Ex-News Junkie
Making things a bit more difficult
Sun Oct 29, 2017 8:07am

Time dilation would vary along the radius of the centrifuge. The design calls for a rim speed of c-1 m/s to give a Lorentz factor of 12243. However, objects stored in the centrifuge are not 2-dimensional, and have thickness. If an object is thick enough that part of it is closer to the center of the centrifuge where the tangential velocity is c-2 m/s and where the Lorentz factor is only 8884, then the temporal rate would be 38 percent faster. This could cause problems for living things whose metabolic processes produce waste products that have to be eliminated from the body. If metabolic processes in the upper body are faster than in the lower body, there might be issues with blood toxicity as just one example.

Initial estimates suggest that even if the centrifuge is approx. 200,000 km in diameter (3 times the size of the Moon's orbit) that this 38 percent temporal rate variance - let's call it a margin of habitability - would be just 30 cm thick. Any human passengers would have to be lying flat, possibly in an induced coma, or at least restrained and experiencing a Virtual Reality environment to keep them comfortable. Rolling biological items (such as people) like hot dogs on a grill might keep them from getting metaphorically burnt on one side, but presents additional design challenges.

On the plus side, a centrifuge 200,000 km in diameter would only have g-forces of 91 million times Earth-normal, and require a levitating magnetic field of just 823192 Teslas to cancel out the g-forces, representing a relaxation of three-orders of magnitude. Besides the ginormous scale of this starship however, the current world record for magnetic fields is just 100.75 Teslas, so there is a long way to go to achieve interstellar travel. Living in space needs to be "old hat". We need to reach a state where a space colony can be transplanted from Sol system to another star system and just carry on doing what they always do, completely independently on external goods and able to survive on space-based resources.

Of course Hollywood has simplified this by using "black box" sleeper pods for interstellar travel. But how do those work? There isn't even a theory. However, if there were a theory on how time itself could be slowed without relativistic machinery, then a starship would be much simpler indeed. A "slow boat" to the stars might still need rotating crews however for the ship to be maintained, and that would necessitate a very large crew compliment, as stated previously.

Fodder for the imagination!

  • Starfield Effects at 66 percent of the speed of lightEx-News Junkie, Sat Oct 28 4:10pm
    The starship would be a "slow boat" to the stars, with an actual speed of only 16 km/sec. But time would run very slowly inside the relativistic centrifuge. If there were a window (more likely a... more
    • Making things a bit more difficult — Ex-News Junkie, Sun Oct 29 8:07am
      • CorrectionEx-News Junkie, Sun Oct 29 8:24am
        200,000 km is 2.3-times the diameter of a geosynchronous orbit around Earth, and nowhere near the size of the Moon's orbit. My bad! This size starship is actually in about the same ball park as many... more
        • Imagery from the movie "Jupiter Ascending"Ex-News Junkie, Sun Oct 29 8:28am
          • Roadmap to Interstellar CivilizationEx-News Junkie, Sun Oct 29 9:24pm
            It seems clear how a starship would eventually be built: First a geosynchronous station would be constructed. A single space elevator cable dropped to the surface of the Earth, and a counterbalance... more
            • Slow Boat versus Hot Rod to the starsEx-News Junkie, Sat Nov 4 11:52pm
              Slow Boat Hot Rod Limiting Factor ok X propellant ok X shielding ok X refuel/resupply ok ok maintenance ok ok geometry & structural stability X ok g-forces X ok freedom of movement of passengers and... more
              • Starship Size ComparisonEx-News Junkie, Mon Nov 6 6:17pm
                Below is a comparison of the sizes of a Space Elevator Ring, and a Starship Ring, neatly sandwiched between the Earth and the Moon's orbit. Image is to scale in units of km.
                • Some professional stuffEx-News Junkie, Sat Nov 11 5:40pm
                  Science Magazine Abstract ... "We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The... more
Click here to receive daily updates