Topic 1.2 - The Moon Flashcards
What is the diameter of the moon?
About 3500km
What is the moons mean orbit distance from the Earth?
380,000km (60 Earth radaii)
What is the moons rotational period?
27.3 days
How is the moons far side different from its near side?
The far side is almost completely devoid of seas and is almost entirely mountainous and heavily cratered
What is the moons orbital period?
27.3 days
What piece of evidence suggests that the lunar seas are younger than the highland areas?
The lunar seas are much less cratered
Why do we only ever see the near side of the moon?
The moon’s orbital period and rotational period is the same
What is a rille and what is it thought to be caused by?
Channel-like depressions in the lunar seas that can be either straight, smoothy-curved or sinus. They are believed to be caused by lava flows
What is a wrinkle ridge and what is it thought to be caused by?
It’s thought to be caused by the buckling of the lunar surface, as a result of the compressive forces within the cooling contracting lava forming ridges up to hundreds of km long
What is a mascon?
(Mass concentration) is a region of the moon’s crust that contains a large positive anomaly which means some areas are denser and so there is more gravity in some places than others
What is a lunar dome?
A type of shield volcano (type of volcano usually built almost entirely of fluid magma flows) that is found on the surface of the moon
How long is a lunar month?
29.5 days
Why is the lunar month 2.2 days longer than the moon’s orbital period?
It takes an extra 2.2 days for the moon, sun and earth to come back into alignment as the Earth would have moved a bit in the time it took the moon to fully orbit
What is the lunar cycle?
The time it takes for the moon to got through the cycle phases in the sky
Who put the first men on the moon?
NASA’s Apollo missions (1960) Apollo 11 (1969)
What was the primary purpose of NASA’s Apollo space programme?
To send humans to the moon and return them safely to Earth
Name 3 further objectives of NASA’s Apollo space programme.
- The collection of lunar soil and rock for analysis on return to Earth
- The deployment of scientific experiments on the lunar surface
- Winning the ‘race’ to the moon against the soviet union and restoring (US) national prestige
Describe the moon landing.
In July 1969, Apollo 11 astronauts Neil Armstrong and Edwin “buzz” Aldrin climbed down from their lunar module (LM) ‘eagle’ and stepped onto the surface of the moon
What is ALSEP?
From Apollo 12 onwards, the each mission’s astronauts deployed a different array of experiments known generally as ALSEP (Apollo Lunar Surface Experiments Package) at each landing site
Name what the 7 individual instruments in ALSEP were employed to measure, analysis and monitor.
- The structure of the moons interior
- The composition and pressure of the lunar atmosphere
- They intensity and direction of the star wind
- Minute changes in lunar gravity
- The presence of micrometeorites and secondary particles ejected by meteorite impacts
- lunar dust
- Thermal and electrical properties of the lunar sub-surface
How long ago was the moon formed?
Approximately 4.5 billion years ago
What is the hypothesis of the moon formation that is widely believed since the moon landing?
It’s called the Giant Impact Hypothesis (popularly known as the ‘Big Whack’) in which the relatively young Earth was struck by a Mars-sized object known as Theia hit Earth and a large amount of Theia’s and the Earths outer layers melted and merged and at the same time a huge amount of debris was thrown into orbit. This material condensed and cooled to form what is now known as the moon
