Knowing The Term Light Year, Astronomy Units To Understand The Universe

Spiral galaxies, part of the universe (photo: dock. NASA)

JAKARTA Whenever they read astronomical articles about space objects, astronomers often add the term light year. However, not many know the meaning of the term.

Although it sounds like a time measure, the light year is a distance. Usually, this term is used when astronomers want to explain the distance of the earth to astronomical objects or explain the distance between the planet and the natural satellites around it.

Light year is a distance traveled by light in one year. This light-based distance measurement is much more efficient because describing space distances with a kilometer-long unit would be very confusing.

Although easy to understand, our distance from space objects is so far away that explanations with kilometer units will not be easy to understand. Therefore, astronomers prefer to use light year units compared to kilometers.

The light is moving very fast because the end has no mass. So fast, light is able to cross interstellar space at a speed of 300,000 kilometers per second and 9.46 trillion kilometers per year.

With this speed, we can imagine that the distance from space is indeed very far. When an astronomer explains that star A is 5 light years away from star B, this year's number only needs to be multiplied by distance per year.

Earth is not only surrounded by planets such as Mercury, Mars, Jupiter, and other planets in the ranks of the solar system. There are still exoplanets and exomoons in this universe so we must be able to understand the term of the light year.

The most distant exoplanet that astronomers have ever discovered is SWEEPS-4 b. The 3.8 times larger planet than Jupiter is about 27,723 light years from Earth. This distance will be difficult to change in units of kilometers, even with the help of a calculator once.

Although difficult to calculate mathematically, we can imagine how far the distance between Earth and SWEEPS-4 b or all objects in this universe, be it planets, galaxies, black holes, and much more.