Question concerning the special theory of relativity?

If I understand it correctly, the speed of light from all frames of reference is the same regardless of motion. How is this exactly possible? If a vehicle is moving say 1000 mph and a light is emitted at the speed in directly the front of the vehicle what happens to ensure the speed remains constant and does not take on the velocity of the vehicle?

I thought maybe two possibilities:

1. The added kinetic energy given to the light is converted directly into mass to compensate the speed.

2. Time slows to compensate for the speed.

Can someone explain?
No light does not have mass but energy can be converted directly into mass at at the speed of light. This has been proven in many experiments many times before.

The first point to consider is that speed is never absolute, only relative, so you can have, say, two observers of a single event, and they will disagree on what they observe.

Say there is a spaceship moving a near-to-light (NTL) speeds relative to two observers. It is moving at .8c relative to observer 1 and .9c relative to observer two.

They will both observe that time is running more slowly on the spaceship, but they will disagree on how much slowly it it running. And neither will be more correct than the other.

So yes, time slows, but not ON the spaceship, just as observed from different reference frames, and not the same from each of the other reference frames. So there is nothing absolute about the change, just relative.

This is not simple stuff. We say it is "counter intuitive", which means it makes no (common) sense. But it is not just theory or conjecture. This has been confirmed on a daily basis in particle accelerators.

Your #2, time and distance dilate to make it true.


We start with the Train and pitcher thought experiment.
You are standing on the ground next to a train track.  A train going 100 km/hr is going past.  On a flat car is a baseball pitcher that you know can throw 195 km/hr fastballs throwing toward toward you.  You have a radar gun so you can measure the speed of the baseballs.
What speed would you measure if the train was coming toward you? (100 + 195 = 295 km/hr )
What speed would you measure if the train was going away from you? (195 - 100 = 95km/hr)

Now we start Special Relativity:

Toward the end of the 1800s scientists measured the speed of light compared with the speed of the earth in orbit.  They expected that knowing the speed of the earth going toward the source of light the velocities would add and that when going away from the source of light the velocities would subtract.  BUT that is not what happened.  It did not matter if they were moving toward the source or away from the source, they got the same value:  roughly 3 * 10^8 m/s.  VERY STRANGE!  They were sure something was wrong.  It was not possible, based on their assumption that Time and Space were absolute (unchanging) for that to be true.  

Einstein's insight:  He thought,"What if the speed of light IS absolute and Time and Space could change to make that true? What does that do to everything else?  He worked it out for all the physical quantities.  It works!  What you get is consistent with what we observe in experiments.

This site will let you play with what happens at near light speed
http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html