topic #1: chapter 22 origin of modern astronomy. section 2: the earth, moon, sun system earth has...
Post on 04-Jan-2016
219 Views
Preview:
TRANSCRIPT
TOPIC #1:Chapter 22Origin of Modern Astronomy
Section 2: The Earth, Moon, Sun System• Earth has two forms of motion:
• Rotation, which is the turning of an object on an axis.
• Revolution, which is the motion of a planet or moon along its orbit.
Section 2: The Earth, Moon, Sun System• The Earth rotates on a tilted axis. (This gives us the seasons.)
• It takes the Earth about 24 hours to make one rotation.
Section 2: The Earth, Moon, Sun System• The Earth makes one orbital revolution in about 365 days.
• When the earth is farthest from the sun it is at its apihelion• About July 4 each year.
• When the earth is closest to the sun it is at its perihelion• About January 3 each year.
Section 2: The Earth, Moon, Sun System• The direction of the tilt of Earths axis determines the seasons.
Section 2: The Earth, Moon, Sun System• The moon rotates around the earth in a similar way to the
earth rotating around the sun.
• When the moon is closest to the earth it is at perigee.
• When the moon is farthest from the earth it is at apogee.
Section 2: The Earth, Moon, Sun System• Due to this rotation we witness phases of the moon on a
monthly basis.
Section 2: The Earth, Moon, Sun System• A waxing moon is when the
moon appears to be growing in visibility.
• A wanning moon is when the moon appears to be shrinking in visibility
• A crescent moon is a moon that is less than half visible.
• A gibbous moon is a moon that is more than half visible
Section 2: The Earth, Moon, Sun System• During the full moon and new moon phases the moon must
pass in line with the earth and the sun.
• At the correct angle Solar and Lunar eclipses may occur.
• Solar Eclipse, when the moon moves directly between the earth and the sun blocking the sun from view.
• Lunar Eclipse, when the earth moves directly between the moon and the sun shadowing the moon from the suns light.
top related