Earth-Moon system Flashcards
What did Eratosthenes measure?
The size of the Earth using an astronomical technique.
What did Aristarchus use to estimate the distance to the moon?
Lunar Eclipses
What is the terminator and how does it vary?
It’s the longitude on the Moon at the edge of the shadow region and it’s location changes daily.
What does the terminator show?
The rims and bowls of the Moon’s craters
What is tidal friction?
Frictional forces that result from the movement of tides on a rotating object caused by its gravitational interactions with another object.
Does the moon rotate as it revolves around the Earth?
Yes
What is the Synodic period of the Moon?
The time between two full moons is 29.5 days
What does the Moons range of declinations depend on?
The tilt of the orbit about the lines of nodes
What is the precession of the Moons orbit relevant to?
Its position in the sky and to why eclipses happen in different dates every year
What happens at a Lunar standstill?
The range of the declination of the Moon reaches a maximum
When do lunar eclipses happen?
At full Moon
What does the inclination of the Moon’s orbit mean for an eclipse?
There may be no eclipse, partial eclipse, or total eclipse
What is the maximum duration of an eclipse?
1.8 hours
What is the cause of a red Moon?
Blue is scattered away more than the red that is refracted towards the Moon
What happens at new moon?
The moons shadow falls on the Earth
When do we get a total eclipse?
When the moon id close to the Earth and the Umbra just reaches the Earth.
What can the Moon’s surface be divided into?
Maria: Any lowlands of the Moon or Mars that resemble a sea when viewed from Earth and Mountainous/ Cratered regions.
What is a meterorite?
An interplanetary chunk of matter that has struck a planet or Moon.
What causes craters on the Moon?
Impacts from Meterorites
How do we know the moon has no atmosphere?
Sharp occultation of stars
No spectroscopic observation of elements
Low scape velocity (Gravity)
Are craters always circular?
Yes whatever the impact angle
Why is there almost no maria on the far side of the Moon?
The crust is thicker there
Do larger craters have larger central cones?
No smaller
When was the moon formed?
About 4.6 Billion years ago
What do overlapping craters provide information about?
The order of events in the Moons history
How can the age of rocks be determined?
With radioactive Dating
What is the Theory on how the moon was created?
Large impact theory: A large body collides with the Earth , eject material into space and this material later formed the moon. e.g. A mars sized body.
