Descriptive Astronomy 10

The main reason that the Earth does not turn to be as Venus is because

The Earth has a carbon cycle

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 of the following statements about the atmosphere of Mars today is FALSE?

droplets of liquid water rain irrigate the surface of Mars regularly

Mars is about ------ size of Earth

half

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

the runaway greenhouse effect

What is one way that we humans are currently making the atmosphere of the Earth more like that of Venus?

we are adding carbon dioxide and other greenhouse gases to the atmosphere, which is leading to global warming

Greenhouse effect is always bad

False

If we move and place the Earth on Venus orbit, the Earth would still be habitable

False

Venus is geologically dead since it does not have an atmosphere to protect it

False

Water exists on the surface of Mars since it is protected by the Martian atmosphere

False

What makes astronomers believe that Mars once had rivers and running water?

Images from orbiting spacecraft reveal ancient channels that look like dried-up river beds on Earth (and our rovers show geological formations made by running water)

Why are there no smaller craters on the surface of Venus, only bigger ones?

In Venus' thick atmosphere all smaller chunks of material burn up before they can reach the surface

Mars appears to have long branching channels that have the appearance of being formed by a flowing liquid. Yet we know that liquids would not stay liquid in the very thin atmosphere we have on the Martian surface? So how can we explain the channels?

Mars had a thicker atmosphere long ago when the channels formed

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

Carbon cycle is one of the reasons that Earth is not as hot as Venus

True

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

Venus

The presence of volcano, lack of erosion, apparent young age of Venus indicate that Venus is geologically

active

On some parts of Mars, it gets cold enough for a gas to freeze out of the atmosphere that does not freeze out by itself at the temperatures and pressures on Earth. This gas makes up some of the polar caps on Mars and is:

carbon dioxide

The main source of the greenhouse effect on Venus due to the presence of carbon dioxide in its atmosphere

carbon dioxide

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

carbon dioxide

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

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

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

it has a thick layer of clouds containing sulfuric acid droplets

The main reason for the runaway greenhouse effect on Venus is because Venus does not have

oceans

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

on Venus, there was eventually no rain to get the carbon dioxide from the surface back to the atmosphere

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

One way in which Mars closely resembles the Earth is:

the length of its day (period of rotation)

Which of the following is NOT a way that Venus resembles the Earth?

the thickness and pressure of its atmosphere