Term
| what are the names of the phases of the moon? |
|
Definition
| new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, waning crescent |
|
|
Term
| what phase is the moon in when half of it is illuminated? |
|
Definition
| quarter phase (because it is a quarter of the way through its lunar phase cycle) |
|
|
Term
| what phase is the moon in when half of it is illuminated? |
|
Definition
| quarter phase (because it is a quarter of the way through its lunar phase cycle) |
|
|
Term
| what causes the lunar phases? |
|
Definition
| what angle we are at in respect to the moon, so how much of the illumination by the sun of it that we can see |
|
|
Term
| does the moon rotate? if so, when do we see which face of the earth and why? what is the motion of the moon called? |
|
Definition
| yes, but we always only see one face because the moon takes exactly as long to rotate on its axis as it does to make one orbit around the earth, this motion is called synchronous rotation |
|
|
Term
| what is the lunar month? what is it also known as? |
|
Definition
| the time it takes the moon to complete on cycle of phases, it is measured with respect to the sun, aka a lunar "day" or a synodic month (29.53 days) |
|
|
Term
| what is a sidereal month? |
|
Definition
| the time it takes the moon to make one orbit of the earth (as measured with respect to stars) (27.32 days) |
|
|
Term
| when does a lunar eclipse occur? |
|
Definition
| when the moon passes through earth's shadow, when the sun moon and earth are all aligned on the line of nodes (only at full moon) |
|
|
Term
| when does a solar eclipse occur? |
|
Definition
| when the sun moon and earth are aligned on the line of nodes (only at new moon)and the moon moves in front of the sun as seen from the earth |
|
|
Term
| where do the planes of Earth's orbit and Moon's orbit intersect? |
|
Definition
|
|
Term
| what are the two parts of the Earth's shadow? which one is darkest? |
|
Definition
| umbra and penumbra, umbra is darkest, in the penumbra part of the sun's surface is visible |
|
|
Term
| what is a penumbral eclipse? a total lunar eclipse? partial eclipse? |
|
Definition
| when the moon passes through the earth's penumbra (moon is full but dimmer), when the moon passes through the earth's umbra, when the moon passes only partially through the earth's eclipse |
|
|
Term
|
Definition
| the period when the moon is completely in the earth's umbra |
|
|
Term
| what part of the sun can you see during a total solar eclipse? |
|
Definition
|
|
Term
| what is a perigee. apogee? |
|
Definition
| when moon is in orbit nearest the earth, farthest away |
|
|
Term
| how did the greeks figure out the earth was round? |
|
Definition
| greeks noted that during lunar eclipses, when the moon passes through the earth's shadow, the shadow is circular |
|
|
Term
| who measured the circumference of the earth? how? |
|
Definition
| eratosthenes, he heard that on the summer solstice the sun shines straight through a well and had no shadow, so he paid someone to walk there and count his steps and calculated the circumference based on that |
|
|
Term
| who calculated the distances of the sun and the moon? did it work? |
|
Definition
| aristarchus (by realizing that during the quarter moon the sun, moon, and earth are at about a right angle), measured the angles wrong, however |
|
|
