kudu midterm 2

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Astronomy

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May 5, 2024

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11/15/2021 Kudu 6. Week 6 - Asteroids, Comets, Meteors, The Sun, Celestial Distances, Stars Please note the questions below can be edited and changed by your instructor. The printed version is NOT guaranteed to match the online version at a later stage. Homework Questions Q1 (1 points) The asteroid belt is found in the gap between which two planets? Select the correct answer O Venus and Earth () Mars and Jupiter O Jupiter and Saturn O Earth and Mars O Saturn and Uranus Q2 (1 points) What was the first asteroid to be discovered in 18017 Select the correct answer O Lutetia O Ida () Ceres O Vesta O Mathilde Q3 (1 points) How do we think Ceres is built? Select the correct answer O It has a metallic core, surrounded by some sort of liquid ocean and a rocky crust. O It has a metallic core surrounded by an icy mantle and a rocky crust. O It has no core but is mostly solid rock with a possibility of water below the surface. QO It has a rocky and metallic core surrounded by an icy mantle, a thin crust and a thin atmosphere. () It has a rocky core surrounded by a water mantle and a dusty crust. https://kudu.com 1/17
11/15/2021 Kudu Q4 (1 points) When talking about objects in the asteroid belt a “rubble pile” refers to what? Select the correct answer A region of the asteroid belt that could have formed an asteroid but was disrupted by gravity from Jupiter or another large body. O O A region with many small rocks thought to have been created when an asteroid was broken up by a large collision. () An asteroid made up of many separate pieces of rock and pebble held together by their collective gravity. Floating clouds of particles created by a non-asteroid body colliding with an asteroid and breaking apart into many pieces. O O Mounds of smaller pieces of rock and other material held on to a larger asteroid by its gravity. Q5 (1 points) What is currently our best model for how the asteroid belt was formed? Select the correct answer Most of the material currently found there was once a single planet which was torn apart and scattered by Jupiter’s tidal forces and collisions with bodies attracted by Jupiter’s gravitational pull. O After most of the solar system had already formed, larger masses from outside of the solar system were drawn in towards what is now the belt by the gravity of the newly formed planets, especially Jupiter. The asteroids were formed in the same way the planets began to form but were kept from growing larger by tidal forces QO from planets like Jupiter which grew more quickly because they were formed in more material dense areas of the solar system. Most of the asteroids were once moons orbiting Jupiter at a speed which the planets gravity could not hold on to indefinitely and they eventually escaped the planet at different times, spreading out into a belt. The material that is now in the belt was once many planetesimals kept from growing larger by tidal forces which were then broken apart into asteroids of different materials by collisions. Q6 (1 points) When a planet is in orbit around a star the gravity of the two bodies cancel out in five relatively stable points. These points are called... Select the correct answer O Newton points. O Stability points. O Near-orbit points. () Lagrange points. O Gravitational bowls. https://kudu.com 2/17
11/15/2021 Kudu Q7 (1 points) The nucleus of a comet is generally very different from an asteroid in that it... Select the correct answer () Contains more ice. QO Is more rocky QO Is generally more spherical QO Is usually made up of many smaller pieces. O Is much denser Q8 (1 points) How are the tails that generally trail away from a comet formed? Select the correct answer () Sublimating ice releases gas and dislodges dust from the comet’s nucleus. O Comets are generally more charged than other bodies and as a result capture solar wind. O Asthe comet passes by planets it pulls away part of the atmosphere with its gravity. O Comets are usually dense enough that they are able to gravitationally attract enough small particles to create a tail. O Wedo not know, it is simply part of the definition of a comet. If a comet did not have a tail it would simply be a meteor. Q9 (1 points) How do the directions of the two tails compare in a comet? Select the correct answer The directions of the two tails depends greatly on what part of the solar system the comet is moving through. The gas O tail generally points away from the Sun and the dust tail generally points towards the nearest planet (if there is a planet close enough to have an effect). o One tail is composed mainly of gas and is attracted by the Sun and as a result faces directly towards it. The dust trail follows the comet from behind but is slightly offset by the Sun’s gravity. o One tail is composed mainly of gas which becomes ionized and faces directly away from the sun while the other is made of dust and trails directly behind the comet. Both tails are attracted towards the Sun from their natural position behind the comet, but the dust tail has more mass O and feels a stronger pull. As a result the dust trail faces more towards the Sun and the gas trail faces more towards the back of the comet. o) One tail is composed mainly of gas which is ionized and always moves as far away as possible from the Sun. The other tail follows behind the comet but is slightly pushed away from the sun as well. https://kudu.com 3/17
