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Astronomy final

What angle would Eratosthenes have measured had the Earth been flat?

0 degrees

A constellation is

A region of the sky outlining a given set of stars

We expect to observe the sun along a path known as the


If a star has a declination of +41'30", then from here in St. Cloud, we would expect the star to transit out meridian at what elevation angle above the local horizon?

About 86 degrees above the southern horizon

The solar day is __________ the sidereal day

longer than

The four seasons on Earth are a result of

tilt of the Earth's axis

The vernal equinox

is a day of equal sunlight and darkness

A solar eclipse can only happen during

a new moon

The length of a sidereal day is determined by

the time between transits of a fixed star

The first quarter moon rises about noon today; what will its phase be, and when will it rise tomorrow?

waxing gibbous, 1pm

If one complete hemisphere of the moon is always lit by the sun, why do we see different phases of the moon?

The Moon shines by reflected light

When the sun is "in Gemini," the most prominent constellation of the zodiak at midnight is


If Earth had the radius of Mars, would the parallax angle increase or decrease?


Sirius has a parallax of 0.38", while Alpha Centauri's is 0.77". Alpha Centauri is about __________ as Sirius.

half distance

The vernal equinos is just now entering Aquarius. In what constellation will it lie in the year C.E. 5000?


The star Thuban in Draco

was an excellent pole star in 3,000 BC.

A planet whose distance from the sun is 3 AU would have an orbital period of how many Earth-years?


About what fraction of your weight on Earth would you feel on the Moon?


Copernicus was the first to come up with the geocentric model


If we see a bright point of light in the sky that changes its position bit by bit over several nights with respect to the constellations, it is probably

a planet

Planets actually stop and move backward during retrograde motion


According to Copernicus, retrograde motion for Venus must occur around

inferior conjunction, when it passes between us and the Sun

Which was not seen telescopically by Galileo?

stellar parallax

When a planet's orbit takes it closest to the sun, it's called


Ptolemy's model was ___________, with Earth fixed in the center of the universe


According to Newton's three laws, planets orbit the Sun due to


According to Kepler, a planet moves __________ when at aphelion versus at perihelion


A wave with period of .01 seconds has a frequency of __________ Hz


The electromagnetic spectrum includes

infrared, X-ray, visible, radio, ultraviolet

A surface at 750K would emit most energy in what band?


What is the surface temperature of the Earth when water just begins to freeze, in Kelvin?


In what regions of the EM spectrum is the atmosphere transparent enough to allow observations from the ground?

FM, near infrared, visible

A star much hotter than the sun would appear to be __________ in color


Astronomers use spectroscopic information to determine which of the following?

relative motion, chemical content of the surface, temperature

The spectrum we see from the sun is


A red photon has higher energy than a blue photon


UV radiation causes more cellular damage because of its longer wavelength and lower energy


As white light passes through a prism, the red (longer) wavelengths bend less than the blue (shorter) wavelengths, forming the rainbow of colors.


The two forms of EM radiation that experience the least atmospheric opacity are

light and radio waves

The radiation our eyes are most sensitive to lies in the color

yellow-green at 550nm

In general, the spectral lines of molecules are

more complex than those of atoms

In a hydrogen atom, the transition from the 2nd to the 1st excited state will produce

the bright red Balmer alpha emission line

The observed spectral lines of a star are all shifted towards the red end of the spectrum. This is an example of

the Doppler effect

If the rest wavelength of a certain line is 600nm, but we observe it at 594nm, then

the source is approaching us at 1% the speed of light

Order the planets according to mass from smallest to largest

Mercury, Mars, Venus, Earth, Uranus, Neptune, Saturn, Jupiter

Order the planets according to orbital distance from the sun from closest to farthest

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Name the terrestrial planets

Mercury, Mars, Earth, Venus

Name the jovian planets

Jupiter, Saturn, Uranus, Neptune

Planetary orbits

are almost circular, with low eccentricities

The total mass of all the known asteroids would make a planet the size of earth


The asteroid belt is located

between Mars and Jupiter

The Kuiper-belt is located

beyond Neptune

The __________ typically have strong magnetic fields

jovian planets

The most plausible theory for the formation of our moon is


Comets typically form bright tails when close to the sun, while asteroids do not. This is because

comets have more ice in them, which boils off to form the tail

Comets seem to spend most of their lives in the

Oort cloud

Due to their great masses, all four Jovian worlds are much denser than the Earth


Barringer Crater in Arizona is an example of a meteorite impact


Most astronomers now believe the demise of the dinosaurs 65 million years ago was caused by a large asteroid impacting the Yucatan peninsula area


Carbonaceous asteroids contain fragile organic molecules


We would expect other planets beyond our own solar system to orbit the equators of their home stars


Which planet by itself contains the majority of mass of all the planets?


The largest asteroid we know of, and probably the only one to be a spherical "world" is


How much advance warning did we receive of the closest approach of asteroid 2002 MN?


The Oort cloud is believed to be

a spherical cloud of cometary nuclei far beyond the Kupier Belt

Tides on Earth are created by

gravitational force of the Moon and Sun

Order the layers of the Earth by decreasing density

Core, Mantle, Crust, Hydrosphere

If the Moon's orbit were much closer to the Earth, the lunar month would be


Our understanding of the structure of the Earth's mantle and core comes mostly from the study of


If the Earth kept its current atmospheric pressure but did not experience a greenhouse effect

the oceans would mostly freeze over

If the surface temperature of the Earth rises substantially, the amount of water vapor in the atmosphere would


Why is the moon heavily cratered, but Earth is not?

