[Sloth]

Clearly, the present never is changed by mischievous time-travellers: people don't suddenly fade into the ether because a rerun of events has prevented their births - that much is obvious.

An absurd statement. Our inability to perceive something does not disprove its existence.

[dirtboy]

New model 'permits time travel'

Kewl. Does this mean I can travel back in time to 1980, to the night I met my ex-wife, and yell at myself "RUN, YOU IDIOT! RUN!"

[PeaceBeWithYou]

Time travel is possible, but not probable since you would have to move your mass backwards or forward to the point that the Earth was in during the time period you wish to visit and then back to the point and time of origin.

The Earth and solar system are moving thru space at about 13 miles per second(IIRC) around the hub of the galaxy which is also moving thru space at an even faster speed. The positional calculations alone are a real bear, and when you look at the energy requirements, and that you have to take that energy supply and a computer, with you to get back, it gets unsurmountable real fast.

For those and other reasons we won't be time traveling anytime soon, if ever.

I just wish I could send a small piece of paper backwards to myself, about 30 minutes, with 6 numbers on it.

[wyattearp]

"You go back to kill your father, but you'd arrive after he'd left the room, you wouldn't find him, or you'd change your mind," said Professor Greenberger.

"You wouldn't be able to kill him because the very fact that he is alive today is going to conspire against you so that you'll never end up taking that path leads you to killing him."

Well! So much for my plans for father's day!

(ducking)

[SJSAMPLE]

Wasn't this the theory used in the most recent movie "The Time Machine".

The guy creates a machine to go back in time to prevent his fiancee from dying, but she keeps getting killed, in different ways, EVERY TIME.

Turns out, the only reason he created the machine was because of her death. His existence in the past meant that SHE HAD TO DIE. Very clever.

[oldbrowser]

So, if you know the present, you cannot change it. If, for example, you know your father is alive today, the laws of the quantum universe state that there is no possibility of him being killed in the past.

So it is impossible to change anything. But then by simply going into the past you would be changing something, the air you breathe ?

You guys are kidding, right ?

[plain talk]

"You wouldn't be able to kill him because the very fact that he is alive today is going to conspire against you so that you'll never end up taking that path leads you to killing him."

Say what? What a stupid article.

[SoothingDave]

"I guess I did steal my dad's keys" - Ted Theodore Logan

[gridlock]

I am not going to let some pencil necked geek
tell me what I can and can not do in the past...

[arkham]

Gibberish...

[The KG9 Kid]

So much for killing Hitler and Karl Marx.

Back to the drawing board.

[NoClones]

these idiots are always forgetting that forms of matter cannot be destroyed, it only changes form...

for example, the elements and molecules that made up michael fox in 1980 were somewheres else 100 years earlier and will be somewheres else 100 years from now...

for better or worse, we are essentially creatures limited to the 'here and now'

[rattrap]

You mean this model?

I thought they had been discontinued.

[Navydog]

I tend to look at time as being like a black hole. When you are born, you start your journey towards the singularity which is death. You cannot escape from the pull of the singularity to return anywhere in the past either in your own lifetime much less before your lifetime. Our own individual existence creates our own personal warp of space time of which there is no possible way to change outside of the control of the will of the creator.

[sonofatpatcher2]

Hummmmmmmmmmmmm!

The how did Bones save Edith and allow the nazis to win WW2 before Kirk allowed her to get run over by that beer truck?

Gad! Time travel sure is confusing, ain't it?

She's dead, Jim!!!!!!

[devane617]

I don't know why everyone seems to dwell on time travel when several parallel universes could exist within the speed of light. Lets say we co-exist with a universe that is speeding at 10,000 time our universe, or 10,000 slower. We could all occupy the same space and never bump into each other, yet still remain well within the bounds of the speed of light.

[HereInTheHeartland]

So this is saying that I couldn't go back in time to the night of Bill Clinton's conception and scream "please no, don't do it" at his father?

[RightWhale]

According to Einstein, space-time can curve back on itself

Einstein objected to that based on physics grounds, but Goedel's solution is valid.

[marblehead17]

ping

[Deo et Patria]

This is a textbook example of what happens when you give immature physicists with no social lives (i) plenty of time on their hands and (ii) access to alcohol.