speed of light

What Time is It in the Universe?

by Fraser Cain August 28, 2014

Check your watch, what time is it? But wait, you’ve actually been moving and accelerating, and according to Einstein, everything’s relative. So what time is it really? It all depends… Fraser Cain on Google+

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How A Laser Appears To Move Faster Than Light (And Why It Really Isn’t)

by Elizabeth Howell February 7, 2014

We at Universe Today often hear theories purporting that Einstein is wrong, and perhaps one of the most common things cited is the speed limit for light used in his relativity theories. In a vacuum, light goes close to 300,000 km/s (roughly 186,000 miles a second). Using a bit of geometry, however, isn’t there a way […]

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Light-travel-time Effect Finds New Astronomical Applications

by David Dickinson February 25, 2013

Sometimes the tried and true methods are still the best, even in observational astronomy. Researchers at the University of Prague demonstrated this recently in a study of the eclipsing binary system V994 Herculis (V994 Her). Researchers P. Zasche and R. Uhla used a method known as the Light-travel-time Effect to verify that V994 Her is […]

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The Alcubierre “Warp” Drive

by Matt Williams August 21, 2011

It’s always a welcome thing to learn that certain ideas that are common to science fiction have a basis in science fact. Cryogenic freezers, laser guns, robots, silicate implants… and let’s not forget the warp drive! Believe it or not, this concept – alternately known as FTL (Faster-Than-Light), Hyperspace, Warp drive, et al – actually […]

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How Does Light Travel?

by Tega Jessa February 8, 2011

You probably know that light and all electromagnetic radiation is a type of energy wave, but how does light travel especially when all other waves like sound need a medium to pass through? This is one of the great mysteries of physics. However, we do have some ideas about why light is able to travel […]

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