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ASTR 1101 Final- Boyajian

Terms in this set (158)

What is the difference between visible light and X-rays?
Wavelength; X-rays have a shorter wavelength than visible light.
The color of visible light is determined by its
wavelength
How do the wavelength and frequency of red light compare to the wavelength and frequency of blue light?
Red light has a longer wavelength and lower frequency than blue light.
What does amplitude reveal about light?
brightness
Which of the following photons carries the smallest amount of energy?
a microwave photon, whose wavelength is 10−2 m
Which of the following lists different types of electromagnetic radiation in order from the shortest wavelength to the longest wavelength?
radio waves, infrared, visible, ultraviolet, X-rays
If the frequency of a beam of light were to increase, its period would _________ and its wavelength would _________.
decrease; decrease
As wavelength increases, the energy of a photon _____ and its frequency _____.
decreases; decreases
If the wavelength of a beam of light were to double, how would that affect its frequency?
The frequency would be two times lower.
When an electron moves from a higher energy level in an atom to a lower energy level
a photon is emitted
If the Sun instantaneously stopped giving off light, what would happen on the day-side of Earth?
It would get dark 8.3 minutes later.
Why is a neutral iron atom a different element than a neutral carbon atom?
An iron atom has more protons in its nucleus than a carbon atom
Which of these stars would have the biggest redshift?
a star moving at high speed away from you
A spaceship is traveling from planet B on the left, toward planet A on the right. The spaceship is traveling at a speed of 15,000 km/s to the left while it sends out a signal with a wavelength of 4 m. If astronomers living on planets A and B measure the radio waves coming from the spaceship, what wavelengths will they measure?
Both Planet A and planet B measure 4 m.
You observe the spectrum of two stars. Star A has an emission line from a known element at 600 nm. Star B has emission lines from the same atom, but the emission line is occurring at 650 nm. One possible explanation for this observation is
that star A is cooler than star B.
As a blackbody's temperature increases, it also becomes _________ and _________.
more luminous; bluer
You observe a red star and a blue star and are able to determine that they are the same size. Which star has a higher surface temperature, and which star is more luminous?
The blue star has a higher surface temperature, and the red star is more luminous.
Why do some stars in the sky appear blue, whereas other stars appear red?
The blue stars have higher surface temperatures than the red stars.
Star A and star B appear equally bright in the sky. Star A is twice as far away from Earth as star B. How do the luminosities of stars A and B compare?
Star A is four times as luminous as star B
A black car left in the sunlight becomes hotter than a white car left in the sunlight under the same conditions because
the white car reflects more sunlight than the black car.
Which of the following factors does not directly influence the temperature of a planet?
the size of the planet
Which of these planets would be expected to have the highest average temperature?
a dark-colored planet close to the Sun
Which of the following was not discovered by Galileo using a telescope?
Mars has a polar ice cap similar to Earth.
The aperture of a telescope is which of the following?
the diameter of the primary lens/mirror
A prism is able to spread white light out into a spectrum of colors based on the property of
refraction.
Before charge-coupled devices (CCDs) were invented, what was the device most commonly used for imaging with optical telescopes?
photographic glass
The major advantage CCDs have over other imaging techniques is that
all of the above (they have a higher quantum efficiency, they have a linear response to light, they yield output in digital format, and they operate at visible and near-infrared wavelengths.)
Why can you see fainter stars with an 8-inch telescope than you can see with your naked eye?
The telescope collects light over a larger area.
You hear a news story about an X-ray telescope being built on Earth. You know this can't be possible because
X-rays do not travel very far through Earth's atmosphere.
Astronomers can use ground-based telescopes to observe in the majority of which of the following parts of the electromagnetic spectrum?
visible, infrared, and radio
NASA's Kuiper Airborne Observatory and the Stratospheric Observatory for Infrared Astronomy (SOFIA) are two examples of telescopes placed in highflying aircraft. Why would astronomers put telescopes in airplanes?
to get the telescopes above the majority of the water vapor in Earth's atmosphere
Which of the following is the biggest disadvantage of putting a telescope in space?
Space telescopes are much more expensive than similar ground-based telescopes.
Which of the following is not a reason to put a telescope in space?
to get closer to the stars
...
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Samples of which celestial object(s) have been brought back to Earth to be studied in detail?
the Moon
Landers, rovers, and/or atmospheric probes have visited which object(s) listed below in an effort to gain new information about our Solar System?
all of the above (Jupiter, Titan-Saturn's moon, Mars, Eros-an asteroid
Which planet receives the least amount of energy from the Sun?
Neptune
Which of these planets has a composition that is most like the Sun?
Jupiter
Why are Jupiter and Saturn not perfectly spherical?
They rotate rapidly.
