zlacker

>>qqqqqu+(OP)
Why does time slow down/go faster with movement compared to another object.

The well known example that if you travel into space you'd gain let's say 5 years and people on earth 25 in the same time or so.

I just don't get it and I can't find any logic explanation.

For instance: Two twins who came to live exactly at the same moment in the year 2000 and both die on their 75th birthday at the same time. One travels into space, the other stays on earth. Earth-brother dies on earthyear 2075,space-brother dies in earthyear 3050 or so...

I know its Einstein's point but that just doesn't instantly make it correct to me.

>>Dutchi+Ik
There are two effects here. One is special relativistic time dilation, and you can derive these effects with very little mathematics (high school is enough). The Wikipedia page has a simple proof, but it's important to realise that this is a result of the postulate that the speed of light is constant. If you travel at 0.99c and emit a photon, it still travels at c, not 1.99c. It's absolutely not intuitive why this should be the case.

The other effect is that time in a strong gravitational field runs slowly.