kasia in a nutshell

Anything falling wold eventually hit whatever's gravity is pulling it, so it will never reach "fastest possible speed".

Yes, anything moving at any speed ages slightly faster, provided it is brought back and compared to something that was stationery the whole time, otherwise the aging is meaningless.

No, you have that backwards.. although you do have the "only when compared to something else" point correct.

Light travels as fast as it does because it only travels through space and not time (ie: even if you were moving at close to the speed of light it would still be traveling at the same distance relative to you, because it's not traveling through time).

So when you travel through space faster, you travel through time slower and vice versa.. hence aging would be slower.. my point about freefall was that in freefall you don't travel through space at all.. hence travel through time at fastest possible speed.

It's fun to think about.

There is no absolute frame of reference... therefore a body in "free-fall" is not any more or less stationary in space, than any other object... it is all relative.

Also if you are hauling ass (the technical term for traveling near light speed) through space, to your hypothetical twin staying on earth, you would be aging more slowly (relative to the observer)... such that on your return (assuming your trip was long/fast enough) your twin would be noticably older. However, you did not actually age slower... you just experienced less "time" compared to your twin on earth.

The frame of reference is space-time, it's absolute.. A body in freefall is not moving through space in reference to space-time.

At least that's how I remember Einstein's reasoning when he claimed Newton was right about an absolute reference.. except it's space-time not space!

I'm utterly confused, as usual, about this matter.

According to my very little knowledge of Einstein's theory, objects bend space-time which is what causes gravitational pull. So your 'free fall' would be a body falling into a space-time 'hole' created by a bigger object (i.e. a planet, star, etc). Ignoring that the body would eventually hit the object, how does that entail that the body is "not moving through space in reference to space-time"?

Mark is right, there is no absolute frame of reference.

Kasia, you should read this tiny and explicative book :

http://www.kolmogorov.com/LandauWIR.html

and then re-think the answer, It really dont makes much sense now because you are mixing ideas about movement, time and references. The train example at the begining clarify this.

Re space-time being absolute: I suppose that works, but it's not much help, since it means you still cannot compare times/durations between different frames of reference without taking their relative motion into account (funnily enough, neither can you compare motions either without taking their time frame into account). After all, neither time nor space is absolute on its own.

Also note that time passes faster or slower depending on the *acceleration* of a system. That also means that simply being closer or further from a gravitional source decelerates or accelerates your time, respectively. (Remember the famous experiment with the clock in a plane at 10km height running faster than one on the ground.) It's also why to a remote observer something falling into a black hole would appear to take literally forever to get there.

In any case, you don't age faster or slower. In _your_ _own_ timeframe, you age at the same pace as anyone else does in theirs. It's just that from _another_ _observer's_ frame of reference, your aging appears to proceed at a different speed than theirs.

I tried to bring this all together better but I have to admit that my grasp on these things has slipped. I used to have it down pat about some 10 years ago. I really should rejuvenate my non-computer interests...

Okay, I was pretty sure I was right and went to google for help..

http://astsun.astro.virginia.edu/~jh8h/Foundations/chapter8.html

General Relativity does state that an object in freefall is not accelerated.

So you could say when a bird poops on your head that in actuality you rushed up to meet the poop! Now there's a point to ponder..

maybe, but the effect of applying relativity theories over "traditional" physics are less than minimal.

There will be another matter if that poo will be traveling at or near enough to the speed of light, then there it will be no point about rushing because it is at/near its own speed limit. ;)

The key is that there is no speed unless you're comparing to something. :)

measuring it from a point located somewhere, yes

I recently saw a talk by a couple of Particle Physics Theorists her at work that believe that some recent evidence points to the the thought that the Speed of Light isn't necessarily constant.

just some food for thought on this interesting topic.

Jason

Your post has me worried. One day you're thinking about relativity, and the next post you're lost in the woods. I guess it's all relative!

I read about relativity over 30 years ago, so maybe I'm not up on all the latest ideas. The free-fall thing really bugged me. Heck, I'd just like my taxes to be lower, to heck with time dilation. :-(