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Quiz 1, 2, 3, 4, 5, and 6.
The concept of gravity acting instantaneously (meaning, faster than the speed of light) between objects was proposed by which famous physicist?
Newton
Einstein
Greene
Hawking
Newton
Current scientific evidence indicates the age of the universe is approximately in which range?
1 to 2 million years old
500 to 700 million years old
4 to 5 billion years old
13 to 15 billion years old
13 to 15 billion years old
From what evidence do astronomers deduce that the universe is expanding?
They can see the disks of galaxies getting smaller over time.
They can see a redshift in the spectral lines of distant galaxies.
They can see the edge of the universe moving away from us.
They can see distant galaxies dissolve, pulled apart by the expansion of space.
They can see a redshift in the spectral lines of distant galaxies.
The Hubble constant for the universe 5 billion years in the future will be:
the same as it is today.
greater than it is today.
smaller than it is today.
No answer text provided.
Smaller than it is today
Which of the following statements about the first few minutes of the Big Bang is true?
The universe was transparent.
The universe was very cool.
Hydrogen fused into helium.
Galaxies began to form.
Stellar cores began to form.
Hydrogen fused into helium.
If you lived in a galaxy far away from the Milky Way, your red-shift measurements would show that galaxies move
toward you out to the Milky Way; away at larger distances.
away from the Milky Way but toward you.
away from you in the same way that Hubble found.
toward you in half the sky, away in the other half.
away from the point where the Big Bang occurred.
Away from you in the same way that Hubble found.
How long after the Big Bang did the Universe become transparent to photons?
Approximately 1 second
About 10 seconds
Around 380,000 years
At several hundred million years
Around 380,000 years
After several minutes of the Big Bang, two main elements were present and still make up the bulk of the interstellar medium near our galaxy today. These are:
hydrogen and carbon.
hydrogen and helium.
oxygen and lithium.
oxygen and nitrogen
Hydrogen and helium
What is meant by 'inflation' of the early universe?
The force of gravity suddenly grew stronger in the past.
Protons expanded to enormous sizes, making new stars.
The universe expanded enormously in a very brief time.
The number of galaxies rises dramatically with distance.
Distant galaxies are much larger than nearby galaxies.
The universe expanded enormously in a very brief time.
Inflationary theory does not explain
why the cosmic microwave background has a nearly uniform temperature in all directions.
why the curvature of the universe appears to be nearly flat.
the sizes of small temperature differences observed in the cosmic background radiation.
what happened before the Big Bang.
What happened before the Big Bang.
Try using the positions of stars on the H-R diagram to estimate the age of the cluster. Refer to the end of the 'Week 2' video to get a sense of what we might expect for older and younger clusters.
Go to: http://jupyter.mnstate.edu:8866/voila/render/Interactives/HR_Diagram.ipynbLinks to an external site. (Links to an external site.)
Now scroll down to 'Interactive Figure 3: Estimating Age using Stellar Evolution Models'. Make sure the 'Pleiades' cluster is selected, and use the toggle bar to set the distance to as close to 135 parsecs (pc) as possible - that is how far light has to travel from that cluster to reach us. Now use the 'Age of Model Stars' toggle bar to try to find the age at which the set of modeled stars best matches the shape of the observed Pleiades already shown on the H-R diagram here. The model line shows where stars in a cluster of a particular age would be expected to plot on the diagram. We can compare light from actual stars in a cluster with (robust) model predictions to estimate the age of the cluster.
The question to answer is: based on the positions of these stars in the Pleiades cluster, which age track (use the bar to toggle through different possibilities) best represents these data? This would be your estimate for the age of the cluster.
Note that there is some scatter - the key here is to identify an age track that a nontrivial number of stars most tightly follows/overlaps. If the interactive figure freezes at any point, just reload the page and that generally fixes it.
a) 2.01 million years
b) 145 million years
c) 822 million years
d) 1.56 billion years
145 million years
Follow-up to Question 1: suppose we observed a star cluster that plotted in all the same locations on the H-R diagram, but we knew it was about 500 parsecs away (over 1600 light years from us). What might our best guess of its age then be? Adjust the interactive figure parameters again to come up with an estimate!
