/sci/ - Science & Math

Okay since nobody responded in the SQT I'll try with a new thread:

So if I sit in a train riding 100mp/h, and another train passes by travelling with the same speed into the opposite direction. I now take my radar gun and check the other train's speed, and it will tell me that train is travelling with 200mp/h. Right?

So let's say that my train is moving with close to lightspeed, and so is the other train. What speed will the radar gun measure?

Now, I don't know the first when it comes to advanced science, but I love science and love learning about it (even if i dont fully understand it).

I was thinking in the shower yesterday, isn't travelling at lightspeed impractical. Even if we found a way to achieve such speeds, the time dilation which occurs when travelling at half light speed would make travelling to a planet lets say 8 lightyears away pretty pointless, i mean maybe not in the grand scheme of things. But I imagine travelling 16 lightyears (there and back) at half light speed would take around 65 years? Im likely wrong.

But lets say it is 65 years, how would you find someone able to survive in space for 65 years. How much food would be needed, surely that would weigh the ship down, how would you fuel the weight, how would you fuel the ship to achieve the speed.

I got a headache shortly after, then I remembered Interstellar (i imagine somebody is mad by this point) when they travel to the wormhole which i guess acts like a shortcut through space.

Then I thought I guess that's the only way we can travel long distances without the time dilation.

I was wondering if anyone would like to confirm my scattered thoughts, discuss them or tell me i'm stupid. Welcome to anything.

Thanks.