# Mass and Acceleration at Light Speed

Yesterday we looked at the two postulates of Einstein’s Theory of Special Relativity. We saw how our view of time is changed by taking the two postulates and applying them to motion at or near the speed of light. Now let’s look at mass and acceleration at light speed.

Looking at the top equation, which we presented yesterday, you can see that at the speed of light, the equation’s denominator becomes 1 – 1, which is zero. Time stops. If the velocity could somehow exceed the velocity of light, the denominator would be the square root of a negative number, which is not possible.

Another one of Einstein’s equations is a description of length in the direction of motion. The second equation shows that an object’s length in motion (L’) is equal to its length at rest (L) times the quantity square root of 1 minus the velocity (v) squared divided by the speed of light (c) squared. Thus the faster you move, the thinner you are in the direction of motion. An object one meter long at rest would be .765 meters at half the speed of light. At the speed of light, it would disappear, because it would have no length. There would be energy, but no physical length. What travels at the speed of light? The answer, of course, is light itself. Light is two-dimensional. It has no thickness in the direction in which it is moving, precisely what Einstein’s postulates predict.

Mass is another quantity that is affected by Einstein’s postulates. The equation for mass is similar to the equation for time. The mass in motion (m) equals the mass at rest (m’) divided by the square root of 1 minus the velocity squared divided by the speed of light squared. As an object moves faster, its mass increases, but it can never reach light speed. What, then, can we know about mass and acceleration at light speed?

One of the fundamental laws of physics is Newton’s Second Law. It says that when we apply force to a mass, the force (F) depends on the amount of the mass (M) and how much we want it to accelerate (A). The equation is F=MA. At the speed of light, the mass of an object would be infinite, and the force required to accelerate it to that speed would also be infinite. Because of the magnitude of the force, the mass would collapse into a black hole long before reaching light speed. So, it is not possible to achieve mass and acceleration at light speed.

Scientists have verified these formulas experimentally. When you accelerate a sub-atomic particle to a high velocity in a particle accelerator, its mass increases. So what created the mass in the first place? Infinite force – one of the properties of God. Proverbs 8:22-31 finds “Wisdom” is the tool God used for everything He created. Einstein has given us an excellent way to get a small understanding of the creation we live in and the wisdom and power of the God who created it.

— John N. Clayton © 2020