The Moon Flashcards
What are maria?
Maria are dark areas on the Moon. Approximately 17% of the lunar surface is classed as maria. These were mistaken by early astronomers for seas.
How were maria formed?
The Moon underwent a time of volcanic activity and lava was forced to the surface. This lava later turned to basalt.
Where is Tycho?
Near the ‘South Pole’ of the Moon.
What are Rilles?
Rilles are cracks or clefts on the lunar surface notably near maria. They are geological faults caused by collapsed lava tubes.
What are Wrinkle Ridges?
Wrinkle ridges are ridges of maria, usually hundreds of kilometres in length. They are not considered mountains, being only around 200 metres high.
How long is the Moon’s orbital period?
The Moon orbits the Earth in 27 Earth days, 7 Hours, 43 minutes and 7 seconds (Approx. 27.3 days).
How often do we see a full moon?
We see two full Moons 29 days apart as the Earth is also moving in space while the Moon orbits around it.
How would you describe the Moon’s rotation?
The Moon has a synchronous (or captured) rotation which means it keeps the same side or face towards the body it orbits. This means that from Earth only one side or hemisphere can be seen.
What is the side of the Moon that we cannot see called?
The FAR side of the Moon. (NOT the dark side)
What is libration?
Sometimes we can see a little more of the poles and sometimes a fraction more of the east and western limbs depending on the Moon’s and Earth’s position.
How are the two ‘sides’ of the moon different?
The far side has fewer maria than the near side, it is more cratered. It is thought that the near side has a thinner crust and has had a higher amount of heat-producing elements.
What is the Moon’s mass compared to the Earth?
Its mass is 81 times smaller than the Earth’s.
What experiments did Apollo leave on the Moon?
Mirrors left there so we can measure the distance to the Moon by laser, seismographs to measure moonquakes and sensors to measure solar radiation.
What is the surface temperature of the Moon in the daytime?
120 degrees celsius
How far is the Moon from the Earth?
384,000km
The Moon has a captured rotation. What is another name for this?
Synchronous
