Is it really not possible for any matter to reach the speed of light?

Question

Applying my very very limited knowledge about relativity base on what i've learned on my previous question. Now there are 3 imaginary galaxies (with linear motion) of the same size & composition which lies on an imaginary straight line, galaxies A, B & C, respectively. A is approaching B at 50% the speed of light, B is stationary & C is approaching B at 60% the speed if light. All observations are relative to me (observing at a comfortable distance, in the comfort of my chair). Is it correct to conclude that galaxies A & C are moving at 110% the speed of light relative to each other? If i were in galaxy A, would i observe galaxy C approaching me at 110% the speed of light? Please explain.

Answer 1

According to Einstein's theory, which has proven to be correct in all tests done on the theory, nothing with matter can reach the speed of light. Because matter is just another form of energy, the faster you go the more mass is added. To go the speed of light, you would have to add infinite energy to a galaxy which would add infinite mass. These infinities make it impossible for anything with mass, like a galaxy, to go the speed of light. Since time also stops for a light beam, according to the theory, another impossibility would be for you to see something approach at or greater than the speed of light.

Answer 2

YES, It is really not possible for matter to exceed the speed of light.



You cannot combine velocities into a relative velocity which violates the fact that matter cannot exceed the speed of light. Neither "A" nor "C" are traveling at velocities in excess of the speed of light. The relative combined velocities are meaningless...



Also, if you think about it...you could never "SEE" anything moving that fast... You might be able to see a 45 Caliber bullet in flight, but you cannot see a 223 Caliber bullet in flight...especially head on, coming right at you...and those velocities are NO WHERE NEAR the speed of light.



Last item: Whatever is moving Galaxy A will also impact the stable position of Galaxy B, and Galaxy B will begin to move at some point. The influence of Galaxy B will affect the flight line of Galaxy C to some extent and affect its flight line to an unknown degree. Merger of all three galaxies will be some kind of cataclismic event that will affect the entire nearby area (say out to 1,000 light years) with immense radion increases and untold amounts of assorted size debris flying in all directions.

Answer 3

The speed of light is constant. Experimental evidence has shown that the speed of light is independent of the motion of the source (that is in your case, the galaxies in which you are observing).



Galaxy A observer would not see Galaxy C approaching at 110% the speed of light since the light emanating from Galaxy C only travels at it's constant speed. More maddening is that if you were an observer sitting on a photon, you would also see the oncoming photons approaching at the speed of light.



You can not equate light approaching from opposing directions the same as automobiles approaching from opposite direcitons. This is the nature of light.

Answer 4

No, you are not correct. You are just scratching the surface of relativity theory. First, there is no such thing as stationary, since there is nothing to be relatively stationary to. In your scenario, A and C would be approaching you from opposite directions at the speeds quoted. However, they would not be approaching each other at greater than the speed of light. If you were in galaxy A, you would observe galaxy C approaching you at some fraction of the speed of light determined by the Lorentz Transform. You can only measure the speed of objects relative to your own reference frame.



The light from each of the galaxies would pass both of the other galaxies at exactly the speed of light, relative to the observers, since the speed of light is constant. In order to allow for the different (sub-luminal) speed observations (of the galaxies themselves) from different locations, time would slow down and length would contract as seen in the other galaxies by an observer in any of the galaxies described.



The comfort of your chair notwithstanding, you cannot consider your frame as the master reference in the universe. What is seen in A is every bit as correct as what is seen in B and C. It is just different.

Answer 5

There is no such thing as "stationary". It is not a thing which exists. There is only relative velocity between two objects.



When adding relativistic velocities, you need a special formula:

s = (u + v) / (1 + u*v/c^2)



where u is the relative velocity between objects 1 and 2, v is the relative velocity between objects 2 and 3, s is the relative velocity between objects 1 and 3, and c is the speed of light.



In your case,

s = (0.5*c + 0.6*c) / (1 + (0.5*c)*(0.6*c)/c^2)

s = (1.1*c) / (1 + (0.3*c^2)/c^2)

s = (1.1*c) / (1 + 0.3)

s = (1.1*c) / (1.3)

s = 0.84615*c



If you were in galaxy A, you would observe galaxy C approaching at 84.6% the speed of light.

Answer 6

You would see it approaching at 110% the speed of light, but oviously it isn't actually moving that fast. The usual analogy is if your next to a train track. A train comes by at 60MPH and someone flashes a light. You would see the light go at the speed of light + 60MPH, but the light is not actually going that fast.

Answer 7

Light IS matter... it is made of light particles (photons), which themselves DO have a mass and are actually there... so you kind of answered your own question...



Can matter reach the speed of Light?... Yes... Light can!