imagine the speed of light is just 100km per hour

100 km per hour is equal to 27.8 meter per second. which is a high speed for driving, but really slow speed for molecule.

beside of special relativity effect, there are much more funny things will happen. if any one who like to look for the effect due to special relativity, one can set the speed of walk of normal people ( 4km per hour ) to be 4% of speed light in any simulation in the web. or for cycling ( 10 to 20 km per hour) is 15%, and a normal driving will be 50%, the special relativity effect become obvious at this speed.

never the less, the things become funny is due to special relativity, which set a maximum speed be the speed of light.

the first thing come up in my mind is, boiling a water. according to statistical mechanic, the average speed of particle is given by

v = Sqrt [ (2 R T ) / M ],

where R is a physical constant (=8.314472), T is temperature, and M is a molar mass of a particle.

for water, the mass is 16 +2 = 18 gram = 0.018 kg.

thus, for room temperature, which is 300K, the average speed is 526 meter per second! which is much faster then the speed of light!, thus the physic is not applicable in this case.

the correct physics for relativistic particle, which moving very close to the speed of light, is by the Maxwell-Juttner distribution.

we don't have to go to that mathematics. all we have to know is, there is no more boiling water, even liquid water does not exist!

how about air? air is mainly composited of nitrogen gas, the molar mass is 0.014 kg , thus, the highest temperature is 2K. , which - 272 degree! and nitrogen will be solid in the temperature!