Astronomy 1001 Midterm
A 100-kilogram satellite orbiting Jupiter or a 100-kilogram satellite orbiting Earth. (Assume both satellites orbit at the same distance from their planets' center.)
100-kilogram satellite orbiting Jupiter The circumference of Jupiter is larger than the circumference of earth therefore the satellite orbiting Jupiter has a larger distance which is important to gravitational potential energy Submit
How many electrons are in an O+5 ion?
3
Oxygen has atomic number 8. How many times must an oxygen atom be ionized to create an O+5 ion?
5
At high noon on the day of the summer solstice, at what altitude above the horizon do we see the Sun in Washington DC? Note that the longitude and latitude of Washington DC are 77.0o W and 38.9o N, respectively.
74o
Which of the cars is accelerating?
A car going around a circular track at a steady 100 miles per hour.
Which person is weightless?
A child in the air as she plays on a trampoline.
Assume we observe with an Earth-orbiting telescope spectrometer a highly luminous star 100 light-years away. Also assume that 2 light-years away from us there is a very cool but thin cloud of gas that lies exactly between Earth and the luminous star. What do we see with the spectrometer?A continuum thermal spectrum with absorption lines
A continuum thermal spectrum with absorption lines
Choose the correct definition of a molecule.
A molecule is a group of two or more atoms bound together.
The diffraction limit is a limit on:
A telescope's angular resolution.
In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. Suppose you see this line at a wavelength of 120.5 nm in Star A, at 121.2 nm in Star B, at 121.9 nm in Star C, and at 122.9 nm in Star D. Which stars are coming toward us?
A,B
Mercury is locked into a "3:2 spin-orbit resonance" which is described in your text. This means that for every two orbits about the Sun, Mercury rotates about its axis 3 times. (Why this happens is complicated, and is not discussed in the text.) Let's divide the surface of Mercury into two sides, A and B, where at the beginning side A is facing the Sun and side B facing away from the Sun. Which statement of the following is correct? (Hint: Draw pictures of Mercury at various points along its orbit. This may not be easy to visualize without them.)
After one orbit, side B is facing the Sun
Which type is the Sun's visible-light spectrum, and why?
An absorption line spectrum. Relatively thin photosphere of the Sun absorbs the specific wavelength from the light emitted from the hot and dense interior of the Sun.
Choose the correct definition of an atom's atomic mass number.
An atom's atomic mass number is the number of protons plus the number of neutrons.
Choose the correct definition of an atom's atomic number.
An atom's atomic number is the number of protons it has in its nucleus
Just as the Sun is setting we see a first-quarter Moon. At what altitude (the angle above the horizon) do we see the Moon?
At 90o
In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. Suppose you see this line at a wavelength of 120.5 nm in Star A, at 121.2 nm in Star B, at 121.9 nm in Star C, and at 122.9 nm in Star D. Explain your answers without doing any calculations.
By looking at the wavelengths of each subsequent star the transition is cleat. Star A and b are nearing the rest wavelength while c and d are further away from it
In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. Suppose you see this line at a wavelength of 120.5 nm in Star A, at 121.2 nm in Star B, at 121.9 nm in Star C, and at 122.9 nm in Star D. Which are moving away?
C,D
Consider the statement "There's no gravity in space." This statement is:
Completely false.
In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. Suppose you see this line at a wavelength of 120.5 nm in Star A, at 121.2 nm in Star B, at 121.9 nm in Star C, and at 122.9 nm in Star D. Which star is moving fastest relative to us ?
D
Earth is closer to the Sun in January than in July. Therefore, in accord with Kepler's second law:
Earth travels faster in its orbit around the Sun in January than in July.
Choose the correct definition of electrical charge.
Electrical charge is a measure of how strongly something will interact with electromagnetic fields.
Under what circumstances can energy level transitions occur?
Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too much or too little energy is offered, the electron cannot make the transition.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Moons cannot have atmospheres, active volcanoes, or liquid water.
False
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Because of their higher frequencies, X rays must travel through space faster than radio waves.
False all light travels through space at the same speed of light
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Because of precession, someday it will be summer everywhere on Earth at the same time.
