astronomy II - Mercury, Venus, Mars

Compare the radius and mass of Mercury to that of Earth.

Radius is 1/3 and mass is 1/28 of Earth

Explain the following features on Mercury’s surface AND draw a picture to help you remember :

Scarps: cliffs that formed from moving crust

Caloris Basin: largest crater basin (1000 mi across); volcanoes around the edge

Chaotic terrain: crazy uplifted surface area exactly opposite Mercury as Caloris Basin

What is the temperature like on Mercury? Why?

ranges from about 800 to -300 F; no atmosphere

Does Mercury have an atmosphere? Explain.

No; low gravity and proximity to the Sun

Where does the water ice on Mercury come from and where do we find it?

found at the poles in deep craters; came from comets and/or volcanoes

Does Mercury have a magnetic field? Explain.

yes but it's about 1% the strength of Earth’s

What is strange about Mercury’s motion around the Sun? Explain why this occurs.

Mercury spins 3 times for every 2 trips around the Sun; highly elliptical orbit

How does Venus compare to the Earth in terms of diameter and mass?

let’s say 95%

What are the components of the Venusian atmosphere?

96% CO2, 3.5% N2, and small amounts of H2O and other gassesWhy is Venus so bright? (hint: it’s the same reason we can’t see the surface from space)

thick atmosphere

How much denser is the atmosphere on Venus than on the Earth?

100x the pressure

What is the temperature like on Venus?

about 900 F at the surface

Explain why Venus has a runaway greenhouse effect.

lots more CO2 and it’s closer to the Sun, evaporating water from past oceans just made it worse

How does it ‘snow’ on Venus given the extreme heat?

galenar and bismuthinite are vaporized at the surface and settle on mountains to then ‘snow’

What are the dominant surface features on Venus? Explain them.

mostly VOLCANIC in origin (volcanoes, pancake domes, lava channels); few crater impacts; low

elevation for most of the surface

What evidence do we have that Venus has an active surface?

not many impact craters

T or F: Venus has the slowest rotation of any planet in the Solar System.

What is Mars named after?

Roman God of war

Compare the diameter and mass of Mars to that of Earth.

diameter is 1/2 and its mass 1/10 that of Earth

Explain the following features on the Martian surface, including how they formed AND draw a

picture:

Valles Marineris: rift near the equator (2500 mi long, 60 mi wide, 4 mi deep); bigger than

Grand Canyon (Venusian war or tharsis bulge)

Tharsis bulge: upland area with 4 huge volcanoes (magma rose from interior)

Olympus Mons: largest volcano in the solar systemDune fields: formed as wind moved away from poles

What are the polar ice caps on Mars made of? Why is there a difference between the Northern

and Southern caps?

dry ice and water ice; difference between of seasons

Why is Mars red?

iron oxide in crust

Explain some evidence of past liquid water on Mars.

dried river beds, Martian blueberries, frozen lake in crater, teardrop water features

What are the components of the Martian atmosphere? How does the density of it compare to

Earth’s?

CO2 (95%) with traces of N2 (3%), O2 and H2O; 1% density of Earth’s

What is the temperature like on Mars?

cold (average of -80 F)

For liquid water to exist on the surface of Mars we think there had to be a thicker atmosphere in

the past. Why is it so thin now?

blasted away by impact; low gravity /low volcanic activity causes it to lose it over time

What are the two moons of Mars? Where did they come from?

Phobos and Deimos; captured asteroids

Explain the differences and commonalities between the interiors of the inner planets.

Commonalities: iron cores, silicate/rocky mantles

Differences: Mercury has a HUGE core relative to its crust