Astronomy: quiz 10

Why does Mars have an overall reddish color when we see its surface from afar?

The material of Mars' surface contains a lot of iron oxide the same chemistry that makes rusting metals look reddish.

Which of the following is NOT a correct statement about the rotation of Venus?

Venus has the longest rotation period of any planet in the solar system. Venus rotates in a retrograde way (east to west). >Venus rotates in roughly the same time period as Earth. the rotation rate of Venus had to be determined from radar measurements.

Astronomers estimate that the plains of Venus are only about 500 to 600 million years old. How do they estimate dates like this?

by counting the craters visible on the surface and comparing crater counts to other worlds

Which one of the following features/phenomena is not seen on Mars?

frozen lake

Which of the following would NOT be one of the problems faced by an unprotected Earthling stranded on Mars? (Unprotected meaning no space suit.)

the composition of the atmosphere the lack of any ozone layer shielding the low atmospheric pressure the lack of liquid water today on the surface >the extreme (high) heat at most latitudes

Which of these terrestrial planets is considered geologically dead?

>Mercury Mars Venus Earth

Which of the following statements about the planet Venus is true?

>it has a thick layer of clouds containing sulfuric acid droplets the atmospheric pressure near the surface is about the same as Earth's its thick nitrogen-oxygen atmosphere acts like a greenhouse to keep the planet hot it rotates on its axis in the same direction as the Earth does

Which of the following is NOT a way we have studied the planet Mars so far?

>sending spacecraft to Mars which have brought samples of the planet back to Earth. landing a spacecraft on the surface and examining the soil in an automated laboratory observing it through telescopes from Earth sending a spacecraft into orbit around it studying samples of Mars that were blasted off the surface by impacts long ago and later found on Earth

How might Mars's weakened magnetic field have allowed for major changes in its climate?

Atmospheric gases were left vulnerable to being stripped into space by solar wind particles.

Which terrestrial planets have some type of active tectonic activity at the moment?

Earth and Venus

Valles Marineris is a deep wide network of chasms stretching for 2500 miles on the surface of Mars. How do we believe such a big set of canyons formed originally?

It was caused by tectonic pressures from deep within the planet.

Why doesn't Venus have seasons like Mars and Earth do?

Its rotation axis is not tilted.

About 75% of the surface of Venus consists of

Lowland lava plains

The largest volcanoes in the Solar System are found on:

Mars

Which of the following show evidence of ancient river beds?

Mars

Why is it so much easier to determine the length of the day on Mars than on Venus?

Mars' atmosphere is generally pretty clear (so the surface is visible) while Venus is always cloudy.

The largest volcano on Mars is called

Olympus Mons

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

Optical illusions

The person who really publicized the idea of canals on Mars and impressed it on the public mind was

Percival Lowell

What wavelength of the electromagnetic spectrum should I use to examine the surface of a planet which is completely covered by a thick layer of clouds all the time?

Radio waves

The planet that most resembles the Earth in size and internal composition is

Venus

How have we been able to construct detailed maps of the surface features on Venus?

by using radar from spacecraft that were sent to orbit Venus

The same gas makes up most of the atmosphere of Mars and Venus is

carbon dioxide

Venus has a high albedo because its surface is covered by

clouds

Where is most of the water on Mars?

in its polar caps and subsurface ground ice

Astronomers believe that Mars formed with a much thicker atmosphere than it has today. Where did it go?

it escaped into space (and some later froze out as Mars got cold

The polar caps on Mars are composed of

mostly solid carbon dioxide and some water ice

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

on Venus nearly all CO2 exists in the atmosphere causing a strong Greenhouse effect

One way in which Mars closely resembles the Earth is

the length of its day

The process by which Venus became so much hotter than the Earth is called

the runaway greenhouse effect