Of Time Travel and Funding

by Paul Gilster on April 10, 2007

Traveling to the planets takes big money and we’ve been part of the squabbing over where NASA money in particular ought to be allocated. But what about projects that take small money? The term is relative, of course, but John Cramer (University of Washington) thinks $20,000 should suffice to run his experiment in time travel, and with NASA’s Institute for Advanced Concepts now shutting down, he’s having a hard time raising it. This Seattle Post-Intelligencer story has more.

We’ve looked at Cramer’s work before, but a brief summary is in order. It involves Einstein’s ‘spooky action at a distance,’ the so-called Einstein-Podolsky-Rosen effect. Quantum entanglement seems to mean that two entangled particles influence each other no matter how far distant in space. That action appears to be instantaneous, which introduces the paradoxical outcome of suggesting that something can communicate faster than the speed of light.

Einstein, of course, would say that’s flat out impossible. Quantum theorists, for their part, have come up with ways of explaining entanglement that don’t involve communication, but Cramer disagrees. He believes that communication does occur but involves movement both forwards and backwards in time. To test the proposition, he would send entangled photons along fiber-optic cables of different lengths, causing the one taking the longer path to be delayed.

Because the photons are engangled, a measurement of one as a particle or a wave determines what happens to the other. Cramer wonders whether he can’t use this effect to make a signal arrive before it was sent. Here’s a description of his idea that the San Francisco Chronicle reprinted from New Scientist:

[Cramer's] extra twist is to run the photons you choose how to measure through several kilometers of coiled-up fiber-optic cable, thereby delaying them by microseconds. This delay means that the other beam will arrive at its detector before you make your choice. However, since the rules of quantum mechanics are indifferent to the timing of measurements, the state of the other beam should correspond to how you choose to measure the delayed beam. The effect of your choice can be seen, in principle, before you have even made it.

Note the ingenuity of the experiment, its elegant simplicity, and its modest budget. This test of what Cramer calls the transactional interpretation of quantum mechanics could tell us whether particle interactions do indeed move both backward and forward in time, a phenomenon known as retrocausality. If they do, we’ve taken a step forward in working out what could one day become the unification of quantum mechanics and relativity. “In 20 years, nobody has been able to tell me why this can’t work,” says Cramer.

With government funding unlikely, the case for cutting-edge experiments funded by philanthropy is stronger than ever. The key here is that the kind of money the Tau Zero Foundation and others will need to raise for a given project isn’t necessarily vast. We’ve already seen that players like Elon Musk and Paul Allen are committed to using part of their personal fortunes for the advancement of space exploration. As the Foundation begins to explore the philanthropic terrain, keep your fingers crossed that less expensive projects like Cramer’s will soon find a receptive audience.

andy April 11, 2007 at 19:39

In special relativity, faster-than-light and time travel are really two aspects of the same thing – the two can be switched between using a Lorentz transform, so different observers will disagree on whether it was FTL or TT.

This is explained, with pretty pictures, here.

So basically, under the conditions where special relativity holds (flat spacetime), once you’ve shown FTL is possible, you’ve also shown that TT is possible.

Daniel April 12, 2007 at 3:15

Why not ask Google? They got cash!
Imagine having a search engine finish indexing as soon as you click go :O

Rich April 12, 2007 at 16:43

“In special relativity, faster-than-light and time travel are really two aspects of the same thing – the two can be switched between using a Lorentz transform, so different observers will disagree on whether it was FTL or TT.”

That’s not quite correct: Lorentz transformations can’t make faster-than-light travel or communication look like (true) time travel or vice versa as “spacelikeness” and “timelikeness” are Lorentz invariant. However, it’s trivial to make a timelike path from the present to the past from spacelike segments, which means that faster-than-light travel can be used to travel backwards in time. Furthermore, both “faster-than-light” and “backwards in time” are agreed upon by all inertial observers.

andy April 12, 2007 at 17:59

Yeah, very sloppy writing on my part which led to an incorrect conclusion: as I should have been aware, the inner product of two four-vectors (such as the spacetime interval) is invariant under the Lorentz transform, so you can’t transform an FTL interval to end up in the past light cone.

What I should have said is that for a path which appears as FTL in one frame, transforming to another frame may give it a backwards-in-time component as viewed in the new frame. If I’ve done the Lorentz transform correctly, this will happen when

β > c/v

Where β is the velocity of the new frame divided by the speed of light and v is the velocity of the FTL signal.

