Question

orbital shape
orbital shape
aphelion (july 2)
perihelion (jan 2)
sun
perigee
apogee
moon orbit
earth orbit

1. why does the distance from the earth to the moon or the sun affect the tides?
2. when will lunar tides be higher, at perigee or apogee? how often does each occur?
3. when will solar tides be higher, at perihelion or aphelion? how often does each occur?

Explanation:

Step1: Gravitational force and tides

The gravitational force is inversely proportional to the square of the distance. A smaller $r$ means a larger $F$, which has a greater impact on tides.

Step2: Lunar tides

At perigee, the Moon is closest to the Earth, so the gravitational pull is stronger, causing higher tides. The Moon's orbital period gives the frequency of perigee and apogee.

Step3: Solar tides

Perihelion is when the Earth is closest to the Sun, resulting in stronger solar - induced tides. The Earth's orbit around the Sun (a year) determines the frequency of perihelion and aphelion.

Answer:

1. The gravitational force between the Earth - moon - sun system affects the tides. According to Newton's law of universal gravitation ($F = G\frac{Mm}{r^{2}}$), where $F$ is the gravitational force, $G$ is the gravitational constant, $M$ and $m$ are the masses of the two objects, and $r$ is the distance between them. A closer distance ($r$ is smaller) results in a stronger gravitational force, which can cause higher tides.
2. Lunar tides are higher at perigee. Perigee occurs approximately once every 27.55 days (the time for the Moon to complete an orbit relative to the stars, the sidereal month). Apogee also occurs approximately once every 27.55 days.
3. Solar tides are higher at perihelion. Perihelion occurs around January 2 each year, and aphelion occurs around July 2 each year, so each occurs once a year.