What is Theory of Relativity – Light and Time? | Definition, Types, Formula & Examples
Speed of Light
One of the important concepts in relativity is the speed of light. You may think that the light is instantaneous, that when you turn on the light in the room, the light instantly illuminates your entire room. However, it seems that light actually travels at a certain speed. This speed is really fast.
The speed of light is 299,792,458 m/s. In other words, light travels 186,000 miles per second. The speed of light is always the same. In physics, it is a constant and is usually represented by the letter “c” in formulas.
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Turns out nothing is faster than light. It was this constant speed of light that inspired Albert Einstein to propose the theory of relativity. Einstein discovered that as objects begin to approach the speed of light, the laws of physics invented by Isaac Newton begin to break. Einstein’s theory of relativity helps explain why this happens.
Light Year
Astronomers use the speed of light to measure the distances between stars and other galaxies on Earth. A light year is the distance light travels in a year. It equals 5,900,000,000,000,000 miles. That’s five trillion, nine hundred billion miles.
Some stars and galaxies are so far away that the light we see left the stars billions of years ago. Light can not only travel quickly, but also travel great distances.
Time Dilation
One of the most interesting results of relativity is time dilation. Time dilation suggests that time will pass more slowly for a person traveling near the speed of light than for a stationary person.
Time and Gravity
In Einstein’s theory of general relativity, he proposed that time passes more slowly when gravity is strong. This means that time will pass faster on the top of the mountain than on the beach. In fact, you will age more slowly at the beach than in the mountains. It’s a very small difference, however, you’ll never notice one.
Light and Gravity
Another concept of general relativity is that light rays are bent in a gravitational field. The Sun actually bends enough that we can see the stars behind the Sun. However, it takes an enormous amount of gravity to bend light significantly. As large as the Earth, it barely deflects light.
Is this Science Fiction?
Much of relativity is like science fiction, especially concepts like time dilation. However, scientists were able to experiment with very precise clocks to prove this theory to be true. This is not science fiction, but reality!
Interesting Facts about the Theory of Relativity
Theoretically, if you could travel faster than the speed of light, time would turn back.
Scientists believe that the universe is expanding and that parts of it are moving away from us at speeds faster than the speed of light.
Albert Einstein once said: “When you’re flirting with a pretty girl, an hour seems like a second. When you’re sitting on the ashes, a second seems like an hour. That’s the theory of relativity.”
Many aspects of relativity have been confirmed by experiments conducted with particle accelerators. Particle accelerators can accelerate electrons and protons to nearly the speed of light.