Lecture 7

Question 1

How long is a full rotation of the Earth with respect to the background stars?

Answer 1

23h and 56m

Question 2

Why is the rotational period of the Earth slowing?

Answer 2

Tidal forces of the Moon slow the Earth’s rotation

Question 3

Why does the Earth occasionally have a faster rotation?

Answer 3

-The Chandler Wobble
-Melting icecaps- mass distribution changes which changes angular momentum

Question 4

What is the shape of the solar system? And how do the planets orbit?

Answer 4

The solar system is shaped like a flattened disc with all of the planets orbiting in the same direction and plane

Question 5

What is the composition of the Sun?

Answer 5

The Sun is made of mostly hydrogen and helium gas and contains over 99.9% of the mass of the solar system

Question 6

What is the composition of Mercury?

Answer 6

-Mainly metal and rock
-Contains an large iron core

Question 7

What are some features of Mercury?

Answer 7

-Desolate
-Cratered
-Long, tall, steep cliffs
-Tidally locked to the sun

Question 8

What are some features of Venus?

Answer 8

-Similar size to Earth
-Has an extreme greenhouse effect
-Atmosphere containing sulfuric acid
-Hotter than Mercury

Question 9

What are some features of the Earth?

Answer 9

-Only planet with surface liquid water
-Has a surprisingly large moon

Question 10

What are some features of Mars?

Answer 10

-Looks similar to Earth but lacks oxygen
-Giant volcanoes
-Huge canyon
-Polar ice caps
-Water appears to have flowed in the distant past

Question 11

What is the composition of Jupiter?

Answer 11

Mainly hydrogen and helium

Question 11

What are some features of Uranus?

Answer 11

-Extreme axis tilt
-Smaller than Jupiter and Saturn
-Several moons
-Rings

Question 12

What are some features of Saturn?

Answer 12

-Giant and gaseous
-Ring system- ice, rock and dust
-Many moons

Question 12

What are some features of Neptune?

Answer 12

-Similar size to Uranus
-No extreme axis tilt
-Many moons
-Rings

Question 12

What are some features of Jupiter?

Answer 12

-Gaseous- no surface
-Much more massive than Earth
-Many moons
-Rings (invisible to the naked eye)

Question 13

What is the composition of Uranus?

Answer 13

Mainly hydrogen and helium but containing other hydrogen compounds like water, ammonia and methane

Question 14

What is the composition of the dwarf planets?

Answer 14

-Rock
-Ice

Question 15

What does the density of the inner planets tell us?

Answer 15

The high density of the inner planets tells us that they are composed of a mixture of iron and rock

Question 16

What does the density of the outer planets tell us?

Answer 16

It shows us that they are composed of gaseous elements like hydrogen and helium

Question 17

How does axis tilt affect planets?

Answer 17

It affects the seasons

Question 18

What are the terrestrial planets and what are their key features?

Answer 18

-The inner most planets
-Rocky
-Small
-No rings
-Solid surface

Question 19

What are the Jovian planets and what are their key features?

Answer 19

-The outer most planets beginning from Jupiter
-Gaseous
-Larger
-Low density
-Many rings
-Many moons

Question 20

Where are most asteroids found?

Answer 20

In the asteroid belt between Mars and Jupiter

Question 21

Where are icy objects found?

Answer 21

In the Kuiper belt beyond Neptune

Question 22

What is the significance of the Oort cloud?

Answer 22

It is the furthest that the Sun’s gravitational pull influences

Question 23

What can the transit of Venus show?

Answer 23

It can be used to measure the scale of the solar system