Astronomy test 4
Which of the these moons has landmarks that are not rotating with the rest of the moon, indicating a subsurface ocean
Titan
suppose that we find a few microbes living in the liquid water below the permafrost layers of mars. which of the following consequences of this discovery is the most likely?
We conclude that the universe is probably filled with life
What astronomers refer to as a "standard candle" is defined as a light source whose
absolute magnitude is known
In a particular binary star system, we are able to determine the masses and diameters of both stars This system is most likely
an eclipsing spectroscopic binary system
The main reason that telescope mirrors can be much larger than lenses is that the mirrors
are lighter because they are thinner
One difficulty with the microfossils that were found in the martian meteorite ALH84001 is that they
are to small
Adaptive optics is used to correct telescopes for
atmospherical turbulence
the viking landers carried out several experiments on martian surface soil in order to detect the presence of life. those same experiments were also carried out on a control sample of martian surface soil that had been sterilized by heat. the purpose of doing experiments on the control sample was to
avoid getting a false positive result
A star with an apparent magnitude of 5.7 and an absolute magnitude of -1.2 would appear in our sky as a star
barely visible to the naked eye
a necessary (but probably not sufficient) condition for a planet to have active plate tectonics is that it
be considerably larger than the planet mars
the problems of stars "twinkling" due to atmospherical turbulence
can be corrected by using a guide star
A main sequence star with less mass than our sun will be
cooler and dimmer
The one wave turning angle of a telescope mirror determines its
diffraction limit on its resolution
The viking landers carried out several experiments on martian surface soil. one of those experiments, the pyrolytic release experiment gave a positive result for the presence of life forms. The result was interpreted to mean
nothing because a sterilized control sample gave the same result
A star with an absolute magnitude of 5.7 and an apparent magnitude of -1.2 would appear in our sky as a star
of dazzling brightness
A converging lens will send the light from a distant star through a point
on the side of the lens opposite the star
from a visual binary star system, we can determine
the masses of both stars in the system
stellar parallax is caused by
the motion of the earth around the sun
the frequency of a wave is defined to be
the number of crests that pass in one second
the diffraction limit of a telescope refers to the effect of
the wavelength of light
Because of mirrors only use one surface, they have a big advantage over lenses they can be
thinner and larger in diameter
The wavelength of the sound waves that correspond to middle-C is about 4 feet. If you are standing 8 feet away from a piano that is playing that note, then between you and the piano there will usually be
two regions of maximum pressure
A star at a distance of 1000pc should have an apparent brightness equal to its absolute brightness multiplied by
10^-4
which of the following magnitudes corresponds to the dimmest star
+5.6
which of the following magnitudes corresponds to the brightest star
-1.5
A star is seen to move by 0.2 seconds of arc between February 1, 1999 and August 1, 199 and then its back to its starting point on February 1, 2000. what is the parallax angle for this star
.1
A star is seen to move by .04 seconds of arc between march 1, 1999 and september 1, 1999 and then back to its starting point march 1, 2000. what is the parallax angle for this star.
.2
The distance modulus of a star at a distance of 10 parsecs would be
0
Our sun is a G2V star with absolute magnitude 4.8. Suppose that a star of spectral type G2V is observed to have apparent magnitude -.2 how far away is it
1 parsec
the apparent brightness of our sun is roughly 1000 watts per square meter. At a distance of 30 times the earth-sun distance, the apparent brightness of our sun would be
1.1 watts per square meter
a star with a distance modulus of zero is at a distance of
10 parsecs
A star is found to have absolute magnitude 4 and apparent magnitude 19. How far away is it?
10,000 parsecs
A star is observed to have an apparent brightness which is 10-6 times its absolute brightness. How far away is it?
10,000 parsecs
Cruising far from the Sun, we notice that the Sun's apparent brightness has dimmed to 0.1 watts per square meter. We know that the apparent brightness at a distance of 1au is 1000 watts per square meter. How far from the Sun are we?
100 au
Our Sun is a G2V star with absolute magnitude 4.8. Suppose that a star of spectral type G2V is observed to have apparent magnitude 9.8. How far away is it?
100 parsecs
Suppose that the color and behavior of a star identify it as a type that we know has absolute magnitude -3. If the star's apparent magnitude is found to be 2, how far away is it?
100 parsecs
Suppose that the color and behavior of a star identify it as a type that we know has absolute magnitude 4.8. If the star's apparent magnitude is found to be 9.8, how far away is it?
100 parsecs
A star is found to have absolute magnitude 4 and apparent magnitude 24. How far away is it?
100,000
Barnards star shows a proper motion of 10.36 arc seconds per year. in 100 years its position in the sky changes by
1036 seconds of arc
A star whose apparent brightness is 10-4 times that of a first magnitude star would have magnitude
11
Suppose that a sound wave has a wavelength of 12 meters and a frequency of 100Hz. What is the speed of sound
1200 m/s
Suppose that a flash of lightning from a cloud 2500 meters away is followed by a clap of thunder two seconds later. Assume that the light arrived in a negligible time and calculate the speed of the sound waves.
