Light travels at 186,282 Miles per Second or roughly 300,000,000 Meters per second, so it does take time for light to travel (i.e. a lightyear = distance light travels in a year.
Now... ...Quickly, E=Mc^2 Energy is equal to the Mass times the square of the speed of light, as Einstein theorized. As a mass begins to approach the speed of light it is converted to energy; so a mass can never really travel at the speed of light, b/c it would take so much energy to get a mass to that speed it would end up as energy itself.
If you ever want to know how much energy a moving object has do this calculation
Mass of the Object in Kilograms = M
Speed of the object = X
Energy would be equal to = M*X^2
So... Pack of cigarettes traveling at 1/2 the speed of light:
Approx 150g * 150,000,000^2 = 22500000 Kg/M/s
22500000 Kg-m/sec = 295,875 Hp
So, if I did this right, you're looking at using 295,875 Horsepower to get it up to this speed, and also to MAINTAIN this speed. And that's assuming travel without resistance (in a vaccuum) and with no other gravitational effects positive or negative.
Relativity is a bit different...
...Think of it this way,
If you're on a schoolbus, and you are standing, holding your lunch dessert at your face, an orange per say. As you drop that orange from your face you will notice that the orange drops down to your feet, in a straight line.
Now, if the bus had a transparent side, and someone who was standing on the street saw you drop that orange they would not see it travel in a straight line they would see it drop in a curved line b/c you and the orange both have forward momentum, as the buss moved forward the orange moved down, bus moved forward orange moved down, eventuall it would have moved in a exponential curve downward (gravity accellerates).
So the moral of this story is... ...you and the orange have the same forward momentum so, to you, the orange moves in a straight line, but to the observer outside, it moves in an exponential curve. This is why you have to consider, in an experiment if your motion is RELATIVE, and what relivance?
another one, real quick.
We're revolving aournd the sun, well, the sun is moving in some general direction, relative to another solar system, which is moving in relation to another galaxy, with is moving in relation to...
...and what's hard is, there is no real point in which you can say that everything is relative to... ...we may discover a point in which the big bang originated, but that is a LOOOONG story...
did I answer your question?
-SF