The Sun is a star, a ball of very hot gas that gives off huge amounts of radiation! The radiation is produced in its core where baby hydrogen bombs explode. Many different stars exist from brown dwarfs to white supergiants. They differ in their temperature, size, color, and lifespan. Some stars change into stars others very quickly, while others stay unchanged over trillions of years.

For example:

• Cooler stars glow red! Emitting low energy long wavelength light.

• And on the other hand, the hottest stars are blue, emitting high energy short-wavelength.

There are three main groups of stars: giants, supergiants, and white dwarf stars. The graph below tells you how bright a star is or how big a star is. 

3,000 K starts with Red dwarf stars. Red dwarf stars are the most common stars in our galaxy. These tiny low-mass stars eat hydrogen slowly because of that red dwarf stars can keep shining for trillions of years! And because the universe is only 13 billion years old all the red dwarfs haven't reached later development stages meaning they are baby stars! They emit low-energy long-wavelength light, giving them that sweet red appearance. 

Red dwarf stars are on the tip of being a star, so if we remove a lil bit of hydrogen it would be brown dwarf. The tiniest, saddest, and coolest(temperature) stars (not a star) are brown dwarfs. They are also known as failed stars. Just like red dwarf stars, they are very hard to detect. They also emit no light and don't shine, as they do not have enough mass for nuclear fusion(baby hydrogen bomb explosions).

(Note: There are many different star color temperatures for dwarfs: Red Dwarf, Yellow Dwarfs, and Orange Dwarfs I won't be speaking about all of them but hey same idea.)

Increasing the temperature to 4000 K(it's in the graph go back up), are red giant stars, they are much cooler and bigger than our Sun. They emit a red-orange tinge.

The size is crazy.

When a star runs out of hydrogen fuel in its core, it starts to collapse because the star's energy is the only force fighting gravity’s pull. Hydrogen fusion(star's energy) begins to expand the outer layers making a red giant. 

Once the red giant is unstable, BOOM turns into a nebula(look at the first picture). After it sheds all its atmosphere the only thing left is its core... Or in other words white dwarf. In about 10 billion years, after its time as a red giant, the Sun will become a white dwarf!!!

Finally, increasing the temperature to 30,000 K is white dwarf stars. White dwarf stars are so faint that none is visible to the naked eye. 

Giant stars blew off their outer layer! Leaving a core that becomes a white dwarf. They are very small and dense; after they can no longer emit light they cool down but they shine because it was a hot star once...

Increasing the temperature to 20,000 K, lies the supergiant stars. Supergiant stars are very big and the largest stars in the universe. Unlike low-mass stars like red dwarf stars or red giant stars, they are massive enough to fuse heavier elements than helium! BUT DESPITE OF THAT Supergiants eat all their hydrogen and helium very quickly. 

- Supergiant stars live fast and die young.

As their fuel runs out...

They must expand into super giants before exploding as supernovas.

When it explodes as a supernova then shrinks to become a black hole! (because they can't lose enough mass to become white dwarfs).

Heartwarming video about the sizes of astronomical objects (MUST WATCH!)

Mini Fun fact

The constellation Orion has countless stars of many temperatures.