3 ms·
Relativity demands and demonstrates that there is no such thing as "'reality' in the physical world". Events only occur and exist in the context of an observer
by T-hawk 16y ago
Relativity demands and demonstrates that there is no such thing as "'reality' in the physical world". Events only occur and exist in the context of an observer.
From the perspective of an Earthbound observer, the photon emitted by the ship will travel from 600kkm away to 300kkm away in one second. (Actually the observer cannot see the photon until another second elapses and it collides with him on Earth.) This observer will see the ship and the photon moving almost together, the ship slower by whatever infinitesimal fraction of c.
From the perspective of a shipborne observer, the photon emitted by the ship will travel from 0 kkm (away from the ship) to 300kkm away also in one second. How do we reconcile this with the knowledge that the Earthborne observer sees the ship and the photon staying together? Length contracts in the direction of travel. So the shipborne observer's meters are very short. The small distance perceived by the Earthbound observer is perceived as a 300kkm distance by the shipborne observer. http://en.wikipedia.org/wiki/Length_contraction http://en.wikipedia.org/wiki/Length_contraction
In general, this is how you resolve paradoxes in relativity: work it out from the perspective of each observer and understand that there is no central objective reality. You will find that you made an assumption that does not hold true across both observers.
http://en.wikipedia.org/wiki/Ladder_paradox http://en.wikipedia.org/wiki/Ladder_paradox
If you can wrap your mind around the Ladder Paradox, you're well on your way to understanding space-time transformations in relativity. The key to the ladder paradox is that there is no such thing as an objective standard of "simultaneous". Simultaneity is specific to each observer; two observers perceive the simultaneity of two events differently.