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Astronomy
n/a
98
Science
Undergraduate 4
12/15/2008

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Cards

Term
If a planet is seeing its Moon in the New Phase right now, in what phase would the planet appear to be when viewed from its Moon?
Definition
Full Planet
Term
What is the reason for the seasons on Earth?
Definition
Earth is tilted with respect to the Sun by about 23.5 degrees
Term
As compared to a cool star, a hotter star emits:
Definition
shorter wavelength, higher frequency, bluer color
Term
At approximately what time does the third quarter Moon rise?
Definition
midnight
Term
The electrons in a cloud of hydrogen gas are making the transition from excited states to the ground state. What does the spectrum of this cloud of gas look like?
Definition
It will consist of a few bright emission lines at very specific wavelengths.
Term
If Earth had its orbit changed so that at all points along its orbit it was always the same distance from the Sun (circular orbit), how would this affect the seasons on Earth?
Definition
the same as they are now.
Term
I detect a star giving off more ultraviolet light than green light. What property of the star can I estimate with this information?
Definition
Its temperature
Term
What do you expect the spectrum of an object that is 1,000,000 Kelvin to be like?
Definition
It should peak at X-ray wavelengths.
Term
What time of year is it dark all day (and night) at the South pole?
Definition
June
Term
A planet with its rotation axis tilted by 40 degrees relative to its orbital plane around its star would:
Definition
have dark all the time on the South pole during its winter
Term
The planets are seen in the Zodiac constellations because:
Definition
they orbit the Sun in the same plane as the Earth does
Term
What makes a transition from a higher energy state to a lower energy state when a photon is absorbed into an atom?
Definition
electron
Term
Which of the following is FALSE?
Definition
The wavelengths of the emission lines produced by an element are different from the wavelengths of an absorption line produced by the same element.
Term
One of the lines of Hydrogen has a wavelength of 121.6 nm. If a cloud of Hydrogen gas is moving TOWARDS us at 200km/s, what will we detect?
Definition
An emission line in the cloud’s spectrum with a wavelength shorter than 121.6 nm.
Term
Why does light come in different colors?
Definition
differences in wavelength
Term
Say you are in the bottom of Happy Valley. How does the force of gravity compare to what it would be on top of Mount Nittany?
Definition
slightly greater in Happy Valley than on Mount Nittany
Term
What kind of a telescope would have to be put in space to be effective?
Definition
X-ray
Term
Dark lines in an absorption spectrum represent:
Definition
particular energies of light coming from a distant object that are absorbed by material in between.
Term
f the mass of the Sun were cut in half, how would the force between the Sun and the Earth change?
Definition
it would decrease by a factor of two
Term
In what way does a 30 meter telescope outperform a 10 meter telescope?
Definition
The images of the 30 meter are 9 times brighter than those of a 10 meter.
Term
On a planet whose Moon is in the same orbital plane as the planet’s orbit around its star, how often will solar eclipses occur?
Definition
Once every orbit of its moon (its month).
Term
Say that our Moon was Full on May 1, 2007. When was the next First Quarterphase after that Full Moon?
Definition
May 22
Term
Why does a neon light appear red?
Definition
It gives off an emission spectrum with mostly red spectral lines.
Term
Why don’t we see the constellation Orion all year?
Definition
As the Earth orbits the Sun, its nighttime side points to different constellations at different points along its orbit.
Term
From Earth, in which type of constellation might you find the planet Saturn?
Definition
Only in a Zodiac constellation
Term
What is the main constituent of the atmosphere of Venus?
Definition
carbon dioxide
Term
The escape velocity needed for an atom in the atmosphere of a planet to escape the gravitational pull of the planet is smaller if:
Definition
the mass of the planet is smaller
Term
The planets of the solar system were formed:
Definition
as individual condensation/accretion centers in a rotating solar nebula
Term
Which of the following is true about Neptune?
Definition
Its atmospheric composition is most like Uranus and its rings are like those of Uranus and Jupiter.
Term
The Oort Cloud is thought to be:
Definition
A spherical cloud of comets surrounding the solar system.
Term
Venus is visible to us:
Definition
only near sunrise or sunset.
