Physicist believes we will travel through time this century

[Moontanman]

I think the idea of why we haven't been visited can be explained by the more realistic view of a time machine. If I could indeed travel back in time from what I've read the limits of your time machine would be the day it was turned on. Traveling back further than the day it was turned on would be impossible. I've read where at least one scientist seems think it could be done quite easily, at least communication back in time if not actual travel. But again he says the limit of the machine would be to back to the day it was turned on. If we had such a communication device and lets say an earth quake caused a huge tsunami to wash away a major city. The future could send a warning to the past to evacuate the city before the wave hits. How would this be seen from the stand point of causality?

[futuretalk]

There are other avenues that could launch travelers through time. Researchers at the new LHC (Large Hadron Collider) in Cern, Switzerland believe their machine can recreate conditions like the “big bang” which created our universe and brought time and space into existence.

The LHC smashes particles into each other traveling at light speeds which cause collisions that scientists theorize can create tiny black holes and wormholes; elements that some predict offer the best chance to prove the concept of time travel.

Princeton University’s Richard Gott describes wormholes as shortcuts through space and time that connect two distant points, like a worm tunnel through an apple. “You can jump into a wormhole and instantly pop out somewhere else in the universe, or into another time. You’ve gone through a tunnel that connects two places in spacetime.”

Physicist Kip Thorne, in an article published in Physical Review Letters was the first to give respect to time travel. While acknowledging that it may be years before humanity develops this technology, Thorne concluded: “From a single wormhole an advanced civilization could one day construct a machine for backward time travel.”

Though the laws of physics do not forbid time travel, the idea has many problems. Say we travel back in time and stop our parents from getting together. This would prevent us from being born; we could not exist, thus our journey in time couldn’t happen. Scientists call this a paradox. We created a present different from the one that already exists.

Clearly, mischievous time travelers cannot change the present. People are not suddenly disappearing because a rerun of events has prevented their birth. Therefore, something is stopping time travelers from changing our present, and physicist Michio Kaku and other forward thinkers believe they know what it is – parallel universes.

This holds that our universe is surrounded by an infinite number of other universes, each one slightly different. If you travel through time and prevent your parents from meeting, you are thrust into a parallel universe where you never existed before; you appear only as a time traveler.

However if time travel has not been developed in your new universe, you could be stranded forever in a world without family and friends.

Longing to visit departed relatives or foil atrocities are the main reasons that keep the dream of time travel alive. But gaining in popularity is the hope that one day we could go back in time and scan the consciousness of lost loved ones before they died, and with tomorrow’s advanced technologies, allow them to continue living in our time.

We dream of a breathtaking “magical future,” and we ponder the wonders that lie ahead as we get closer to the 22nd century? Will time travel become part of our future? Only time will tell.

[Michael Mooney]

The "What is Time?" thread awhile back has several arguments, including mine on what time is and is not, which precludes "time travel."

I request from any/all "believers" in "time travel" to get serious about "what it is" in the ontological sense. Is it "real" in the sense of being reversable or "fast forward-able.?" (Not *really!*)

If the future has not yet happened and the past has already happened, then neither is presently real ...and since "it is always now" (everywhere) one can not "visit" events which have not yet happened (except in imagination) or are already over (except in memory and historical records of all sorts.)

Michael

[futuretalk]

I agree that today, time cannot be defined properly. Many forward-thinkers even doubt that time exists. Perhaps when humanity reaches the point shortly after artificial intelligence surpasses human intelligence (mid-2030s?), we will have a more definitive understanding of time’s complexities.

However, time travel theories may not necessarily be impossible. For humans to access past and future events in real time to accomplish a number of goals, could become possible as our technologies advance exponentially in the coming centuries.

Much of our science and technology world started out as fiction, but with human ingenuity, became reality. Could this happen with time travel, after we develop a better understanding of what time is? Maybe it will.

[futuretalk]

Our universe is constantly in motion and has been since its beginning. Most scientists believe that time exists and that it plays an important role in the future of the universe.

However today, exactly how time impacts with humanity and will we ever learn to control it are questions without answers. Tomorrow we may develop answers, but for now this writer is willing to accept these as mysteries waiting for solutions.

