Is time travel Possible? If so should we do it?

[Rogue]

I need a break from politics.
Not possible but if it were the consequences would be bad. I haven't seen the Butterfy Effect but from the previews I think it hits on some of the dangers.

[ReverseLunge]

I do time travel all the time.

[Soldier]

Some of the theoretical dangers. There is another theory (Crichton used it in "Timeline") that it is incredibly arrogant to believe that we insignificant beings could actually alter the flow of time itself. He put forth that history will always find a way to right itself - minor things may change, but the major outcomes will remain the same.

Other angles to look at it from: Some say that the surest sign time travel isn't possible is that the universe doesn't exist. Some say the surest sign is that we haven't been visited by tourists from the future yet.

Of course, look at the way things have been going. Transition from neandrathals to humans? Slimmer, less body hair, larger heads with bigger foreheads, not as sloping. More dexterity, larger eyes.

Difference between current humans and 'greys' (the aliens with the big bug eyes)? About the same. Are they, perhaps, these tourists from the future? Generally good about staying stealthy and just watching, but occasionally caught?

I'm not even getting into multiverse theory yet.

One never knows...

[telkanuru]

Next person to quote Chrichton as a valid scientific reference dies. I have a good friend who is a quantum physicist, and he found 'Timeline' to be a good book, because he couldn't stop laughing.

And we have already sent photons back in time, so there's your answer.

[Soldier]

I never said he was a valid scientific reference - I only said that was where I read that certain point of view on time travel.

So far as I know, pretty much everything concerning the topic is still purely theoretical. If you know anything more solid, I would be quite happy to hear about it - for example, please tell more about these photons!

[Philistine]

{snip}
And we have already sent photons back in time, so there's your answer.

We have????

When?

--Philistine

[alexisdafencer]

we could kill ourselves or unravel the very fabric of time!!!but if we r meant to have time travel, only time will reveal it self, cause everything is destined just like you r destined to be reading this post right now.ima 12 yr old fencer, live with it

[mollusk]

We have built a time machine, but it only works one way and it only works on socks. It's called a dryer. I believe that they send only one sock of a pair of socks into the distant future or the distant past. They clearly must do SOMETHING with them.

[Iwant2bafencer]

I definitely say no. We're too dangerous as humanbeings.

[telkanuru]

We have????

When?

--Philistine

Yeah, some scientists sent some light through some argon gas polarized in a special way and made it arrive well before it should (ie. nanoseconds). It was all over the papers about a year ago.

[Kettu]

I read about some time machine that made news in Connecticut. I don't know all the specifics, just that they could only send the particles back through a loop to a point that they started..

Either way, it shouldn't really be dabbled with.

[Philistine]

Yeah, some scientists sent some light through some argon gas polarized in a special way and made it arrive well before it should (ie. nanoseconds). It was all over the papers about a year ago.

But that wasn't photons travelling faster than light--it was the phase velocity of the light pulse. It's a small but important distinction. No photon actually travelled faster than light, and no information could be transferred by this means--it's basically a "wave crest."

It's similar to the fact that if you point a laser at the moon, and rotate it quickly enough, the "dot" on the moon will appear to move faster than light.

--Philistine

[Joan of Ark]

yup and yup! I think we should travel in time when we are able to.....

[D+F+P=Hadouken!]

Ummmm... its a bad idea to go back in time. I'm snazzy with going forward in time. That is to assume that the future has already happened. Now what about these photons.

[Gav]

You can theoretically build a time machine but you can only go back to the point when the machine was built. The fact that we don't see any time travellers is often held up as a reason against them being built (IMHO a fallacious argument).

The idea of the butterfly effect is flawed if you view it from our current understanding of quantum mechanics. Simply put, you change the past and the future you end up in is the one that you caused - because of the infinite number of futures available and collapsing possibilities...

However the idea of complementarity [Einstein may have been right all along] may have been disproved recently so the idea that there are an infinite number of universes and possibilities may itself be flawed...

Then there is the question of free will and predestination. Is time fixed? Are we able to tell with our current level of understanding? One intersting [although stupid] concept that I came across recently was that we are all computer simulations in some huge VR model. I'm not kidding, this was a serious suggestion by a well known physiicist.

[Louweasel]

This photon thing - forgive me if I've misunderstood, but something "arriving faster than it should", even if that were to be faster than the speed of light, is not going back in time. Its just going extremely fast. The speed of light is the fastest thing we currently know, and it may or may not be the fastest speed possible. But something going faster than that is not therefore going back in time.
Or have I got the wrong end of the stick?

Anyway, I don't really believe time travel is possible.

Even if it were, it seemslike a ratherbad idea.

Anyone read "Making History" by Stephen Fry? Drop whatever you are doing and go out and buy it NOW. Read it immediately!

[Schiavona]

Einstein basically said that time travel and faster than light travel were one and the same thing.............I believe I understood the theory at one point, but there's been a lot of beer under the bridge since then.

[dunastor]

Time travel is possible, and has been for a long time.

I do it every second of the day.
Oh wait a minute, that's just travelling.

OTOH, if you pass some time zones, you're travelling time too.

[CarlKnoch]

Sometimes when I get really drunk I time travel. I go from the bar to my bed hours later.

[npkeith]

Actually, if you read Robert L. Foward's "Indistinguishable From Magic" he explains how time travel is (at least theoretically ) possible. It involves a black hole spinning so fast that it's event horizon is distorted. Apparently this (theoretically) creates a double event horizon, where the dimensions of space and time are mixed up in the space between the two - travel in space inside, and you have travelled in time on the outside. There is just the little problem of surviving entry into a black hole, and the other one of ...getting out again.

Like I said theoretically possible.