Does an object in motion get longer or shorter as it approaches the speed of light?

it elongates.

it elongates to an outside observer. but to the ruler itself, it stays the same size and everything around it begins to get slower and slower until it stops moving altogether (at the speed of light)

look up the theory on what happens when an object approaches a black hole. it will stretch to an outside observer because the closer you are to the event horizon, the faster you will accelerate. eventually the bit of the ruler closest to the hole will be accelerating at a faster rate than the farthest bit and it will stretch out.

It will compress.

its called length contraction.  
http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/tdil.html

It seems like it will elongate becasue from observation things that move fast appear to blur into along streak.  This is an illusion that manifest becasue the human visual system cannot proecess data when the eyes are in rapid (aka sacadic eye movement) eye movement.

The object will appear to become shorter in the direction of motion to or from the observer.

But it is important to understand that if you were with the moving object, you would not notice any change at all. Nor would an observer that was moving at a much lower speed in relation to this object. This is a RELATIVE effect" one that an observer will observe, but not something that 'happens' to the object in any observer-independent way. That is why it is called "relativity".

But do not think this means this is all a sort of illusion. If I am going near to light speed, the distance to a star will become shorter, AND I will travel though that shortened space at an appropriate speed. If the distance 'appears' to be halved - if the space is contracted by half - I will actually pass through it in half the time.

But this gets stranger still, since, if you were on the moving object, you would see exactly that the Earth, and not you, had ITS dimension contracted.

MidAtlantean2 said, "The object will appear to become shorter in the direction of motion to or from the observer."

Yes.  An important word there is "appear."  According to Einstein, If you attempt to measure the length of the object as it whizzes past you, you will get a smaller number than if you had measured it while you were riding along on top of it.  Is it *REALLY* shorter?  Well, that's where you have to decide what you mean by "real."  It's the same object either way.  It's world line in Minkowski spacetime is the same world line either way, so in one sense, no, it's not really shorter.

In another sense though, what is real to YOU is what you can measure, and if you try to measure the object when it is flying past you, any technique you use will come up with the shorter measurement.  So, in that sense, the object really does get shorter the faster it moves.