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Dr. Christopher S. Baird

How do space ships fly faster than light?

Category: Space      Published: February 14, 2013

By: Christopher S. Baird, author of The Top 50 Science Questions with Surprising Answers and Associate Professor of Physics at West Texas A&M University

Voyager spacecraft
Voyager I took 36 years to leave our solar system. Real space travel is very time consuming because nothing can go faster than light and everything is so far apart. Public Domain Image, source: NASA.

Nothing can travel faster than light. This is not a question of technology, but of fundamental physics. Special relativity tells us that nothing can travel faster than the speed of light in vacuum (671 million mph or 300 million meters per second). This limitation applies to baseballs, protons, space ships, and cell phone signals. No alien species, no matter how advanced, can travel faster than light. Universal physics forbids it. As objects approach the speed of light, they get harder and harder to accelerate further. It would take an infinite amount of energy to exactly reach the speed of light, let alone pass it. This fact is proven everyday in particle accelerators such as the Large Hadron Collider (LHC) built by CERN. The LHC currently accelerates very small bunches of protons to 99.999997% the speed of light (planning to reach 99.9999991% the speed of light by 2015). The LHC uses 800,000,000 kilowatt-hours of energy a year to get tiny bunches of protons up to these speeds. That's as much energy as released by 30 plutonium-core nuclear bombs. All that energy is used to get a handful of hydrogen nuclei close to the speed of light. Movies and television shows that depict space ships traveling faster than light are portraying pure fiction. While nothing can travel faster than light, this limitation does not necessarily rule out rapid travel to the stars. Physics has not yet invalidated the concept of wormholes, which are shortcuts to other parts of the universe by curving spacetime. Shows that depict faster-than-light speeds are physically unrealistic, while those that accomplish interstellar travel through wormholes could be more realistic. Fiction writers and producers purposely break this law of physics to enable their heroes to travel to alien planets without taking thousands of years to do it. Sometimes authors work around this speed limitation by putting planets and stars unrealistically close, but doing so does not make the science more credible.

Topics: faster than light, light, space movie, space ship, speed, speed of light, warp speed