Shared Flashcard Set

Details

astr 110 final
n/a
120
Astronomy
Undergraduate 2
05/05/2013

Additional Astronomy Flashcards

 


 

Cards

Term
What makes the north star, polaris, special?
Definition
It appears very near the north celestial pole.
Term
Which of the following statements about constellations is false?
Definition
Most constellations will be unrecognizable hundreds of years from now.
Term
What is 6.10167 in degrees, minutes, seconds, notation?
Definition
6 degrees, 3 minutes, 10 seconds
Term
You are standing on Earth's equator. Which way is Polaris, the North star?
Definition
on the northern horizon
Term
By locating the north celestial pole (NCP) in the sky, how can you determine your latitude?
Definition
The altitude of the NCP is your angular distance from the North Pole,
Term
Which of the following statements about the celestial equator is true at all latitudes?
Definition
It represents an extension of Earth's equator onto the celestial sphere.
Term
What is a circumpolar star?
Definition
A star that always remains above your horizon.
Term
How many arcseconds are in 1(degree)?
Definition
3,600
(60 minutes in a degree x 60 seconds in a minute)
Term
On a cosmic calender, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on a planet in a solar system?
Definition
1 second ago
(1 month = 1 billion years)
Term
The constellations which lie along the path that the Sun travels are called
Definition
the zodiac
Term
The ancient goal of astrology was to
Definition
predict human events
Term
What is the Hawaiian name for Mercury (Hint: it follows the sun)
Definition
Ukaaliali'i
Term
At Kukaniloko on Oahu, the shadow surrounds the center of the concentric circles in a petroglyph
Definition
at sunset on the summer solstice
Term
He discovered that Jupiter has moons.
Definition
Galileo
Term
When we see Venus in its full phase, what phase would Earth be in as seen by a hypothetical Venetian?
Definition
full
Term
He developed a system for predicting planetary positions that remained in use for some 1,500 years
Definition
Ptolemy
Term
How did Eratosthenes estimate the size of Earth in 240 B.C.?
Definition
by comparing the maximum altitude of the Sun in two cities at different latitudes
Term
during the Dark Ages in Europe, the scientific work of the ancient Greeks was preserved and further developed primarily by scholars in
Definition
Baghdad
Term
Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe?
Definition
to explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky
Term
The contreversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun
Definition
Copernicus
Term
What is the Heat contained in a gas?
Definition
The total kinetic energy of the particles in the gas
Term
How much energy is needed to ionize Hydrogen?
Definition
13.6 eV
Term
Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion the object will
Definition
continue to move in the same way until it is acted upon by a force
Term
Which of the following statements correctly describes the law of conversion of energy?
Definition
The total quantity of energy in the universe never changes
Term
Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that
Definition
a planet travels faster when it is nearer to the sun and slower when it is farther from the sun
Term
What is the acceleration of gravity of Earth?
Definition
9.8 m/s^2 downward
Term
As long as an object is not gaining or losing mass. a net force on the object will cause a change in
Definition
velocity
Term
From Kepler's third law, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to
Definition
4 astronomical units
Term
Speed and velocity are the same thing. True or false?
Definition
False
Term
If you double the mass of fusion material in a hydrogen bomb, you quadruple the amount of energy generated. True or false?
Definition
False
Term
The frequency of a wave is
Definition
(all of the above)
Term
At which lunar phase(s) are the tides least pronounced (e.g. lowest high tides)?
Definition
both the first and third quarters
Term
We can see each other in a classroom right now because we
Definition
reflect visible light
Term
The allowed shapes for orbits under the force of gravity are
Definition
ellipses, parabolas, and hyperbolas
Term
How can an electron in an atom lose energy to go from a higher energy level to a lower energy level?
Definition
It releases a photon equal in energy to its own energy drop
Term
If a material is transparent, then it
Definition
transmits light well
Term
The esc velocity from Earth is
Definition
11 km/sec
Term
The amount of gravitation potential energy released as an object falls depends on
Definition
the distance it falls
Term
The force of gravity is an inverse square law. That means that, if you double the distance between two large masses, the gravitational force between them
Definition
weakens by a factor of 4
Term
The tides on Earth are an example of
Definition
the universal law of gavitation
Term
Without telescopes or other aid, we can look up and see the Moon in the night sky because it
Definition
reflects visible light
Term
Captain Cook came to the South pacific to
Definition
(all of the above)
Term
A hot dense, glowing object -solid or gas- emits what type(s) of radiation?
Definition
