Expert: Tom Whiting - 7/16/2009

Question


I am led to believe that light is the fastest know moving item/object in space and time, But also it measures time too. So if i was travelling at the speed of light in my space ship, and i wanted to got 10 billion light years away to a star i can see in space from earth.

  It would take me 10 billion years to get there, so if my space ship could fold the fabric of space and time and allow me to travel 10 billion light years in 1 second. Say that this kind of star as a life expectancy of 1 billion years, then when i get there the star would not be there????????????????????????????????????????????????????????????????????????????????



thats because it as taken the light 10 billion years to get to earth, for me to see it now and it only lived a billion years, so it as been dead 9 billion years. But im also led to belive the further you travel into the universe the further back in time you go to the start of it??????



So does that just mean that most objects we can see in the universe we will never be able to visit them, because if we could travel through a wormhole we are actually traveling faster then the speed of lights, that fast we go past it into nothing ness where there are no starts no light just pitch black, i cant get my head around breaking the speed of light, because light is time.



so its true to say if i was looking in my telescope and i saw a star cluster create a new star and it was 100 million light years away, that means that the star was formed 100 million years ago because it as taken it 100 million years to travel that far to earth for me to see it now? and if i was to step through a wormhole to its location in space then if the star was there it would be a 100 million years old?



So lets say i travelled to the furthest star custer or whatever it is we can see about 46 billion light years away, and i could get there by folding space and get there in 1 second, then would i be able to see other stars and galaxys again?. Because new stars can form anywhere and expand in all directions? and when space expands we expand with it but keeping the same distance from the sun and all orbits stay the same, the same gravity rules apply all over the universe?.



So that would emply that the universe is changing rapdily and expanding in every location to keep an constant balance on the fabric of space and time to stop it from streching too far apart and creating holes in space/time?



So if thats the case then if i was to travel 46 billion light years away in a second travelling faster then light in a sence i would in fact be in the same location seeing a completly new universe, Because from where i am now the fabric of space time is expanding at the same rate as where earth is in the universe so if i travel further than 46 billion light years lets say i programme it to take me 50 billion light years?.

   Then i would not be abe to see earth but only be able to see 46 billion light years away from either direction from where i am, so i would see a new universe further in a direction which takes me further away from earth and like wise if i travelled in the other direction????????????????







PLEASE HELP ME UNDERSTAND  

Answer
Hi Michael,
Ok, first a few factual ground rules.  If we could travel light
speed (we can't) then time becomes zero for the traveler.
So yes, if we could go light speed, then time to travel say
10 billion light years would be zero time (well, a few seconds
for acceleration and deceleration)...but 10 billion years would
have passed on the Earth while you make your several second trip.
The speed of time passage is directly related to your velocity
relative to light speed. The Lorentz Transformation equation gives
time dilation at velocity v equal to the time at rest divided
by the square root of { 1-velocity squared over lightspeed squared.}

So time dilation becomes infinite (time becomes zero) at light
speed. The same equation works for mass too, as it increases toward
infinity, and becomes infinite at light speed. Therefore, we cannot
travel light speed, but just UNDER light speed.

Wormholes, while they exist at the quantum level (very small sub-atomic level)...do not exist at the macrolevel, nor does folding space or time warps or any of that science fiction stuff.  So we
can eliminate all those 'fictional' questions involving all that
science fiction hogwash.
Oh, we know of nothing at 46 billion light years. The Universe began
about 13.7 billion years ago with the Big Bang...and time began at
that instant too (and so did space)...so we're limited to "only"
seeing things out to about 13 billion light years.

Light doesn't "measure" time...time passage is independent of light
photons, but times passage by an observer, is based on the observers
velcity, relative to the maximum speed which is c or lightspeed.
The faster you go, the slower time passes.

Yes, if one leaves for a galaxy that is 10 billion light years
distant (as seen from Earth)...then, even though you get there in
a few seconds on your slow moving watch, 10 billion more years would
have passed on Earth AND your hypothetical galaxy at that distance);
so yes, in that case, there is a good possibility that it won't
be at that location, or even still existing, when you get there
at near light speed. And we can also unequivicoally say that the
Earth won't be there when you get back, as the sun goes red giant
phase in 2-4 billion more years....Earth time.

When you travel outward, you aren't going "back in time"...your time
does not become negative, (it only slows way down) only if you exceeded light speed, then time goes backward (YOU get a square root of a negative number) in your Lorentz equation...and that's impossible, so faster-than-light is impossible too.  So space travel,
even the extreme that you are talking about, does not go backward
in time...you just don't age as fast as if you had stayed motionless
on Earth.  And time on the body you are heading for, is still moving
...at normal speed too. Only the body getting close to light speed
experiences the time dilation effect...you onboard your spacecraft.
All other times are proceding....as normal.

Light is not time, so it would not be pitch black...all the objects
ahead of you would be highly blue-shifted (due to the doppler effect)
and all the objects behind you would be highly red-shifted. The
speed of light is a constant for everyone everywhere...it's only
the frequency that changes, not the speed. Unlike sound, the speed
of light is not dependent on the speed of the source, or the speed
of the receiver.  It's the same speed for everyone everywhere, no
matter what their velocities are. (Special Relativity, Einstein
circa 1917).

There is no "balance" in the fabric of space-time, so you don't
even have to worry about that one.  This ain't a 'balance scale".
And there are no 'holes' in the so-called fabric...your reading too
much fiction, and confusing science-fiction with real science.

We can't even see the SUN anymore once beyond about 100 lightyears
(it drops below naked eye at that point)...let alone see the Earth.

True, space is expanding, and accelerating it's expansion, but it's
currently only the Hubble Constant of 71 Km/second, per megaparsec...
a megaparsec is equal to 3.26 million light years, so it's not
even measureable on the local Solar System scale of 6 light-hours, it's so small. (And it's only the space expanding, not the matter, and the expansion does not create any "holes"....that's all fiction
too.

Suggest you get yourself a copy of Einstein's General and Special
relativity (circa 1917-1919)...then you will learn and know what those special effects are once you get up near light speed. General deals with gravity, and Special deals with high velocities up near lightspeed.  Also grab a copy of a textbook called Astronomy 101
and read that too...afterward, then you'll have most of these questions answered for you. And AVOID all science fiction stories
and all false science websites that are metaphysical in nature.
You've got to keep fictional information separate from factual
science information.  (assuming you want to learn the unbiased
truth about space and science).
Clear Skies,
Tom Whiting
Erie, PA USA