Can something exceed the speed of light?

AI Thread Summary
The speed of light is established at 3*10^8 m/s through Maxwell's equations and wave theory, and it is a fundamental postulate of relativity that nothing can exceed this speed. When a body experiences constant acceleration in space, its inertial mass increases with velocity, preventing it from reaching or exceeding the speed of light. Observers moving with the accelerating body will perceive constant force and acceleration, but this will not hold true for external observers. Absolute velocity is a misconception; all speeds are relative, and no object's speed can exceed the speed of light. The confusion often arises from discussions about group and phase velocities of light in different media, where light can appear to exceed its speed in a vacuum.
ahmedhassan72
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How was the speed of light proved to be 3*10^8...also How it was proved that nothing can exceed the speed of light?...and what will happen if something moves under the effect of certain force with constant acceleration in space i.e the net force on it is constant and not equal zero...is that possible and will that body at certain instant exceed the speed of light ?and if so what will happen...another question, does my absolute velocity in the universe exceed the speed of light i.e I move with 100 km/h the Earth moved with x km/h and the galaxy and so on ...
Thanks for consideration
 
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ahmedhassan72 said:
How was the speed of light proved to be 3*10^8
Using Maxwell's equations & the wave equation.
ahmedhassan72 said:
...also How it was proved that nothing can exceed the speed of light?
It is a consequence of one of the postulates of relativity.
ahmedhassan72 said:
...and what will happen if something moves under the effect of certain force with constant acceleration in space i.e the net force on it is constant and not equal zero...is that possible and will that body at certain instant exceed the speed of light ?
No since the body's inertial mass increases with velocity (http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html).
 
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ahmedhassan72 said:
How was the speed of light proved to be 3*10^8...
It was first deduced, then measured. (Given our modern understanding, it is now defined to be a certain speed.)
also How it was proved that nothing can exceed the speed of light?...
It's a consequence of relativity.
and what will happen if something moves under the effect of certain force with constant acceleration in space i.e the net force on it is constant and not equal zero...is that possible and will that body at certain instant exceed the speed of light ?and if so what will happen
While the force and acceleration will appear constant as measured by observers moving with the body, it will not appear constant to others. The speed of the body with respect to any other object will never reach light speed.
...another question, does my absolute velocity in the universe exceed the speed of light i.e I move with 100 km/h the Earth moved with x km/h and the galaxy and so on ...
There's no "absolute" velocity; all velocities are relative. No, your speed with respect to anything will be less that the speed of light.
 
We have to careful about whether we are talking about the group or the phase velocity. This is where the confusion comes in when people say they made light travel faster than the speed of light, they mean the group (or is it phase?) velocity of light through a specific medium. Nothing can travel faster than light in a vacuum, light can exceed its group (phase?) velocity in a medium like water, and give off pretty blue radiation.

I hope someone else can explain this better than me.
 
ahmedhassan72 said:
another question, does my absolute velocity in the universe exceed the speed of light i.e I move with 100 km/h the Earth moved with x km/h and the galaxy and so on ...
Thanks for consideration

What are the speeds of these objects being measured with respect to?
 
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