CH 14

How can astronomers measure the age of a meteorite that fell from the skies?

They measure the amount still left of radioactive materials in the meteorite, and how much has turn into decay products

A type of planet that our surveys of exoplanets are revealing around other stars, but we don't have any examples of around the Sun are:

Super-Earth's

When a periodic comet leaves its dusty debris behind in its orbit, the Earth can intercept this debris and

have a meteor shower as the dust burns up

The ages of stony meteorites have been measured to be roughly equal to:

the oldest ages we have measured for any bodies in the solar system

Which of the following pieces of observational evidence does our modern "solar nebula" theory of the formation of the solar system NOT explain directly?

the plane of the orbit of Pluto

Astronomers call the vast, rotating cloud of vapor and dust from which the solar system formed:

the solar nebula

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

meteorites

Astronomers estimate that about 25 million meteors strike the Earth's atmosphere each day. How come we haven't run out of meteors in the long history of the Earth?

meteors are pieces of dirt left over from the formation of our solar system and from old comets; there is a huge supply of small dirt particles from both sources

The Murchison meteorite that was found in Australia in 1969 is important to scientists because it contained

organic materials, such as amino acids

The telescope in space that allowed astronomers to find thousands of exoplanets and exoplanet candidates by making very careful measurements during a planet transit was called:

Kepler

The tallest mountain on a terrestrial world is:

Olympus Mons (Mt. Olympus) on Mars

The typical meteor is

a small solid particle, no bigger than a pea

If everything in the solar system is moving around, why do the Perseid meteors repeat regularly around August 11th or so?

Because the Earth in its orbit intersects the same swarm of meteor particles at the same time each year

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

Which of these worlds is the most active geologically? a. Venus b. Mars c. Mercury d. the Moon e. all of the above are equally active these days

Venus

At the beginning of the solar system's history, a ready supply of proto-planets or mini-planets crashed into the developing planets and each other - something astronomers call the "era of giant impacts." How long do astronomers estimate this era lasted?

about 100 million years (0.1 billion)

One of the best proofs that our theory of how the solar system formed is correct is that astronomers now observe

disks around other stars which show evidence of gaps where planets may be forming

When a chunk of cosmic material the size of a golf ball or a baseball hits the Earth's atmosphere it makes a

fireball

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

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 reason that Olympus Mons, the tallest mountain on Mars, is taller than Mount Everest (the tallest mountain on Earth) is that: a. the gravity on Mars is less, so a larger mass can support itself against its own weight b. Mars has a much larger molten core than the Earth c. there are no continental plates that move sideways on Mars, while there are such sliding motions on Earth d. the Earth's Moon has a much stronger pull than the moons of Mars e. more than one of the above

more than one of the above the gravity on Mars is less, so a larger mass can support itself against its own weight there are no continental plates that move sideways on Mars, while there are such sliding motions on Earth

When the solar system was forming, the building blocks from which the protoplanets gathered together were the:

planetesimals (a few km to tens of km wide)

How do astronomers know that the age of the solar system is about 4.5 billion years old?

radioactive dating of the primitive meteorites indicates they have that age (since they are left-over building blocks of the solar system)

One way to find a new meteorite is to:

search the area beneath or close to the point where a bright fireball was seen to burn out

Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system

temperature

Which of the following is not a characteristic that worlds in our solar system have in common:

that all the planets have solid surfaces on which we can see impact craters

One region on Earth that has become a rich source of new meteorites in recent decades (including the meteorite from Mars that got famous because some scientists claimed they had found evidence for the building blocks of life on Mars) is:

the Antarctic

the reason that worlds like the Earth are differentiated is that

the continuing impacts on a growing protoplanet eventually melted the entire body

Some years some meteor showers, such as the Leonids, feature many more meteors than at other times. What is the cause of these "meteor storms"?

the dust freed from some comets is clumpy and not evenly distributed along its orbit

For solid rocky worlds, a general rule is

the larger the world, the slower it cools off and the more it will keep its internal heat

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that

those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger

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)

A student in your class whom you kind-of like asks you come to watch a meteor shower. What exactly are you being invited to?

watching the left-over dirt from a comet burn up by friction as the pieces hit the Earth's atmosphere