A continuous spectrum
Term
Why do astronomers need different telescopes designs to observe across the electromagnetic spectrum?
Definition
Photons of different energy behave differently and require different collection strategies
Term
What are the two most important properties of a telescope?
Definition
Its light collecting area and angular resolution
Term
When the thirty meter telescope is built, it will be three times bigger than any other optical telescope and will operate at wavelengths 3 times smaller than current telescopes. Its max resolution will be (remember that 1.22 wavelength/diameter)
Definition
nine times the max resolution of current telescopes
Term
In what wavelength range was interferometry first routinely used?
Definition
radio
Term
Which of the following is not a good reason to place observatories on remote mountain tops?
Definition
to reduce light pollution
Term
Where was the first permanent European astronomy telescope located?
Definition
Punahou school
Term
King kalakaua was a modern man in every sense of the word, he
Definition
(all of the above)
Term
Rank the five terrestrial worlds in order of size from smallest to largest:
Definition
Moon, mercury, Mars, Venus, Earth
Term
How does the sun's mass compare with that of the planets?
Definition
It is a thousand times more massive than all the planets combined
Term
Which optical telescope on Maunakea has the largest single piece of glass (reflecting mirror)?
Definition
The Subaru telescope
Term
According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?
Definition
The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk
Term
Which planet has the highest average surface temperature, and why?
Definition
Venus, because of its dense carbon dioxide atmosphere
Term
Which of the following in not an exception to the general patterns of motion in the solar system?
Definition
the rings of saturn
Term
Which optical telescope on Maunakea has the largest reflecting mirror
Definition
The Keck telescope
Term
Which of the following is not a characteristic of the inner planets?
Definition
The all have substantial atmospheres
Term
Which planet could an astronaut visit without the need for a spacesuit (and survive)?
Definition
None; an astronaut would need a spacesuit to survive a visit to any other planet in the solar system
Term
What is the esc velocity below?
v(esc)= [(2x10^*23)(8x10^13) over 1x10^-16]^1/2 m/s
Definition
4x10^3 m/s
Term
Which of the jovian planets have rings?
Definition
(all of the above)
Term
How do asteroids differ from comets?
Definition
Asteroids are made of rocky material. comets are made of icy material.
Term
What parts of a comet points most directly away from the sun?
Definition
the ion tail
Term
where are the Trojan asteroids located?
Definition
surrounding Jupiter
Term
Which of the following is furthest from the sun?
Definition
a comet in the Oort cloud
Term
Which is the closest to the temp of the core of the sun?
Definition
10 million K
Term
Based on its surface temp of 5,800 K, what color are most of the photons that leave the Sun's surface?
Definition
green
Term
What is a meteorite?
Definition
a fragment of an asteroid from the solar system that has fallen to the earth's surface
Term
how far is mars from the sun?
Definition
1.6 AU
Term
which is the closest to the average distance between asteroid in the asteroid belt?
Definition
1 million km
Term
what is a possible solution to the solar neutrino problem?
Definition
the electron neutrinos created in the sun change into another type of neutrino that we do not detect
Term
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
Definition
a million years ago
Term
which is closest to the temp of the core of the sun?
Definition
10 million K
Term
suppose you put two protons near each other. because of the electromagnetic force, the two protons will
Definition
repel each other
Term
how much mass does the sun lose through nuclear fusion per second?
Definition
4 million tons
Term
at the center of the sun, fusion converts hydrogen into
Definition
helium, energy, and neutrinos
Term
what processes are involved in the sunspot cycle
Definition
the winding of magnetic field lines due to variations in the sun's rotation
Term
a star's luminosity is the
Definition
total amount of energy that the star radiates each second
Term
which of the following correctly states the luminosity-distance formula?
Definition
apparent brightness= luminosity over 4(pi)x(distance)^2
Term
what are the standard units for apparent brightness
Definition
watts per square meter
Term
A star's luminosity is the
Definition
total amount of luminous energy that the star radiates each second
Term
on a hertz-russell diagram, where would we find stars that are cool and dim?
Definition
lower right
Term
on a hertz-russell diagram, where on the main sequence would we find stars that have the greatest mass?
Definition
upper left
Term
on the main sequence, the stars obtain their energy
Definition
by converting hydrogen to helium
Term
since all stars begin their lives with the same basic composition, what characteristic most determines how they will differ?
Definition
mass they are formed with
Term
what type of star is our sun?
Definition
low-mass star
Term