11/15/2021 Kudu Q10 (1 points) There are two types of comets, short period comets and long period comets. These two types are classified by what aspect of the comet? Select the correct answer O The size of the comet. O The region from which the comet originated. () The time-length of the comet’s orbit. O The comet’s distance from the sun. O The comet’s plane of orbit. Q11 (1 points) A comet that passes too close to the Sun and very quickly loses all of its mass is called... Select the correct answer O Asolar comet. O A comety. O Adead comet. O A trojan comet. () A sun-diver. Q12 (1 points) How are comets still around 4.5 billion years after the formation of the Sun? Select the correct answer Comets are constantly coming in and out of the solar system, so most of the comets we see today were formed near younger stars and travelled into our solar system. O The comets that still exist in our solar system pass through regions of icy material and dust during their orbit, picking up enough of it to replenish any material lost during their orbit. Comets only come close enough to the Sun to sublimate for a very short portion of their orbit, most of their orbit is in cold enough regions that they do not lose any material. The comets we see now are not the same that existed in the inner solar system billions of years ago. New ones are constantly brought in from repositories at the edge of the solar system. The rate of sublimation of the ice on most comets is so low that the comets can go on for extremely long periods of time, even in astronomical time lines. https://kudu.com 4/17
11/15/2021 Kudu Q13 (1 points) When the first detailed pictures were taken of a comet astronomers were surprised to find that the nucleus was as dark as asphalt. This is because... Select the correct answer () The reflective ice is buried beneath a thick layer of darker dust. O Not much sunlight can reach the regions where comets tend to orbit. (O The icy substances on comets form in crystallized patterns that do not reflect light well. (O The cameras on board the spacecraft used to take the photos were flawed. O All of the reflective ice on the comet was concentrated into one spot which was not visible by the camera. Q14 (1 points) How is the gas that makes up a comet'’s tail generally emitted from the nucleus? Select the correct answer O Itis emitted from dozens of tiny holes, usually on the side of the nucleus closest to the Sun. O No gas is emitted, all of the gas on a comet already exists in its tail. () Itis emitted in a few spots, seen as bright spots on the darker nucleus in pictures. O Gas is usually emitted from one somewhat large spot facing the Sun. O Itis slowly emitted over the entire surface, coming out too slowly to be seen in pictures. Q15 (1 points) What substance, now crucial to life on Earth, is thought to have maybe come from asteroid collisions earlier in the planet’s history? Select the correct answer () Water. O Large amounts of carbon. O Oxygen. QO Iron. O Methane. Q16 (1 points) Organic molecules including amino acids have been found in the coma of a comet, indicating that life on Earth may have oriains outside of the nlanet. https://kudu.com 5/17
11/15/2021 Kudu R~ R R el I DI SR I Select the correct answer ) True QO False Q17 (1 points) If an object entering Earth’s atmosphere is large enough to reach the surface it goes through three stages, first it passes through space, then it streaks through the atmosphere, and finally it impacts the Earth’s surface. What are the names, in that order, for the object at each stage? Select the correct answer O Meteor, meteoroid, meteorite. O Meteoroid, meteorite, meteor. O Meteorite, meteoroid, meteor. () Meteoroid, meteor, meteorite. O Meteor, meteorite, meteoroid. Q18 (1 points) What causes the bright streaks we often refer to as shooting stars? Select the correct answer O Solar wind showing through the atmosphere in concentrated spots. QO Light from small or distant stars briefly becoming much hotter due to a huge explosion on its surface. () Superheated gas in the atmosphere that has been compressed by small objects at high speeds. QO Light from the fire of burning objects in the atmosphere heated and evaporated by friction. QO Light from the Sun reflected off of small objects in Earth’s orbit. Q19 (1 points) About how large are most meteors that hit the Earth’s atmosphere? Select the correct answer () Smaller than a grain of sand. O About one meter across. O About the size of a grapefruit. O One or two centimeters across. https://kudu.com 6/17
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