Observation about relativistic space travel:

Math says if we get up to 0,999c our spacecraft will be running about 20 times the speed of light, so says you inside the spacecraft. Of course the outside world knows if you are going say, 20 light years, you will still be taking 20 years to get there, Earth time.

But here is something interesting:

If you are going 0.999c you and everything on the craft will be shortened also by that same factor, 20 or so. So if your spaceship is 2000 meters long, it would now be about 100 meters long. Here is the interesting part:

Say you have a 2 meter ruler in your hand. If you point it in the direction of motion, it is now 100 mm long. But if you point it sideways, it resumes being 2 meters long.

Anyone find fault in that analysis? It seems you should be able to see that quite clearly AND if that is the case, all you need is two two meter rulers at 90 degrees apart, one pointing to the ceiling and floor the other to the sides of the craft and you should be able to measure your velocity by just seeing the difference in the two lengths now presented.

It seems to me from the POV of the traveler, you know you are 2 meters tall so the ruler if pointed up and down would be your height. But move it 90 degrees to horizontal, it looks to me like the traveler would think it had grown to 40 meters long!

So it looks like you would have a ruler speedometer!

One thing: how would it be like for people to actually live in a condition like that, where they would KNOW left and right is way off in distance from up and down?

I was thinking about the way information flows in the brain and here on Earth there would be no measurable difference in the time it takes for information to flow up and down in your brain V left and right.

It seems therefore at 0.999c there would be a 20 to one speed difference in information going left and right (perpendicular to the direction of travel) V information flow in the direction of travel.

would there be cognitive consequences for such a scenario?

Originally posted by sonhouse
If you are going 0.999c you and everything on the craft will be shortened also by that same factor, 20 or so. So if your spaceship is 2000 meters long, it would now be about 100 meters long.

Wouldn't it be, from the point of view of the people on the ship, the rest of the local universe rushing by? Then the shortening will be outside where it belongs and inside is business as ordinary. 🙂

Originally posted by JerryH
Wouldn't it be, from the point of view of the people on the ship, the rest of the local universe rushing by? Then the shortening will be outside where it belongs and inside is business as ordinary. 🙂

I don't think so, the shortening is one dimensional. The other dimension is untouched by relativistic motion. I think if you raised your arm straight up in the air it would be like you think it should be but if you held your arm out to the side it would look like it grew 20 times its length from your POV.

No an observer inside the ship, or in it's reference frame will observe the ship to still be 2000m long.

They will instead observe the rest of the universe to be contracted in the direction of travel.

Originally posted by googlefudge
No an observer inside the ship, or in it's reference frame will observe the ship to still be 2000m long.

They will instead observe the rest of the universe to be contracted in the direction of travel.

You are actively trying to be a party pooper🙂 So up and down and left and right will be no different from the POV of the traveler? Thought I was on to something there.

So there would still be a way I guess using spectrometry, looking at the shift sideways V the shifts in front and back. Or just looking forward V looking behind and comparing spectrum averages.

Originally posted by sonhouse
You are actively trying to be a party pooper🙂 So up and down and left and right will be no different from the POV of the traveler? Thought I was on to something there.

So there would still be a way I guess using spectrometry, looking at the shift sideways V the shifts in front and back. Or just looking forward V looking behind and comparing spectrum averages.

No. The whole point and foundation of relativity is that the laws of physics, and the results of any
test conducted, in two otherwise identical reference frames that are moving with respect to each other
are identical.

You cannot tell the difference between you in your spaceship moving at 90%C in a stationary universe
and you being stationary in a universe moving at 90% the speed of light. Or anywhere in-between.

There is no privileged reference frame from which you can measure from.

Originally posted by googlefudge
No. The whole point and foundation of relativity is that the laws of physics, and the results of any
test conducted, in two otherwise identical reference frames that are moving with respect to each other
are identical.

You cannot tell the difference between you in your spaceship moving at 90%C in a stationary universe
and you being stationary in ...[text shortened]... anywhere in-between.

There is no privileged reference frame from which you can measure from.

So the gist of that is you would not see anything different in your spaceship, it would be the universe that would look screwy.

Originally posted by sonhouse
So the gist of that is you would not see anything different in your spaceship, it would be the universe that would look screwy.

!thgiR

Originally posted by FabianFnas
!thgiR

eheh! So the gist of all that is you CAN go 0.9c with nothing more to worry about than a speck of dust hitting your spaceship with the energy of a cannonball🙂

Originally posted by sonhouse
eheh! So the gist of all that is you CAN go 0.9c with nothing more to worry about than a speck of dust hitting your spaceship with the energy of a cannonball🙂

Relativistic windshield wipers?

Originally posted by JerryH
Relativistic windshield wipers?

Lots of ice in front, say a mile thick layer🙂

Originally posted by sonhouse
Lots of ice in front, say a mile thick layer🙂

You're not getting me up there naked in a mile of ice. I'm not lighting around until Transnuclear Annihilanators.

Originally posted by JerryH
You're not getting me up there naked in a mile of ice. I'm not lighting around until Transnuclear Annihilanators.

That's right, and the field accelerator, which accelerates without rockets and you feel what the residual acceleration is set to, so one G inside and 100,000 g's outside🙂 And of course, the space skipper, where through advanced quantum physics, we skip across space somewhat like a flat stone flung across the surface of a pond, so we skip say, 1000 light years at a jump or anything else in between all in on microsecond so you are effectively doing a billion times the speed of light. That is not very good to get to the other side of the universe however, oh it's great for local travel, the nearby galaxies and such but it will still take 50 or more years at that rate to get to the other side of the universe.

Then there is the dimension jumper, so you can bug out of our universe entirely, find yourself a nice young universe to skip in to. Say one only 4 billion years old or so instead of our 14 billion year old universe approaching old age.

We are working on the necessary patents right now...

Originally posted by sonhouse
And of course, the space skipper, where through advanced quantum physics, we skip across space somewhat like a flat stone flung across the surface of a pond, so we skip say, 1000 light years at a jump or anything else in between all in on microsecond

I had no idea what was in the works. I'm selling my annihilanator, I want to get in on that hip skipper!

Originally posted by sonhouse
instead of our 14 billion year old universe approaching old age.

14 billion is not old, it's just now becoming most interesting.

Originally posted by JerryH

Originally posted by sonhouse
[b] And of course, the space skipper, where through advanced quantum physics, we skip across space somewhat like a flat stone flung across the surface of a pond, so we skip say, 1000 light years at a jump or anything else in between all in on microsecond

I had no idea what was in the works. I'm sellin ...[text shortened]... pproaching old age.[/b][/quote]
14 billion is not old, it's just now becoming most interesting.[/b]

Latest is we are headed for a BIG ass waterfall, the literal dissolution of EVERYTHING including Donald Trump🙂 But in about ten billion years or so.

http://phys.org/news/2015-06-cosmic-stickiness-favors-big-rip.html