AST 4 Flashcards

Big Bang
Terms Definitions
radio waves
communication
newton's 1st law
inertia
corona
the sun's outer atmosphere
Kinetic Energy
the energy of motion
Hubble's law?
Ho = v/DHo= 72km
Which moon has the densest atmosphere?
Titan
• X-ray and gamma-ray telescopes employ the same basic design as optical instruments
False
The main constiuent of Earth's atmosphere is nitrogen.
True.
Earth's atmosphere consists mostly of ___ gas.
Nitrogen
According to Kepler's second law of planetary motion, when a planet moves in its orbit so that it is closer to the sun, its orbital speed
increases
Rays
BRIGHT EJECTA shot out along specific directions
spectrum
a separation of light into its constituent wavelengths, using a prism or grating
Super Clusters
Clusters of galaxies that come together (can be 100 million light years across)
• Infrared astronomy can only be done from space
False
Hubbles Law
this is a relationship between VELOCITY of recession and DISTANCE, and gives an estimated distance to distance to distant galaxies
Red dwarf stars
long lifetimes --> 10_12 years
stellar evolution
the changes in size, luminosity, temperature, and chemical composition that occur as a star ages
Earth wobbles in space due to gravitational influence of the sun and moon. (Different Stars will become the north star)
Precision
Which type of telescope has its scientific equipment mounted inside the telescope tube?
prime focus
Cosmic Background Explorer
In 1989, the Cosmic Background Explorer satellite (COBE) determined a value of 2.7 K for the universal temperature. The cosmic microwave background displays a high degree of isotropy and provides strong support for the cosmological principle. It should be noted that the cosmic microwave background contains more energy than has been emitted by all of the stars and galaxies that have ever existed in the universe.
A neutrino is:
an elusive massless (or nearly massless) particle produced in the proton-proton cycle
The largest moon in the solar system, bigger but not as massive as Mercury, is
Ganymede
waning crescent
phase btw last/third quarter and new moon
Because it has a higher percentage of ________, Neptune appears even bluer than Uranus
Methane
• What is the dominant wavelength in nanometers of the light coming from a very hot star (about 29,000 K)?
100nm
proton-proton chain
n the Sun, four hydrogen nuclei (protons) fuse into one helium-4 nucleus by way of the proton0proton chain. Gamma rays and subatomic particles known as neutrinos and positrons carry off the energy released in the reaction.
Step 1: two protons fuse to make a deuterium nucleus (1 proton and 1 neutron). This step occurs twice in the overall reaction.
Step 2: the deuterium nucleus and a proton fuse to make a nucleus of helium-3 (2 proton, 1 neutron). This step also occurs twice in the overall reaction.
Step 3: two helium-3 nuclei fuse to form helium-4 (2 protons, 2 neutrons), releasing two excess protons in the process.
Blue supergiant
short lifetimes --> 2 x10_7
Higher luminosity, burns up quicker
neutron star
a very compact, dense stellar remnant composed almost entirely of neutrons
How many times does the Moon rotate about its axis during one orbit around the Earth?
1
Which planet is NOT known to have a ring system?
Mercury
galactic year
Time taken for objects at the distance of the Sun (about 8 kpc) to orbit the center of the Galaxy, roughly 225 million years.
The sequence of fusion reactions that converts helium to carbon in the cores of red giant stars is:
the triple-alpha process
Which three worlds have almost identical densities?
Mercury, Venus, and Earth
Absorption Line Spectrum
Appears as a rainbow with specific colors missing from the rainbow
White Dwarfs
Helium core begins to fuse as Carbon and He burning begins. outer layers are pushed away from the star in the form of planetary nebula. the small white hot core remains.
mantle
of a planet) The rocky layer that lies between a planet's core and crust.
People say that there is a black hole in the Milky Way is that True?
Yes
What is the dominant gas in Venus' atmosphere?
Carbon dioxide.
Which of these phases of the moon is best viewed during the early afternoon?
Waxing Crescent
Kepler's Second Law
Planets sweep out equal area in equal time
At what phase would the tides be least noticeable?
third quarter
• The temperature of a distant star is determined to be 59,000 K. How much more power does it emit than the sun does?
10,000 times more
inverse-square law (of light)
the law stating that an object's apparent brightness depends on its actual luminosity and the inverse square of its distance from the observer
What is a CCD?
It's an electronic detector that can be used in place of photography for making images.
What happens to the pebbles?
Pebbles stick together to form boulders
Hubble's Law states that:
The farther away a galaxy, the greater its redshift
What is a system made up of the sun and the nearest few stars?
solar neighborhood
The Chandrasekhar Limit is
the upper mass limit for a white dwarf
Rotation period of the Sun
shorter near the equator, causes a twist and amplifies the magnetic field
cosmic microwave background radiation (CMB; CMBR)
The remnant radiation from the Big Bang, which we detect using radio telescopes sensitive to microwaves (which are short-wavelength radio waves).
Solar day > Sidereal day
Since the Earth orbits the Sun, it must turn a little further than 360°to face the Sun (Solar=3.9 minutes longer than sidereal)
Why can stars emit light?
At the center of most stars hydrogen is being converted into helium through a pressure called nuclear fusion, this creates a huge amount of energy.
What is the ecliptic plane?
The plane of the Earth's orbit around the Sun.
Why can't planets closer than Jupiter get very big?
Their sphere of influence is small
How is energy transported from the center of the Sun to its surface?
radiation in the central regions and convection in the outer regions
Which of the following have an icy composition?
most comets and rings of Saturn
when the universe was 10 years old, the density of radiation was
much greater than that of matter
What are the rings of Saturn made of?
Mostly tiny particles composed of water ice, rocky and carbon compounds.
The central black holes observed in a few other galaxies thus far have masses of
50 million - 3 billion solar masses
The major presence of water detected on the Moon is in
the floors of deep craters in the polar regions as ice deposits that never thaw
The surface of the Moon and Mercury are:
Similar with many craters and the least evolved compared to the terrestrial planets.
Harlow Shapley concluded that the earth is not at the center of the Galaxy because:
The earth is not at the center of the distribution of globular clusters
What is the formula that tells us Earth's angular momentum at any point in its orbit?
Angular Momentum = m x v x r
What is thought to lie at the center of Jupiter?
a massive core of rocky materials with some iron mixed in
Ch.22 Q#33: Based on current evidence, which of the following is considered a likely candidate for the majority of the dark matter in the galaxies? (a) subatomic particles we have not yet detected in particle psychics experiments (b) swarms of relatively
A is the best choice as both B and C can be considered dark matter but they would only count for a small percentage of mass. While non-baryonic matter/subatomic particles not yet detected would be the best choice as in the book they say that WIMPs would make up most of the matter in the universe yet they even said themselves that they can't really prove it lol
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