Relativity

Physicists have got a puzzle: the speed of light is constant, no matter how fast you're going or which direction you're going. If you follow along in the direction of light, according to nice normal Newtonian physics, your measurement of light should be slower than if you're heading "upstream" so your velocity is added to the light's. It doesn't happen that way.

Lorentz and FitzGerald came up with an explanation: light moves through the ether at a constant rate, and the faster you go the more your measuring equipment shrinks, so it is always measured the same rate. This retained the concept of absolute space and time.

Einstein chucked absolute space and time--and the possibility of "absolute simultaneity"--when he redefined "simultaneous" in terms of clocks synchronized by light flashes. Then Einstein had two postulates: the laws of physics are the same for uniformly moving observers, and light always propagates at the same speed, c, which is independent of the source's motion. In other words, light is not like a baseball, which if you're riding a train at 5 mph and you throw it at 5 mph it will be going 10 mph relative to the ground. No. Light goes at c, and senders always send light at c and measurers always measure light to go c, whether the sender or measurer is moving or not.

It's weird, yes it is. It's also weird that even though modern physicists have thrown out the ether, they still keep Lorentz's equations because they correctly describe the phenomena.

Just to add a bit of fun, when things go faster time slows down. Apparently, then, light is timeless. Time also slows down in gravity wells. I wonder if there's a point where something in a gravity well becomes timeless? I know a creationist researcher from Sandia Lab is theorizing that the universe looks much older than 6000 years because Earth is in a gravity well and time is going slower for us, and therefore the stars really are much older.

I think that if you've got God, you have an absolute. I know this is true in morals and truth; I suspect it is also true in time and space. I wish I understood all this better.