Recent content by Anthea Lawn

Not exactly. It only works because you "pre-arranged" everything beforehand by telling the two guys all the relevant information *before* you set the lighthouse going. So the information already existed for the two guys before the lighthouse started spinning - it didn't need to travel anywhere.

Hehe, actually the spot of light on the wall isn't a physical thing in itself, so there is no reason why it cannot travel faster than the speed of light. For the same reason, some oscilloscopes can rightly claim writing speeds greater than the speed of light (since the spot on the screen isn't...

A lot depends on the route the electricity takes through your body. That's why a lot of TV repairers (in the good old days when TVs were actually repaired rather than just thrown away) used to work with one hand in their pocket. The reason is that if the other hand touches a high voltage the...

You could simplify the problem (as indeed is often posed as a teaser in physics textbooks) and say that you're going to stand on the conveyor belt with a torch and then switch the torch on whilst pointing it in the direction of motion. If the conveyor belt is going at 100mph then the light...

Image you are a snail at one corner of a large (2-dimensional) sheet of tarpaulin and you want to get to the opposite corner. That would take ages. But imagine you could fold the 2D tarpaulin so that the opposite corners became adjacent. You could then crawl across and then unfold the tarp...

The wikipedia page has a pretty good basic description of steering the shuttle in space. http://en.wikipedia.org/wiki/Space_Shuttle_orbiter The aerodynamic look of the shuttle is basically only to help it through the Earth's atmosphere; up in space it could be shaped like the statue of...

It's not impossible although it does play with your mind a bit. However, as a startoff I'd recommend that you get a thorough understanding of Special Relativity first. When you've got that cracked, then General Relativity will come to you a lot easier. Good luck with it !

It would be interesting if the speed of light were slower than the speed of sound. For example, you would hear the thunder before you saw the lightning flash. In Terry Pratchett's Discworld novels, the speed of light is very slow, making for some interesting physical effects.

Bear in mind that this is the speed of light IN A VACUUM. When light travels through a medium such as air or water, it slows down to a speed of .. well, it depends on the medium. This slowing down is basically (without going into details) what causes refraction.

Your example is also a little complicated by having the observer travel round in a circle which means that his distance from the clapping person is actually the same at all times. This is a different scenario to the observer traveling in a straight line (eg in the infamous railway carriage often...