The Moon (Earth, Moon and Sun)

Question 1

What is the mean distance of the moon’s orbit of the earth?

Answer 1

380 000km (about 60 Earth-radii).

Question 2

What is the strength of the moon’s gravity compared to the earth? Why and what does it cause?

Answer 2

It’s only about 1/6 of the earth’s due to the small mass of the moon.
It is the most likely reason for the la k of any significant atmosphere.

Question 3

What is the reason for the permanency of one side of the moon to always face us?

Answer 3

This is because the moon’s rotational period is the same as its orbital period (both 27.3 days). This is a captured orbit.

Question 4

Name different features of the moon and where they would be found?

Answer 4

• Ocean of Storms (left and between very top and middle)
• Copernicus crater (towards left but in middle horizontally.
• Kepler crater (Just left of Copernicus crater)
• Sea of Crises (opposite ocean of storms so right)
• Apennine Mountains (In middle but slightly up)
• Sea of Tranquility (towards right but in middle)
• Tycho crater ( in middle on bottom)

Question 5

When was the far side of the moon first observed?

Answer 5

By a dual-lens camera on the un-manned Soviet probe Luna 3 or Lunik 3 in October 1959.

Question 6

What are Maria?

Answer 6

Also known as seas, they are large, dark-grey, relatively smooth lunar features. Astronomers once thought that they were filled with water (now known to be iron-rich basaltic rock)

Question 7

What are the highlands on the moon?

Answer 7

Lighter-grey, mountainous, highly-cratered features composed of anorthosite (a course grained igneous rock)

Question 8

What is the diameter of the moon?

Answer 8

Just under 3500km (about one quarter of Earth’s diameter

Question 9

What are rilles?

Answer 9

These are narrow channel-like depressions in the lunar seas that can either be straight, smoothly-curved or sinuous. Most are believed to have been caused by lava flows.

Question 10

What are wrinkle ridges?

Answer 10

Thought to have been caused by the buckling of the lunar surface as a result of compressive forces within the cooling, contracting lava, forming ridges up to hundreds of kilometres long.

Question 11

What does a relatively small number of craters in the lunar seas compared with the highland regions imply?

Answer 11

That the former are much younger in age.

Question 12

What is the space programme which had the primary purpose to send humans to the moon and return them safely to Earth? When was it conceived?

Answer 12

Apollo which was conceived in the 1960s

Question 13

What further objectives were there on the Apollo missions other than to travel to the moon and back?

Answer 13

• The collection of lunar soil and rock for analysis on return to Earth
• The development of scientific experiments on the lunar surface
• Winning the space race against the Soviet Union and restoring national prestige as Russia had been the first to send a human into space.

Question 14

When was the first Apollo mission that landed on the moon?

Answer 14

Apollo 11 in July 1969 and with astronauts Neil Armstrong, Buzz Aldrin and Michael Collins.

Question 15

Where did Apollo 11 land?

Answer 15

The sea of tranquility

Question 16

How many astronauts explored the moon?

Answer 16

12

Question 17

What is the ALSEP?

Answer 17

Apollo Lunar Surface Experiments Package, which were different arrays of experiments.

Question 18

What is EASEP?

Answer 18

Early Apollo Surface Experiments Package, a smaller package than ALSEP that was installed by Apollo 11 astronauts .

Question 19

What was each package powered by?

Answer 19

A Radioisotope Thermoelectric Generator controlled by a centre station, and commands were received from and data transmitted to Earth via a simple radio antenna.

Question 20

What were the individual instruments in each ALSEP used to measure, analyse and monitor?

Answer 20

• The structure of moon’s interior
• The composition and pressure of the lunar atmosphere
• The intensity and direction of the solar wind
• Minute changes in lunar gravity
• Presence of micrometeorites and secondary particles ejected by meteorite impacts.
• Lunar Dust
• Thermal and electrical properties of the lunar sub-surface

Question 21

What is LRRR? (ALSEP)

Answer 21

Laser ranging retroreflector that was used to reflect a laser back to Earth in order to determine accurately the Earth-moon distance using the radar technique.

Question 22

How long ago, having been predicted, was the formation of the solar system?

Answer 22

Approx 4.5 billion years ago

Question 23

What is the Condensation or Co-formation hypothesis?

Answer 23

The earth and moon formed at the same time and place from material within the solar nebula.

Question 24

What is the Capture hypothesis?

Answer 24

The moon was formed a great distance from the Earth and subsequently captured by the Earth’s gravitational pull during a ‘close encounter’.

Question 25

What is the Fission hypothesis?

Answer 25

A rapidly spinning Earth caused a large blob of material to spin off (creating what is now the Pacific Ocean?), and form the moon.

Question 26

What evidence is there to prove that the Earth and Moon were not formed together?

Answer 26

The Apollo missions revealed that magnetometers were unable to detect the presence of any significant lunar magnetic field and analyses of rock revealed that the density of the moon is very different to the Earth. This suggests no substantial iron core (unlike the Earth) and implies that the Earth and Moon were not formed together.

Question 27

What is the Giant Impact Hypothesis?

Answer 27

A.k.a the Big Whack. The theory now accepted by most scientists a young earth struck by a Mars-sized object known as Theia that probably shared the same solar orbit. During the impact Theia and a large portion of the Earth’s outer layers melted and merged, and at the same time a huge amount of debris was thrown into the Earth-orbit. This material coalesced and cooled to form what is now the moon.

Question 28

What evidence is there to prove the Giant impact hypothesis?

Answer 28

• relative abundances of the isotopes of oxygen in moon rocks identical to Earth’s saying they formed same distance from sun.
• lack of water and other volatile compounds in lunar rocks (similar to those in Earth’s mantle) collision with lots of energy vaporised them.
• The discovery of KREEP rich rocks predicts that an ocean of hot, cooling magma would have surrounded the moon and KREEP Rich magma would have crystallised in region below lunar crust