Astronomy Exam #3

How does planet size affect cooling time and atmosphere retention?

Larger planets have longer cooling times and better ability to retain an atmosphere.

What indicates that a planet's surface is younger and more active?

A younger surface has fewer craters due to more recent resurfacing.

What is one unique feature of Earth's atmosphere?

It contains 79.1% Nitrogen and 20.9% Oxygen.

What geological process contributed to the formation of Earth's atmosphere?

Outgassing from volcanic activity.

What is the primary greenhouse gas in Earth’s atmosphere?

Carbon Dioxide (CO2).

What is the significance of volcanic activity on Earth compared to the Moon?

Earth has active volcanoes, whereas the Moon does not.

What evidence suggests that Mars once had liquid water?

Presence of ancient drainage channels and rounded pebbles called blueberries.

What major aspects differentiate Venus from Earth despite their similarities?

Venus has no magnetic field, no water, and a very dense atmosphere made of CO2.

What theory explains the origin of the Moon?

The Giant Impact theory suggests the Moon formed from debris after a Mars-sized body collided with Earth.

What is a characteristic of the gravitational effects on Io, Jupiter's moon?

Io experiences heating due to gravitational pull from Europa and Ganymede, keeping its interior molten.

What defines regular vs. irregular moons?

Regular moons have nearly circular orbits and prograde motion; irregular moons have highly elliptical orbits and can have both prograde and retrograde motion.

Why is Mars' atmosphere thin compared to Earth's?

Mars has no magnetic field, which allows solar wind to erode its atmosphere, combined with impacts.

What does the term 'Runaway greenhouse effect' refer to in relation to Venus?

A process where heat causes oceans to evaporate, increasing atmospheric CO2 and trapping heat.

What is the process by which Earth's CO2 cycle operates?

CO2 dissolves in oceans, forms minerals like limestone, and is released back into the atmosphere through geological activity.

How do the densities of terrestrial and giant planets compare?

Terrestrial planets are high density and low mass, while giant planets are low density and high mass.

What evidence of life on Mars exists according to the lecture notes?

No definitive evidence, but ancient conditions suggest it might have had life or Earth-like climates.

How does the temperature and gravity impact atmospheric gases?

Lighter gases escape more easily, while heavier gases tend to remain closer to the surface.

What factors contributed to Earth's internal heat?

Radioactive decay and heat trapped from the formation process.

What role does the Earth’s atmosphere play according to the lecture?

It keeps Earth warmer, protects against harmful radiation, and allows for breathing.

What is the cause of volcanic activity in the innermost satellite of Jupiter, Io?

The volcanic activity on Io is primarily caused by tidal heating, which arises from the gravitational pull from Jupiter and the other Galilean moons.

Does the solar system end at the location Pluto? Explain.

No, the solar system does not end at Pluto. It extends beyond Pluto to the Kuiper Belt and the Oort Cloud, which contain many other celestial bodies.

What are the names of the two possible sources of comets in the solar system?

The Kuiper Belt and the Oort Cloud.

Order the planets according to size.

1. Jupiter
2. Saturn
3. Uranus
4. Neptune
5. Earth
6. Venus
7. Mars
8. Mercury.

Order the planets according to density. (High to low)

1. Earth
2. Mercury
3. Venus
4. Mars
5. Neptune
6. Uranus
7. Saturn
8. Jupiter.

Name two planets whose rotation is retrograde.

Venus and Uranus

Name one satellite whose orbit is retrograde and was likely captured.

Phoebe