Astronomy is the study of planets, stars, comets, asteroids, galaxies, and the universe. Astronomy covers anything that exists outside the Earth's atmosphere.
See: https://www.space.com/16014-astronomy.html
Check out Google Sky to see more stars and galaxies: https://www.google.com/sky/
Andromeda Galaxy contains approximately a trillion stars, and it is 2.5 million light years away from Earth.
Saturn's rings named.
Possible evidence of water on Mars' past.
Bok globules are relatively small, dense clouds of dust and gas where star formation may begin.
Baby solar system with protoplanetary disk. The protoplanetary disk is where planets may form out of the dust and gas.
2M1207b is an exoplanet orbiting a brown dwarf, 2M1207.
Asteroid Itokawa, a Near-Earth Object (NEO).
Astronomy is not astrology. Astrology concerns itself with how celestial bodies influence human affairs. Astronomy simply studies celestial bodies and their movements, evolution, formation, and end.
Astronomy is not UFOlogy. UFOlogy is concerned with Unidentified Flying Objects (UFOs) and on whether these can be explained as evidence of extraterrestrial visitors or not. Although some branches of astronomy are concerned with life in our universe (astrobiology and exobiology), researchers who work within these branches do not generally accept an "extraterrestrial visitor" explanation for UFOs.
You will see the term "light-year" or "light-minute", or any derivative, used often in this LibGuide. A light-year is the distance that light travels in a year, which is about ten trillion kilometers or 6 trillion miles. The light-year is a unit of distance, not of time. The speed of light in a vacuum is 300,000 kilometers per second, and nothing can travel faster than light. Everything we see in outer space is seen as it was in the past because of this speed limit. The Andromeda galaxy is 2.5 million light-years away from us. Thus, we are seeing it as it was 2.5 million years ago! But this is just the beginning. The Andromeda galaxy as seen from the Earth is seen at an angle so that there is a near side, and a far side that we can also observe. The diameter of Andromeda is approximately 200,000 light-years. This means that what we see on the far side of the Andromeda galaxy will be 200,000 years older than what we see on the near side. Stated in other terms, the light from the far side of Andromeda is about 200,000 years older than the light from the near side. When you look up at the sky, the farther you look in space, the farther back you also look in time.
The Future of Humanity by 
The Grand Design by 
Seven Brief Lessons on Physics by For an overview of the importance of astronomy in society, check out this link:
https://www.iau.org/public/themes/why_is_astronomy_important/
