4 ms·

When I say 'in reality' I mean physically. Say the rocket earthbound and is 2x300kkm from the earth, the question again, will the photon collide with the earth

When I say 'in reality' I mean physically. Say the rocket earthbound and is 2x300kkm from the earth, the question again, will the photon collide with the earth or still be 300kkm from it? The problem I have with light as a unit of reference is that 'perception' is not the same as 'reality' in the physical world.

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.
Stormbringer 16y ago
From the earth observer's point of view in one second the photon will have moved 300 megameters, and the spaceship with astronaut will be 1 meter behind it. From the astronauts points of view only 1/300,000,000th of a second will have passed. They are going to smack into the planet and won't even know what hit them. The resulting explosion will make Tunguska look like amateur hour with a whoopee cushion.

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.

Stormbringer 16y ago

From the earth observer's point of view in one second the photon will have moved 300 megameters, and the spaceship with astronaut will be 1 meter behind it. From the astronauts points of view only 1/300,000,000th of a second will have passed. They are going to smack into the planet and won't even know what hit them. The resulting explosion will make Tunguska look like amateur hour with a whoopee cushion.