Astro Exam 2

The observation that began the 19th and early 20th century fascination with Mars as a place for life was:

Schiaparelli's seeing what seemed to him to be long straight features on the red planet

Which of the following, produced at the core of the Sun, will take the shortest time to emerge from the Sun's photosphere (surface)?

a neutrino

At their centers, all the jovian planets have cores made of:

a solid mixture of rocky and icy materials under great pressure

Which statement about the Sun's rotation is TRUE?

The Sun rotates at different rates at different latitudes on the Sun

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 statements about the Sun's photosphere is NOT TRUE?

The photosphere is significantly hotter than all the layers of the Sun beneath it (further inward)

The atmosphere of Venus is mostly carbon dioxide, and the atmosphere of the Earth has water vapor. Why are these two gases absent in the atmosphere of the satellite around Saturn called Titan?

Titan is so cold that carbon dioxide and water vapor freeze out

If there are at least a million asteroids, how did spacecraft like Galileo survive their trip through the asteroid belt?

although there are many asteroids, they are widely spaced (there is lots of space between them)

The Red Spot of Jupiter is:

all of these

Which of the following is evidence for volcanic activity on Venus?

all of these

The most common element in the Sun is

hydrogen

One of the key reasons that professional astronomers (as opposed to the public) are interested in comets is that they

are icy pieces left over from the time that our solar system formed that can give us clues about that early time

Why were asteroids not discovered until the 19th century?

asteroids are generally small compared to planets and require a good telescope and patient searching to spot them

Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

aurorae (northern and southern lights)

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

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

In its overall composition, the Moon roughly resembles:

the Earth's crust and mantle

Our modern understanding of Pluto is that it is a member of

the Kuiper Belt (of trans-Neptunian objects)

Which of the following does the composition of a planet like Jupiter resemble:

the Sun

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

the runaway greenhouse effect

Which of the jovian planets does NOT have any satellites?

you can't fool me, all the jovian planets are accompanied by satellites

If no one has ever visited the core of the Earth, how do we know that it is made of metals?

circulating liquid metals in the core set up a large (measurable) magnetic field

One of the most perplexing issues raised by the discovery of thousands of exoplanets is the existence of "hot Jupiters" - planets with the masses and compositions of Jupiter, but orbiting closer to their stars than Mercury does in our solar system. What is our best idea currently about how such "hot Jupiters" came to be?

hot Jupiters formed further out in their star system, and then migrated inward somehow

What is one important way in which both the Moon and Mercury are different from Earth?

they do not have an atmosphere

Which of the following is a way that the planet Mercury is similar to the Moon?

its surface is heavily cratered

Chunks of solid material that survive passing through the Earth's atmosphere and are found on the Earth's surface are called

meteorites

Where in the Sun does fusion of hydrogen occur?

only in the core

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

optical illusions

Callisto, the fourth moon of Jupiter's, takes 17 days to orbit Jupiter. If I stand on the surface of Callisto and see Jupiter high in the sky over my head, and then wait 8.5 Earth days in the same spot, where will I see Jupiter?

overhead, where it was before

The largest volcano on Mars is called:

Olympus Mons (Mt. Olympus)

The large reservoir of comet nuclei far beyond Pluto, from which we believe new long-period comets come into the inner solar system, is called:

the Oort Cloud

The world in the solar system that is most active volcanically is:

Io

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

Which of the eight planets has a smaller mass than Mercury?

You can't fool me, Mercury has the smallest mass of the eight planets

Which of the following is NOT a correct statement about the ways the jovian planets differ from the terrestrial planets?

all the jovians have satellites around them and none of the terrestrials do

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

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)

The first technique that allowed astronomers to find exoplanets involved:

measuring changes in the radial velocity (Doppler shift) of the star caused by the pull of orbiting planets

The Global Oscillations Network Group (GONG) Project is engaged in:

measuring the pulsations of the Sun from stations around the world

Today we realize that the source of energy for the Sun is a process called

nuclear fusion

Earthquake producing faults are much more likely to be found

on the boundaries of continental plates, where they meet other plates

According to the theory of plate tectonics

slow motions within the mantle of the Earth move large sections of the crust around

Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth's layers to happen?

the early Earth must have been so hot it was like a liquid and heavier things sank to the middle

Comets change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE?

the gravity of the comet nucleus holds on to the evaporated material, and it all eventually freezes back into the nucleus

A college friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the Sun and makes the following observation: "The whole idea of the atomic nucleus is pretty ridiculous. If an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. Since even I learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." How would you answer his argument?

the nuclear force, which is attractive over short distances like the nucleus, and stronger than electricity, holds the nucleus together

Which of the following is NOT one of the key reasons that so many spacecraft from Earth have visited Venus and Mars?

their atmospheres are very similar to the Earth in terms of their chemical make-up

What makes astronomers think that impact rates for the Moon must have been higher earlier than 3.8 billion years ago?

there are ten times more craters on the older highlands than the younger maria

How do astronomers know how strong the magnetic field of the Sun is?

they measure the Zeeman effect (the splitting of spectral lines)

Among solid worlds, which type of world is most likely to have significant geological activity?

those that are the largest (and retain heat the best)

What evidence can you give that shows the surface of Jupiter's moon Europa must be relatively young?

we see very few craters compared to the surfaces of Callisto and Ganymede