Time has Velocity?

The period between school semesters is fraught with peril.  It would be like a ship of the line (circa 1857) traversing a shoal known for harboring Reefs of Peril®.  If you don't keep your mind active it's going to crash.  In an effort to stave off the intake of water followed by certain ingestion by a shark I have been reading The Fabric of the Cosmos by Brian Greene.  It is a good read but somewhat slow at times.  I did want to share something briefly that I came across and in conjunction with a previous post I did on time travel.  Greene was explaining relativity and the effect that moving clocks run slower.  I have often times had difficulty with these subjects since I have trouble identifying who the observer is at the moment.  If you were to look at a situation from the point of view of the other guy (the moving object), you would have a completely different problem.  Anyway, this is not about that.

The thing that Greene mentioned was about how time and space work.  The top speed in the universe (so far) is lightspeed (that speed from Star Wars that would make the galaxy the size of our solar system).  Also remember that one moves both through 3D space and also through time from one second to the next.  Greene wrote that one's total velocity through space-time is equal to the speed of light.  Wha?  Your speed through space plus your speed through time is equal to the speed of light.  Basically, if you're sitting still and not moving at all your speed would be 3 times 10 to the 8 meters per second.  Alright?  Now, start moving.  Since your total speed in space-time can't exceed lightspeed, some of your velocity in time must be transferred to your motion in space!  Whoa!  Thus your watch starts going slower.  Get going faster and faster and a crap-ton of your temporal velocity gets stolen by the space motion.  That's why if you approach lightspeed in your ship, turn around after a  few years (by your clock!) and come back to Earth that you'll find many a decade have gone by (according to the Earth clocks).  I believe the real explanation would be nothing like this, but it was the best description for the reason moving clocks go slower that I've ever seen.  How cool, eh?

Disclaimer: After writing this post I notice that I used speed and velocity, but being too lazy to fix it, know that I meant velocity with every instance of the word speed.