This article is about various types of celestial bodies in the universe. The universe is the collection of different types of matter and energy.
All the objects that are visible in the sky are called celestial bodies. (Human-made satellites are not celestial bodies.)
For example, Stars, Planets, Satellites, Asteroids, Meteoroids, Comets, etc.
What is Universe?
The universe is everything that exists in space. The universe is made of voids (empty spaces) and all the matter. It includes galaxies, stars, planets, and all other forms of matter and energy.
The Universe is considered to have 3 types of substances:
(1) Normal Matter
(2) Dark Matter
(3) Dark Energy
Normal Matter
> It includes all the atoms that make up stars, planets, animals, plants, and every visible object in the Universe.
> Approximately, 5% of the universe is normal matter.
Dark Matter
> The mysterious, invisible substance of the universe is called dark matter.
> Approximately, 25% of the universe is dark matter.
Dark Energy
> Mysterious energy or force that affects the universe. It is the opposite of gravity and it is expanding the universe.
> Approximately, 70% of the universe is dark energy.
What is a Galaxy?
Matter of the universe is found in the groups and clusters of galaxies. It is believed to have 100 – 200 billion galaxies in the universe. A Galaxy is a huge collection of gases, dust, and billions of stars and their solar systems. We are part of a galaxy called the Milky Way.
Our galaxy has more than 200 billion stars. Sun is one of these stars. Sun has its own planetary system which is called the Solar System.
There are so many other stars that have planetary systems (Solar systems). More than 500 planetary systems have been discovered in our galaxy.
| Stars Big bodies are made of hot gases having their own light and heat. Example: Sun  |
Planets Bodies that don’t have their own heat and light. They are very small as compared to the stars. Planets get light and heat from the stars. Planets move around the stars. Example: The Earth  |
Satellites Smaller bodies move around the planets. Example: The Moon.  |
Dwarf Planets Small planets that move around the Sun but do not have the characteristics of a planet. Example: Pluto  |
Comets Comets are much smaller than dwarf planets. They are giant pieces of rock and ice that travel through space and release gas and dust. They look like a coma in the sky.  |
| Asteroids Very small rocky and metallic objects that travel through space. They are smaller than the comets. The diameter is from 1 meter to a few hundred km. Example: Asteroid belt between Mars and Jupiter.  |
| Meteoroids Meteoroids are space objects that range in size from dust grains to small asteroids. They have a diameter of up to 1 meter. They come from asteroids. After entering into the atmosphere they start to glow. Then they are called a meteor. Example: Shooting stars.  |
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