The Earth-Moon-Sun System Flashcards
What is the relative size of the earth?
1.0x (relative to the earth)
What is the relative size of the moon?
0.27x (relative to the earth)
What is the relative size of the sun?
109x (relative to the earth)
What is a sidereal day?
A time between two consecutive transits of the first point of Aries.
What is a synodic day?
A synodic day is the period for a celestial object to rotate once in rotation to the star it is orbiting and is the basis of solar time.
What is the difference between a synodic and a sidereal day?
A synodic day is 4 minutes longer than a sidereal day
What is the role of the sun in determining solar time?
Apparent solar time (true solar time) is based on the apparent motion of the actual sun.
What is the mean sun’s role in determining mean solar time?
Mean solar time is the hour angle of the mean sun, plus 12 hours.
How do you determine local mean time?
Local mean time differs continuously with the obsever’s longitude and is not standardised over a time zone.
What is the Equation of Time?
Equation of time = AST - MST
What is AST?
Apparent Solar Time
What is MST?
Mean Solar Time
