HW3

When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum

red-shifted (shifted toward the red end of the light spectrum)

All the planets (without exception)

revolve around the Sun in the same direction

A planet in our solar system whose composition resembles that of our Sun is:

Jupiter

Which of the following is NOT a terrestrial planet?

Jupiter

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

What planet can come closest to the Earth in its orbit and look brightest in our skies?

Venus

Some objects in space just don't have what it takes to be a star. Which of the following is a "failed star", an object with too little mass to qualify as a star?

a brown dwarf

According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth?

about 3.5 billion years

Which of the following is a way we believe that the early atmosphere of the Earth differed from the atmosphere we have today?

all of these answers: there was no ozone layer early on there was probably more carbon dioxide early on than there is today there was little if any free oxygen early on

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

carbon dioxide

The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect

The main greenhouse gases in the atmospheres of the terrestrial planets are

carbon dioxide and water vapor

The smaller objects in the solar system composed mainly of ices (frozen gases) that usually orbit far from the Sun are called:

comets

One piece of evidence that can help astronomers sort out how the planets in our solar system formed is

finding circumstellar disks of material around nearby stars

If you were to take a large sample of the four giant planets, the most common element you would find in them is:

hydrogen

A planet in the "habitable zone"

is at a distance where liquid water can exist on the surface.

The inner planets are made mostly of rock and metal because:

it was so hot where the inner planets formed that the lighter materials evaporated

The spectroscopic radial velocity method preferentially detects

large planets close to the central star.

Since angular momentum is conserved, an ice-skater who throws her arms out will

rotate more slowly.

Which of the following is NOT a method for detecting extrasolar planets?

the Jovian method

Which of these is NOT a result of Global Warming?

the Ozone Hole

Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call:

the solar nebula

Which of the following characteristics do all four terrestrial planets have in common?

they all have solid surfaces with signs of geological activity on them

The environment depends on a delicate balance between ____________ light coming in from the Sun and ____________ light escaping back into space. [Select the answer that fills the blanks above in the correct order]

visible ; infrared