List of Terms and Concepts
- Altitude
- as used here, the height of an object above the average surface of the Earth's oceans.
- Analemma
- a term in astronomy used to describe the plot of the positions of the Sun on the celestial sphere throughout one year. Closely resembles a figure-eight.
- Apogee
- is the farthest point that a satellite or celestial body can go from Earth, at which the orbital velocity will be at its minimum.
- Eccentricity
- a measure of how much an orbit deviates from a perfect circle. Eccentricity is strictly defined for all circular and elliptical orbits, and parabolic and hyperbolic trajectories.
- Equatorial plane
- as used here, an imaginary plane extending from the equator on the Earth to the celestial sphere.
- Escape velocity
- as used here, the minimum velocity an object without propulsion needs to have to move away indefinitely from the Earth. An object at this velocity will enter a parabolic trajectory; above this velocity it will enter a hyperbolic trajectory.
- Impulse
- the integral of a force over the time during which it acts. Measured in (N·sec or lb * sec).
- Inclination
- the angle between a reference plane and another plane or axis. In the sense discussed here the reference plane is the Earth's equatorial plane.
- Orbital characteristics
- the six parameters of the Keplerian elements needed to specify that orbit uniquely.
- Orbital period
- as defined here, time it takes a satellite to make one full orbit about the Earth.
- Perigee
- is the nearest approach point of a satellite or celestial body from Earth, at which the orbital velocity will be at its maximum.
- Sidereal day
- the time it takes for a celestial object to rotate 360°. For the Earth this is: 23 hours, 56 minutes, 4.091 seconds.
- Solar time
- as used here, the local time as measured by a sundial.
- Velocity
- an object's speed in a particular direction. Since velocity is defined as a vector, both speed and direction are required to define it.
Read more about this topic: Geocentric Orbit
Famous quotes containing the words list of, list, terms and/or concepts:
“The advice of their elders to young men is very apt to be as unreal as a list of the hundred best books.”
—Oliver Wendell Holmes, Jr. (1841–1935)
“Thirty—the promise of a decade of loneliness, a thinning list of single men to know, a thinning brief-case of enthusiasm, thinning hair.”
—F. Scott Fitzgerald (1896–1940)
“One of the most highly valued functions of used parents these days is to be the villains of their children’s lives, the people the child blames for any shortcomings or disappointments. But if your identity comes from your parents’ failings, then you remain forever a member of the child generation, stuck and unable to move on to an adulthood in which you identify yourself in terms of what you do, not what has been done to you.”
—Frank Pittman (20th century)
“Institutional psychiatry is a continuation of the Inquisition. All that has really changed is the vocabulary and the social style. The vocabulary conforms to the intellectual expectations of our age: it is a pseudo-medical jargon that parodies the concepts of science. The social style conforms to the political expectations of our age: it is a pseudo-liberal social movement that parodies the ideals of freedom and rationality.”
—Thomas Szasz (b. 1920)