What Is Galaxy? Definition And Following Examples
WHAT IS GALAXY – In this topic, we are going to know the definition of galaxy and identify the following examples.
According to NASA, it is basically a huge collection of gas, dust, and billions of stars, planets and their solar systems. All of these are held together by gravity.
It is derived from the Greek term galaxias (γαλαξίας) which literally means “milky”.
They are categorized into three, based on visual morphology:
- Elliptical
- One where it has an approximately ellipsoidal shape and a smooth, almost featureless image.
- Spiral
- This type consists of a flat, rotating disk of stars, gas, and dust.
- Irregular
- This type does not have a distinct regular shape like the other two.
Examples
- Milky Way
- Where our Solar System resides. Its name came from how it’s described from Earth. It is a translation of the Latin term via lactea which is from the Greek word galaxías kýklos ( γαλαξίας κύκλος ) which means “milky circle”.
- Andromeda (Messier 31, M31, NGC 224)
- A spiral type which is 2.5 million light-years away from Earth. Its name came from the constellation of which it appears.
- Sombrero (Messier Object 104, M104 or NGC 4594)
- A lenticular galaxy in the Virgo constellation which is 31.1 million light-years away from Earth. Its name came from its appearance that looked like a sombrero hat.
- Mayall’s Object (Arp 148)
- It is the result of two colliding galaxies which is found at about 500 million light years away from the Ursa Major constellation. It was discovered by American astronomer Nicholas U. Mayall, where the galaxy’s name came from.
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