Someone Smart help me out

Im just trying to get my head around this.

I watched a documentary on TV earlier, and the scientist said that if ET had a powerful enough telescope to see straight to Earth and the streets they would be seeing the Victorians, not us how we are now.?

Now i hope im getting this right, the further away from Earth you get time changes? So if Joe Bloggs went up on a space craft and jumped 100 million light years away from Earth, how many Earthly years would of passed? So if he went back to Earth his spacecraft would be ancient?

Am i getting this right? I feel like my brain is melting trying to comprehend it.

reply to post by Haydn_17


No, it's because the speed at which light travels and the distance which the aliens are away.

In theory we could place a giant mirror in deep space - many, many light years away - and if we had a powerful enough telescope - we could point it at the mirror and view the planet Earth as it was in the past.

It all relates to the speed of light, because this is like the speed limt of the universe, we cant "see" past it, so even when we see light from the sun its a few minutes old so we see the sun as it looked about 8 minutes ago, the further we look into the cosmos the more back in time we go.
Which is why we can tell what the universe looked like earlier on, we actually see the way it was the further out we look.

reply to post by Haydn_17


It would depend on how far off the aliens are. It all relates to the speed of light.

Originally posted by Haydn_17
Im just trying to get my head around this.

So if Joe Bloggs went up on a space craft and jumped 100 million light years away from Earth, how many Earthly years would of passed? So if he went back to Earth his spacecraft would be ancient?

If Joe instantly jumped 100M light years away from Earth, the light from Earth would have left 100M years ago to reach Joe where he is now. This is similar to seeing a lightning bolt before you hear the thunder.

You know I have heard about this and read about it loosely on here and it is one of those things I can't seem to wrap my head around either.

It is very cool but I too want someone to explain it! Do they have an idiots guide for it

S&F cause I want to know too!

Victorians? They'd probably be seeing dinosaurs. If the planet in question is 65+ million light years away, so maybe I'm exaggerating.

Only if we believe that those "out there" use telescopes familiar to us as humans...our technology and all...kind of a far out assumption to make, but oh well, it's TV.

It's basically the same concept as the Betelgeuse Supernova.
I may be off on the exact number of years, but I think that star is around 640 light years away from us. So, if it had gone Supernova 639 years ago, then we would see it next year.

Heres a link to some infomation that may help clear it up for you.
www.astrosociety.org...

It takes light one second to travel 300,000 kilometers (186,000 miles). The Moon is toughly 400,000 kilometers away, so it takes light from Earth, say a laser or radio transmission, just over a second to get there. This is why there is a time lag in the recordings of the Apollo astronauts. The Sun is 149,600,000 kilometers away, so it takes the light from the Sun about 8 minutes to reach us. The nearest star is so distant it would take light over 4 years to reach it. This means that if they somehow could see us, the light they would be seeing was already 4 years old. The further away a star is from us, the longer it would take the Sun's light to reach it.

This video might help you to wrap your head around a truly complex phenomena; effects of light travel on matter.




In an attempt to answer your original question, I believe where you heard this is presuming b the observing party is in synch with our current time, thus seeing us as far back in the past as it took for their light to reach us, and we would see them in that distant past, but if we could instantly materialize in their location, it would be currently that far in the future, hope this helps.

But you see so far as we know instantly appearing in the location of an observed place is so far impossible.

If everything was created with a big bang, we would trawel away from the big bang point with near the speed of light.
But as we know, we would also start slowing down and light would start overtaking us.

Does that mean, what we see out there is actually the future

reply to post by Mianeye


What we see 'there' is actually the past, WMAP.

science.nasa.gov...

It's speculated sub atomic particles, (quarks, gluons, etc...) exited the Big Bang exponentially faster than light speed, but when things cooled enough for matter to form, atoms, it became impossible for continued travel faster than light. Why it's detected that matter is speeding up is explained by a force stronger than gravity, dark energy. We make up simple funny names for things we can't explain.

We see into the past each and every day . When you look at the sun you are looking roughly 8 min into the past . It take the light from the sun roughly 8 min to reach us here on Eath .

Have you ever been to a base ball game and sat in the cheap seats ? You may have experienced a similar delay with sound . At a baseball game , in the " cheap seats " you will see the player hit the ball and then after a short delay you will hear the crack of the bat hitting the ball . That delay is sound based and how long it takes the sound to travel to you . The same thing is true with light when we are dealing with vast distances .

By all logic from what I understand of travel approaching light speed I have yet to wrap my head around the idea of traveling BACKWARDS in time. I myself only understand that you can only travel FORWARD in time because of how time is effected by speed of travel. Once you leave at great speed you can never go backwards by description of what is taking place to you as you travel. You leave traveling forward, your time slows, there is no backwards notion of travel, ie. you can't get to where you haven't begun yet, the ultimate paradox. What you may see may be in the past but if you go there very briskly it is in the future from where you started from.

You simply can't arrive at a place you never yet left, you would arrive at a different place, or a different time, in the future of your existence.

I invite any theories of backward time travel explanations other than Sci Fi.

That IS a theory of backwards time travel, only observational rather than physical.

Light travels at ~186,000 miles per second.. If you can relocate more rapidly than that, or if you exist elsewhere than the origin of the light you observe, you are seeing what happened in the past.

To take it to the extreme, when you look at your wife, you see light reflected off of her some hundreds of a billionth of a second ago. While the time frames are imperceptable to us, the fact that light has a speed other than instant, means that an observer recieves it some measure of time after it is transmitted.

This is the principle that was the basis of the alien signal received in the movie Contact. The aliens sent back a clip of Hitler's address at the 1936 Summer Olympics. This was the first signal from Earth transmitted into space, and it took 26 years to reach the aliens (Vega is 26 light-years away). When the aliens received it, they sent it back to us, complete with encoded information on how to build a big wheel. It then took a further 26 years to travel back to us.

Hitler's address was in 1936. It reached Vega in 1962, so, in this case, the aliens of Vega were seeing Earth just prior to WWII, when, in fact, we were in the middle of the Cuban Missile Crisis. When the return signal reached Earth, I had just been born.

For aliens to be seeing the Earth as it was in the Victorian Era, they would have to be located around 150 light-years from us.

reply to post by Fiberx
I understand what you are saying, but that is from a fixed point, two person's standing still, and traveltime from point A (emiter) and point B (wiever).

What i was thinking was.

If everything starts from the same point ( Big bang) and travel away together (Mass and light) how can it be the past we are seeing, when the light around us is traveling with us at the same speed or faster?

Or maybe im just to stupid to understand it