Constellations are groups of stars that form patterns in the night sky. Today, we identify with 88 known constellations. A Middle Eastern civilization called the Sumerians are thought to have given the first names of the constellations we know today , about 5,000 years ago. In this article, you will also learn about the Solar System and the speed of light.
Constellations
The largest constellation is called the Hydra, which is represented by the shape of a sea serpent. The smallest constellation is the Crux Australis, which is known as the Southern Cross. The constellation that offers the most stars that can be seen with the naked eye is the Centaurus , the Centaur. Other well known constellations include the Big Dipper, the Little Dipper, Orion the Hunter, and Canis Major (the Great Dog).
The Solar System
The Solar System formed around 4,560 million years ago. Alongside moons, comets and other celestial bodies, the Solar System was home to a handful of planets. Orbiting the Sun, the planets are attracted to it because of gravity. For those of you that don’t know, Pluto is no longer a planet and the eight remaining are Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and of course, Earth. Pluto was downgraded in 2006 by the International Astronomical Union. It is now categorized as a ‘dwarf planet.’
Speed of Light and Light Years
Have you ever heard the saying “traveling at the speed of light?” In space, light travels at a speed of 186,282.4 miles per second or 670,616,696 miles an hour. To get an idea of just how fast that is, consider what we see when we gaze into the sky and look at the nearest star. The light we see was actually left behind more than four years ago. The time it takes light to reach Earth is different when it comes from other bodies in space.
To understand this, you have to become familiar with the measurement of a light year, which measures distance , not time. Distances in space are often expressed as light years, which is the distance it takes for light to travel in a year. Below you will learn it takes light to reach the Earth from the following celestial bodies:
· Moon , 1.26 seconds
· Sun , 8 minutes 17 seconds
· Neptune (the furthest planet) , 4 hours 21 minutes (when the planet is at its maximum distance from Earth)
· Most distant star in our galaxy , 62,700 years
· From nearest body outside our galaxy , 174,000 years
· Furthest visible star , 2,309,000 years
· Most distant known quasar , 14,000,000,000 years
The distance at which we could never see the Sun with the naked eye is 60 years.