The Moon has no atmosphere

According to the theory of plate tectonics, early dinosaurs were able to walk to almost any part of the Earth's landmass


What is not a result of plate tectonics?

the grand canyon

Methane could contribute to global warming if a significant amount more is released into the atmosphere


Compared to Earth, the moon lacks a hydrosphere, atmosphere, and magnetosphere


Which layer is unique among the terrestrial planets?


At what phase would you expect to find extremely high and low tides?

new and full moons

The critical part of the atmosphere for protecting life on the ground from excessive UV radiation is the

ozone layer

In noting that the Earth is "differentiated," we mean that

the density increases as you descend downward toward the core

Where is the newest material in the Earth's crust found?

At the edge of tectonic plates

Name three principal divisions of the structure of the Earth's interior

mantle, outer core, inner core

Although it has no liquid water, Mercury has a tidal bulge


Scarps on Mercury were probably caused by

the crust cooling and shrinking

Venus' surface temperature cools off at night


Saying that Venus rotates "upside down" or has a retrograde motion is pretty much the same statement


Radar mapping of the surface of Venus shows evidence for vast oceans at some time in the past


What is the main constituent of the atmosphere of Venus?

carbon dioxide

If we tried sending a lunar lander to land on Venus

it wouldn't survive to touch down

The consistency of the surface features of Venus can be explained by

massive planet-wide volcanism at some time in its "recent" past

The evidence for plate tectonic activity on Mars is mostly from


What is the main constituent of the atmosphere of Mars?

carbon dioxide

The Mars Rover found undisputed microfossils, proving life once existed on Mars


Which terrestrial planets lack seasons?

Mercury, Venus

In brightness, Jupiter is second only to the planet __________ most of the time


Jovian planets exhibit extensive tectonic activity


What would Jupiter have needed to be a star?

enough mass to make the planet hotter

Jovian planets are mostly __________ below the outer atmosphere


We base our estimates for the rotation rate of the Jovian planets on what property?

magnetic field rotation

In keeping with its Greek god, Neptune probably contains a lot of water, in a slushy mantle ocean


Uranus' rotation axis is tipped over 98 degrees, so its magnetosphere is tipped over the same amount


The Galileo mission put a spacecraft into orbit around Jupiter. How did it do this?

Used a gravity assist from Venus and Earth

Small deviations in a planet's orbital motion

imply the nearby presence of a massive body

Compared to Saturn, Jupiter is about

three times more massive and denser

The two outer Jovians appear bluish in color because

methane gas in their atmospheres absorbs red light well

In the telescope, __________ shows the most turbulent atmosphere with changes easily seen


The oblateness of the Jovian disks refers to their __________ equatorial diameters, compared to the polar diameters


The oblateness of the Jovian disks is caused by their


Because it has a higher percentage of __________, Neptune appears even bluer than Uranus


Which of the moons is bigger than Mercury?


The source of energy for Io's volcanism is assumed to be

tidal stresses

What would you weigh on the surface of Ganymede, compared to your weight on Earth?


The estimated density of Ganymede is greater than that of Io because it is more massive


The moon Triton is expected to be destroyed within 100 million years because

it has a retrograde orbit

In terms of composition and density, the atmosphere of Titan is closer to our own than any other place we have found in the solar system


Methane drives the weather on Titan, for there it can be liquid, solid, or gas


The tectonics we see on Triton are similar to grooves on Ganymede


Spacecraft have imaged erupting volcanoes on Io and Triton


The haphazard terrain of Miranda suggests it was broken up by impact after it had differentiated, then fell back together randomly


The surface of Saturn's moon Enceladus is the most reflective of any in the solar system, suggesting very fresh ice is exposed


All four ring systems orbit the equators of the Jovian planets outside their Roche limits


A resonance with Mimas clears out the ring particles from Cassini's Division


Which element is critical to the formation of the volcanic surface of Io?


The mare on Ganymede were formed by

water erupting and spreading over the surface

Of the Jovian satellites, which shows the oldest, most cratered surface?


Why are the rings of Saturn so bright?

they are made of young, fresh water ice.

If Saturn takes about 30 years to orbit the Sun, and its rings were seen edge-on in 1995, when will they appear most open at solstice?


The shape of the 1st quarter phase of the moon is caused by the

direction from which the sunlight strikes the moon

If the moon was 3rd quarter last Saturday, what will it be this Saturday?

At or very near new

If we see a first quarter moon today, what will people on the other side of the Earth see later today?

first quarter moon

When does the moon rise throughout various phases?

New - 6am
1st quater - noon
Full - 6pm
3rd quarter - midnight

Which features are older: flow channels or eroded craters?

eroded craters

What is the name of the largest canyon on Mars?

Valles Marineris

What kind of pressure does Mars' atmosphere have?

thinner than Earth's

Which are older: uneroded craters or eroded craters?

eroded craters

What is currently considered to be the most likely cause of the flow channels?


What caused some of the erosion on the eroded craters?

wind and/or flowing water

Sort Mars' surface features by age

eroded craters, flow channels, uneroded craters

There were some impact craters created after the flow channels were formed


How does the tilt of Mars compare with Earth?

about the same

How do seasons on Earth compare with Mars?

about the same

Is the temperature difference on Mars between + and - 45 degrees larger/smaller than on Earth?

larger on Mars

There is a lag time between when the sun is highest in the sky and when the average temperature is hottest. What causes this?

water takes time to heat up/cool down

Which Jupiter moon revolves fastest?


The mass of Jupiter is greater than the sun.


Continuous spectra

A spectrum in which all of the wavelengths is present

Emission spectrum

Produced by an excited gas

A redshift of a set of spectral lines indicates

Something is moving away from you

Spectroscopy is limited to just the visible spectrum


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