Travel at Light Speed by standing still?

Originally posted by daniel_g

Place everything on a 1 dimension system. Set Earth at the origen (Vearth = 0), Vgalaxy is then -0.99c and Vspacecraft = +.99c

= (-0.99c - 0.99c) / (1-((-.99c)(0.99c)/c^2))
= -1.98c / 1+0.9801
= -1.98c / 1.9801
= -0.999949498c

don't ask me about the negative sign, but I think it's there to denote that the objects are moving away from each other.

the way you were doing it was for two objects moving in the same direction at equal velocity which ends up as
0/(1-vbva/c^2) = 0

The negative sign only works with the earth as the origin.

What if you set the galaxy as the origin? Vearth is +.99c and Vspacecraft is +.99c.



[edit on 10/7/10 by GobbledokTChipeater]

surely if the universe is expanding at the speed of light then "light" maybe just starting to reach these parts. They are becoming "uncovered" if you like?

would this co-incide with the theory that travelling close to the speed of light makes you invisible (or something invisible) as the light is yet to reach you?

ofcourse though, could someone who is closer to the "edge" of the universe be able to see more of the universe (past its edge) because the light from their time and place has reached it before ours?

is the location of the "edge" of the universe only relative to our location, and completely different to someone closer/further away?

reply to post by WhatsHappening


Those are great questions and I have been asking myself the same ones forever. What is our universe in for it to expand in? What is the edge of the universe? A wall? A simple "line in the sand"? What would happen if you crossed that line? Would light follow?

My theory is that the universe is just part of the ever bigger standard models that we know...

Atomic model --> Nucleus + surrounding electrons
Solar system model --> Nucleus (sun) + surrounding planets
Galaxy model --> Nucleus (center of axis) + surrounding star systems

Does this mean that there is there a Universe model??? Perhaps it is just another threshold yet to discover...That the edge of our universe is in fact the part that touches the alternate time line universes and that the expansion is actually just the continuation of time.

Too much thought for this morning... lol

Magnum



[edit on 10/7/10 by Magnum007]

Originally posted by GobbledokTChipeater
The negative sign only works with the earth as the origin.

What if you set the galaxy as the origin? Vearth is +.99c and Vspacecraft is +.99c.

Good question, the problem is that va and vb must be known relative velocities. In this case you only know the speed of the galaxy and the speed of the spacecraft relative to Earth.

If you were to use the galaxy as the origin, then you'd have to know the speed of the Earth relative to the galaxy, and the speed of the spacecraft relative to the galaxy which is what we were trying to find in the first place. The solution u' would then give you the velocity of the spacecraft relative to Earth.

You're rigth though, the sign depends mostly on how we chose the coordinate system

May I suggest that if a way to vibrate fast enough in the vacuum of space is achieved we can let the universe pass us on a molecular level, thus appearing to move at light speed by just "standing still" as the OP suggests.

We are all aware its impossible for our propulsions to reach light speed due to mass, but if propulsion is no longer the factor, what then?


The molecular movements used from vibrations of friction, which is how the movement of the universe would be observed. Ex. If you shoot a bullet into water the friction tears it up and stops it. If you hold said bullet in a wave pool and drop it then it follows the path of energy. If you cause it to vibrate it will get to where its going slower, but more water passes it to achieve the end result.

Vibrations and friction could in turn equal travel through movement of other materials before the subject is effected. There is possibly a math equation I could figure out to explain this but it would take time.

Perhaps one of you wants to try it. How much vibration it takes per x of weight to cause y amount of friction and how much y of friction is required for z amount of W(water in my example) movement.

Originally posted by daniel_g

Originally posted by GobbledokTChipeater
reply to post by dlifesjrny

 

In relation to other things in the universe, you are moving at above light speed.

However in relation to anything close by/meaningful, you are barely moving. It's all relative.

That first statement is simply not true under relativity. In relation to anything, no matter where, in the universe you are moving below the speed of light.

