Section 3 Flashcards
How was Uranus discovered
Herschel saw it in his telescope
1781
How was Neptune discovered
Through mathematical prediction by Adams and LeVerrier
1846
Why do Uranus and Neptune appear blue-green in color
A high abundance of CH4 (methane) in their atmospheres
Which is the solar system’s most featureless planet
Uranus
Which planet has the most exaggerated seasons
Uranus
On which planet was the Great Dark Spot seen?
Is it still there
Neptune
No, it had disappeared by 1955
What most likely produces the magnetic fields of Uranus and Neptune?
How do we know
Compressed liquid water oceans.
A lack of ammonia in their atmospheres.
How where the rings of Uranus and Neptune discovered
Occultations of a distant star by both of these planets
Which world was discovered by the use of a blink comparator
Pluto
What is unique about the Pluto-Charon system
Mutual synchronous rotation
What observations finally gave us good data about Pluto and Charon
A series of eclipses and transits
Why do many argue that Pluto is not truly a planet?
Do all astronomers agree
It has not dominated its region of the solar system.
Many do not agree with this
Where are the Kuiper belt objects located
Orbiting the Sun farther away than Neptune
Where are most of the solar system’s asteroids located
Asteroid Belt (between Mars and Jupiter)
What are the Kirkwood Gaps
Regions without asteroids in the Asteroid Belt (due to orbital resonances with Jupiter)
Where are the Trojan asteroids located
In Jupiter’s orbit (at stable Lagrange points)
Why are the Apollo asteroids of such concern
They cross the Earth’s orbit (impact threats)
Which solar system objects may be best described as “dirty snowballs”
Comets
Where are most of the solar system’s comets thought to reside
Oort Cloud
In which direction are comets’ tails pointed
Away from the Sun
What is happening on the night of a meteor shower
Earth passes through the orbit of a comet
What appears to have wiped out the dinosaurs about 65 million years ago
A major impact
What was the Solar Nebula?
What event most likely caused it to begin to collapse
The cloud of gas and dust that our solar system formed from.
A nearby supernova
Why are terrestrials closer to the Sun and Jovians farther from the Sun
This is where the material existed to form these types of planets
What are exoplanets?
What are the two main ways that we can detect them
Planets orbiting other stars.
Doppler shifts and transits of the star they orbit
What happens in one proton-proton chain reaction
4 hydrogen fuse to make 1 helium, with two neutrinos and energy produced
From which layer of the Sun’s atmosphere does most of the visible light come from
Photosphere
What are granules?
Where do we find them?
Convection cells seen in the photosphere
What color does the chromosphere appear?
Why
Reddish/pinkish, due to hydrogen alpha emission
Why does the corona appear so dim in visible light
It is extremely hot gas, so it emits most of its energy in the x-ray spectrum
From where does most of the solar wind escape from the Sun
Coronal holes
What are the giant loops of gas seen hanging over the limb of the Sun called
Prominences
What are solar flares
Very energetic explosions in the Sun’s atmosphere
About how much longer will the Sun live before it begins its death process
About 5 billion years
What is the solar neutrino problem
We see only 1/3 of the predicted number of solar neutrinos
Today, what are the spectral types for the stars?
What do they represent
OBAFGKM
They represent surface temperatures (listed from hottest to coolest)
How do M stars compare to O stars
M stars are cooler, less massive, have longer lives and are far more numerous
About how many stars make up our Milky Way galaxy
About 200 billion
What type of galaxy is the Milky Way
Spiral galaxy
What are the best seasons to view our galaxy
Spring and fall
How are galaxies spread throughout the universe
Galaxies reside in clusters, which reside in superclusters separated by voids
What is the importance of Olbers’ Paradox
The night sky is dark, so the universe is not infinite, eternal and static
General relativity predicted what about the universe?
Has it been verified
The universe must expand or contract.
Hubble later verified it is expanding
What are the three big pieces of evidence supporting the Big Bang
The expansion of the universe, the cosmic Helium abundance, and the C.M.B.R.
How close to time zero does physics currently describe the universe’s nature
10 to the -43rd seconds
What currently appears to be the fate of the universe
Expand forever
Do most astronomers believe life exists elsewhere in the universe?
Why
Yes, due to the vast number of stars and the Sun is really just an average star
What type of signal do we expect to one day detect from an intelligent civilization
A powerful radio signal with some form of mathematical content
What was the result of the Miller-Urey experiment
The formation of amino acids
What does the Drake Equation attempt to predict
The number of intelligent civilizations in the galaxy today
