The only sure way to know if a head or body is dead is to check its eyes for dilation, that is brain death. And Even then you may not know because the brain shuts down like a navy ship seals flooded compartments.

To the person with the head cut off, I would assume (because Ive never had my head cut off) that time dilation would make it an eternity.

Time dilating kitty!

>> ^omnistegan:
Then what is the reference point for speed in space? For speed on Earth we can use the surface of the Earth as a reference point for speed, and in our own solar system we can use the Sun, but at what speed is the Sun moving? And in reference to what? And what does that make of the speed and direction of motion of the Earth? And us? So are we really moving? or is everything moving around us in reference to our own perception?



That has 2 answers really, a metaphysical one and a physical one.

First, let us use the physical reality in which we experience. The most modern explanation of motion is the law of relativity. The law of relativity states that each observer has a valid claim in saying the they are moving and the object in reference is staying still. So in other words. The person on the train has just a valid assertion that the train is moving and the man is staying still, as the man on the ground saying he is moving and the train is standing still. In other words, it is your observation that is true for you, and it is their observation that is true to them. Both are valid claims. One is not righter than the other.

This realization was huge for science. To quote wikipidia on the matter:

“Special relativity overthrows Newtonian notions of absolute space and time by stating that time and space are perceived differently by observers in different states of motion. “

So, in essence, there is no such idea in relativity as what is “really” moving or not moving. Everything is happening as you experience it in your own frame of reference! Mind blowing I know. This is what is known as special relativity however, general relativity has to deal with gravity and acceleration which complicate matters greatly because of time dilation and space time curvature.

Now, metaphysically speaking space and time might not be real things in and of themselves. They might be complete fabrications of the mind. There is no necessity for time to exist, the universe could exist very much like a formula which is timeless and without space. In other words, the idea of time, space, motion, and all these fundamental things could really just be a subject of the mind and not of the universe itself. I personally believe that there is not objective time, space, or motion. These are all subjects of the mind and not of the universe itself. I think of the universe as a formula and those ideas of time and space and motion only occur inside the formula; that huge equation of everything we know.

So in essence, my metaphysical understanding of the universe actually gives way to special relativity. I would say the truth of what you observe is an unshakable experience. In other words, no one can say that you didn't experience something the way that you experience it. But that experiences in and of itself doesn't point to any underlying truth of how the universe actually works. In other words, your experience with the stuff of the universe is filtered through your mind and changed from the stuff it actually is to the stuff your brain understands; it is no longer the actual but the interpreted. We have no subjective way to show any of the stuff we experience actually maps onto the actual, it just isn't possible.

While I do not doubt the effect of time dilation, I have serious doubts about our capabilities to test and measure it. When you take a clock up into a plane and fly it around, a lot of environmental factors change besides speed over time, several of which could be responsible for an error of such a small magnitude.