Chapter 2 Flashcards
(27 cards)
Waning
Decreasing
Waxing
Increasing
Lunar Eclipse
When the Earth lies directly between the Sun & Moon. Earth’s shadow falls on the Moon.
Solar Eclipse
When the Moon lies directly between the Sun & Earth. Moon’s shadow on Earth.
Umbra
Where sunlight is completely blocked
Penumbra
Sunlight is partially blocked
Total Lunar Eclipse
Moon through Earth’s umbra
Partial lunar eclipse
Part of the moon through Earth’s umbra
Penumbrial lunar eclipse
Only through the Earth’s penumbra. Most common.
What is the path of the Sun?
Ecliptic on the celestial sphere.
What causes precession?
Torques from other planets
Proper motion of stars
Stars move relative to each other, constellations not fixed.
When are the equinoxes?
What is the latitude?
March 21 & September 21
0 degrees
When are the solstices?
December 21 & June 21
Horizon
Boundary between Earth and Sky
Zenith
Directly overhead
Meridian
Imaginary line stretching from due South, through the zenith, to due North
What are circumpolar stars?
Stars that never set.
Define: Equinox
two points at which the hemispheres are equally illuminated
Define: Solstice
two points at which sunlight becomes the most extreme for the two hemispheres
How long is the lunar phase?
29.5 days
What would you see if you lived on the moon and you looked at Earth when people on Earth saw a full moon?
A new Earth
What phase of Earth would you see if you lived on the Moon during a crescent phase?
A gibbous Earth
Why do stars rise and set?
Earth’s rotation makes it appear that way