Earth-Moon-Sun-interactions Flashcards
Demonstrate an understanding that the Moon and Sun appear to be the same size when viewed from Earth.
The Sun is about 400 times larger than the Moon however it is also about 400 times further away from Earth than the Moon.
What is the time period of the Moons lunar phase cycle?
29.5 days.
What is a solar day?
A solar day is the time taken for the Sun to move from its highest point in the sky back to its highest point the following day. This is exactly 24 hours.
What is a Sidereal day?
A sidereal day is the time it takes for the Earth to actually rotate once on its axis. A sidereal day is four minutes shorter than a solar day (23 hours 56 minutes).
Why is a solar day is longer than a sidereal day?
The solar day is longer than the sidereal day because the solar day is when the Sun returns to the same point in the sky so the Earth has to rotate around one extra degree (0.986 degrees to be precise).
Demonstrate an understanding of the term apparent Sun.
The time that is shown off a sundial on the actual day.
Demonstrate an understanding of the term mean Sun.
The time that is shown on a watch that is unreliable but averagely correct.
What is the equation of time?
Apparent solar time take away the mean solar time.
Describe aurorae and recall from where on Earth they are most likely to be observed.
Aurorae are most likely to be observed at the poles and are made up of trapped solar particles in the Van Allen Belts.
What are the lengths of different types of eclipses?
Type of Eclipse
Solar (Total)
Solar (Annular)
Lunar (Total)
How can a sundial be used to tell time?
In the middle is usually a large protrusion called a gnomon. It is this that causes the shadow to fall on the disc. The equation of time is then used to determine the time.