Each season on Uranus lasts approximate 21 Earth years because
Uranus's rotational axis is tipped by 45 degrees relative to it orbital axis.
A planet will have bands in its atmosphere like Jupiter and Saturn if
the wind speeds vary greatly with latitude
What causes the distinct bluish tint of the ice giants Uranus and Neptune?
Methane in their atmospheres preferentially absorbs the red component of the Sun's light and reemits the blue part, giving the bluish tint.
The poles of Uranus can have a higher temperature than its equator because Uranus
has a large axial tilt relative to its equator.
We refer to some of the inner regions of Jupiter and Saturn as metallic hydrogen because they
efficiently conduct electricity.
If you could watch Saturn starting from the beginning of the Solar System, which of these features of Saturn would come together first?
rocky core
Neptune and Uranus probably took longer to form than Jupiter and Saturn because the solar nebula was _________ at the radius of Neptune and Uranus.
not as dense
Which property of a moon might lead you to believe it was a captured asteroid?
It rotates in the opposite direction than its planet rotates
If a moon has a retrograde orbit, then it
all of the above (orbits in the opposite direction than its planet rotates, orbits in the opposite direction than its planet revolves around the Sun, orbits in a clockwise direction as viewed from the planet's North Pole)
Cryovolcanism occurs when
low-temperature liquids explode through the surface because of increasing pressure underground.
Which giant planets have rings?
All of them
*If our Moon had active volcanoes
the Moon would have a thick hydrogen atmosphere, Earth might have a ring, the Moon's surface would have more craters than it currently does, life could not exist on Earth, or the Moon would have different phases than we see today.
Extremophiles on Earth have been found
in all of the above (in the scalding waters of Yellowstone's hot springs, in the bone-dry oxidizing environment of Chile's Atacama Desert, in the Dead Sea, in the deep subsurface ice of the Antarctic ice sheet.
Which of following is false?
Pluto has a mass that is 10 times less than Earth's mass.
Suppose we discover a comet whose orbit was very highly eccentric, retrograde, had a very large tilt with respect to the ecliptic plane, and a period of 2,000 years. Where is the most likely place of origin for this comet?
the Oort Cloud
The meteoroids in the Leonids meteor shower, which occurs every November, come from
dust melted off Comet Tempel-Tuttle.
Antarctica is the best hunting ground for meteorites for all of the following reasons except
more meteorites fall there than on other locations on Earth.
Density, temperature, and pressure increase as you move inward in the interior of the Sun. This means that the weight of the star pushing inward at a given radius _________ as you move inward toward the core.
increases
What do astronomers mean when they say that the Sun makes energy by hydrogen burning?
The Sun is fusing hydrogen into helium and releasing energy.
If the core of the Sun were hotter than it is now, how would the Sun's energy production change?
It would produce more energy per second than it does now.
Which of the following is not a result of an increase in solar activity?
None of the above; all of these are caused by increased solar activity (the altitudes of orbiting satellites decrease, airplanes have trouble navigating, stronger auroras are seen, power grids can be damaged.
The Sun's internal magnetic field becomes tangled up over time because of
differential rotation.
What advantage do you gain by having two eyes that are separated on your face, rather than being very close together?
stereoscopic vision, which allows you to determine distances
Stars with a larger brightness must be
any combination of the above (closer to us than fainter stars, larger in size than fainter stars, intrinsically brighter than fainter stars).
Which spectral type has the strongest hydrogen absorption lines?
A
Which sequence correctly lists the spectral classes of stars in order from hottest to coolest?
O B A F G K M
What spectral class is the Sun?
G2
Which stars are the most common?
Stars with a smaller mass and radius than the Sun's are most common.
Main-sequence stars range in mass from approximately
0.08 to 150 M⊙.
The Hertzsprung-Russell diagram is a graph of _________ for stars.
luminosity versus temperature
Any of the following properties could be plotted on the horizontal axis of an H-R diagram except for
Luminosity
In which region of an H-R diagram would you find the main-sequence stars with the closest habitable zones?
center
The habitable zone for the Sun covers the area that is between _________ from the Sun.
0.9 to 1.4 AU
*Why was the comet or asteroid impact 65 million years ago (ironically) an event that benefited the evolution of humans?
It deposited a significant amount of nitrogen into the Earth's atmosphere; it led to an increase in global UV radiation, which killed off most of the forests and jungles; Mammals got an evolutionary boost; Plant life began to decline; It brought human DNA to Earth.
Which of the following is not a property of life known on Earth?
It is self-sufficient, since it has its own internal source of energy
The earliest life-forms on Earth likely appeared
within a billion years after the formation of the Solar System.
Which of the following is not an example of extremophiles?
organisms that photosynthesize
If you travel in your time machine 2 billion years back in time. What would happen?