Take 3 points in the universe: A distant galaxy, the Earth, and you.
If Earth was moving away at .99c relative to the distant galaxy, and you suddently took off from Earth at .99c relative to Earth and moving away from the galaxy, then you'd still be traveling below c relative to the distant galaxy.

OK let's take 3 different points in the universe. The earth is our reference frame. We draw an X-Y-Z coordinate system. Let's say on January 1, 2010 along the positive X axis we see a galaxy moving away at 0.99c, which was 13 billion light years away when the light left it.

Along the negative x axis we see another galaxy moving away from Earth at 0.99c, also 13 billion light years away when the light left it.

Now let's calculate the relative movement of those two galaxies as of January 1 2011. It's 1 year later so the +x galaxy will have moved 0.99 light year in the +x direction. The -x galaxy will have moved 0.99 light years in the -x direction. So from Earth's perspective, the distance between those two galaxies has increased 1.98 light years in only one year.

So how can the distance between them increase by 1.98 light years in only one year, if nothing can travel faster than light?

Physicists don't really believe that nothing can travel faster than light. You hear that all the time but that's only in a local sense. A galaxy with a lookback time of 13 billion light years is not local.

deep-space-astronomy.suite101.com...

Many sources discussing deep space astrophysics or cosmology claim that certain galaxies move away from the Milky Way Galaxy at faster than light speeds. To the reader who is familiar with even the most basic principles of Einstein's theory of Special Relativity, this statement may be very puzzling. How can anything go faster than the speed of light when Special Relativity strictly forbids it?

The resolution to this apparent contradiction turns out to be partly from a loop hole in Special Relativity and partly from choosing less ambiguous wording.
An Expanding Universe Bends the Rules of Special Relativity

The most well-known rule of Special Relativity states that nothing can travel through space faster than the speed of light. This rule has been verified by physicists time and time again and is now taken to be a scientific fact. There is, however, a loophole in that rule which emerges from the words "through space". Space itself can stretch, warp and do many strange things without violating this rule. If the space between two galaxies stretches then to each galaxy the other will appear to be moving away at some speed. However, this is not motion in the usual sense of the word.

[edit on 11-7-2010 by Arbitrageur]

Originally posted by The Bear Man
May I suggest that if a way to vibrate fast enough in the vacuum of space is achieved we can let the universe pass us on a molecular level, thus appearing to move at light speed by just "standing still" as the OP suggests.

I don't think so, Tim.

What this sounds like is one of those butt-awful woo-physics syncretisms. The giveaways are "vibrate", and "pass us by on a molecular level" (what other level are you proposing?).

The molecular movements used from vibrations of friction, which is how the movement of the universe would be observed.

Observations of position and/or velocity don't really depend on vibrations or friction. Friction with what? Vacuum? What do you propose is 'vibrating'?

why would u want to travel @ speed of light

its still useless

the best way is to study quantum physics, particles work in very weird characteristics that would be much more helpful for us to explore space and everything else ....

Originally posted by Arbitrageur
Now let's calculate the relative movement of those two galaxies as of January 1 2011. It's 1 year later so the +x galaxy will have moved 0.99 light year in the +x direction. The -x galaxy will have moved 0.99 light years in the -x direction. So from Earth's perspective, the distance between those two galaxies has increased 1.98 light years in only one year.

So how can the distance between them increase by 1.98 light years in only one year, if nothing can travel faster than light?

I appreciate you mentioning the loophole that allows anything (not just galaxies) to travel FTL, however its worth mentioning that said loophole does not apply to the example quoted above.

In that particular case there is still nothing exceeding light speed in our frame nor in their own frames. The distance at which the two galaxies separate relative to us does not represent their relative speed.

Keep in mind, at relativistic speeds newtonian equations are no longer valid so you can't just say v = change in distance over time.

Originally posted by Bedlam
What this sounds like is one of those butt-awful woo-physics syncretisms. The giveaways are "vibrate", and "pass us by on a molecular level" (what other level are you proposing?).

