ASTR FINAL EXAM (part 4)

Which of the planets below have more than one moon?

Mars (Mars has two moons, Phobos and Deimos, thought to be captured asteroids.)

What planet comes closest to the Earth and looks brightest in our skies?

Venus (Venus is only about 0.3 AU away at inferior conjunction. It also has highly reflective clouds that make it appear bright.)

The planet that rotates backwards relative to its direction of revolution (obliquity = 177 °) is ...

Venus (Venus rotates backwards, unlike the other planets. It and Uranus are the only two that don't rotate in the same direction as their revolution.)

The hottest planet in the solar system is ...

venus

A significant feature of Mercury is the Caloris Basin? What is believed to have caused this feature?

A very large impact which sent huge shockwaves through the entire planet. (The Caloris Basin is believed to be caused by a major impact. The resulting shockwaves created a jumbled terrestrial feature on the opposite side of Mercury.)

Why is the Martian volcano Olympus Mons so large?

Because Mars does not have plate tectonics so lava from a hot spot continues to come through the crust at the same location. Feedback:

On which of the bodies below could a human being step out of a spacecraft and survive without any protective gear (special suit, oxygen tanks, etc.)?

You can't fool me - there is no other planet on which we could survive unprotected (None of the planets have the oxygen atmosphere we need to avoid suffocation. In addition, most are too cold, too hot, or otherwise unpleasant places to be without spaceships or special gear.)

The same gas makes up most of the atmosphere of Mars and Venus. What is this gas?

carbon dioxide

Which of the following is a characteristic of Terrestrial Planets?

located in inner solar system (Terrestrial planets are located in the inner Solar System, near the Earth.)

Which of the following is not a characteristic of Terrestrial planets?

low density (Terrestrial planets are made of rock and metal, which are denser than the gases and ices that makes up the a large part of the Jovian planets.)

A crucial difference that helps explain why Venus is so hot and the Earth isn't is that:

on Venus, there was eventually no ocean to remove carbon dioxide from the atmosphere

The canals that late 19th and early 20th century observers thought they saw on Mars turned out to be:

optical illusions

Mercury's most distinctive geological feature is the presence of

scarps (These are giant cliffs most likely due to rapid shrinkage as the planet cooled.)

The hot surface temperature of Venus is primarily due to ...

the greenhouse effect

One way in which Mars closely resembles the Earth is:

the length of its day (period of rotation)