Astronomy ch 13, 14, 15

the first asteroid to be discovered (which is also the largest one) is called

Ceres

in the far future an entrepreneur with a large fleet of space ships decides to capture and bring to earth some valuable asteroids. if at that time there is a shortage of usable metals on earth what type of asteroids should the employees search for?

M-type

which statement about the sun's rotation is true?

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

which of the following statements about the tails of comets is false

a comet always have a nice long tail even when it is far from the sun

The typical meteor is

a small solid particle, no bigger than a pea

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)

Astronomers have found that the level of the sun activity varies over the centuries. How did they come to realize that this is so?

all of the above

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 a lot of space between them)

one of the key reasons that astronomers 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

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

More than 75% of the known asteroids:

can be found in a belt between Mars and Jupiter

coronal mass ejections fro the sun have many serious effects on or near the earth. which of the following is NOT one of these affects

causing huge cyclones around the equator of the earth

When the Dawn spacecraft explored the largest asteroid Ceres, it discovered white spots that appear to be salt and volcanic mountains made of water ice. This led astronomers to which of the following ideas

ceres may have (or may have had) a liquid ocean under its crust

the fact that some asteroids cluster in what are called asteroid families is probably a result of

collisions which broke up larger bodies into a number of smaller ones

short period comets like comet hailey

come back again and again at predictable intervals

the hottest zone in the sun is the

core

Which part of the Sun's atmosphere has the lowest density (number of atoms per unit volume)?

corona

the ten million tons of particles that escape the sun each year in the form of the solar wind get out mainly through regions called

coronal holes

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

Astronomers first detected the presence of a wind of particles coming from the Sun by

dramatic and sudden changes in the spectrum of the corona

the sun's chromosphere and corona were discovered

during total eclipses of the Sun

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 most common element in the sun is

hydrogen

a main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of

ice

the galileo spacecraft passed by which two asteroids and sent back close-up images and data

ida and gaspra

according to our textbook what is the best way to defend ourselves against an asteroid which is on course to collide with the earth in 7 years

if we do it early enough we could explode something on or near the asteroid to deflect it slightly so that years later it would miss the earth

Some of the early planetesimals that formed the solar system still survive today. Where would you find such planetesimals?

in the asteroid and kepler belt

As astronomers have learned more about the structure of the Sun, they have found that it

is made entirely of hot gas

in 1994 a comet was observed to break into more than 20 pieces and collide with which giant planet

jupiter

why do astronomers today think that we have an asteroid belt and not a planet between mars and jupiter

jupiter's gravity prevented material in that zone from getting together

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

Astronomers now realize that active regions on the Sun are connected with

loops of magnetic field emerging from the surface of the sun

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

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

Three kinds of worlds are round in our solar system. Which of the following is NOT a type of world that is typically round?

minor planet (asteroid)

The reason that Olympus Mons, the tallest mountain on Mars, is taller than Mount Everest (the tallest mountain on Earth) is that:

more than one of the above

astronomers estimate that there may be a trillion comet nuclei orbiting beyond pluto. why then do we not see more comets in our skies

most comets remain in stable orbits beyond pluto only a few have their orbits disturbed and come into the inner solar system

which of the following statements about near-earth objects is true

neos can include both asteroids and comets that cross the earths orbit

On which world besides the Earth could a human being step out of his spacecraft without a space suit and air tanks and be confident of surviving?

none of the above

If our estimates of the number of comets in every part of the solar system are correct, the total mass contained in comets must be:

on the order of the mass of all the planets put together

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

organic materials, amino acids

Two small moons in the solar system have been found to be captured asteroids. These two moons are

phobos and deimos around mars

If you were to glance up at the sun the part of the sun that you can see directly is called its

photosphere

one reason we know more about the surface composition of the asteroid vesta than about most other members of the asteroid belt is that

pieces of vesta have landed on earth as meteroites

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

planetesimals (a few kn to tens of kn 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)

which of the following is not an accomplishment of the rosetta mission to comet churyumov-gerasimenko (c-g)

rosetta took samples of the surface material of comet c-g and sent them back to earth

The Sun's chromosphere contains many jet-like projections that stick up into the transition region. These spikes of gas are called:

spicules

what is the best reason astronomers have come up with to explain why the sunspots are cooler than and look darker

sunspots are places where the strong magnetic fields in the sun resist the upward motion of bubbling hot gases from underneath

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-earths

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 main reason that worlds like the Earth are differentiated is that

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

As you go upwards from the Sun's photosphere,

the density (number of atoms in a unit volume) decreases

according to astronomical tradition who gets to suggest the name for the newly discovered asteroid

the discoverer of the asteroid

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

which part of a comet is the densest

the nucleus

astronomers have concluded that the sun'a activity varies in an 11 year cycle. which of the following statements about this cycle is true?

the number of sunspots gets larger and smaller over the course of 11 years

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

the large reservoir of comet nuclei far beyond pluto from which we now believe new long-period comets come into the inner solar systemis called

the oort cloud

the sun's photosphere is

the part of the sun from which the light comes that we can see when we look at the sun with our eyes

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

what mechanisms do astronomers believe is responsible for making the sun's outer atmosphere so much hotter than its photosphere

the sun's magnetic field (interacting with the charged particles) heat up the atmosphere

sunspots are darker than the regions of the sun around them because

they are cooler than the material around them (although still very hot compared to earth's temperatures)

When larger fragments of Comet Shoemaker-Levy 9 crashed into Jupiter in 1994,

they exploded in jupiters atmosphere releasing energy equal to millions of megatons of TNT

Comets get significantly brighter in our skies as they approach the Sun because

they get bigger as the ice evaporates

Which of the following is NOT a way that Jovian planets can be distinguished from terrestrial planets?

they have many more craters from collisions that happened early in solar system history

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 turned into decay products

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)

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

Your ASTR1110/H classmate 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

how do astronomers know what the outer layers of the sun are made of

we take an absorption line spectrum of the sun and the absorption lines tell us what elements are present in the outer layers