Stars are celestial bodies made out of hydrogen and helium atoms that give off light and heat from the nuclear objects inside their cores. In fact, if you go outside at night and look up, you will see small white dots in the sky, those are stars.
Fun Fact: Did you know the sun is a star?Stars can be classified by their sizes, here are the three main catogories for the star size:
The 7 Main Spectral Types of Stars:
Galaxies are systems of millions or billions of stars, together with gas and dust, held together by gravitational attraction. They consist of stars, planets, and vast clouds of gas and dust, all bound together by gravity. The largest has trillions of stars and can be more than a million light-years across. The smallest can contain a few thousand stars and span just a few hundred light-years. Nearly all large galaxies are thought to also contain supermassive black holes at their centers.
Types of Galaxies:
Spiral galaxies are the most common type of galaxy found throughout the universe. Around two-thirds of all spiral galaxies have a bar-like structure, thus classified as barred spiral galaxies. The rarest type of galaxy is the elliptical double-ringed galaxy. Irregular galaxies are among the smallest galaxies scientists have observed. However, they can also be very bright. Like spiral galaxies, irregular galaxies are often filled with gas, dust, and lots of bright young stars.
Fun Fact: Did you know that the galaxy we live in is called Milky Way?Here are some common names of galaxies:
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