When I was nine years old I saw a magazine that showed if you went really fast to Andromeda galaxy, then you’d age really slowly. The magazine suggested the round trip on Earth would take 2,000,000 years while the astronaut would age 20 (at least that’s what I think I remember). It also said that many scientists couldn’t believe this was true, and I knew at once I didn’t want to be like them. I promised myself, in a nine year old way, that I’d pay more attention to the means of getting the answers than to the answers themselves.
Einstein’s theories of relativity predicted this and there are probably no theories in science that have been more tested and proven right. The reason for these theories is odd measurements that showed nothing can go faster than the speed of light. This is very counter intuitive (so of course I love it). If we have two cars approaching each other at 99 mph a radar gun in one car would show the speed is 198 mph. If two spaceships were going at each other at 99% the speed of light, the radar gun (or any other way to measure it) would show the speed at a bit under the speed of light, not 198%.
To get this result means the faster you go the shorter your spaceship has to be and the slower time goes. This is in Einstein’s Special Relativity theory. Einstein’s General Relativity theory says the greater the gravity the slower time goes meaning if you’re closer to the Earth the slower time goes. This means time is a very local phenomenon. The passage of time for your feet is generally slower than for your head. And when you’re in a car driving down the street at 20 mph it’s slower than for you than for the people you left in the house.
The National Institute of Standards’ clocks are now so accurate they can measure these time differences. Check out this story on their website, “NIST Pair of Aluminum Atomic Clocks Reveal Einstein’s Relativity at a Personal Scale“. With expected improvements they’ll be able to measure time differences of 1 cm (less than ½-inch) elevation! Future improvements will bring this down to 1mm (about a dime’s thickness). Rocks my world, but I’ve loved accurate time ever since I ran across WWV on shortwave and after a while realized they were telling me time to better than 1 second accuracy. This was in an age when you’d be proud if your wrist watch was only off a minute a day. Now I wear a watch that resets itself nightly with WWV broadcasts to be less than 1/100 second off.
But one thing has kept me up a little later at nights lately. Another effect of near light speeds is increasing mass of the object. Those atomic particles they’re accelerating to huge velocities under the Swiss-French countryside to find the Higg’s particle weigh a lot more than they do when they’re sitting still.
The problem I have is imagining a big lead shield at the back of the spaceship protecting the astronauts. As it gets near light velocities doesn’t this get so much mass it turns into neutronium, just like a neutron star, with its gravity crushing the astronauts and sort of making it obvious who’s going really fast thus violating Special Relativity? I’ve done the requisite searches to understand this but have yet to find someone who seems to have a handle on this. If you find something let me know so I can sleep better! Please.