False. Precession does not change the amount of axis tilt and therefore does not effect the pattern of the seasons.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). If Earth's orbit were a perfect circle, we would not have seasons.
False. Seasons are caused by the axis tilt. Therefore, the orbit does not effect the seasons.
A comet is seen to pass close to the Earth every 90 years. Where did this comet originate?
From the Kuiper belt
A small celestial body of approximately 10 km diameter enters the inner solar system and flies by close to the Earth (thereby causing a doomsday panic!). Its plane of motion is observed to be at an angle of 75 degrees to the ecliptic. From where did this object most likely originate?
From the Oort cloud
What is the leading hypothesis for the origin of the Moon?
It formed from the material ejected from Earth in a giant impact.
What's unusual about our moon
It's surprisingly large relative to the planet it orbits.
The most common form of iron has 26 protons and 30 neutrons. State its atomic number, atomic mass number, and number of electrons (if it is neutral).
Its atomic number is the number of protons, which is 26. Its atomic mass number is the number of protons and neutrons totaling 56. If the atom is neutral then it has the same number of protons and electrons and therefore there are 26 electrons.
Which is the most likely explanation for why Mars has no magnetic field?
Its core is likely too cool to cause convection within it.
Which would be the most likely consequence were all the hydrogen ices to sublimate (turn from solid to gas) at temperatures around 75 K? [This is Chapter 7 and 8 material. Hint: you'll want to refer to Table 7.1 of your text.]
Jupiter would not be a gas giant planet
Choose the correct definition and two examples of kinetic energy
Kinetic energy is the energy an object has due to its motion. A car driving down the highway or molecules of hot, raising up air have kinetic energy.
Suppose that two stars are separated in the sky by 0.1 arcsecond. Choose the correct statement describing, what will you see if you look at them with a telescope that has an angular resolution of 0.5 arcsecond.
One point of light that is the blurred image of both stars.
In winter, Earth's axis points toward the star Polaris In spring, the axis points toward
Polaris
Choose the correct definition and two examples of potential energy.
Potential energy is energy that is stored. Two examples are mechanical energy in a compressed spring and gravitational energy in a rock on the top of a hill.
Choose the correct definition of precession, and the correct explanation how does it affect what we see in our sky.
Precession is the change of direction in which Earth's axis points. The celestial poles slowly move relative to the stars. In about 13000 years the star Vega will be the North star instead of Polaris.
Choose the correct definition and two examples of radiative energy
Radiative energy is energy in the form of light. Sunlight and radio waves carry this form of energy.
List the different forms of light in order from highest to lowest energy.
Radio Infrared Visible Ultraviolet X Rays Gamma Rays
Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity?
Size
The major way in which we learn about Earth's interior is through
Studying seismic waves
Decide whether the discovery should be considered reasonable or surprising. A solar system has six terrestrial planets and four jovian planets. Each of the six terrestrial planets has at least five moons, while the jovian planets have no moons at all.
Surprising This is surprising because Jovian planets typically have more moons because of their gravitational force because they're gaseous planets
Suppose that the condensation temperature of "rocks" were same as that for metals (see Table 8.1 of your text), i.e., 1000-1600 K instead of 500-1300 K. Assuming the fractional abundances of each type of matter are those given in Table 8.1, which of the following is the least plausible statement?
The mass of the Earth would likely be smaller than it is in our solar system
New York City has coordinates of 40∘N and 74∘W. Where does the north or south celestial pole appear in the sky of New York?
The north celestial pole appears in the sky of New York at an altitude of 40∘ at north.
Beijing and Philadelphia have about the same latitude but different longitudes. What can be said about the tonight's night sky in these two places?
The sky will look about the same.
What is responsible for the sunlight energy we receive from the Sun?
Thermonuclear fusion at the center of the Sun
Although all the known stars rise in the east and set in the west, we might someday discover a star that will rise in the west and set in the east. Choose the correct explanation why does the statement above make sense (or is clearly true) or does not make sense (or is clearly false).
This statement does not make sense. The stars moves because of the Galaxy's rotation around it center. So, during the day, al the stars must move in the same direction.
