1. How many words related to the solar system do you know? Complete a solar system word scramble! Using these 24 letters, try to come up with 10 words during this 5 minute warm- up. M A N N T S Y O O L M E A D L G Y T S U P L R A N R T S M A N M E O R O O E X A A C O N E T N O O C S T L A T E R T I O I S E T

2. Basics! *Please take out your IAN for today’s notes!

3. 1665 explained why the planets stay moving around the sun: inertia and gravity 1st law: inertia -a body will continue in a straight line unless acted on by a force. Gravity keeps the moving planets in orbit around Sun

5. Revolution Vs. Rotation  Earth rotates (spins) on its axis. One rotation per 24 hours  This is day and night.  Earth revolves around the Sun. One revolution happens every 365 1/4 days.  This one year.

6.  When an object spins on its axis  Earth rotates once every 24 hours  Gives us day and night

7.  Sun is directly at 23.5° north or south latitude.  Summer (June 21) solstice has the longest daylight/shortest night in the Northern Hemisphere.  The winter solstice (December 21) is the shortest daylight/longest night in the Northern Hemisphere.  Of course these are reversed if you live in Australia!

8.  Means “equal night.” Days and nights are equal in time.  Axis is not tilted towards or away from the Sun.  Sun is directly over the equator.  Vernal equinox (spring) occurs around March 21 st.  Autumnal equinox occurs around September 23 rd.  Again if you lived in the Southern Hemisphere these would be reversed!

9.  When an object goes around another object  Earth revolves around the sun once every  365 1/4 days.  That is one year.

11.  The path an object takes around another object  Earth’s orbit is an ellipse.

12.  An object in motion will stay in motion unless acted on by a force.  Baseball in space

13.  The force of attraction between two objects.  Affected by mass and distance

14.  Inertia is what keeps the planets moving in space.  Gravity is what keeps them moving around the sun.

16. Modern Astronomy The invention of the telescope and the description of gravity were two milestones in the development of modern astronomy. In the 200 years following Newton’s discoveries, scientists made many discoveries about our solar system. But they did not learn that our galaxy has cosmic neighbors until the 1920s.