1250m/s
A star whose apparent brightness is 10-6 times that of a first magnitude star would have magnitude
16
The star 36-Ophiuchus is six parsecs from our Sun. The light from this star in the "serpent holder" constellation has been traveling for approximately
20 years
Suppose that a sound wave has a wavelength of 2 meters and a frequency of 1000Hz. What is the speed of sound?
2000 m/s
Suppose that a flash of lightning from a cloud 5000 meters away is followed by a clap of thunder two seconds later. Assume that the light arrived in a negligible time and calculate the speed of the sound waves.
2500m/s
The star pi^3-Orionis is 8 parsecs from our Sun. The light from pi^3-Orionis has been traveling for
26.4 years
The velocity of sound waves is roughly the same for all wavelengths. Suppose that a sound wave has a wavelength of one meter and a frequency of 1000Hz. The wavelength of a 500Hz sound wave would then be
2m
The star alpha-Centauri C has moved across the sky by 3853 seconds of arc during the last thousand years - slightly more than one full degree of arc. Its proper motion is
3.853"/yr.
The velocity of sound waves is roughly the same for all wavelengths. Suppose that a sound wave has a wavelength of one meter and a frequency of 1000Hz. The wavelength of a 250Hz sound wave would then be
4 m
The star kruger 60 shows a heliocentric stellar parallax almost exactly .25 seconds of arc. the distance from our sun to kruger 60 is
4 parsecs
The habitable zone of a planetary system is defined to be the region where
Planetary surfaces permit the existence of liquid water
You hear a 1000Hz tone from a radio that is 20 feet away from you and listen for 4 seconds. How many pressure maxima pass by your ear?
4000
You hear a 1000Hz tone from a radio that is 10 feet away from you and listen for 5 seconds. How many pressure maxima pass by your ear?
5000
The red line of a spectrum is normally at a wavelength of 656 nm. In the light of a star that is moving toward us, we might expect to see that red line at a wavelength of
650nm
The red line of a spectrum is normally at a wavelength of 656 nm. In the light of a star that is moving away from us, we might expect to see that red line at a wavelength of
660nm
The star delta-Eridani shows a heliocentric stellar parallax of almost exactly 1/9 seconds of arc. The distance from our Sun to delta-Eridani is
9 parsecs
Which of the following discoveries would lead to the conclusion that the universe is probably filled with life, both in our solar system, and in the planetary systems of other stars?
A few microbes with a completely alien biochemistry are found beneath the soil of mars
A star of spectral type M should look
RED .
which of the following colors indicates the coldest star?
Red
Which of these is a statement of the fermi paradox
Any long lasting technological civilization should be obvious and might even be visiting us, so where are they
GO TO 24.101
B
Which of the following spectral classes corresponds to the highest surface temperature (on this list) ABFGK
B
Which of the following spectral types corresponds to a star on the main sequence
B4V (the v)
A star of spectral type O should look
Blue
Which of the following colors indicates the hottest star?
Blue
you see a reflecting telescope with a short, stubby tube and the eyepiece at the back. this telescopes uses the
Cassegrain focus
GO TO 24.102
D
GO TO 24.103
D
Go to 24.104
E
Which of these moons has geysers of water shooting out through cracks in the moon indicating a subsurface ocean?
Enceladus
Which of the moons has patterns of ctacks in the ice on its surface indicating a a subsurface ocean
Europa
Here is the Drake Equation: N = R*×fp×ne×fl×fi×fc×L In this equation, L stands for the
Expected lifetime of a communication capable of civilization
Which of the following spectral types corresponds to the star with the highest surface temperature. K0,K5,G0,G5
G0
The main reason to suspect that enceladus has a subsurface of ocean water is
Geyesers of water shooting out through cracks in the moon
The range of distances of a planet . from its primary star that will permit the existence of liquid water on the planets surface is called
Habitable zone
If we detect that a star is sometimes moving toward us and sometimes moving away and also find that this pattern repeats at regular intervals we know for sure that the star
Has at least one object of unknown type orbiting around it
one requirement for a planet to support earth type life is that it is considerably larger than mars. what is the reason for this requirement
It is necessary for the planet to have active plate tectonics to close its carbon cycle
Which of the following spectral classes corresponds to the lowest surface temperature (on this list) ABFGK
K
Which of the following spectral types corresponds to the star with the lowest surface temperature. K0,K5,G0,G5
K5
The main reason to suspect that titan has subsurface ocean of water is
Landmarks that are not rotating with the rest of the moon
Which of the following statements best describes the presence of water on mars
Mars probably had liquid water flowing on its surface at some time in the past
the most energy efficient way to send signals across interstellar distances is thought to be
Microwave radio
The reason that most seti programs choose to listen at microwaves radio frequencies is that
Microwaves are the most energy efficient way to send information
you see a telescope with a long tube and the eyepiece sticking out the side near the top. this telescope uses the
Newtonian focus
one of the experiments carried out by the viking landers was to use a mass spectrometer to analyze the gas given off from a heated soil sample. The result of that experiment established that martian soil contains
No carbon compounds at all
Here is the Drake Equation: N = R*×fp×ne×fl×fi×fc×L In this equation, N stands for
Number of communication-capable civilizations in our galaxy
The main reason to suspect that europa has a subsurface ocean water is
Patterns of cracks in the ice on its surface
The difficult part of seti program is that you do not know what frequency band that extraterrestrials are using, so you need to listen to them all. The SERENDIP IV program, running on the Arecibo radio telescope, accomplishes this task by
Sending a batch of signals to each of several million home computers for analysis
The microfossils that were found in the martiain meteorite ALH84001 are
Subject to continued argument because of doubts that they are biological origin
A technological civilization that lasts for astronomically significant periods of time should make an obvious and visible impact on the galaxy and should figured out how to visit us by now. That leads to the question "so where are they" this statement and question usually referred to as
The fermi paradox
The focal point of a lens is
The place where it sends rays that are parallel to the axis
In SETI programs the "water hole" refers to
The range of signal frequencies between emissions caused by hydrogen and hydroxyl molecules
The viking landers carried out several experiments on martian surface soil. The final conclusion from those experiments was
The surface of mars is extremely hostile to all forms of organic matter
The main reason that the SETI@home system needs to use the computing power of 5.2 million participating home computers is that
They are collecting and analyzing signals on millions of different radio channels
The star Wemadeit shows a stellar parallax angle of 0.4 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that
Wemadeit is closer to our sun than waytoofar
The fact that the surface of mars shows no tectonic activity means that one of the requirements for continuing life might be missing.