Term
Planet A has an orbit with a semi-major axis of 3 Astronomical Units. Planet B has an orbit with a semi-major axis of 12 Astronomical Units. How does the orbital period compare between the two planets? Use P squared = a cubed to estimate.
Definition
Planet B has an orbital period 8 times longer than Planet A.
Term
How would an inflated landing module bounce if it were dropped onto the surface of Earth from the same altitude as it was on Mars?
Definition
It would bounce lower and fewer times than it did on the surface of Mars.
Term
How does Pluto’s mass compare with that of Earth’s Moon?
Definition
The Moon is roughly 7 times more massive than Pluto.
Term
How was Earth’s Moon formed, according to the currently most-accepted theory?
Definition
It formed from debris produced by the collision of a Mars-sized object with the Earth.
Term
Why does Mars have seasons?
Definition
Its axis is tilted relative to its orbital plane.
Term
Which planet is able to retain the largest (by radius and by volume) atmosphere?
Definition
Jupiter
Term
The process of formation of the Solar System
Definition
took only a small fraction of the age of the Solar System.
Term
Which is smallest?
Definition
Saturn’s moon Encledus
Term
Which of the following is typical of a Terrestrial planet?
Definition
evidence for volcanic activity
Term
What are the most abundant gases in Jupiter’s atmosphere?
Definition
hydrogen and helium
Term
Which has the lowest average density?
Definition
Uranus
Term
Which of these planets has rings?
Definition
Jupiter
Term
Which fact about Mars is NOT true?
Definition
Mars has a thicker atmosphere than Earth does.
Term
Mars has a mass that is 1/10th the mass of the Earth and a radius that is 1/2 the radius of Earth. Compare the force of gravity on Mar’s surface to that on the surface of Earth using the proportional relationship F is proportional to M/R 2
Definition
Gravity on Mars is 4/10ths as strong as on Earth.
Term
The Sun is at one focus of the elliptical orbit of the Earth around the Sun. What is at the other focus?
Definition
Nothing
Term
Which of the following are the jovian planets?
Definition
Jupiter, Saturn, Uranus, Neptune
Term
Which of the following statements is TRUE?
Definition
The planet Uranus is blue-green and virtually featureless.
Term
The surface of Venus is hotter than the surface of Mercury because:
Definition
Venus is more massive and is able to retain a thick atmosphere.
Term
What fraction of the solar system’s mass is in the Sun?
Definition
About 99%
Term
How do astronomers measure the temperature of stars?
Definition
By looking at which absorption lines are present in the star’s spectrum.
Term
How do we determine the age of a star cluster?
Definition
by identifying the type of stars that have just turned off the main sequence
Term
A hypothetical star has a parallax of 0.05 arcseconds. How far away is it?
Definition
20 parsecs
Term
A 10 solar mass star:
Definition
will eventually develop an Iron core
Term
A star that is twice the mass of our Sun would have a habitable zone that:
Definition
includes Mars but not the Earth
Term
The largest fraction of nearby stars (e.g. within 100 light years) are:
Definition
red dwarfs
Term
What happens when a planet passes in front of its star (i.e. between the star and us)?
Definition
The star decreases in brightness and the star moves towards us
Term
A 16 solar mass main sequence star is at a smaller distance than a 1 solar mass main sequence star. Which star appears brighter?
Definition
the 16 solar mass main sequence star
Term
The event horizon of a black hole is:
Definition
the minimum distance from which light can escape
Term
A cold, irregularly shaped region in the interstellar medium that diminishes or completely obscures the light from background stars is called a//an:
Definition
dark dust cloud
Term
In nuclear fusion, energy is produced because:
Definition
the mass of the reacting chemicals is larger than that of the products.
Term
Is the Milky Way Galaxy currently participating in Galactic cannibalism, and if so what is it devouring?
Definition
It is currently pulling apart and ”eating” the Sagittarius Dwarf Galaxy.
Term
Fill in the blank in the following chemical reaction that occurs in the Sun: Deuterium+ proton = ?? + energy:
Definition
helium-3
Term
What happens when you drop a clock into a black hole?