Comments welcome.

[GAHD]

Time is but a function of matters entropy IMO. If you wanted to "travel back in time" you would have to literally reverse the entropy of every particle in the universe save those that make up yourself.

I don't think it's remotely possible.

[lawcat]

Originally Posted by GAHD

Time is but a function of matters entropy IMO. If you wanted to "travel back in time" you would have to literally reverse the entropy of every particle in the universe save those that make up yourself.

I don't think it's remotely possible.

True. IMO when some speak of time travel, they must be talking of super-relativistic motion; faster than light. There are some indications, with particles disappearing and appearing--tunneling, as well as non-locality, that such speeds are possible--although it is not widely accepted. Such theories would mainly hold truth for information, where we could cheat physical universe by sending information faster than light across the spacetime--at "relativistic" instant. So, in essence, one could send information into the future, relative to the motion of physicial universe.

But, to go into past is a different matter. First, all information already travels into past relative to now (everything that happened is left behind). Yet we have no idea that anyone is receiving it but us in now due to information storage capabilities. Second, irreversibility, as you say creates impossibility of past-travel. Third, one can stay in the past relative to the forward moving universe, but at the expense of matter--as in the black hole. Dense mass can stay at the bottom of the the gravity hole delayed or frozen in time relative to the rest of the universe. Lot's of problems with travels to the past.

[futuretalk]

Most physicists agree that time travel does not violate any of the known laws of physics. Now whether it’s practical or not is another story; and today, it most certainly is not practical.

Michio Kaku, in his recent book, “Physics of the Impossible” believes that to harness a wormhole would require capturing all the mass energy of a galaxy.

But the most promising design for a time machine is the “transversable wormhole,” a hole in spacetime in which a person could freely walk back and forth in time. On paper, transversable wormholes can provide not only faster-than-light travel, but also travel in time. The key to transversable wormholes is negative energy.

A transversable wormhole time machine would consist of two chambers. Each chamber would consist of two concentric spheres, which would be separated by a tiny distance. By imploding the outer sphere, the two spheres would create a Casimir effect and hence negative energy. Assume that a Type III Civilization (we could get there in 300-500 years or so?) is able to string a wormhole between these two chambers (possibly extracting one from the spacetime foam).

Next, take the first chamber and send it into space at near light-speed. Time slows down in that chamber, so the two clocks are no longer in synch. Time beats at different rates inside the two chambers, which are connected by a wormhole.

If you are in the second chamber, you can instantly pass through the wormhole to the first chamber, which exists at an earlier time. Thus you have gone backward in time.

The problems with this design though are as follows: the wormhole may be quite tiny, much smaller than an atom (but it could send information back in time). And the plates may have to be squeezed down to Planck length distances to create enough negative energy.

With the neurons we possess today, this technology is far beyond our ability to turn into reality; but with the “Golden Age of Intelligence” expected between 2035 and 2050, and a few hundred years to work on it, sending information back in time to perform for us could one day become a “piece of cake.”

Comments welcome, Dick Pelletier

[lawcat]

I am not concerned with machine construction for time travel. Whatever it is , it appears that it has to be some sort of tunnel which bypasses the physical spacetime.

The biggest problem with any theory is that matter does not move in time, or in space, but in spacetime. Matter needs space. Thus, matter must move in spacetime, not merely time.
When matter moves in spacetime, matter must move at relativistic speeds. Some particles may be able to cheat the spacetime constraints through tunneling, but such particles will merely be moving faster in spacetime, so they will get to the target in relatively less time. So, we say, relatively to us the particles are in the future of our spacetime. But the problem is one of contraint of spacetime, and speed of travel, not of travel in time merely.

IMO, the only thing that can truly move only in time is thought.

[futuretalk]

Your idea makes sense, lawcat, and many physicists agree with you. In fact, most experts believe that matter can never be sent through a wormhole. To utilize this natural wonder, we must format information in such a manner that allows it to be sent through wormholes.

I do not believe we have the thinking ability today to develop solutions to time travel issues, but I am convinced that in the future, possibly as early as the last half of this century, humanity will advance to the point where we can begin to develop this wild technology. I believe that this is in our future.