Astronomy Final exam Flashcards

Terms Definitions
which terrestrial planet rotates slowly and backwards?
venus
consider radioactive uranium with a half life of 700 million years. If you started with a rock consisting of 100% pure uranium, how much of the original uranium would be left after 2.1 billion years?
1/8th
how many different spectral emission lines can an atom with just 5 energy levels produce? making a little sketch might help
10
the temperature of Earth is about 280K. Consider a planet that is less massive than the Earth such that the escape velocity from this planet is half that of Earth. What would the temperature of this planet have to be in order to hold onto an atmosphere of
70K
now that the universe has been manufacturing elements besides hydrogen and helium for some time, what percentage of the mass in the universe has been converted into heavier elements?
1-2%
what wavelength photon carries twice the energy of a photon with a wavelength of 400 nanometers
200 nanometers
what one property, more than any other, determines how long a planet remains geologically active?
its size
as of today, the number of planets found orbiting other stars is closest to
500
The "Grand Tour" of all four Jovians was conducted by
Voyager 2
what is the smallest object that can cause continental scale devastation (not mass extinction) if it impacts the Earth?
300 meters
which term has the most in common conceptually with a solar day?
synodic month
consider two objects held several feet above the ground. one object has a very small mass. the other is quite massive. which of the two objects feels the strongest gravitational force from the earth?
the massive object
if your aim is to achieve the same resolution at any wavelength, working at which wavelength will force you to build the largest telescope?
radio
what two factors are most important in forming a thin flat planetary disk from an immense diffuse and nearly spherical cloud of dust and gas?
rotation and gravity
you know that the bright star vega is directly overhead at 11 p.m. on August 1 every year. you observe vega directly overhead at 9pm. what is the approximate date?
september 1
the sun has a temp of 6000k and produces nearly blackbody spectrum that peaks at a wavelength of about 500 nanometers. another star has a spectrum which peaks at 1000 nanometers. this star has a temp of about?
3,000 K
How long ago did the last Earth impact occur that delivered megatons of energy to the earth's atmopshere and surface, leveling a region the size of a major city?
103 years ago
how long does it take the earth to complete one full rotation on its axis with respect to the stars?
one sidereal day
rank the planets and sun from least total mass to the most
terrestrial planets, jovian planets, sun
which of the following statements about the celestial sphere is not correct?
the north celestial pole always lies directly above any observers head
The planet's orbital period is:
The time it takes to return to the same location in the sky, relative to the Sun.
The most likely scenario for the formation of the Earth's moon is
formation from the debris of a catastrophic collision between the earth and an object
kepler's law of equal areas, in simplest terms, states
planets move faster when they are closer to the sun
the spring equinox will occur at 621 pm on march 20. at this instant what will happen?
the sun enters the northern celestial hemisphere
How do the densities of the Jovian and Terrestrial planets compare?
All terrestrials are denser than the Jovians
eclipses do not occur at every new and full moon because
the moon's orbit is tilted with respect to the earth's orbital plane
what is special about the comet about to be visited by the stardust spacecraft on Feb. 14?
it is the first comet to be visited before and after it has passed near the sun
two hot solid objects of same size are side by side, but one appears 81 times brighter than the other. how does the brighter object's temperature compare to the fainter one?
the bright one is 3 times the temperature of the fainter one
what percentage of the earth's atmosphere consists of gases other than oxygen and nitrogen?
1%
objects at room temperature (300 kelvins) emit blackbody radiation primarily in which part of the electromagnetic spectrum?
infrared
Planetary orbits are
almost circular, with low eccentricities
list the jovian planets
saturn, jupiter, uranus, neptune
a lunar eclipse occurred in december. in which months can you be certain that there will NOT be a lunar or solar eclipse?
march
The Jovian planets
all have rings around their equators
considering only the solid particles, rank the three material below in order of increasing abundance (least to greatest amount) in the region of the solar system where saturn formed.
metal, rock, ice
roughly how many stars are in a typical galaxy?
10^11
Which planet is most similar to Sun in terms of its built composition?
Saturn
which planet type of planet will likely have the least chance of retaining an atmosphere?
weak gravity
high temperature
order contributers to astronomy in time sequence
copernicus, brahe, kepler, newton
neglecting gravity, if you are swinging a ball around on a string and the string breaks, which of the following "laws" best describe the motion of the ball after the string breaks?
newton's law of interia
What are the Jovian planets?
Jupiter, Saturn, Uranus, and Neptune only
what gas in the list below was likely the most common in the Earth's first atmosphere shortly after its formation?
carbon dioxide
at what time does the moon rise on the day of a total lunar eclipse?
sunset
how long does totality last for the longest solar eclipses?
a few minutes
The Kuiper Belt is an "outer asteroid belt" consisting of what types of solar system bodies?
? Icy comet-like bodies
which object below as a density nearly identical to that of the earth?
both venus and mercury
abnormally weak high tides and abnormally weak low tides occur at
first quarter and last quarter moon
The terrestrial planets include little of the hydrogen and helium dominated by the mass of the interstellar cloud from which the solar system formed. this compositional different occurs because the terrestrial planets
formed from the solid particles in their region of the disk
an artificial satellite remains in orbit because
as the satellite falls toward the earth under the influence of gravity its moving just fast enough so that the ground curves away under it at the same rate as it falls
Masses of the planets are easiest to determine if
They have natural satellites whose motions can be precisely measured.
the sun appears in front of a different constellation each month due to the
earth's orbital motion around the sun
what property of a gas of atoms does the temperature measure?
the average speed of atoms
What statement about the motion of the planets is correct?
Most orbit above the Sun's equator. All revolutions of major planets are counterclockwise. The orbits of most planets are almost circular, with low eccentricities. Most planets rotate in the counterclockwise direction when viewed from the North.
in a scale model of the solar system in which the sun is a basketball how large is the earth?
a bit smaller than a pea
what determines whether an atom is, for example, a carbon atom or an oxygen atom?
the number of protons in the atomic nucleus
an observer in hawaii, at latitude +18 degrees, will see what?
the celestial pole low in the sky, with few circumpolar stars visible
an observer staying at a fixed location on the "near side of the moon
will see the sun rise and set once each lunar month and the earth hangs motionless in the sky
the best time of year to go out to observe the constellation associated with your birthsign is
six months before or after your birthday
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