Recent content by welshvegan

There is such thing as a beam of light. If I shine a light from a flashlight, that is a beam of light, right? If not, then what is it? It also takes time to reach somewhere. I will study the the spacetime diagrams. Thanks :)

Thanks guys so much, it is very slowly getting clearer. I'm going to continue to do a lot more studying on this, as it is no way as simple as I thought. In our worldly everyday idea of time, it is just very difficult for me to get my brain around the concept of someone aging slower at .99999c...

1. If a photon does not experience time, then why does it take time to reach somewhere?

I hope that you can bear with me on this, as I till cannot grasp: 1. Does length contraction only affect the astronaut and his spaceship? 2. How is 4 light years actually 1 light year if traveling at .99999c? 3. Why does time contract for the astronaut but not for a beam of light?

Thanks Fredrik. So the secret to this is in the length contraction on the astronaut?

This question is the very reason that I have joined physicforums.com. My understanding is this so far: If I am standing on earth, watching the spaceship heading for Alpha Centuri, to me it will take the spaceship four years to get there. However, for the astronaut, who is actually on the...