The term "Point of Apoapsis" refers to the point in the orbit of a celestial body that is farthest away from the body it is orbiting. The word "apoapsis" is pronounced /əˈpɔɪpsɪs/ using IPA phonetic transcription. The first syllable, "a-", is pronounced like the vowel sound in "cat," followed by the syllable "-po," which is pronounced with a long "o" sound like the word "go." The final part of the word, "-apsis," is pronounced with a short "i" sound like the word "his." The entire word is accented on the second syllable.
Point of apoapsis refers to the position in an orbit around a celestial body where an object is farthest from the focus of its orbit. Typically used in the context of orbital mechanics, the point of apoapsis marks the highest point in an elliptical orbit. This term is commonly used in relation to objects orbiting the Earth, such as satellites or spacecraft, as well as planetary bodies orbiting the Sun.
In order to fully understand the concept of the point of apoapsis, one must also be familiar with the concept of periapsis. The point of periapsis is the opposite of the point of apoapsis, referring to the position in an orbit where an object is nearest to the focus of its orbit. These points together determine the shape and characteristics of an orbit, including the eccentricity and semi-major axis.
The point of apoapsis is significant in celestial mechanics as it marks the furthest distance an object will reach in its elliptical orbit. At this point, the gravitational force from the celestial body being orbited is at its weakest, causing the object to move at its slowest speed. Understanding the point of apoapsis is crucial for calculating the orbital trajectory and predicting the motion of objects in space.