4. The Planets

The element that can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn's magnetism is:

hydrogen

At their centers, all Jovian planets have cores made of:

hydrogen and helium in the form of a gas

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

the thickness and pressure of its atmosphere

Why does Venus looks so bright from Earth

It is relatively close to the Earth and is covered by clouds that reflect much of the sunlight

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

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

carbon dioxide

By far the most abundant element in the giant (jovian) planets is:

hydrogen

Which of the following is NOT a way that Jupiter differs from terrestrial planets

its surface has many more craters from early collisions

The bluish color that makes the atmosphere of Neptune so beautiful to the human eye is caused by the interaction of sunlight with what gas?

methane

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

the runaway greenhouse effect