Where are we in Space?
Earth, the planet we live in, has one natural satellite called the moon, which is about one quarter of its size.
Earth is the 3rd planet orbiting the Sun, in addition to the 7 other planets and their moons, comets, asteroids, meteors, dust and gas, all which make up the Solar System.
The Solar System is located in a galaxy called the Milky Way and lies on the edge of one of its long-curved arms.
The Milky Way is one of the largest galaxies in a cluster, known as the Local Group. Our galaxy, the Milky Way, also has a supermassive black hole in the middle.
Millions of galaxy clusters make up the Universe.
A galaxy is a large group of stars, gas, clouds of dust and empty spaces that rotates but is all held together by gravity. Types of galaxies include:
- Spiral galaxies: such as our galaxy the Milky Way, are disc-shaped galaxies that spin slowly, looking like whirlpools, and often have 2 arms that curl out from the center.
- Barred spiral galaxies: have arms that wind out from the ends of a central bar of stars rather than from the core.
- Elliptical galaxies: ball or egg shaped.
- Irregular galaxies: have no shape.
The nearest neighbors?
The Milky Way Galaxy is part of a cluster, known as the Local Group of galaxies. The Andromeda Galaxy is the largest galaxy of the Local Group, followed by the Milky Way and the Triangulum Galaxy. There are around 30 other smaller galaxies in the group.
Andromeda is our closest galactic neighbor. It is said that five billion years from today, our Milky Way will collide with it, but we might not notice it.
Proxima Centauri, discovered in 1915, a red dwarf star, is the nearest neighbor to us. It lies in a group of three stars called Alpha Centauri.
How were the planets named?
All of the planets, except for Earth, were named after Greek and Roman gods and goddesses.
- Mercury: Hermes, Roman God of travel
- Venus: Aphrodite, Roman Goddess of love and beauty
- Mars: Ares, Roman God of War
- Jupiter: Zeus, The King of the Roman Gods
- Saturn: Kronos, Roman God of time
- Uranus: Uranus, Roman God of the Sky
- Neptune: Poseidan, Roman God of the Sea
- Pluto, which is now classified as a dwarf planet: Hades, Roman God of the Underworld
- Earth: English/German name which simply means the ground