Our Solar System

• The Sun and all the bodies that orbit around it make up our solar system.

• The solar system is about 9.3 billion miles across and includes planets, moons, comets, asteroids, and other bits of rock and dust.

• The sun sits in the middle while the planets travel in circular paths called orbits around it. The planets travel counter clockwise in the same direction,

• The inner planets are Mercury, Venus, Earth, and Mars. The outer planets are Jupiter, Saturn, Uranus, and Neptune. They are separated by the asteroid belt.

Life Cycle of Stars

1. Young Star: energy from nuclear fusion is equal to force of gravity.

2. Red Giant: unstable forces cause star to expand. 3. White Dwarf: small dense stars resulting from the

collapse of Red Giant4. Black Dwarf: loses energy and becomes a cold, black

object in space.5. Neutron Star: very dense object made up of neutrons.6. Black Hole: a stellar object so dense light cannot

escape.

Constellations• Constellations are not real! They are imaginary. Poets, farmers,

and astronomers have made them up over the past 6,000 years. • On a really dark night, you can about 1000 stars. The

constellations help us identify stars by breaking up the sky into manageable sections.

• Since different constellations are visible at different times of the year, you can use them to tell what month it is. This was very helpful to farmers in the past.

• Every star in the sky belongs to a certain constellation.• In 1929, the International Astronomical Union adopted official

constellation boundaries that defined the 88 official constellations that exist today.

Phases of the Moon

• Crescent: when we can see only a sliver of moon’s disk• Full: when moon's disk is light because earth is between

sun and moon• Gibbous: when we can see roughly ¾ of the moon’s disk• Quarter/Half: when we can see only half of the moon’s disk• New: when moon’s disk is dark because moon is between

sun and earth• Waning: when moon seems to be getting smaller. Going

from full to new• Waxing: when moon seems to be getting bigger, going from

new to full.