So, we're all living on one of many planets, in one of many solar systems, in one of many galaxies, in the one universe that we're aware of.
So we're pretty insignificant. But hey, luckily we, as a species, have the ability to discover and learn about the great world around us.
Let's start with something familiar...
'The Sun' is the name we have given to the only star in our solar system. It's a big ball of really hot gas. We can feel its heat from Earth and we're between 91 and 94.5 million miles away depending on our position of orbit.
The sun, like all other stars gets its energy from burning its gases by nuclear fusion. It's around 14 000 000°C at the center (where the fusion of atoms happens), but only 6000° at the surface. Most stars are made up almost entirely of two main gases: hydrogen and helium.
Our Sun was born from a cloud of gas around 5 000 million years ago. It is made up of different layers of gas; the surface is called the photosphere. Huge flames of hot gas occasionally explode from here. They're called Solar Flares and Prominences.
I'll just throw this out there:
Our Sun has a 1 393 000 kilometer diameter. It rotates once every 27 Earth days.
It has 8 planets orbiting it (Poor Pluto :/)
As with all stars our Sun will eventually die, but luckily for us, we've got about another 5 000 million years until this occurs. When it does, it will have used all its hydrogen and helium will become its main fuel. It'll expand to around 100 times larger and 1000 times brighter. It will then be a Red Giant. It will then shrink to a white dwarf star, only the size of the Earth.