Still, couple an FTL drive and a relativistic drive and you’ve got yourself a time machine…

Edg Duveyoung April 13, 2007 at 11:04

http://www.physorg.com/news95605211.html

Here’s a real world example of how we can try to peer over the “event horizon” and see how life, not just physics, is subtly and intimately connected to quantum dynamics.

This is good stuff!

Edg

DeepQ April 18, 2007 at 18:11

The experiment appears simple enough, and it should be easy to find funding, even if from corporate sources.

So, is this related at all to the work of Tore Wessel-Berg (Norway) and his bitemporal neoclassic theory? In that published theory, time is allowed to flow backward within specific microcosms, and the “spooky” problems with QM get resolved quite elegantly.

David April 19, 2007 at 18:45

This is a very interesting theory. I read another story about how to see if time travel is a possibility by making a national holiday of sorts. The writer(s) tell a story of how humans in the present time pick a day that will be forever known as the day to come back to, and if time travel is possible, then they will go back to that day. I don’t want to go in depth about it, but here is the story:http://asiko.org/?p=40

bob April 20, 2007 at 10:13

Ahhh- IF only H. G. Wells were alive—NASA could have funded his machine and theory about time travel!!

ljk April 24, 2007 at 10:52

Quantum physics says goodbye to reality

physicsweb April 20, 2007

*************************

University of Vienna physicists
claim to have performed an
experiment that rules out a broad
class of hidden-variables theories
that focus on realism in the quantum
world — giving the uneasy
consequence that reality does not
exist when we are not observing…

http://www.kurzweilai.net/email/newsRedirect.html?newsID=6713&m=25748

Motorcycle Guy April 27, 2007 at 7:42

I would figure $20,000 is nothing. Why is he even having problem finding funding. I could see where a $1,000,000 project might have problems but come on $20k..

ljk June 14, 2007 at 15:36

Public donates to UW scientist to fund backward-in-time research

Seattle Post-Intelligencer June 12, 2007

*************************

University of Washington physicist
John Cramer has received more than
$35,000 from folks nationwide to
test his idea that entangled photons
involve signaling, or communication,
in reverse…

http://www.kurzweilai.net/email/newsRedirect.html?newsID=6907&m=25748

george scaglione June 23, 2007 at 16:44

yes motorcycle guy i tend to agree with your point of view above.but yes i have read that he has garnered his funding and shall indeed try! i’d love to hear more about that! thank you, george

brain November 1, 2007 at 23:40

[quote]Ok, here’s the conundrum: If this proves time travel were possible, why wouldn’t the people who are able to time travel in the future (after the technology is developed) go back in time and invest in the technological development? Thus, removing the problem of funding time traveling?

The fact that funding is difficult, while not proving that time travel is impossible, lends itself to the idea that it will never happen.[/quote]

simple really…cannot go back to before time travel was created.

Matt May 16, 2008 at 0:00

I’ve already traveled through time, 30years, and it’s not all that good.

Problem is I’m stuck in forward, at the rate of 60 seconds per minute, bloody protons…

Robert D February 7, 2009 at 22:28

Many people seem to have the answers to yes or no, when it comes to time travel,black holes, quantum physics and so on, i can see by all the different ideas above, that we all may have to wait until another 4 or five prodigies show up to give the average thinking scientist some new knowlege, that only those 4 or 5 peolple will be capable of doing, because without these special people we would all still be getting around on foot. When these types of people show up its like winning the lottery. With out them the 98 pecent of everyonelse may not have anything to research, i hope another one shows up soon.

tBoonePickens April 15, 2009 at 9:49

People, please read up on entanglement & FTL. It’s actually not that difficult to understand why it does not provide for FTL communication. Also, going back in time is impossible. It’s an exercise in meaninglessness! First of all, who says time is something that you “can travel” anyways? Time is simple: it is change; nothing more and nothing less. You can have more change (like time “speeds” up), less change (like time “slows” down), or no change (like time stays “still”), but you can’t have negative change. I hope that clears things up. BTW, even if the “super string” theory of “alternate universes” is correct (which I HIGHLY doubt) you would still NOT be traveling to the past through time; instead, you would be traveling to alternate universes; not the same thing. Also, c is the universal speed limit…it is the speed of time! Once you reach c you will have used up all of your available time in the universe!

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