which of the following correctly states the luminosity-distance formula?
Definition
apparent brightness=luminosity over 4(pi)x(distance)^2
Term
what is a planetary nebula?
Definition
the expanding shell of gass that is no longer gravitationally held to the remnant of a low-mass star
Term
why does a star grow larger after it exhausts its core hydrogen?
Definition
hydrogen fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward
Term
In the end, the remaining core of this star (see graph) will be left behind as
Definition
a white dwarf made primarily of carbon and oxygen
Term
Which of the following is closest in mass to a white dwarf?
Definition
the Sun
Term
Suppose that you measure the parallax angle for a particular star to be 0.5 arcsecond. The distance to this star is
Definition
2 parsecs
Term
Why is there an upper limit to the mass of a white dwarf?
Definition
The more massive the white dwarf, the greater the degeneracy pressure and the faster the speeds of its electrons. Near 1.4 solar masses, the speeds of the electrons approach the speed of light, so more mass cannot be added without breaking the degeneracy pressure.
Term
What is the ultimate fate of an isolated white dwarf?
Definition
It will cool down and become a cold black dwarf.
Term
What types of stars end their lives with supernovae?
Definition
stars that are at least several times the mass of the Sun
Term
Observationally, how can we tell the difference between a white-dwarf supernova and a massive-star supernova
Definition
The spectrum of a massive-star supernova shows prominent hydrogen lines, while the spectrum of a white-dwarf supernova does not
Term
Which element has the lowest per nuclear particle and therefore cannot release energy by either fusion or fission?
Definition
iron
Term
From a theoretical standpoint, what is a pulsar?
Definition
a rapidly rotating neutron star
Term
How does the gravity of an object affect light?
Definition
light coming from a compact massive object, such as a neutron star, will be redshifted
Term
How do we know what happens at the event horizon of a black hole?
Definition
we don't know for sure; we only know what to expect based on the predictions of general relativity
Term
To esc from a planet that is 4 times as massive as the Earth, you will need to travel how many times as fast as the esc velocity from Earth?
Definition
2 times as fast
Term
How can we see through the interstellar medium?
Definition
by observing only the brightest visible source
Term
What evidence supports the theory that there is a black hole at the center of our galaxy?
Definition
The motions of the gas and stars at the center indicate that is contains a million solar masses within a region only about 1 parsecs across
Term
Who discovered of the first quasar?
Definition
Cyril Hazard, ex rugby player
Term
What is the major difference between an elliptical galaxy and a spiral galaxy?
Definition
An elliptical galaxy lacks a disk component.
Term
What is a rotation curve?
Definition
rotational velocity of material in a galaxy plotted against distance from the center of the galaxy
Term
What is the thickness of the disk of the Milky Way?
Definition
1,000 light years
Term
What diameter of the disk of the Milky Way?
Definition
100,000 light years
Term
What is the main difference between Active Galatic Nuclei?
Definition
Most are found in spiral galaxies rather than ellipticals and have no jets of relativistic particles streaming from their centers.
Term
Which of the following types of galaxies are most spherical in shape?
Definition
spirals
Term
If there is no dark matter in the Milky Way Galaxy, what is one of the alternative explanation for the observations (mentioned in class) ?
Definition
Another possibility – Perhaps gravity on large scales, such as the size of galaxies, doesn't work the same way as gravity does on the small scales we can measure.
Term
What might be causing the universe to accelerate?
Definition
We don't know (might be dark energy but we don't know what dark energy is)
Term
How long after the Big Bang
was the Planck time, before
which our current theories are completely unable to describe conditions in the universe?
Definition
Planck time (10^-43 sec)
Term
I observe a galaxy that is 100 million light years away and moving toward us: what do I see?
Definition
100 million light year old (blueshifted)
Term
Where do the photons in the cosmic background radiation originate?
Definition
the end of the era of nuclei
Term
Approximately how long did the era of nucleosynthesis last?
Definition
3 minutes
Term
Why can't current theories describe what happened during the Planck era?
Definition
No theory of quantum gravity. However there are two theories gravity and quantum mechanics.
Term
What is Hubble's law?
Definition
Mathematical expression of the idea that more distant galaxies move away from us faster. v=H(0)xd, where v is galaxy's speed away from us, d is its distance, and h(0) is Hubble's constant
Term
How many particles are required to explain the hundreds of particles found today?
Definition
28
Term
Currently, the distribution of galaxies in the universe appears to be?
Definition
Clusters and clumps
Groups and surfaces surrounding vast voids
Supporting users have an ad free experience!