Observations of position and/or velocity don't really depend on vibrations or friction. Friction with what? Vacuum? What do you propose is 'vibrating'?

Based on his bullet in water example I think he is proposing the existance of an aether, and the flow of aether in any one direction is the flow of time. If instead of traveling through time in a straight line we moved in a second or even a third degree of freedom then more time would pass by us thus we could speed things up (I do see a lot of problems with this in terms of the energy it would require to travel on a straight line vs 'vibrating', but I'll leave it at this).

Relativity does not contemplate the existance of an aether or anything remotely close but other theories might.

The Bear Man forgive me if that's not what you meant, but if that's not what you were trying to say could you clear it up?


[edit on 12-7-2010 by daniel_g]

reply to post by Bedlam


A vacuum is not frictionless.

Molecularly speaking if you vibrate that which makes up an object/person fast enough you can physically pass through otherwise solid objects. If you used this method while also allowing a bit of friction you wont move quite forward, but instead with wherever your basic motion is from. Like I said with the water example, you will still go as you are going, but everything else will pass you more quickly thus giving you "travel" of sorts

to simply put it.

light is dependent on the mass of the universe around it.

the expansion of the universe is independent of light if "The Universe" is correct.




[edit on 12-7-2010 by quantumdragon]

Originally posted by daniel_g
I appreciate you mentioning the loophole that allows anything (not just galaxies) to travel FTL, however its worth mentioning that said loophole does not apply to the example quoted above.

The space between the galaxies is expanding, is it not? Isn't that the loophole? Expanding space?

[edit on 12-7-2010 by Arbitrageur]

because the universe is expanding it will take a lot longer to get somewhere else.

The OP's suggestion will not work at al

Suppose you are in a car (car =universe) driving at 90 m/h and in the car you throw a bal with 10 m/h. The relative speed of the bal should be 100m/h.

But the car is the universe so how do leave the universe to get your lightspeed?

Originally posted by The Bear Man

A vacuum is not frictionless.

Sure it is.

Molecularly speaking if you vibrate that which makes up an object/person fast enough you can physically pass through otherwise solid objects.

Only in really bad "The Flash" comics, and the occasional Superman. In terms of classical DC comics (pre-reboot), I'd have to assume Cosmic Lad and Captain Marvel could likely do the same since they both had "super speed" powers.

In real life, that's not true.

Like I said with the water example, you will still go as you are going, but everything else will pass you more quickly thus giving you "travel" of sorts

No, if you "vibrate" in the physics sense in a medium with "friction", you generate heat but you don't go any faster. Unless you're traveling so slowly on a hard surface with real friction, instead of, say, boundary layer drag in water, that you're actually sticking, in which case vibrations may lower your "stiction" level and keep you from hanging.

I would like to thank all the participants in the ongoing debate in this thread. I've had quite an enjoyable read thus far.

I'm surprised nobody mentioned the near-uselessness of being able to anchor one's self in place and let the universe whiz by. It's a one-way trip. You'd still need to be able to get back to where you came from. Unless the universe speeds back past you in the reverse direction, which it won't, you're stuck very far from home.

Originally posted by Arbitrageur
The space between the galaxies is expanding, is it not? Isn't that the loophole? Expanding space?

Yes, that is the loophole your quoted text mentions, but it does not apply to your example. Two galaxies moving away from each other with an observer in the middle does not equate to expanding universe.

In fact, if anyone was to make any sense to text you provided, we could conclude that two galaxies moving towards each other could *appear* to separate at FTL if the space between them was to suddently expand, even if for a brief moment.

Note however they mention that 'this is not motion in the usual sense of the word', that's the huge clue that tells us expanding universe is not equal to FTL travel.

[edit on 12-7-2010 by daniel_g]

I think that the History Channel is a little off here. There simply cannot be a frame of reference where an observer would see two bodies separating at a speed greater than c. When this limit is approached, time starts to bend to allow the relative speeds to exist, but you cannot record a speed greater than c from any one frame.