Astronomy: Chapter 7, 13, 14
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
Between 1992 and today, astronomers using large telescopes have discovered many icy pieces that orbit in the same region as the orbit of Pluto. These are believed to be members of the
Kuiper Belt
The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call:
planetesimals
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)
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
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?
100 million years
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:
Antarctic
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 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:
Ceres may have (or may have had) a liquid ocean under its crust
When a chunk of cosmic material the size of a golf ball or a baseball hits the Earth's atmosphere it makes a
Fireball
The scientist who first proposed that comet nuclei were "dirty snowballs" was:
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:
Giotto
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 Jupiter's formed further out in the solar system, and then migrated inward somehow.
If you were to take a large sample of the four giant planets, the most common element you would find in them is:
Hydrogen
The first asteroid confirmed to have a satellite (moon) was
Ida
The two asteroids from which close-up images and data have been returned by the Galileo spacecraft are:
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 then miss the Earth
In general, the further planets are from the Sun, the cooler they are. What other factor can have a significant influence on a planet's surface temperature?
It's atmosphere (whether it has one and how thick it is)
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?
M-type
The tallest mountain on a terrestrial world is:
Olympus Mons (Mt. Olympus) on Mars
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:
Oort Cloud
The first trans-Neptunian object astronomers found (in 1930) is called
Pluto
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.
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?
The people doing the survey began to find the same objects over again, indicating they were reaching the limits of their survey.
In the far future, a visiting tourist from another planetary system asks to see the most massive object in our solar system. Where would you take him/her/it?
The sun
How have astronomers learned what different asteroids are made of?
They examine the spectrum of the sunlight that reflects from the asteroid
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
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
Of the following planets, which do NOT have satellites (moons)?
Venus
On which planet (besides the Earth) do we still see a high level of geological activity on the surface today?
Venus
Which of the following statements about the tails of comets is FALSE?
a comet always has a nice long tail, even when it is far from the Sun
Which of the following places is most likely NOT to be differentiated?
a small asteroid
Radioactive dating techniques have revealed that our Earth and Moon are approximately how old?
about 4.5 billion years
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)
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?
asteroid Ida
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?
from counting craters on each asteroid's surface
Generally, planets and moons in our solar system are named after
gods and goddesses from mythology
In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its
half-life
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
In studying the surfaces of solid bodies in the solar system, astronomers have learned that the number of craters (per unit area):
is roughly proportional to the age of the surface we are examining
Which of the following ways that jovian (giant) planets differ from the terrestrial planets is NOT CORRECT?
jovians (being larger) rotate significantly more slowly than terrestrials
In a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villain has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg. for his weapon to work. After how much time will the weapon no longer be a threat?
just a little after 2 hrs
In addition to hundreds of smaller objects they have been discovering in the Kuiper Belt recently, astronomers were surprised to find
larger bodies, with sizes as big as Pluto (now called dwarf planets)
The Murchison meteorite that was found in Australia in 1969 is important to scientists because it contained
organic materials, such as amino acids
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
On Earth, we can get the age of various parts of our planet by finding rocks that contain radioactive atoms. Which other world do have a good number of rocks from to do this kind of age analysis?
moon
Which part of a comet is the DENSEST?
nucleus
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 call the vast, rotating cloud of vapor and dust from which the solar system formed:
solar nebula
Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call:
solar nebula
The reason that worlds like the Earth are differentiated is that
the continuing impacts on a growing protoplanet eventually melted the entire body
According to astronomical tradition, who gets to suggest the name for a newly discovered asteroid?
the discoverer of the asteroid
In the four terrestrial planets, the densest, heaviest materials are at the center and not evenly distributed throughout the planet. Scientists interpret this observation to mean that:
the four terrestrial planets must once have been hot enough to be molten (like a liquid)
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
Halley's Comet was given that name because Edmond Halley was
the scientist who pointed out that the orbit of the comet was such that it should return every 76 years or so
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
When larger fragments of Comet Shoemaker-Levy 9 crashed into Jupiter in 1994,
they exploded in Jupiter's atmosphere, releasing energy equal to millions of megatons of TNT
Which planet in the solar system has not been examined by spacecraft instruments that have either flown by or orbited them?
you can't fool me, spacecraft have visited all the planets in our solar system
On which of the planets (other than Earth) could a human being step out of a spacecraft and survive without any protective gear (special suit, oxygen tanks, etc)?
you can't fool me; there is no other planet on which we could survive unprotected
When chemists say that a planet's upper regions are reduced, they mean that these regions
are dominated by the element hydrogen and its compounds
The smaller objects in the solar system made of rock and metal (most of which orbit between Jupiter and Mars) are called:
asteroids
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
More than 75% of the known asteroids:
can be found in a belt between Mars and Jupiter
In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result?
A fireball briefly brighter than the Sun could be seen in the sky
Two small moons in the solar system, known since the 19th century, turn out to be captured asteroids. These two moons are:
Phobos and Deimos around Mars
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 comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was
Shoemaker-Levy 9
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
The fact that some asteroids cluster in what are called asteroid families is probably the result of:
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
The smaller objects in the solar system composed mainly of ices (frozen gases) that usually orbit far from the Sun are called:
comets
What is one way that astronomers have actually gotten an idea of the age of the surfaces of terrestrial planets other than the Earth?
counting craters
During the process of differentiation,
heavier materials sink to the centers of molten planets
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
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 rate at which a collection of the same radioactive atoms will decay depends on:
only on internal processes within the atoms; nothing external matters
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 typical meteor is
a small solid particle, no bigger than a pea
The Shoemaker-NEAR spacecraft explored two asteroids, Mathilde and Eros. A big difference between them is that:
Mathilde appears to be pile of "rubble" (a collection of separate rocks) while Eros is solid
The planet closest to the Sun in the solar system is:
Mercury
You are the captain of an interplanetary tour ship and a wealthy tourist from Texas asks you to take him to see only the "largest darn planets" in the solar system. Which of the following would you NOT include in your tour?
Mercury
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 of our solar system and from old comets; there is a huge supply of small dirt particles from both sources.
Which of the following statements about NEO's (Near Earth Objects) is TRUE?
NEO's can include both asteroids and comets that cross the Earth's orbit
Which of these worlds is the most active geologically?
Venus
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
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
A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of
ice
Which of the following statements about the unusual object Chiron is FALSE?
it is one of the largest asteroids, just a little smaller than Vesta
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
Comets get significantly brighter in our skies as they approach the Sun because
more than one of the above
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 (a thousand billion) 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
Today, the chemistry of the terrestrial planets does not include a lot of free hydrogen. Chemists call the chemistry in places like the Earth:
oxidized
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 meteorites
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)
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
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
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 future interplanetary tourist whose parents kept him too warm as a baby asks for your help to find a "really cold place" in the solar system. Which of the following would be the coldest place to take him?
the moons of Neptune
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
What is the most important reason that astronomers have learned more about our planetary system in the last 30-40 years than all of history before then.
we have been able to send spacecraft to gather information about planets and moons up close