Time 7

Before Einstein and the theory of relativity time was considered the one constant in the universe. It was absolute and everybody measured it the same way. So when Newton used the analogy of a giant clock for the universe, he met a very accurate consistent clock. But with Einstein that is not so. For Einstein the thing that is the same for everyone is the speed of light. It doesn’t matter where you are (save perhaps parallel universes or something like that) or how fast you are going if you measure the speed of light it is always the same. And now I would like to spend a few days on spacetime. We’ve already went over that briefly in past posts but I would like to go a bit more in depth. And we shall start with the horrible little picture I’ve included. It’s a 2-D picture that looks like it’s in 3-D and represents a 4-D phenomena. It starts by locating your point in space. That’s the arrow that points to the origin and says observer. Now let’s say on this hypersphere of the present, the observer arrow happens to find you in a very dark place for example a very large cavern. A very large cavern. And let’s say you have a flashlight. Now if you were to stand in that one spot and turn your flashlight on then you would produce a cone of light not unlike the one in the picture. You like would be moving away from your location in the hypersphere of the present as fast as is physically possible, and any action you do, say hop on your super-jet-powered-hoverboard and follow your flashlight’s light, would have to take place inside that cone of light. Now, but what does this tell us about you or more importantly how you are going to get out of the cavern in time to see tomorrows football game? Nothing it tells you nothing. That’s why it’s a horrible little graph. But it is a good way to think about the present and the past and the future and to incorporate time into the picture.