What if you traveled faster than the speed of light?

Almost As Fast As the Speed of Light?

We covered the original question, but what if we tweaked it to say, "What if you traveled almost as fast as the speed of light?" In that case, you would experience some interesting effects. One famous result is something physicists call time dilation, which describes how time runs more slowly for objects moving very rapidly. If you flew on a rocket traveling 90 percent of light-speed, the passage of time for you would be halved. Your watch would advance only 10 minutes, while more than 20 minutes would pass for an Earthbound observer.

You would also experience some strange visual consequences. One such consequence is called aberration, and it refers to how your whole field of view would shrink down to a tiny, tunnel-shaped "window" out in front of your spacecraft. This happens because photons (those exceedingly tiny packets of light) -- even photons behind you -- appear to come in from the forward direction. In addition, you would notice an extreme Doppler effect, which would cause light waves from stars in front of you to crowd together, making the objects appear blue. Light waves from stars behind you would spread apart and appear red. The faster you go, the more extreme this phenomenon becomes until all visible light from stars in front of the spacecraft and stars to the rear become completely shifted out of the known visible spectrum (the colors humans can see). When these stars move out of your perceptible wavelength, they simply appear to fade to black or vanish against the background.

Of course, if you want to travel faster than a speeding photon, you'll need more than the same rocket technology we've been using for decades. Perhaps pulling on blue tights and a red cape isn't such a far-fetched idea after all.

Related Articles


  • Brandeker, Alexis. "What would a relativistic interstellar traveler see?" Usenet Physics FAQ. May 2002. (July 20, 2011) http://www.desy.de/user/projects/Physics/Relativity/SR/Spaceship/spaceship.html
  • Carl Sagan's Cosmos. "Travels in Space and Time." YouTube. Video uploaded Nov. 27, 2006 (July 20, 2011) http://www.youtube.com/watch?v=SIfRZhztNos
  • Hawking, Stephen. The Illustrated Brief History of Time. Bantam. 1996.
  • Lemonick, Michael D. "Will We Ever Travel at the Speed of Light?" Time. Apr. 10, 2000. (July 20, 2011) http://www.time.com/time/magazine/article/0,9171,996616,00.html
  • NOVA Physics + Math. "Carl Sagan Ponders Time Travel." NOVA. Oct. 12, 1999. (July 20, 2011) http://www.pbs.org/wgbh/nova/physics/Sagan-Time-Travel.html
  • Ptak, Andy. "The Speed of Light in a Rocket." NASA's Imagine the Universe: Ask An Astrophysicist. Jan. 2, 1997. (July 20, 2011) http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970102c.html
  • Rees, Martin. "Universe: The Definitive Visual Guide." Dorling Kindersley Limited. 2008.