If an astronaut goes on a space walk outside the Space Station, she will quickly float away from the station unless she has a tether holding her to the station. Choose the correct explanation why does the statement make sense (or is clearly true) or does not make sense (or is clearly false)
This statement is false. She and the Space Station share the same orbit and will stay together unless they are pushed apart.
I live in the United States, and during my first trip to Argentina I saw many constellations that I'd never seen before. Choose the correct explanation why the statement makes sense (or is clearly true) or does not make sense (or is clearly false)
This statement makes sense, because the constellations visible in the sky depend on latitude. Since Argentina is in the Southern Hemisphere, the constellations visible there include many that are not visible from the United States.
If a distant galaxy has a substantial redshift (as viewed from our galaxy), then anyone living in that galaxy would see a substantial redshift in a spectrum of the Milky Way Galaxy. Choose the correct explanation why the statement makes sense (or is clearly true) or does not make sense (or is clearly false).
This statement makes sense. The redshift means that we see the galaxy moving away from us, so observers in that galaxy must also see us moving away from them—which means they see us redshifted as well.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). The walls of my room are transparent to radio waves.
True Radio waves pass through most walls, which is the reason that you can receive radio broadcasts in your home.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Thanks to interferometry, a properly spaced set of 10-meter radio telescopes can achieve the angular resolution of a single 100-kilometer radio telescope.
True this statement is true but the telescope has lower sensitivity
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). This morning I saw the full moon setting at about the same time the Sun was rising.
True. During a full moon, the earth is on the opposite end of the horizon than the moon. Therefore causing the setting of the moon and rising of the sun.
Choose the correct conditions, under which two atoms are different isotopes of the same element.
Two atoms having the same number of protons and different numbers of neutrons.
Are there any exceptions to the rule that planets rotate with small axis tilts and in the same direction that they orbit the Sun?
Venus and Uranus are exceptions.
What do we mean when we say that energy levels are quantized in atoms?
We mean that the electrons can have only discrete values of electrical potential energy in atoms.
The south celestial pole is 35 ∘ above your southern horizon. What does it tell you?
You are at latitude 35 ∘S.
We see (blank) when we look a dense hot object emitting light.
a continuous spectrum
If you heat a rock until it glows, its spectrum will be:
a thermal radiation spectrum
The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is:
above Earth's atmosphere
We see _____________________spectrumn when we look through a cloud of gas at a dense hot object emitting light
an absorption line
Which of the following three kinds of objects resides closer to the Sun on average?
asteroids
Consider the following three atoms: Atom 1 has 7 protons and 8 neutrons; atom 2 has 8 protons and 7 neutrons; atom 3 has 8 protons and 8 neutrons. Which two are isotopes of the same element?
atoms 2 and 3
For each of the following, which object has more gravitational potential energy? A bowling ball perched on a cliff ledge or a baseball perched on the same ledge.
bowling ball perched on a cliff ledge The bowling ball has a more mass than the baseball and therefore it's gravitational potential energy is larger
The set of spectral lines that we see in a star's spectrum depends on the star's:
chemical composition.
Which lists the major steps of solar system formation in the correct order?
collapse, condensation, accretion
Leftover ice-rich planetesimals are called
comets
Compared to the Sun, a star whose spectrum peaks in the infrared is:
cooler
A diver on a 10-meter platform or a diver on a 3-meter diving board.
diver on a 10-meter platform The diver on the 10-meter platform is higher and therefore has a larger gravitational potential energy because it depends on how far it can fall as a result to gravity
Ionization is the process by which
electrons escape from atoms.
We see an (blank) when we look at a cloud of thin and hot gas
emission line spectrum
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Thanks to adaptive optics, the telescope on Mount Wilson can now make ultraviolet images of the cosmos.
false Mount Wilson is a ground based telescope so because of atmospheric absorption it cannot observe ultraviolet images
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). I wanted to see faint details in the Andromeda Galaxy, so I photographed it with a very short exposure time.
false We can use the shutter to control the exposure time of an image, the amount of time during which light collects on the detector. A longer exposure time means that more light reaches the detector, allowing the detector to record details that might be too faint to be seen in shorter exposures.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). New technologies will soon allow astronomers to use X-ray telescopes on Earth's surface.
false X rays are absorbed by the atmosphere and don't reach earth's surface
How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?
four times
As an interstellar gas cloud shrinks in size, its gravitational potential energy:
gradually transforms into other forms of energy.