Definition
The clock appears to be advancing slowly from the point of view of an outside observer, but normally for an observer falling with the clock.
Term
In which part of the Sun are gamma rays produced?
Definition
the core
Term
Which is the longest time?
Definition
the time it takes for a photon to pass through the radiative zone of the Sun
Term
Which star is the closest if all have the same apparent brightness?
Definition
white dwarf
Term
If two stars are the same temperature, how can one be more luminous than the other?
Definition
It can have a larger radius.
Term
A planetary nebula:
Definition
is the ejected envelope of a low to intermediate mass star
Term
A supernova can occur when:
Definition
material from a companion star falls onto a white dwarf
Term
Which of the following is TRUE?
Definition
A brown dwarf is a case where the temperature of a protostar did not grow enough to burn Hydrogen.
Term
The stars in the halo of our galaxy are:
Definition
older and redder than those in the disk.
Term
How can we see through the dusty plane of the Milky Way disk in order to study star formation?
Definition
Look at infrared radiation with the Spitzer Space Telescope.
Term
Which of the following is FALSE?
Definition
A star with spectral type of B is sometimes hotter than a star with spectral type A, and sometimes colder.
Term
What element is only produced in a supernova explosion?
Definition
gold
Term
Which is true about cold dark matter?
Definition
Cold dark matter particles travel more slowly than hot dark matter particles.
Term
Which source is the most luminous (or would be, if all its energy were output in visible light)?
Definition
A gamma-ray burst.
Term
Which force holds the quarks together within a proton?
Definition
The ’strong’ force, through exchange of gluons.
Term
Which is a reason that we know dark energy is a ma jor component of the universe?
Definition
The universe is flat and regular matter doesn’t contribute enough energy density.
Term
When examining a spectrum of a particular galaxy, an astronomer notices that the spectral lines are shifted toward shorter wavelengths. What does this mean?
Definition
the galaxy is very likely to be one of the nearest galaxies to the Milky Way
Term
Why can’t we see back the whole way to the Big Bang?
Definition
The radiation scatters off matter frequently so the Universe is opaque.
Term
Which is the smallest?
Definition
The Solar System.
Term
What type of boson is responsible for the electromagnetic force?
Definition
photon
Term
An up quark has charge +2/3, a down quark has charge -1/3, and a strange quark has charge -1/3. The Sigma0 particle is formed by a combination of two down quarks and one strange quark. What is its charge?
Definition
-1
Term
Which of the following is TRUE?
Definition
We see distant galaxies as they were billions or even tens of billions of years ago.
Term
Among these choices, which is the first thing that happens in the history of the universe?
Definition
formation of nuclei of helium
Term
Which of the following statements is definitely FALSE?
Definition
There is an absence of space beyond the boundaries of our observable universe.
Term
What do quasars look like?
Definition
Individual stars in the Milky Way.
Term
Does the existence of quasars imply that radiation can escape a black hole?
Definition
No, the emission of radiation occurs before material falls in through the event horizon.
Term
Which of the following makes a meson?
Definition
an up quark and an anti-down quark
Term
What property of dark matter leads to it keeping galaxy clusters together?
Definition
It produces gravity due to its mass.
Term
What did the Wilkinson Microwave Anisotropy Probe (WMAP) measure?
Definition
differences in the temperature of radiation coming from the Big Bang from different directions
Term
What fraction of the energy density of the universe consists of dark matter?
Definition
21 percent
Term
Compared to spiral galaxies, elliptical galaxies have...
Definition
...less gas, less dust, and less new star formation.
Term
What happens to the planets in a galaxy when that galaxy collides with another galaxy?
Definition
Nothing, because the spaces between stellar systems in a galaxy is much larger than their size.
Term
If extra dimensions do exist, why wouldn’t we see obvious evidence for them in everyday life?
Definition
They would be quite small and hard to detect.
Term
How do astronomers measure the mass of a supermassive black hole?
Definition
by measuring the speed at which stars move in its vicinity
Term
What produces the afterglow of a gamma-ray burst?
Definition
Collision of expanding stellar material with gas and dust in the interstellar medium.
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