In astronomy, when the Moon follows its elliptical orbit around the Earth and reaches the point where it is closest to the Earth, what is this point in the orbit called?

Introduction / Context:
The orbits of celestial bodies are often elliptical rather than perfect circles. As a result, there are special names for the points in an orbit where a body is closest to or farthest from the object it revolves around. For the Moon orbiting the Earth, identifying these points is basic astronomical knowledge and is frequently tested in general science and astronomy questions.

Given Data / Assumptions:

• The question concerns the orbit of the Moon around the Earth.
• It asks for the technical term for the point where the Moon is closest to the Earth.
• The options given are Perigee, Apogee, Perihelion and Aphelion.
• We assume standard definitions used in astronomy for Earth centered and Sun centered orbits.

Concept / Approach:
The terms perigee and apogee are used for objects orbiting the Earth. Perigee is the point in the orbit that is closest to the Earth, while apogee is the farthest point from the Earth. In contrast, perihelion and aphelion are used for objects orbiting the Sun, with perihelion being the closest point to the Sun and aphelion the farthest. Because the question is specifically about the Moon orbiting the Earth and about the closest point, the correct term must be perigee.

Step-by-Step Solution:
1. Identify that the orbit described is the orbit of the Moon around the Earth. 2. Recall that for Earth centered orbits, perigee denotes the closest point to Earth and apogee denotes the farthest point. 3. Note that perihelion and aphelion are used for orbits around the Sun and are not directly appropriate for the Moon Earth system. 4. The question asks for the closest point to the Earth, so choose perigee, not apogee. 5. Therefore, the point where the Moon is closest to the Earth in its orbit is called perigee.

Verification / Alternative check:
Astronomy textbooks and reliable online references define perigee as the point in the orbit of the Moon or an artificial satellite at which it is nearest to the Earth. They similarly define apogee as the point at which it is farthest from Earth. For Earth orbiting bodies like the Moon or satellites, the prefix "geo" is implied in these terms. For bodies orbiting the Sun, definitions shift to perihelion and aphelion. This consistency across sources confirms perigee as the correct answer for the Moon closest approach to Earth.

Why Other Options Are Wrong:

• Apogee refers to the point in the Moon orbit around the Earth where it is farthest from the Earth, not the closest.
• Perihelion means the point in the orbit of a planet or other body around the Sun where it is closest to the Sun, which does not apply to the Moon orbit around the Earth.
• Aphelion is the farthest point from the Sun in a Sun centered orbit and is again not the correct term for the Moon closest approach to the Earth.

Common Pitfalls:
Students sometimes confuse perigee and perihelion because both start with the prefix "peri", which means near. The key is to remember that "geo" relates to Earth and "helio" relates to the Sun. Another common error is mixing up closest and farthest points and incorrectly choosing apogee when the question clearly asks for the closest approach. To avoid such mistakes, it helps to connect perigee with near Earth, apogee with away from Earth, perihelion with near Sun and aphelion with away from Sun.

Final Answer:
The point in the Moon orbit where it is closest to the Earth is called perigee.