What is Jupiter's main ingredient?
hydrogen and helium
The most abundant ingredient of the Sun and Jupiter is:
hydrogen.
Where should you put a telescope designed for ultraviolet observations?
in Earth orbit
Some nitrogen atoms have seven neutrons and some have eight neutrons; these two forms of nitrogen are
isotopes of each other.
If you see the color red in an X-ray image from the Chandra X-Ray Observatory, it means:
it depends: the colors are chosen arbitrarily to represent something about the X rays recorded by the telescope. Submit
Suppose Earth had a second moon, called Swisscheese, with an average orbital distance double the Moon's and a mass about the same as the Moon's.
longer According to Kepler's third law, distant objects have longer orbital periods
If you wanted a radio telescope to achieve the same angular resolution as a visible-light telescope, it would need to be:
much larger.
Decide whether the discovery should be considered reasonable or surprising. A solar system has several terrestrial planets and several larger planets made mostly of ice. (Hint: What would happen if the solar wind started earlier or later than in our solar system?)
reasonable This is reasonable because larger planets are usually like jovian planets which are cold and it is possible for jovian planets to be interrupted by solar winds
Decide whether the discovery should be considered reasonable or surprising. Radiometric dating of the oldest meteorites from another solar system shows that they are a billion years younger than rocks from the terrestrial planets of our system.
reasonable This is reasonable because there is no reason to believe that other solar systems shouldn't be the same age as ours
Decide whether the discovery should be considered reasonable or surprising. A solar system has 12 planets that all orbit the star in the same direction and in nearly the same plane. The 15 largest moons in this solar system orbit their planets in nearly the same direction and plane as well. However, several smaller moons have highly inclined orbits around their planets.
reasonable The smaller moons would be bound to their planets on the same plane because of their mass
A spectral line that appears at a wavelength of 321 nm in the laboratory appears at a wavelength of 328 nm in the spectrum of a distant object. We say that the object's spectrum is:
redshifted.
Decide whether the discovery should be considered reasonable or surprising. A solar system has four large jovian planets in its inner solar system and seven small planets made of rock and metal in its outer solar system.
surprising Jovian planets are normally not in the inner solar system because they need to be where its cold enough for them
Decide whether the discovery should be considered reasonable or surprising. A solar system has many rocky asteroids and many icy comets. However, most of the comets orbit in the inner solar system, while the asteroids orbit in far-flung regions much like the Kuiper belt and Oort cloud of our solar system.
surprising This is surprising because comets usually form in the outer solar system where its colder. Asteroids are usually inner
Decide whether the discovery should be considered reasonable or surprising. A solar system has several planets similar in composition to the jovian planets of our solar system but similar in mass to the terrestrial planets of our solar system.
surprising We do not know how to make a jovian planet with abundant hydrogen and helium gas without a core of hydrogen gas compounds
Decide whether the discovery should be considered reasonable or surprising. A solar system has 10 planets that all orbit the star in approximately the same plane. However, five planets orbit in one direction (e.g., counterclockwise), while the other five orbit in the opposite direction (e.g., clockwise).
surprising If planets are orbiting a star on the same plane, it is assumed that they are all orbiting in the same direction
Decide whether the discovery should be considered reasonable or surprising. A solar system has four Earth-size terrestrial planets. Each of the four planets has a single moon that is nearly identical in size to Earth's Moon.
surprising Reasonable because it is similar to our own solar system
If there is going to be a total lunar eclipse tonight, then you know that:
the Moon's phase is full.
Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false).
true Stars twinkle because of air turbulence in earth's atmosphere. The air turbulence does not happen in space beyond earth's atmosphere so the stars would not twinkle on the moon
Compared to an atom as a whole, an atomic nucleus is
very tiny but has most of the mass.
Compared to their values on Earth, on another planet
your mass would be the same but your weight would be different.
