universe

**Captain Jin** · June 28, 2010, 09:38 AM

So I was reading something about how if mankind could travel at faster than light travel it would take something around four years to reach Alpha Centauri. Now, with that in mind I was also reading that while you would only age four years that people back on Earth would not... I don't really understand this whole concept because your body ages the same. I find the whole relativity of time and what not in space very confusing. If I go on a trip to Alpha Centauri, take four years to get there and spend two years there before returning which takes another four years I'm gone for ten years. So I've aged ten years but people on Earth have aged much more, right? How does that work exactly?

**~~Sensei Kiisu~~** · June 28, 2010, 09:41 AM

Originally Posted by Captain Jin

So I was reading something about how if mankind could travel at faster than light travel it would take something around four years to reach Alpha Centauri. Now, with that in mind I was also reading that while you would only age four years that people back on Earth would not... I don't really understand this whole concept because your body ages the same. I find the whole relativity of time and what not in space very confusing. If I go on a trip to Alpha Centauri, take four years to get there and spend two years there before returning which takes another four years I'm gone for ten years. So I've aged ten years but people on Earth have aged much more, right? How does that work exactly?

Time is not a flat dimension, and it can be warped. It does not run parallel to 'space' as once thought,

think of it this way - if you travel 60 miles an hour in a car, and see another car going the same speed in the same direction, it appears to be going very slow, however if you are stationery, you are lucky to see it.

The closer you get to the speed of light, the more warped time becomes for you, so you will experience time in progress a lot faster than people on Earth, and so your body will not age as it would back on Earth.

It's a lot to get your head around, and I'm no expert, but I'm sure someone else will be able to help provide a more detailed explanation (:

**numerosdecimus** · June 28, 2010, 10:06 AM

The ingenius simplicity of the theory of relativity shows that time, space, energy and mass are all related to one another, all are quantifiable dimentions. The following equasion exposes all:

E=m(c^2). E for energy, M for Mass and C for the speed of light.

If you accelerate to half the speed of light, you will not see light going pass you by at 150000Km/s, instead light will still pass by you at the speed of aproximately 300000km/s.

If the light of light does not change, then something must bend, and that something is time, in order for light to be seen from inside the ship at it's conventional speed.

Everthing inside the vehicle travelling at half the speed of light will slow down if seen by an observer outside the ship, while for those inside the ship, time outisde the ship will accelerate.

**Elfdude** · June 28, 2010, 08:09 PM

Originally Posted by Captain Jin

So I was reading something about how if mankind could travel at faster than light travel it would take something around four years to reach Alpha Centauri. Now, with that in mind I was also reading that while you would only age four years that people back on Earth would not... I don't really understand this whole concept because your body ages the same. I find the whole relativity of time and what not in space very confusing. If I go on a trip to Alpha Centauri, take four years to get there and spend two years there before returning which takes another four years I'm gone for ten years. So I've aged ten years but people on Earth have aged much more, right? How does that work exactly?

It all has to do with the maximum speed of light. As you approach the maximum velocity times slows down in order to prevent you from breaking that speed of light. Thus in a rocket ship travelling 99.99999-% of the speed of light if you got up from your seat (assuming inertial dampeners exist) and ran forward you would not exceed the speed of light. Space, and time literally curve to prevent this from happening. If you could hypothetically observe this interaction you would see the person who stood up not standing up at all but rather not moving at all. Time from their perspective is moving as per normal but from our perspective it's all but stood still. For obvious reasons you couldn't ever observe this but we can imagine it.

Time is not concrete as it appears. For example our GPS systems must correct for a relativistic distortions of time from their perspective because their clocks run slower than ours because they're moving faster than we are on the ground.

The only way around this rule is to distort space ourselves. This can be accomplished with the combined effects of gravity and negative energy, wormholes or a myriad of other solutions. The gravity and negative energy solution is the best understood however and we've even calculated how to build it. Now if we could figure out how to generate a gravity field and how to collect more than tiny bits of negative energy we could build it and fly across the universe as fast as we can distort it.

