To that end, suppose on our rocket we had a perfectly efficient engine that converted 100% of the fuel into energy for the ship. This gives us an idea of just how much fuel we would need (at minimum).
So What About Light?
From the photon’s perspective, the instant it is emitted in the Andromeda galaxy, it strikes your eye.
Aether or…
After the Michelson-Morley experiment, several theorists tried to explain the results by supposing that Earth dragged the aether along with it, or imposed other conditions to explain our inability to observe the aether. But then Einstein proposed special relativity, which eliminated the need for aether altogether.
The Attraction of Curves
When we say gravity is a curvature of space, what does that really mean? It all has to do with the fact that the laws of physics are the same from any vantage point.