Organization of the universe
The Scale of the Universe
The universe is big, really, really big There is 1 universe– it’s made of MANY galaxies--- which are made of tons of stars and gas. Some (about 1%) of stars also have planets making solar systems.
Galaxies Contain: Stars Planets Nebula gas Black holes Space
There are 3 types of galaxies:
Galactic Scale
Irregular Galaxies youngest galaxies contain a lot of nebula gas Many new and young stars No real shape
Irregular Galaxies
Spiral Galaxies ‘middle aged’ galaxies star formation still happening Old and young stars Have nebula clouds Have a bulge in the middle and a thin disk. Have “arms”
Spiral Galaxies
Elliptical Galaxies older galaxies very little gas or star formation anymore Round or oval shape Mainly old stars
Elliptical Galaxies
OUR GALAXY Is called the Milky Way Is a spiral galaxy has a diameter of about 100,000 light-years. And about 100 billion stars OUR solar system lies about halfway out one of the arms (25,000 light-years from the center).