3.1 Earth Science

3.1 Earth Science

1. How do astronomers measure distance in space?

   • Parallax
     • how the position of a star changes based on the Earth's orbit around the sun
   • Light Year
     • How long it takes light to travel in one year
       • The highest speed light can travel is 3.0 x 10^8 m/s
       • It only takes 8 minutes for the Sun's light to travel to the Earth
   • Astronomical Unit
     • A unit of distance based on the distance between the Earth and the Sun, 150 million meters
       • This helps compare distances within our solar system

2. Hierarchy of the Universe:

   • Universe
   • Observable Universe
   • Galaxy Cluster
   • Galaxy
   • Solar System
   • Planet
   • Satellite (moon)

3. What is a Galaxy?

   • A huge group of stars and star systems bound together by gravity.
     • Galaxies are very large
       • The Milky Way is 100 thousand times bigger than our solar system.
   • Types of galaxies:
     • Spiral
     • Elliptical
     • Irregular
     • Quasars

4. What is a solar system?

   • A solar system contains...
     • A star
     • Planets
     • Other things that orbit the sun (meteorites, asteroids, etc.)
   • Our Solar System contains...
     • 8 planets
     • Millions of asteroids, meteorites, etc.
     • Many dwarf planets