Time Travel, Live at VCON 40

While Toren and Kevin were at the HP Lovecraft Film Festival, Joe was at VCON 40 talking “Time Travel” with Eric Fell, Barbara Beall, Joe Haldeman and Mr. Dr. Greg Bole!

Music: “Out of Line” by Aphasia





5 Responses

  1. Hi Joe,

    I’m the guy at VCON who told you that I had spent the night before re-reading “A Brief History of Time” and various physics text books to which you responded “Oh shit.”

    With general relativity it is important to keep track of different reference frames: pilot of spaceship reference frame versus the stationary observer reference frame. One of the things that there seemed to be some confusion about was length contraction. You can have an observer who sees a 100m ship as 50m long ship due to length contraction, but on the ship the pilot sees the ship as 100m. Now can the ship that from the observers view be trapped in a 70m trap? No, the ship is still 100m, it just looks like it is 50m. The reference frame with regard to length, mass, and time are normal to the person on the ship, but to outside observers things get weird.

    This is due to due to how reference frames are treated by general relativity. It involves the Lorentz transformation, which is a series of equations thought up by Hendrik Lorentz around the same time Einstien came up with relativity. Lorentz transformations handles how length, mass, or time is handled when there is an universal speed limit, c (speed of light) in a vacuum, between different observers. At velocities much less than c Lorentz transformations become classical mechanics where differences in observers don’t matter.

    General relativity allows for the existence of wormholes, known as Einstein-Rosen bridges (mentioned in Thor). The problem is that these are incredibly unstable. You don’t want to fly into one of these as they are incredibly unstable and you ship would be slammed into a singularity upon their collapse. No, this isn’t a good type of slamming as a singularity is a point of infinite density in space-time. This is because normal space-time has positive energy density causing space-time to have positive curvature. Imagine you have a kickball from your youth and take a finger on each hand and press into the ball and attempt to make your finger tips touch. The surface of the kickball is space-time with positive curvature.

    Enter quantum mechanics where you can shift around energy density: Instead of a ball, take the same material as the kickball and make it into a square that is saddle shaped. Once again try the experiment with your two fingers, does it work? The surface of the saddle is space-time with negative curvature, which requires negative energy density. This leads to a hypothesis that if one can create regions of space-time with negative curvature that you can create stable wormholes. A test for negative energy density does exist which is known as the Casimir effect, predicted first in 1947 by the aptly named Dr. Casimir. The first experimental demonstration of the Casimir effect was in 1997 by Dr. Lamoreaux .

    The experiment: two parallel plates in a vacuum. In the vacuum virtual particle-antiparticle pairs comes into existence, separate, then rejoin and annihilate. Due to the closeness of the two plates only virtual particle pairs of a certain wavelength can form between plates, whereas all pairs can form outside the plates. A pressure is observed pushing the plates together and this creates the signature for a possible region of negative energy density, which possibly creates a region of space-time with negative curvature.

    Hypothetically if we can create a region of space-time with negative energy density, then we can create a region of space-time with negative curvature, which could hypothetically create stable wormholes, and therefore time travel.

    The gap between the plates in experimenting on the Casimir effect is 10 nm, I’m having trouble on historically finding the x-y of the plates as well. Maybe give me some more time…

    University of Washington: B.S. Physics
    University of Washington: B.S. Earth and Space Sciences: Physics
    University of Washington: M.S. Geophysics

    I am a master of science!

    As an undergrad I focused on space plasmas and advanced propulsion and spent about a year and a half working at UW’s advanced propulsion lab, this involved study of the field of Magnetohydrodynamics ( a blend of Navier-Stokes equations and Maxwells equations). As a graduate student I focused on remote sensing and studied how we can tell what’s going on in the atmosphere. I’ve forgotten a huge amount of math since then, like the ability to do integrals on matrices.

    Other things include me being an Eagle Scout (you don’t want to heat frostbite up too fast because it may cause nerve damage). I’m also an ordained minister in the Church of the Flying Spaghetti Monster.

    P.S. Kevin, I felt that after Lovecraftian madness in Portland, you might be in the mood for the DVD I gave Joe at VCON.

  2. Joe, you mentioned that time travel is basically magic – Larry Niven had the same idea! He has a whole series of stories where, in the far future, they invent time travel – but since Time Travel is *fantasy*, the machine only takes trips into fantasy lands! The premise is that our hero is sent back to recover extinct animals, such as a Horse, Leviathan and Gila Monster – but the creatures he brings back are all beasts from fantasy – so he ends up with a Unicorn, Ahab’s white whale, and an actual fire-breathing dragon.

  3. I’m a little bit surprised you guys didn’t bring up Time’s Arrow or Tapestry from ST:TNG. Time’s Arrow was a pretty straight closed loop scenario, but Tapestry is a sort of unique what-if time travel kind of thing. But I’m honestly -shocked- that you didn’t bring up https://en.wikipedia.org/wiki/A_Sound_of_Thunder ! That’s like -the- word on “better not fuck up the past” in time travel stories. 😉

    From a lit standpoint, I can’t recommend Kage Baker’s Company series enough. I will literally talk someone’s ear off about how awesome it is, but given that we’re limited to text, I’ll just stick to saying it’s superlative and amazeballs. It’s kind of hard to describe in a way that doesn’t spoil anything, but the gist of it is that there is a company in AD 2355 that invented both immortality and time travel, but you can only go back; you can’t go forward, and the immortality process only works on toddlers and younger. So they create immortals in the past to labor their way through history and ‘save’ things that will then be ‘discovered’ in the future and be sold off for massive profit. Extinct animals, lost paintings, whole cultures, etc. But after a few thousand years of rescuing priceless things from stupid mortal monkeys who insist on starting wars and destroying things in the name of one pointless cause after another, they start to wonder if their mortal masters up in the future are all that awesome to begin with…

    It’s crazy good, and I’m so pleased she was able to finish the series before she died. (Although depressing as hell that she did; so many more stories there!)

    The first book is its own contained story set in Tudor England, so it’s a slight tonal shift between that one and the rest of the series, but I promise it’s worth it.