Things I learned last night at a lecture about the speed of light:
1. The speed of gravity is the same as the speed of light. Have no idea what it means that gravity has a speed, but have emailed my dad and am hoping to find out soon.
2. The speed of light may have been faster at the beginning of time than it is now. Einstein thought it was always the same, but scandalously, Einstein might have been wrong about that.
3. There is a horizon at the edge of the galaxy beyond which we cannot see because light from anywhere beyond that point hasn't had enough time to get here since the birth of the universe. But as the universe gets older and older, we can see farther and farther.
4. Possibly there are teensy little particles that make up gravity and space and time, just like there are teensy little particles that make up people and light and fishes and whatnot.
Thing I am a little disappointed not to have learned:
1. Why E=MC2.
1. The speed of gravity is the same as the speed of light. Have no idea what it means that gravity has a speed, but have emailed my dad and am hoping to find out soon.
2. The speed of light may have been faster at the beginning of time than it is now. Einstein thought it was always the same, but scandalously, Einstein might have been wrong about that.
3. There is a horizon at the edge of the galaxy beyond which we cannot see because light from anywhere beyond that point hasn't had enough time to get here since the birth of the universe. But as the universe gets older and older, we can see farther and farther.
4. Possibly there are teensy little particles that make up gravity and space and time, just like there are teensy little particles that make up people and light and fishes and whatnot.
Thing I am a little disappointed not to have learned:
1. Why E=MC2.
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