Im so confused what to write about Astronomy?

[Walid Q]

What should i write about astronomy? i got its definition ...

but what could i possibly write? the main points??? anyone know?

dont worry i wont steal anyone knowledge i just want to learn.

[Michael Steen]

This is a little broad, and I don't have much to go on, but I'm assuming you are doing this for a high school essay in an introductory course on astronomy.
First, you can't write about "astronomy." The topic is just too big. Why not break it down to something simple like the seasons or the phases of the moon? These two could be combined, in fact, with eclipses, and you could show that it's the tilt of the Earth and the Moon's orbit that's involved with all of them.
Or you could explore the 4 main moons of Jupiter. How about the recent discoveries about Saturn's moon Titan? You could write about what a black hole is and explain the event horizon, or even "speculate" on what would happen to you if you got too close to one.
You could write about the origins of our own moon. How about dark matter? Did you know that the matter we see through telescopes of all kinds is not nearly enough to hold the galaxies together? Not by a long shot! The missing matter is called dark matter, and scientists all over the world are trying to figure out what it is.
Finally (and there are hundreds more topics), you could write about one of the great heroes of astronomy--Copernicus or Galileo or Kepler or Newton--and show how the boundaries of our knowledge were expanded by these great geniuses.
Just some thoughts. Good luck.