a carbon-return process
We see what appears to be a single star. However, when the light from the star is put through a spectrometer, we see two distinct spectra, shifting back and forth. The star is actually
a double-line spectroscopic binary system
which of the following requirements for life appears to lacking on the planet
a global carbon-return process
The word Parallax in the term Spectroscopic Parallax is used because the term refers to
a method for finding the distances to stars
A star whose full spectral type is K2V
a red main sequence star
A mirror that is supposed to bring light from a star directly overhead to focus must be shaped like
a shallow bowl with open part facing up
We see what appears to be a single star. However, when the light from the star is put through a spectrometer, we see that its spectrum is shifting back and forth. The star is most likely
a single-line spectroscopic binary system
In a particular binary star system, we are only able to determine a minimum mass for each star and cannot determine the angle between our line of sight and the plane of the stars' orbits. This system is most likely
a spectroscopic binary system
In a particular binary star system, we are able to determine the masses of both stars in the system as well as the angle between our line of sight and the plane of the stars' orbits but cannot determine the diameters or atmospheric compositions of the two stars. This system is most likely
a visual binary system
Of all the things that might go wrong with distances found by using the method that astronomers refer to as the "distance ladder," which of these is the one that an astronomer would say is most likely?
distant objects are not behaving the same as nearby objects
Which of these answers describes the fundamental assumption that is behind all of the methods that astronomers refer to as the "distance ladder?"
distant objects are similar to nearby objects
Which of the following pictures is the most like the main sequence on a hertsprung russel diagram
goes downwards and not a big curve at the end (look at 24.302)
A main sequence star with more mass than our sun will be
hotter and brighter
In the Hertsprung Russel Diagram, a main sequence star might be found
in the lower right or upper left
The range of signal frequencies between absorption bands caused by hydrogen and hydroxyl molecules
is referred to as the "water hole" and is the frequency band that SETI programs usually choose
from the broadening of its spectral lines one can determines a stars
luminosity class
which of the following statements best describes the presence of water on mars ?
mars has water frozen in its ice caps and may have liquid water below its surface
Suppose that a star has a spectrum that includes red, blue, and violet lines spaced in the pattern of the lines from hydrogen but the violet lines are at 444nm and 420nm instead of the usual 434nm and 410nm. From this evidence, you can conclude that the star is
moving away from us
Suppose that a star has a spectrum that includes red, blue, and violet lines spaced in the pattern of the lines from hydrogen but the violet lines are at 424nm and 400nm instead of the usual 434nm and 410nm. From this evidence, you can conclude that the star is
moving toward us
The earths motion around the sun causes
nearby stars to shift back and forth once a year
For a spectroscopic binary star system, we can determine
only a minimum mass for each star
Planets that are in orbit around stars other than our own sun are most often found by observing
small wobbles in their primary stars
Consider a light source whose absolute magnitude can be deduced from the properties of the light that reaches us from that source. Astronomers often refer to this sort of object as a
standard candle.
spectroscopic parallax uses
stellar spectra to locate stars in the HR diagram
the luminosity class of a star is determined by measuring
the broadening of spectral lines
the wavelength of a wave is defined to be
the distance from one crest to the next
the velocity of a wave is defined to be
the distance traveled by a crest divided by the time taken
For an eclipsing spectroscopic binary star system, we can determine
the masses and diameters of both stars in the system
A mirror that is shaped like a shallow bowl sitting on the table with its open ending facing up will focus light that come
vertically down from above
The star Wemadeit shows a stellar parallax angle of 0.2 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that
waytoofar is closer to our sun than wemadeit
