: : A Quasar is 60 billion light years away. Right now : : on that quasar the are watching us enter the Cenozoic : : era. If they had a device to see well enough than : : they could watch us right this second 60 billion : : years ago. If someday it is possible to travel many : : many many light years we might be able to view earth : : as it was a long time ago. Is this somewhat right?

: Do yo mean 60 Million light-years?

: John

: Actually, 60 M sounds right, but that places us in the Cretaceous period of the Dinosaurs. If you pack up right now and travel at NON-RELATIVISTIC speeds away from earth, and you live long enough to get to X-million LY from earth, your vision of earth from that distance would be as it was X-million Years ago. After all, when you are stationary, light from anywhere travels to reach you at a given velocity, and you will see light from that source as it appeared years ago according to your distance from that object. This is not the same as time travel, however, and a million years to you will seem like a million years to your friends back on earth, as long as you don't approach light speed. Once you approach light-speed, time dilation takes over and aging slows...but this is still not the same as time travel. Time marches inexorably forward, and only slows down when relativity says so.

• ...but no futuroids have travelled back to visit us yet? or have they? - Jun_Carlo_Velasco/">Jun Carlo Velasco - May 19, 1998 - 07:32 UTC
• Re: opinions of time travel - Bob/">Bob - July 20, 1998 - 23:37 UTC
  • Re: opinions of time travel - Bill Jacob - October 16, 1999 - 21:29 UTC