notes galaxies
TRANSCRIPT
Galaxies!
Yes, there are more than just our own.
Galaxies are…
Massive systems of stars, dust and gas held together by gravity.
Galaxies usually have a clump of stars at the center called the central bulge. Most larger galaxies have a black hole at the center.
Spiral Galaxies… Distinct central
concentration of stars (bulge) at center with spiral arms radiating outward.
Spiral galaxies make up approximately 60% of the galaxies in the Universe.
Barred Spiral Galaxies…
Similar to a regular spiral galaxy but with a cross bar cutting through the center with arms swirling at the ends
Elliptical Galaxies…
You guessed it! They are elliptical in shape!! (I know you know what that means…)
Irregular Galaxies…
These are the galaxies that are neither elliptical nor spiral; they are a variety of shapes.
Our Galaxy is…..The Milky Way Galaxy!
Barred spiral galaxy 120,000 Light years
in Diameter Every star we see in
the night sky (between 100-400 billion stars)
Rotates Clockwise
great
What’s in the center?
We know that we have what’s called a “central bulge”.
It has been recently confirmed that there is a massive black hole in the center of the Milky Way.
WHAT?!?!? Black Hole?? Nooo!
The Black hole has 4 million times the mass of the sun, but is billions of times weaker than black holes in other galaxies.
Sooo… Don’t worry! It’s not going to “suck” us into it. We’re fine. (but if it did, you know what would happen…. We would DIE)
Our closest neighbor: Andromeda!
• Andromeda is our closest neighboring galaxy
• It is approximately 2.5 million light years away from us and is classified as a spiral galaxy.