The theory of relativity states that when matter approaches the speed of light, its mass becomes infinite. 24 Channels. This means that the speed of light serves as the speed limit for the entire universe.

The speed of light is so constant that it is used to define international standard measurements such as meters (and by extension miles, feet and inches), according to the US National Institute of Standards and Technology. It also helps determine the kilogram and the Kelvin temperature unit using complex equations.

But despite the speed of light being recognized as a universal constant, scientists and science fiction writers spend time thinking about faster-than-light travel. So far, no one has demonstrated a true warp engine, but that hasn’t slowed our collective push for new stories, new discoveries, and new areas of physics.

What is a light year?

A light year is the distance light can travel in one year – approximately 10 trillion kilometers. This is one of the ways astronomers and physicists measure vast distances in our universe.

The light travels the path reflected from the Moon to our eyes in approximately 1 second, meaning that the Moon is approximately 1 light second away from us. It takes about 8 minutes for sunlight to reach our eyes and cover the distance from the Sun to the Earth, meaning the Sun is located about 8 light-minutes away. Light from Alpha Centauri, the closest star system to us, takes about 4.3 years to reach us, meaning Alpha Centauri is 4.3 light-years away.

This principle allows astronomers to see the universe as it was after the Big Bang, which occurred approximately 13.8 billion years ago. Objects 10 billion light years away appear to astronomers as they did 10 billion years ago (relatively shortly after the beginning of the universe), not as they appear today because they may no longer exist.

Interesting facts about the speed of light

• Is there anything faster than the speed of light? NO! Light is the “universal speed limit” and, according to Einstein’s theory of relativity, the fastest speed in the universe: 300,000 kilometers per second.
• Is the speed of light constant? The speed of light is a universal constant in vacuum, similar to the vacuum of space. However, light may slow down somewhat when it passes through an absorbing medium such as water (225,000 kilometers per second) or glass (200,000 kilometers per second).
• Who discovered the speed of light? One of the first measurements of the speed of light was made by Römer in 1676 by observing the moons of Jupiter. The speed of light was first measured with high accuracy in the Michelson-Morley experiment in 1879.
• How do we know the speed of light? Roemer was able to measure the speed of light by observing the eclipse of Jupiter’s moon Io. As Jupiter approached Earth, Roemer noticed that Io’s eclipses occurred slightly earlier than when Jupiter was farther away. Roemer attributed this effect to the fact that light takes longer to travel a greater distance when Jupiter is farther from Earth.

What moves faster than the speed of light?

Although the speed of light is often referred to as the speed limit of the universe, it is actually expanding slightly faster than the speed of light. The universe is expanding at a rate of just over 68 kilometers per second for each megaparsec of distance from the observer.

So a galaxy 1 megaparsec away from the Milky Way is moving at a speed of 68 km/s, a galaxy two megaparsecs away is moving away at about 136 km/s, etc.

At some point, at an incomprehensible distance, the rate of expansion exceeds the scale and exceeds the speed of light, and all this is due to the natural, orderly expansion of space.

Special relativity puts an absolute speed limit on the universe, but Einstein’s 1915 theory of general relativity allows for different behavior when the physics we study ceases to be “local.”