You would probably die due to the severe scarcity of oxygen.
If we model the history of the Earth as a single calendar year, on what day would the dinosaurs be wiped out by a large asteroid or comet?
Christmas Day
Which one of the following is not an element commonly found in living organisms?
helium
Which element is not represented in the acronym SPONCH?
Carotene
The Drake equation estimates the number of
extraterrestrial life forms within the Milky Way, capable of communication
Which of the following Solar System objects is not a good candidate for future searches for life?
Venus, because it can host extremophiles
If we wanted to look for other civilizations within the Milky Way, where should we look?
far from the galactic center, because planets are less exposed to harmful gamma rays and X-rays coming from the galactic center
If future exploration of the moons of Jupiter and Saturn discover primitive life forms, it would imply a __________ probability of finding an advanced civilization somewhere else in the Milky Way because ____________________________________.
higher; it shows that life can exist in environments that are very different from those found on Earth
Which of the following bodies of the Solar System has not yet been landed upon by spacecraft?
Europa
The Solar System body to which humans have dedicated the largest number of landing missions so far is
Mars.
What does "habitable zone around a star" mean in the current framework of the search for exoplanets?
the region around the star where planetary temperatures would not be too hot or too cold and liquid water could exist
The ability of a celestial body to retain an atmosphere would depend mainly on which of the following properties?
mass and size
Planets that are close to their stars may lack the day-night cycle due to
being tidally locked.
Scientists define the habitable zone in our Solar System as being (roughly) bracketed by the orbits of
Venus and Mars.
Why are the high-mass stars less likely to have planets with advanced/intelligent life forms?
High-mass stars are too hot, and their habitable zone is too far from them.
Based on what you know of the Earth's evolutionary timeline, what percent of Earthlike planets in a star cluster with an age of 2 billion years likely hosts intelligent life?
0 percent
*What would be the main factors determining whether water can exist in a liquid state on the surface of a planet?
The presence of photosynthetic and highly intelligent life forms; the age and mass of the central star; the atmospheric pressure and temperature on the planetary surface; the color and temperature of the central star; the existence of carbon-based biology
The main goal of the Breakthrough Listen project is to search for
electromagnetic signals from civilizations inhabiting habitable plane
We search for intelligent life in the universe most effectively by
all of the above (sending out spacecraft with messages on them, using radio telescopes to search for radio signals, monitoring ultraviolet radiation emitted by stars, sending spacecraft to explore other worlds).
SETI, the Search for Extra Terrestrial Intelligence, is an initiative developed and supported by the federal government.
False
Which of the following items is not part of the Breakthrough Starshot project?
Sending nanocrafts to the Vega, the star that Jodi Foster visited in the movie contact
Nowadays, the number of confirmed exoplanets is approaching
5,000.
People argue against the possibility of time travel by saying, "If humans will eventually be able to travel back in time, then where are all the tourists from the future?" This idea is similar to the ___________, only applied to time travel instead of alien space travel.
Fermi paradox
In 1974, astronomers sent a message toward globular cluster M13. If life exists there, and it returns our signal, we won't receive it for at least another 50,000 years. Why?
M13 is far enough away that even light takes a very long time to reach it.
If the most pessimistic assumptions in the Drake equation were true, we would
have to wait for millions of years to get a message back from the nearest intelligent life.
In a simplified version of the Drake equation (N = NHabitable Planets × flife × fciv × fnow), we expect the term fciv to be small if
primitive life is common but intelligent life is rare.
Which of the following is not considered a potential solution to the question of why we lack any evidence of a galactic civilization?
The galactic civilization probably is undetectable because they operate under different laws of physics from the ones we know.
In general, how does the size and location of a star's habitable zone depend on the star's mass?
The smaller (less massive) the star, the smaller and the closer-in the habitable zone.
Which of the following is not considered crucial for life to exist on some world?
liquid water
How did oxygen (O2) get into Earth's atmosphere?
It was released by life through the process of photosynthesis.
The two Voyager spacecraft carry a message from Earth, just in case an alien civilization ever runs across them.
True
If they existed, and if they were watching, a civilization on the nearest exoplenetary system to us, Proxima Centauri B, would think that
The president of the United States is Barack Obama
Why is the spectral sequence of stars not alphabetical?
The original alphabetical labeling did not correspond to surface temperature and thus had to be reordered.
Which of the following statements about spectral types of stars is not true?
The spectral type of a star cannot be used to determine its color.
On a Hertzsprung-Russell diagram, where would we find stars that are cool and large?
upper right
On a Hertzsprung-Russell diagram, where would we find stars that have the hottest temperatures and largest luminosities?
upper left
Which of the following is the most common type of main-sequence star?
an M star
A star of spectral type G lives approximately how long on the main sequence?
