why does mass increase and time decrease as we approach the speed of light?

Question

how can our mass increase?
mass always remains a constant.

Answer 1

Consider we are approaching a source of light and at the same time measure the speed of light. We expect the speed of light to increase from the value C.

If we are receding from a source of light, we expect the speed of light to be less than the value C.

Experiments conducted to measure the speed of light from a moving laboratory did not give any change in its value.

This constancy of speed of light which is independent of the speed of the observer in either direction has made us to review our knowledge about length, time and mass.

If we stick to the hypothesis that length, mass and time are all absolute and will not change under any circumstances, then we must be able to measure the speed of light greater when we move toward it and less when we move away from a light beam.

But it was experimentally proved that light’s speed is constant whether one is moving toward it or away from it.

Then the only other possibility is the length, time and mass must change their values in such a way that when we use a measuring rod and clock in the moving reference frame it must yield the constant value on comparison to the measuring rod and clock maintained in a reference frame which is at rest.

That is length, mass and time are not absolute but they are relative to reference frames.

In a moving frame, length will be shortened on comparing it to that in a stationary frame.

Similarly time will move slowly in a moving frame.

However, measurement of speed of light will yield the same value in both the frames.

Various experiments conducted with micro particles like electrons protons which can move fast nearly equal to the speed of light, has proved that their mass increase when they move swiftly.

Answer 2

This is relative of course. If you were moving very close to the speed of light, someone on Earth would see you getting more massive, and time slowing down for you. But according to you, nothing has change. You still feel the same, and time is passing normally for you.

This effect is called "Special Relativity", as proposed by Einstein over 100 years ago. It is a consequence of light travelng at a constant speed of 300,000 km/sec in all referential frames, meaning that even if you'r moving at close to the speed of light and you turn on a flashlight, the light beam coming out of the flashlight would still be traveling at 300,000 km/sec according to you, as well as someone on Earth.

Answer 3

I have not the answer, but look my link.
This was established by special relativity. To demonstraie it takes a lot of place