Chapter 13

In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result? a. A large earthquake was felt all over Europe and Asia b. A fireball briefly brighter than the Sun could be seen in the sky c. It broke apart and large pieces of rock fell from the sky, killing thousands of innocent people d. The Earth's orbit around the Sun changed in a measurable way e. It burned up so high in the atmosphere, absolutely nothing could be felt or seen on the ground

A fireball briefly brighter than the Sun could be seen in the sky c. It broke apart and large pieces of rock fell from the sky, killing thousands of innocent people

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

Ceres

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: a. all asteroids are made of frozen water b. Ceres is really one of the terrestrial planets that got kicked out of its former orbit c. Ceres may have (or may have had) a liquid ocean under its crust d. Ceres formed from the breakup of a much larger body, a solid planet bigger than Jupiter e. The next thing to search for on Ceres are spots made of pepper

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

The scientist who first proposed that comet nuclei were "dirty snowballs" was: a. Edmond Halley b. Fred Whipple c. Eugene Shoemaker d. Isaac Newton e. Jan Oort

Fred Whipple

The spacecraft that got the closest to the nucleus of Halley's Comet and sent back dramatic photographs of what the nucleus looked like was: a. Giotto b. Venera c. Pioneer d. Mariner 13 e. the Enterprise

Giotto

The first asteroid confirmed to have a satellite (moon) was

IDA

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? a. The only thing we could do would be to move some people to the Moon so they could survive b. 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 then miss the Earth c. Asteroids are all rubble piles, so the only thing that would protect us would be a huge thermos-nuclear explosion that vaporizes the entire asteroid d. There is no problem, because all asteroid burn up by friction in the Earth's thick atmosphere e. There is no possible protection for us; if an asteroid is headed our way, we are all doomed

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 then miss the Earth

Why do astronomers today think that we have an asteroid belt and not a planet between Mars and Jupiter? a. a planet exploded and broke apart b. Io's volcanoes produced asteroids c. Jupiter's gravity prevented material in that zone from getting together d. the Sun's wind stops "blowing" there e. the solar system needed fashion accessories

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

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 his employees search for? a. primitive b. C-type c. S-type d. M-type e. none of the above

M-type

The Shoemaker-NEAR spacecraft explored two asteroids, Mathilde and Eros. A big difference between them is that: a. Mathilde appears to be pile of "rubble" (a collection of separate rocks) while Eros is solid b. Mathilde is a "real" asteroid, while Eros is a comet that has lost some of its ice c. Mathilde is always inside the orbit of the Earth, while Eros is always outside our planet's orbit d. Mathilde is going to impact the Earth, while Eros will never come near our planet e. you can't fool me, the two asteroids have exactly the same properties; that's why the same spacecraft could explore them

Mathilde appears to be pile of "rubble" (a collection of separate rocks) while Eros is solid

. Which of the following statements about NEO's (Near Earth Objects) is TRUE? a. we have identified just about all NEO's with diameters greater than 1 km b. no NEO has passed closer to the Earth than the orbit of the Moon c. it is unlikely that any NEO's have hit the Earth during our planet's history d. NEO's can include both asteroids and comets that cross the Earth's orbit e. we are not able to obtain information about the shape or size of any of the NEO's at present

NEO's can include both asteroids and comets that cross the Earth's orbit

Two small moons in the solar system, known since the 19th century, turn out to be captured asteroids. These two moons are: a. Io and Europa around Jupiter b. Dione and Titan around Saturn c. the Earth's moon and antimoon d. Phobos and Deimos around Mars e. none of the above

Phobos and Deimos around mars

Which of the following is NOT an accomplishment of the Rosetta mission to Comet Churyumov-Gerasimenko (C-G)? a. Rosetta matched orbits with Comet C-G and flew alongside b. Rosetta dropped the Philae lander on Comet C-G c. Rosetta took close-up images of Comet C-G and sent them back to Earth d. Rosetta took samples of the surface material of Comet C-G and sent them back to Earth e. Rosetta turned off the spacecraft systems to save power far from the Sun, and turned them back on as it got closer to the Sun

Rosetta took samples of the surface material of Comet C-G and sent them back to Earth

In 2012, NASA's Spaceguard Survey concluded that astronomers had now identified 90% of the asteroids with diameters greater than 1 km. How could astronomers know that they had reached this goal? a. Asteroids larger than 1 km are so rare and so big, they have always been easy to keep track of b. NASA is now able to keep track of everything in the solar system out to Pluto with great precision; nothing remains to be discovered in that region c. Most of the near-Earth objects that big are comets, and they all have big tails which are easy to see d.The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey e. This was fake news; in fact, we can't ever know if we have found 90% of the larger near-Earth objects

The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey

How have astronomers learned what different asteroids are made of? a. The only way is to send a spacecraft to each asteroid and bring a chunk of it home b. They measure the x-rays that all asteroids give off c. They wait until the asteroid has a tail of gas behind it and measure that tail d. They examine the spectrum of the sunlight that reflects from the asteroid e. There is no way at the present time to know what asteroids are made of

