Category Archives: Relativity

Q: How can wormholes be used for time travel?

Physicist: A good way to think about a wormhole is as a single region of space.  That is, while the ends may be in two different locations, the wormhole itself is a single “piece of space”. So, even if you … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 17 Comments

Q: What’s the difference between black holes and worm holes? Could black holes take you to other universes?

Physicist: The short answer is: A worm hole is a “tube made of spacetime” that connects two different regions.  If it’s set up right, you could enter one side of the tube and exit the other end somewhere else, or … Continue reading

Posted in -- By the Physicist, Astronomy, Math, Physics, Relativity | 36 Comments

Q: CERN’s faster than light neutrino thing: WTF?

Physicist: The story here is that CERN has been generating neutrinos, firing them 730km, to a detector in Gran Sasso, Italy, and those neutrinos have been consistently (so far as their instruments say) arriving 60 ns (0.00000006 seconds) earlier than … Continue reading

Posted in -- By the Physicist, Experiments, Paranoia, Relativity, Skepticism | 32 Comments

Q: Hyperspace, warp drives, and faster than light travel: why not?

Physicist: Firstly: no.  But, if you’re really set on it: maybe.  The essential problems are that moving faster than light (FTL) requires impossible acceleration (not difficult but impossible in a “doesn’t make sense to talk about” kind of way), and FTL … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 21 Comments

Q: Does light experience time?

The original question was: Given that light is moving at light speed, and time slows down as a massive object approaches the speed of light, does light travel through time?  Does the whole time slowing down thing just not apply … Continue reading

Posted in -- By the Physicist, Philosophical, Physics, Relativity | 120 Comments

Q: How do velocities add? If I’m riding a beam of light and I throw a ball, why doesn’t the ball go faster than light?

Physicist: Everything in special relativity, no matter how weird, eventually boils down to the speed of light being the same to everyone.  It’s just not immediately obvious how.  The very short answer is: if v and w are pointing in … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 23 Comments