Speaking of wasted posts.. :)

You're absolutely incorrect. Time travel is possible and this has been affirmed by most of the prominent theoretical physicists. Time travel into the future, that is. If you fly at 0.99c to a star 10 light years away and back, you will have travelled into the future. Time is not "something we has humans created in our own mind" because time is in fact defined by light.

Travelling backward in time is debateable. Without going too far into quantum physics, certain tenets of quantum theory tend to suggest that the past is "set in stone" and can be seen, but not "accessed." In other words, if we could utilize wormholes (yes, wormholes exist -- they go through hyperspace) effectively we could look back in time (possibly hear, depending on the size of the "wormhole") but not "travel" back in time. Other theories suggest that you can only travel back in time in such a manner that would not destroy time. In other words, you could travel back to your 5th birthday, but you wouldn't be able to change anything -- you'd live your life as you lived it previously. Like TiVo. Anyway, there's my bit.

I agree with trickykid, and I disagree with Iceman.

Time is an illusion created by movement and space. It's not an actual dimension, or anything that really exists. There is no such thing as time, only things moving through space.

Iceman is wrong about traveling into the future. When you travel at .99c, to a star 10 light years away, and then back again, you've still aged 20 years.

yep.. 20 years to our standards of our own earth spinning around the sun..

Hi Guys,

umm...i think it is possible if u are in the 'matrix' or you can travel faster than the speed of light which is 300 million m/s.

Have u guys ever watch the movie 13th floor, maybe we are leaving this world soon once you became THE ONE.

Wrong :)

A "year" is not exactly a unit of time, at least not in the way we use it. We describe a year as the time it takes the Earth to revolve around the Sun once. A second, however, is an actual measure. A second is defined as the time it takes light to travel 1/(3*10^6) of a meter in a vacuum (approximation). The speed of light in a vacuum is a universal constant. What does this mean? The second is a universal constant.

If you fly at 0.99c to a star 10 light years away, then back again, you may have aged 20 "years" or so, meaning the Earth has revolved around the Sun 20 times, but you have not aged the same number of seconds as someone who remained on Earth. You have thus travelled forward in time.

First of all, this is irrelevant to the point we are discussing. I didn't expect anyone to needle-prick my use of the word year.

I have two objections. First, "time travel" is commonly understand as a person disappearing and then re-appearing in the same spot, yet in the future. Usually, the person pops out hundreds of years in the future. So, what we are talking about, by definition, shouldn't be called "time travel".

Second, the original discussion was whether time exists or not. This "spaceship travelling at near the speed of light" concept does not prove that time exists.

Time is a human mental construction. The only way to tell that "time" has passed, is to notice how something has moved through space. Think about it. The clock on the wall measures time by moving the arm across a distance. The atomic clock counts "time" by measuring the vibration movements of particles. Even the basic concept of a year is measured as the movement of the Earth around the Sun. If you go walking from point A to point B, the only way to tell that "time" has passed, is to know that you have moved a certain distance in space. If there was no movement at all in the entire universe, would there be time? Time is the illusion of an "after-effect" coming from the fundamental elements at play in our universe.

As a great person once said..time is dependant on the observer, a cockroach will have a completely different time than a human.. As would a person living on a larger planet...
The most recentl thing in time travel is the idea of manipulating light into a circle to get it spining faster than the speed of light creating the great 'vortex' .. Only hearsay tho..

"Time is an illusion.

Lunchtime doubly so."

(Prize for first person to correctly identify the quotation!)

If going faster than the speed of light takes you into the future does that mean everytime Jean Luc hit warp speed he was going forward in time? Everytime he went for shore leave would everyone back on the planet he last left be about three hundred years old? Or does this prove that Star Trek was just a silly program? <g>

How did this thread metamorphosise into a bizarre time travel thread?

It's late, I need to spend some time in bed. Or at least the hands on the clock need to move round for a while as I sleep.

Nighty night.

Rob (Time Lord)

Actually...
 

To whoever posted before, I wasn't criticizing the use of the word year. Jeez.

Someone said "well it's all relative because a year on Earth is different then a year somewhere else blah blah" or something similar. That's what I was referring to.

Going faster than the speed of light (if you believe Einstein, it's impossible for something with mass to accelerate from subluminal speeds to luminal or superluminal speeds) would actually send you back in time. Remember that you can't "poof" back in time this way, but you would actually be going backwards in time. Time would go the same speed, only backwards. This is all theoretical, of course, but this is the behaviour predicted to be adhered to by tachyons, if they happen to exist.

Wormholes, on the other hand, are entirely different. They don't go through realspace.

If you want to believe that "time" is imaginary, fine (there is such thing as imaginary time, mind you).

The enterprise doesn't actually go faster than light, the warp drives bend space and set the distance closer..
Seen event horizon? similar concept but event horizon does it better..
yea anyway..thats my favourite distribution :)

That's more or less what a wormhole does. It deals with an exorbitant amount of energy which increases the space-time curvature to the point where it "folds" and the two sides come close enough together that a wormhole forms to connect the two. That's the best way to explain it, really, although wormholes exist naturally below the Planck level and don't require Casimir injection except to create artificially.

ooh ooh...since no ones complaining about the subject change..

A small vote..
Do you think a black hole is

A) exactly that, a hole in space etc etc etc

B) Is still a star but is compressed to a point and mass that we don't understand

C) Something else (insert thought)

I thought about it for ages (weeks) and my answer is B ..

I'll tell you what a black hole is :)

First of all, a black hole does not have to be a collapsed star. In fact (please don't ask me to explain, it's quite honestly over everyone's head ;) ), there is evidence that all matter eventually collapsed to an infinitely small state over an infinite timeframe. That means if you stick a proton in the middle of nowhere it'll eventually become a black hole :)

Remember that gravity obeys the inverse square law. That means that the smaller something (assuming constant mass) the more gravitational effect it has.

Anyway, about black holes. Black holes are singularities, pure and simple. For our purposes we'll assume we're talking about a star that collapsed to black hole status.

The black hole retains the momentum (magnitude and direction) that the star had. That means more or less that the black hole will spin similar to the spin of the star. A black hole isn't actually a hole in space. It's a singularity, but it has yet to be proven that it connects to another singularity. That would be a wormhole, of course. Two singularities that connect to eachother in hyperspace = wormhole.

Then again, it has also yet to be proven that black holes exist. Regardless, it is generally believes that black holes are *not* wormholes. This has to do with tidal gravity and the space-time curvature around black holes, and the formation of wormholes in general. This of course does not rule out the possibility that a black hole might indeed lead through a wormhole through hyperspace to another black hole. Not that that'd get you anywhere. You'd be dead before you got to the center, you'd die going through the wormhole, and you'd die in the black hole at the other end (white holes are fantasy).

I wonder what people will think of them in 200 years time..
It does kinda go to show that a small object can create gravity..controllable or not..mainly not..

Iceman, what is your field of study? I'm guessing you're either a mathematician or a physicist.