Lecture 7 Flashcards
How long is a full rotation of the Earth with respect to the background stars?
23h and 56m
Why is the rotational period of the Earth slowing?
Tidal forces of the Moon slow the Earth’s rotation
Why does the Earth occasionally have a faster rotation?
-The Chandler Wobble
-Melting icecaps- mass distribution changes which changes angular momentum
What is the shape of the solar system? And how do the planets orbit?
The solar system is shaped like a flattened disc with all of the planets orbiting in the same direction and plane
What is the composition of the Sun?
The Sun is made of mostly hydrogen and helium gas and contains over 99.9% of the mass of the solar system
What is the composition of Mercury?
-Mainly metal and rock
-Contains an large iron core
What are some features of Mercury?
-Desolate
-Cratered
-Long, tall, steep cliffs
-Tidally locked to the sun
What are some features of Venus?
-Similar size to Earth
-Has an extreme greenhouse effect
-Atmosphere containing sulfuric acid
-Hotter than Mercury
What are some features of the Earth?
-Only planet with surface liquid water
-Has a surprisingly large moon
What are some features of Mars?
-Looks similar to Earth but lacks oxygen
-Giant volcanoes
-Huge canyon
-Polar ice caps
-Water appears to have flowed in the distant past
What is the composition of Jupiter?
Mainly hydrogen and helium
What are some features of Uranus?
-Extreme axis tilt
-Smaller than Jupiter and Saturn
-Several moons
-Rings
What are some features of Saturn?
-Giant and gaseous
-Ring system- ice, rock and dust
-Many moons
What are some features of Neptune?
-Similar size to Uranus
-No extreme axis tilt
-Many moons
-Rings
What are some features of Jupiter?
-Gaseous- no surface
-Much more massive than Earth
-Many moons
-Rings (invisible to the naked eye)
What is the composition of Uranus?
Mainly hydrogen and helium but containing other hydrogen compounds like water, ammonia and methane
What is the composition of the dwarf planets?
-Rock
-Ice
What does the density of the inner planets tell us?
The high density of the inner planets tells us that they are composed of a mixture of iron and rock
What does the density of the outer planets tell us?
It shows us that they are composed of gaseous elements like hydrogen and helium
How does axis tilt affect planets?
It affects the seasons
What are the terrestrial planets and what are their key features?
-The inner most planets
-Rocky
-Small
-No rings
-Solid surface
What are the Jovian planets and what are their key features?
-The outer most planets beginning from Jupiter
-Gaseous
-Larger
-Low density
-Many rings
-Many moons
Where are most asteroids found?
In the asteroid belt between Mars and Jupiter
Where are icy objects found?
In the Kuiper belt beyond Neptune
What is the significance of the Oort cloud?
It is the furthest that the Sun’s gravitational pull influences
What can the transit of Venus show?
It can be used to measure the scale of the solar system
