"What about time travel"?
Marshall Barnes is a research and development engineer in the area of advanced concept science and technology, a member of the Philosophy of Time Society and has proved he's smarter than Stephen Hawking. Time travel is his number one area of research and he's currently winning the race with Ronald Mallett of the University of Connecticut to build the world's first time machine. Not knowing who the guest was, he paused for a moment and then shook his head and reached for the phone when he heard the guest, scientist Sir Charles Shults, begin to talk about using wormholes for time travel, a model created by Kip Thorne, and a model that Marshall has proved won't work and has won recognition for proving that even high school students could see the problem with it.
Marshall did get through on a line but the screener would only allow him to ask a question, no comment. So Marshall did, but he was cut off immediately afterward, prevented from saying anything further as Shults responded to the question inaccurately. So, Marshall, has issued the following email to Shults to set the record straight:
(Shults begins his comment on time travel at 26:57, Marshall comes on at 33:30)
Dear Sir Shults:
I am the Marshall from Yellow Springs who called you the morning you were on Coast To Coast AM, concerning your comment about using wormholes for time travel to the past by putting one on a rocket. I was denied the ability to reply to your response by the Coast To Coast AM screener, and since you said that you would like to see any sort of information that would prove otherwise, I will do so now.
My question was in relation to how you could believe such a scenario if you are aware of the twins paradox. Your response was as if I was questioning the twins paradox, which I wasn't. What I was pointing out is the simple fact that time travel via the twins paradox is in the direction of the future and only occurs due to the fact that the traveling twin is going very fast for a long period of time. The period of time always equals that which has transpired back on Earth. The effects of such a long trip, however, are not resultant upon the clocks and aging of the traveling twin, due to the time dilation effect that is produced by the high velocity excursion. It is because of the velocity of the traveling twin - for a long period of time, that the traveling twin doesn't age as much, and is allowed to travel to the distant future.
Conversely, Thorne's wormhole model, which you were referring to without attribution, forgets this basic fact and erroneously assumes that the wormhole aging slower will then be used to connect to the past. This can be shown to be false simply by asking how does the wormhole inside the rocket connect to a past when the nothing else inside the rocket does? The age of the wormhole, in this case, is irrelevant. The confusion originally seemingly arose from a different scenario, where a wormhole mouth was already connected to a past exterior universe. The extrapolation - from actual past, to time dilated reference frame, was made but isn't accurate. The rocket is still in the same exterior universe (to use Thorne's term) as the Earth is. Thus, the wormhole mouth will be younger on the rocket but the rocket is still within the same exterior universe as the Earth. This is the key to the problem. How can a rocket doing the exact same thing as it does in the twins paradox, suddenly be connected to the past just because of a wormhole onboard, which, by the way, is connected to the other mouth on Earth? If you're on Earth and go through that mouth to the one onboard the rocket, you will age differently there and see the time onboard is different from that on Earth, but at no point is the wormhole opening to the past, because the rocket is not in the past. Even if you were to remove the wormhole from the rocket, it would make no difference, since now the younger wormhole is still not connected to an exterior universe in the past. It's just younger.
That's how the twins paradox works - the traveling twin ages slower and as such the traveling wormhole will age slower, so let's say if the wormholes were to have a half life of 20 years, the half life of the wormhole mouth on the rocket would be extended versus the one on Earth. However, at no time is the traveling wormhole connected to a space in the past. You as much stated the same thing when you mentioned the decay rate of particles slowing down in accelerators as opposed to those not in the accelerator. Do the accelerated particles go into the past - because their decay rate is extended? I think not.
Thorne's wormholes for time travel model is a good example of how many scientists don't understand complex time geometries. They stop short, they fall for hidden assumptions, and mostly because it's not their true concern. Temporal mechanics is part of what I do, as the nature of time is the main fundamental area of research that I am involved in. I presented my first lecture at a science conference on this very subject at the 2004 Mars Society conference in Chicago http://www.pressbox.co.uk/
I hope this clarifies for you the problem I was trying to cite during my call. I feel strongly that it is important to dispense accurate information to the public, especially on complex issues such as time and time travel, because it is far too easy to allow these issues to remain clouded with convoluted explanations that only hurt the progress that could be made otherwise.
Marshall Barnes, R&D Eng
At this time, no word yet from Sir Shults. Marshall will be appearing live on Richard Syreet's The Conspiracy Show to discuss time travel, the secrets of the film Looper and why MIT's Ed Farhi is wrong about time travel, 11PM EST on October 14th. Check local listings for stations that may carry it, or listen live on the web.