**Maximus Macro** · June 28, 2010, 09:11 PM

http://www.youtube.com/watch?v=IM5rCpnBRDU

watch all 5 parts it should answer your question

**Hakkapeliitta** · July 08, 2010, 12:19 AM

Time Dilation. The faster you travel the slower time passes, the closer to a gravity well you are the slower time passes. A practical example is the GPS as said earlier.

This is actually what I sometimes try to comprehend as I sit on the toilet

The only way around this rule is to distort space ourselves. This can be accomplished with the combined effects of gravity and negative energy, wormholes or a myriad of other solutions. The gravity and negative energy solution is the best understood however and we've even calculated how to build it. Now if we could figure out how to generate a gravity field and how to collect more than tiny bits of negative energy we could build it and fly across the universe as fast as we can distort it.

Is this related to the "Alcubierre Drive"?

**Tacitursa** · July 10, 2010, 11:32 AM

There's also the theory that if you could enter a blackhole and exit again you might be in a different time period (past or future) due to gravity distoring space/time so much.

**Captain Jin** · July 10, 2010, 01:34 PM

Okay, so I've read through the replies and did lots of other reading. It's very interesting. I guess they did an experiment to test the theory and put two synchronized atomic clocks to the test. One on a super fast jet and the other just on the ground. After the flight the plane landed and the clock aboard showed it's clock was behind the one on the ground. That's just crazy.

So then the idea of it is even if we ever attain FTL travel how do you account for time dilation?

**Elfdude** · July 12, 2010, 05:01 PM

Originally Posted by Captain Jin

Okay, so I've read through the replies and did lots of other reading. It's very interesting. I guess they did an experiment to test the theory and put two synchronized atomic clocks to the test. One on a super fast jet and the other just on the ground. After the flight the plane landed and the clock aboard showed it's clock was behind the one on the ground. That's just crazy.

So then the idea of it is even if we ever attain FTL travel how do you account for time dilation?

There's several options:

Create a warp drive, a warp drive doesn't move the ship so much as the universe around the ship. This conveniently allows you to make the distance of your trip shorter through modification of space, since speed is distance over time, if you make the distance shorter you needn't ever violate the speed of light.

Teleport, there's many different interesting conceptions on this idea. A stutter drive that teleports your ship incrementally forward rather than accelerating at all would easily be able to travel over the speed of light plus mass and momentum and inertia would all no longer matter. Its unclear how to teleport anything other than data at this point in time however, a much higher understanding of the quantum universe is required. Alternatively we might just be able to teleport across the universe.

Create a wormhole, a wormhole does much the same as a warp drive except that instead of moving space around your ship, your ship creates a gate that acts like a wormhole on the apple, the distance through the hole is shorter than the distance across the surface of the apple thus you exceed the speed of light without actually exceeding the speed of light.

These are just the options that seem reasonable from our perspective at this moment in time. The equations and blueprints to design a warp drive already exist, only the materials to do it (subatomic particles and energies we've only obtained nanograms of) are impossible to make on the scale that we would need at this point in time.

**~~removeduser_4536284751384~~** · July 10, 2010, 03:05 PM

if you were orbiting the solar system at a distance of one lightyear at the speed of light you would be able to watch the earth flying around the sun really really fast, and if you waited long enough, although likely within your lifetime, the sun would burn out.

We can never, ever, ever go faster than the speed of light. It takes the same amount of energy to accelerate from 99% c to 99.9% c as it does to accelerate from 90% c to 99% c and so on. It would take infinite energy to go the speed of light. This has been proven to the same extent as thermodynamics, it's basically unquestionable.

However that doesn't mean quick travel to other solar systems is impossible. If humans ever work out how to create and sustain wormholes they, could be used to move to very distant locations extremely quickly. If you imagine the 3 dimensions you experience squashed into 2, this diagram explains it pretty well.

Of course that's only a 2-d representation of something noone could otherwise visualize. But basically if one could be created linking someplace close to earth with basically anyplace you might want to travel you could do it very very fast.