1. Earth in Our Universe

2. Big Bang Theory: the universe originated billions of years ago in an explosion from a single point of nearly infinite energy density. (red shift & cosmic background radiation evidence) (2 min. video)

3. Elliptical, & Irregular.
Galaxies are a large-scale group of stars 100,000 light years across (100 – 400 billion stars per galaxy).
Believed to be between 50 billion to 1 trillion galaxies in the universe.
3 main types: Spiral,
Elliptical, & Irregular.
(1 min. video)
Light-year: distance light
travels in one year at a
rate of 186,000 miles per
second. (669,600,000 mph)

4. Nebular Theory: force of gravity caused gases and dust to contract with a densely packed core to form our solar system about 5 billion years ago (3 minute video)

5. https://www.youtube.com/watch?v=YU6X3SPZAJo (2 minute video)

7. White dwarf stars are very dense: its mass is comparable to that of the Sun, while its volume is
comparable to that of Earth.
Black dwarf stars are a
white dwarf that has
cooled down to the
temperature of the
cosmic microwave
background, and so
is invisible.
Neutron stars are
city-size stellar objects with a mass about 1.4 times that of the sun.

9. https://www.youtube.com/watch?v=mn3Egf59F8c (3 minute video)

10. Sun-Earth-Moon System: https://www. youtube. com/watch
Sun-Earth-Moon System: (4 min. video)

11. https://www.youtube.com/watch?v=JQmgttClZCc (3 minute video)