Angular Velocity

So that last post started off alright, but ended up being a bunch of moral pontificating goo, so let's try something else.

I was reading an article on Cracked.com (a humor website I frequently visit) a while ago regarding the theoretical difficulties associated with time travel. There were a bunch of interesting points, but the one that stood out to me had to deal with the correlation between space and time. Depending on how much Discovery Channel you've watched out of boredom in your life, you may (I was going to write "may or may not", but seriously doesn't saying "may be" or "might be" automatically imply that the opposite can be true? I guess that's for a different post) be familiar with the widely understood notion that the universe is expanding (or contracting, whatever), with galaxies and such moving throughout the void in all directions. So what was proposed on Cracked was that should we actually devise a way to travel back in time to, say, the same spot 20 years ago today, the time traveler would likely find him or herself in the middle of space, since the earth would not have reached that point in space yet. So the solution would likely be extensive calculations, and charting, and blah, and blah, and blah, and that's not the point I'm getting at.

What I am getting at is that we're all moving. All the time. Whether you're sitting still, or being trapped in a block of ice by some evildoer, despite being completely motionless, you, along with the rest of the planet and everybody on it, are always traveling across some distance in space as the earth rotates around its axis, revolves around the sun, and orbits some massive black hole in the center of the milky way or whatever.

The reason we're not constantly holding on for dear life is the same reason you can walk around on a moving train car without being Spider-man. There's some scientific name for it, but it escapes me, so basically it's that when on board an object moving at a constant velocity, you can pretty much move freely relative to that object. The same applies to skateboards, cars, and airplanes. Trouble, from a balance standpoint, only arises when the object accelerates (or decelerates, which is just accelerating in the opposite direction), that's when you should consider holding on for dear life. As a quick aside: that would make for a half decent movie plot, either the earth starts accelerating and no one knows why, or some villainous scheme is hatched to accelerate the rotation of the earth. Buildings would fall, there would be floods, storms, the whole shabang. I'll keep that in mind, but it's all besides the point.

The point to take from that is that despite your personal action or inaction, you always have some velocity relative to a stationary point in space. An object at rest has a velocity of 0 on earth, but in terms of the universe has a velocity of 0 + the Earth's Velocity. Simple enough, right? Well, no, since it's really a matter of angular velocity, acceleration, centripetal force, gravitation constants, and a whole bunch of other physics variables. But I'm no physics major, so for the sake of this post I'm going to stick with velocity. If anyone ever reads this and happens to know a bit about physics and wants to call bullshit on this whole thought process, go ahead, I'm just throwing ideas out here.

So we're all moving, all the time, so what? Well where this becomes interesting is when you take into account that velocity is a vector, in that it has both a magnitude and a direction. Going 35 mph north east is the same as going -35 mph southwest, moving at a high velocity in one direction is the same as moving at a low velocity in the opposite.

This comes into play when considering the whole expanding universe thing that I previously mentioned. For simplicity's sake, let's say the Earth is traveling, along with the rest of the galaxy, eastward at a speed of 5 mph. Now lets say you decide, while on earth to drive westward at a speed of 20 mph. While you've increased your speed by 20 mph on earth, you've actually decreased your speed relative to the rest of the galaxy by 15 mph. Again, the way the universe moves is much, much more complex than that, but it's interesting to think that depending on the direction you're facing while walking, you may actually be decreasing your velocity in the universe.

As I've mentioned, I'm no physicist, not even close. A lot of this is probably so wrong that Newton's ghost is plotting his revenge, and after typing it out, I don't even know if the logic of it all is sound (Or maybe it's all right, and I've just made some kind of ground breaking discovery! [Definitely not]), but it was an interesting thought nonetheless. Now that I look at it, it probably would've made more sense and had been easier to explain using airplanes, but oh well. It's fun to flex the old brain muscle from time to time, even if the brain isn't a muscle and what you're thinking is very probably horribly incorrect. So...uh, yeah.

C