Geodesy and Celestial Mechanics

The average distance from the Earth to the Sun is about 149.6 million kilometers, often rounded to 149 million.

The circumference of the Earth is approximately 40,000 km. Dividing this by 360 degrees gives roughly 111 km per degree.

Light takes about 1.3 seconds to travel from the Moon to the Earth.

Aphelion, the point where the Earth is farthest from the Sun, occurs in early July, specifically around July 4th.

Magnetic declination is the angle on the horizontal plane between the magnetic north (direction of the compass needle) and true north (geographical meridian).

A point where earth and sky seem to meet is called horizon.

Due to its slow rotation, one solar day on Mercury (sunrise to sunrise) lasts approximately 176 Earth days.

The average distance from the Earth to the Sun is approximately 93 million miles, often referred to as one astronomical unit. The other options are significantly incorrect distances.

The Earth completes one full rotation on its axis approximately every 24 hours, which defines the length of a day. A year is the time taken to orbit the Sun.

Approximately 71 percent of the Earth's surface is covered by water, primarily in the form of oceans.

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Perihelion

The Equator is a unique geographical line, so it requires the definite article 'the'.

The Moon's diameter is approximately 3,474 km, while Earth's diameter is about 12,742 km. This makes the Moon roughly one-fourth the size of Earth.

One parsec is defined as approximately 3.26 light-years.