Question

astronomy study guide
earth and moon
period:

1. kepler’s first law states that the orbital path around the sun has a ______ shape.

kepler’s second law states that a planet travels faster the ____ it is to the sun yet the area is always equivalent. kepler’s third law states that a planet’s orbital period (revolution) squared is ____ to distance from the planet to the sun cubed.

1. earth’s shape is an ____ ____.
2. precession and ______ are the “wobbling” and “nodding” motions the earth makes every 23,000 years.
3. the earth makes 1 ____ on its axis in a day & makes 1 ____ around the sun in a year.
4. earth’s seasons are caused by the planet’s ____° tilt on its __ combined with its ____.
5. an ______ is a day when the earth has equal amount of daylight and darkness. there are two a year. on what dates do they occur?

1.
2.

1. a ______ is the longest day or night of the year.
2. a ______ eclipse occurs when the moon casts a shadow on the earth.
3. a ______ eclipse occurs when the earth casts a shadow on the moon.
4. the ______ hypothesis explains that a small planet collided with earth. the impact sent some debris into space to orbit around earth. this debris eventually joined together to form our moon of today.
5. ______ of the moon and earth are always in light and darkness.
6. ______ rotation describes the state which the moon’s orbital and rotational periods are equal. this why we only see one side of the moon.
7. know the phases of the moon, their order including waning and waxing phases of the moon. how much visible surface of the moon is illuminated for each? write below the images.

waxing ____ → waning ____ →
images of moon phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, waning crescent

Explanation:

Question 1 (Kepler's Laws)

Kepler's first law: Orbital paths are elliptical. Second law: Planets move faster when closer to the Sun (equal area swept). Third law: \( T^2 \propto a^3 \) (period squared proportional to semi - major axis cubed, so "proportional" or "equal" in ratio context).

Earth is an oblate spheroid (flattened at poles, bulging at equator).

Precession (wobble) and nutation (nodding) are Earth's cyclic motions over ~23,000 years.

Answer:

s:

1. Kepler’s first law: \(\boldsymbol{\text{ellipse}}\)
2. Kepler’s second law: \(\boldsymbol{\text{closer}}\)
3. Kepler’s third law: \(\boldsymbol{\text{proportional (or equal)}}\)

Question 2 (Earth's Shape)