Banned from SteveHoffman forums

[classd4sure]

Hmmm, I think what's being neglected is the point of origin. The point of origin is never A. There's one point of origin, and two travellers each having their own destinations.

So say you the observer on earth aims the light at point A for 5 seconds, then take two seconds to swing it to B and aim it there for 5 seconds more.

What you'll see in a year (wouldn't it really be two years though, it has to go there and back) is a dot on A for five seconds, and after it vanishes, two seconds later it appears on B. It's not because it went from A to B faster than light, it's because they both left from the same point of origin, two seconds apart, and hit different destinations but at equal distance.

Yeah?

Best,
Chris

[SY]

Chris, that's right. But, form the POV of the observer, the spot of light (something totally analogous to a shadow) moved from 1 to 2, a distance of a light year, in seconds.

If there weren't the two year delay, relativity WOULD be violated because information would be transmitted at greater-than-c.

[janneman]

As I said, hmmmm... My head aches, but I *think* I get it. Thanks guys. Next one's on me.

Jan Didden