They examine the spectrum of the sunlight that reflects from the asteroid

Which of the following statements about the tails of comets is FALSE? a. the tail always points away from the Sun b. some comets have both a gas tail and a dust tail c. the tail of a comet can sometimes be ahead of the comet in its orbit d. a comet always has a nice long tail, even when it is far from the Sun e. the Earth can pass through the tail of a comet without suffering any harm

a comet always has a nice long tail, even when it is far from the Sun

If there are at least a million asteroids, how did spacecraft like Galileo survive their trip through the asteroid belt? a. NASA sends its spacecraft above and below the orbits of the asteroids in the belt to avoid collisions b. spacecraft use a magnetic repulsion tool to make sure asteroids do not come too close c. although there are many asteroids, they are widely spaced (there is lots of space between them) d. the known asteroids are typically less than a centimeter across, so they do not represent a danger to spacecraft e. you can't fool me, NASA has lost over a dozen spacecraft to collisions with asteroids

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

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

A baseball pitcher wants to impress his girl-friend with how strong his throwing arm is. On which of the following bodies would the pitcher be MOST likely to be able to throw a baseball (a fast ball) so fast it would actually go into orbit? a. Earth b. Mars c. Ganymede d. Titan e. asteroid Ida

asteroid ida

Why were asteroids not discovered until the 19th century? a. although asteroids are the same size as the planets, they are completely covered with dark dusty material, which means they reflect almost no light b. in their long looping orbits, it was not until the 19th century that an asteroid came close enough to the Earth to be detectable c. several asteroids collided with each other in early 1801, calling them to the attention of astronomers d. asteroids are generally small compared to planets and require a good telescope and patient searching to spot them e. only after Halley's work did astronomers think to look for the tails which allow us to spot an asteroid

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

More than 75% of the known asteroids: a. cross the Earth's orbit at least once as they revolve around the Sun b. are made of icy material that is highly reflective c. were once part of a planet as large as Jupiter d. lie farther out from the Sun than the orbit of Saturn e. can be found in a belt between Mars and Jupiter

can be found in a belt between Mars and Jupiter

The fact that some asteroids cluster in what are called asteroid families is probably the result of: a. resonances with the jovian planets b. collisions which broke up larger bodies into a number of smaller ones c. comets which pass through the asteroid belt and attract asteroids to them d. strong magnetic fields found in some asteroids e. random chance

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

Short-period comets like Comet Halley

come back again and again at predictable intervals

Different asteroids reflect different percentages of the light falling on them. This is due to the fact that they have different:

compositions

Astronomers have realized that the surface of Ida is older than the surface of Gaspra. How do they measure this? a. we have radioactive rock samples from each asteroid to analyze b. the surface composition (elements and compounds) can easily tell us the ages c. from counting craters on each asteroid's surface d. from the magnetic field of each body, which weakens with age e. it's purely a guess; astronomers have no way of really measuring the ages of these asteroids

from counting craters on each asteroid's surface

A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of a. metals b. carbon compounds c. ice d. vapor (gas) e. you can't fool me, astronomers don't really know what comets are made of

ice

The two asteroids from which close-up images and data have been returned by the Galileo spacecraft are: a. Ida and Gaspra b. Vesta and Ceres c. Eros and Toutatis d. Chiron and Pholus e. you can't fool me, we have no close-up views of any asteroids except possibly for the moons of Mars

ida and Gaspra

Comets get significantly brighter in our skies as they approach the Sun because a. they reflect more sunlight as they get closer to the source of light b. they get bigger as the ice evaporates c. they get closer to the Earth than when they were outside the orbit of Mars d. they move faster and faster e. more than one of the above

more than one of the above

One reason we know more about the surface composition of the asteroid Vesta than about most other members of the asteroid belt is that a. Vesta's volcanoes still spew out a lot of material that goes into orbit around Vesta b. Vesta's surface is made of water ice and is extremely reflective c. pieces of Vesta have landed on Earth as meteorites d. Vesta's orbit crosses the Earth's orbit roughly once a century e. Vesta's surface markings happen to resemble a human face and thus have intrigued astronomers ever since this large asteroid was discovered

pieces of Vesta have landed on Earth as meteorites

According to astronomical tradition, who gets to suggest the name for a newly discovered asteroid? a. the president of the country of the discoverer b. a special committee of the U.N. set up for this purpose c. the discoverer of the asteroid d. a special committee in Italy, where the first asteroid was discovered e. authors of astronomy textbooks

the discoverer of the asteroid

Comest change as they approach the Sun in their orbits. Which of the following statements about a comet approaching the Sun is FALSE? a. the solid water ice in a comet begins to evaporate just beyond the orbit of Mars b. comets close to the Sun can evaporate enough material to become as large or larger than Jupiter c. the gravity of the comet nucleus holds on to the evaporated material, and it all eventually freezes back into the nucleus d. when the ice evaporates, some dust frozen into the ice is freed up to join the comet's coma and tail e. the evaporation is not always even, but can occur in spurts (where jets of material are seen moving away from the comet nucleus)

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

Which part of a comet is the DENSEST? a. the nucleus b. the atmosphere (coma) c. the dust tail d. the gas tail e. the hydrogen cloud

the nucleus

Halley's Comet was given that name because Edmond Halley was a. the first person to ever see that comet b. the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so c. the chief scientist who designed the probe that flew by the comet d. the first person to be hurt by pieces falling off the comet e. prime minister of England at the time the comet was discovered

the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so