10 billion years
All stars spend approximately the same amount of time on the main sequence
False
From the center outward, which of the following lists the "layers" of the Sun in the correct order?
core, radiation zone, convection zone, photosphere, chromosphere, corona
Why do sunspots appear dark in pictures of the Sun?
They actually are fairly bright but appear dark against the even brighter background of the surrounding Sun.
Suppose that, for some unknown reason, the core of the Sun suddenly became hotter. Which of the following best describes what would happen?
Higher temperature would cause the rate of nuclear fusion to rise, which would increase the internal pressure, causing the core to expand and cool until the fusion rate returned to normal.
The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about
105 years ago.
Most of the energy produced in the Sun is released in the form of visible light from the photosphere. However, some energy is released from the upper layers of the solar atmosphere. Which of the following best describes where other forms of light are released?
The chromosphere is the source of ultraviolet light, and the corona is the source of X rays.
Which of the following statements about the sunspot cycle is not true?
The rate of nuclear fusion in the Sun peaks about every 11 years
What processes are involved in the sunspot cycle?
the winding of magnetic field lines due to differential rotation
True or false: The Sun generates energy primarily by nuclear fission.
True
Nuclear power plants on Earth do not create energy in the same way as the Sun
False
The core of the Sun is at a temperature of about 20,000 K
False
The Sun will exhaust its nuclear fuel in about
5 billion years.
To estimate the central temperature of the Sun, scientists
use computer models to predict interior conditions.
How does the Sun's mass compare to Earth's mass?
The Sun's mass is about 300,000 times the mass of Earth.
The Sun's surface seethes and churns with a bubbling pattern. Why?
We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface.
Which of the following correctly compares the Sun's energy generation process to the energy generation process in human-built nuclear power plants?
The Sun generates energy by fusing small nuclei into larger ones, while our power plants generate energy by the fission (splitting) of large nuclei.
Every second, the Sun converts about 600 million tons of hydrogen into 596 million tons of helium. The remaining 4 million tons of mass is
converted to an amount of energy equal to 4 million tons times the speed of light squared.
The first planets around other Sun-like stars were discovered
about two decades ago.
Which of the following methods has not yet detected planets around other stars?
detecting the light from the planet itself by expertly blocking out the light of the host star
Most of the planets discovered around other stars
are more massive than Earth and orbit very close to the star.
By itself, the Doppler technique provides a measure of a planet's
Both A and D (Minimum mass and orbital period).
The transit method of planet detection works best for
big planets in edge-on orbits around small stars
A planet is detected via the Doppler technique. The velocity change of the star is a measure of
the planet's orbital period and eccentricity.
The depth of the dip in a star's brightness due to the transit of a planet depends most directly on
the planet's size.
Why are many of the newly detected extrasolar planets called "hot Jupiters"?
Their masses are similar to Jupiter but they are very close to the central star and therefore hot.
Prior to 2009, most known exoplanets were discovered by
the Doppler technique.
How does the Kepler mission look for planets around other stars?
It looks for slight back and forth shifts in a star's position in our sky.
Which of the following is not expected for a "hot Jupiter" that orbits 0.05 AU from its star?
intense volcanism
What is a meteorite?
fragment of an asteroid from the solar system that has fallen to Earth's surface
A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.
pea-size particle from a comet
Why does the plasma tail of a comet always point away from the Sun?
The solar wind electromagnetically "blows" the ions directly away from the Sun
The number of comets in the Oort cloud is probably about
a trillion.
On average, how often do impactors about 10 km in size, large enough to produce mass extinction, hit Earth?
once every hundred million years
A spacecraft traveling through the asteroid belt has a high risk of being destroyed through a collision.
False
Pluto's gravity affects the orbit of Uranus, and this fact was used to discover Pluto.
False
Why is Saturn almost as big as Jupiter, despite its smaller mass?
Jupiter's greater mass compresses it more, thus increasing its density.
Why are there no impact craters on the surface of Io?
Io did have impact craters but they have all been buried in lava flows
What causes synchronous rotation?
A massive planet exerts a tidal force on a moon that causes the moon to align itself such that its tidal bulges always point toward and away from the planet.
Which of the following is not due to tidal forces?
the retrograde orbit of Triton (a moon of Neptune)
Planetary rings are
all of the above (nearer to their planet than any of the planet's large moons, orbiting in the equatorial plane of their planet, composed of a large number of individual particles that orbit their planet in accord with Kepler's third law, known to exist for all of the Jovian planets).
Which of the following planets cannot be seen with the naked eye?
Neptune
We can see each other in the classroom right now because we
reflect visible light.
You observe a distant star. You find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared. What do you conclude?
The star is moving away from you.
True or False: Lines of a particular element appear at the same wavelength in both emission and absorption line spectra.
True
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