1.05 million years
50 million years
486 million years
1.23 billion years
1.05 million years
Radiating objects emit spectra that can be studied to learn about the object's _______.
a) area
b) temperature
c) density
d) chemical content
e) (a) and (b)
f) (b) and (c)
g) (b) and (d)
g) (b) and (d)
Which of the following is not a possible aftermath or byproduct of a supernova?
a) black holes
b) neutron stars
c) electron stars
d) triggered formation of another star
c) electron stars
Human eyes are most sensitive to which wavelength?
a) 550 cm
b) 550 mm
c) 550 nm
d) 550 microns (um)
c) 550 nm
Sequence the following in increasing wavelengths:
a) radio, ultraviolet, infrared, visible, X-rays
b) X-rays, ultraviolet, infrared, radio
c) ultraviolet, X-rays, infrared, radio
d) radio, infrared, visible, ultraviolet, X-rays
b) X-rays, ultraviolet, infrared, radio
Suppose we could measure one property of a protostar. Which property would tell us most about its future evolution?
a) Its temperature
b) Its radius
c) Its color
d) Its luminosity
e) Its mass
e) Its mass
Place in order, from youngest to oldest (1 - 4), the sequence of the evolutionary stages of a Sun-like star:
a) T-Tauri, Main Sequence, Red Giant, White Dwarf
b) Main Sequence, White Dwarf, Red Dwarf, T-Tauri
c) White Dwarf, T-Tauri, Red Giant, Main Sequence
d) Red Giant, T-Tauri, White Dwarf, Main Sequence
a) T-Tauri, Main Sequence, Red Giant, White Dwarf
Venus as a whole radiates as a blackbody with average temperature of 230 K. Use Wien's Law to calculate the wavelength of the strongest radiation for this blackbody.
* Note - you would want to be aware of to which part of the electromagnetic spectrum this wavelength corresponds. The wavelength regions listed below are all accurate for the numbers given...you're only calculating the right number right now.
a) 120 nm, UV
b) 12 microns, IR (but closer to visible than microwave)
c) 12 mm, microwave
d) 12 m, radio wave
b) 12 microns, IR (but closer to visible than microwave)
The 'supernova trigger' hypothesis suggests that...
a) stellar formation could be initiated by molecular cloud collapse as a result of a nearby supernova
b) supernova seed nearby stars with heavy elements that cause those stars to also collapse
c) a star that collapses into a supernova cycles between red supergiant and neutron several times before settling into a black hole
d) a supernova will pull nearby smaller stars into its core before exploding
a) stellar formation could be initiated by molecular cloud collapse as a result of a nearby supernova
Suppose a thousand solar masses-worth of interstellar gas forms into a group of stars of all masses. If you came back a billion years later, where would that gas (matter) now be?
a) Almost all in white dwarfs, black holes, and neutron stars.
b) Most of it collected into the heaviest stars that formed.
c) Nearly all of it would have turned back into interstellar gas except for a small amount in black holes.
d) Much still in the same low-mass stars, but some back as interstellar gas or later generations of stars.
d) Much still in the same low-mass stars, but some back as interstellar gas or later generations of stars.
Where is the 'snow line' of our Solar System located?
Between the Sun and Mercury
Between Venus and the Earth
Between Mars and Jupiter
Between Neptune and Pluto
Between Mars and Jupiter
The Virial theorem quantifies the balance between ____ and ____ energies in terms of predicting when a molecular cloud will begin to collapse to make a star.
gravitational and thermal
mass and compositional
centrifugal and centripetal
fusion and fission
nuclear and gravitational
Gravitational and Thermal
The numerous craters we see on the solid surfaces of so many Solar System bodies are evidence that:
the young Sun was so hot that it boiled these bodies.
they were bombarded in their youth by many solid objects.
they were hot in their youth with widespread volcanoes.
all the planets were once part of a single, very large, and volcanically active mass that broke into many smaller pieces.
they were bombarded in their youth by many solid objects
Arrange the following in order of increasing density:
molecular clouds, interstellar medium, stars, neutron stars, black holes
black holes, neutron stars, stars, interstellar medium, molecular clouds
neutron stars, stars, black holes, molecular clouds, interstellar medium
interstellar medium, molecular clouds, stars, neutron stars, black holes
Interstellar medium, molecular clouds, stars, neutron stars, black holes
Which of the following is the least significant process in the disk around the star where planets form?
Gravitational attraction
Spinning
Nuclear fusion
Heating
Nuclear fusion
Sequence the following important processes of planetary formation. Note you need to choose the one that lists them in the right order, starting with the earliest.
collisional accretion, gravitational collapse, chemical condensation, snowflake accretion
gravitational collapse, collisional accretion, chemical condensation, snowflake accretion
chemical condensation, gravitational collapse, snowflake accretion, collisional accretion
chemical condensation, snowflake accretion, collisional accretion, gravitational collapse
Chemical condensation, snowflake accretion, collisional accretion, gravitational collapse
Short-lived isotopes in the early Solar System allow us to date the relative timescales of early processes, like when different types of materials condensed (which helps us refine our models of Solar System formation). Which of the following is not a short-lived isotope? Note that we can write the short-lived isotope carbon 14 as either 14C or C-14. The latter notation is used below because Canvas is not permitting superscripts in the answer fields.
Al-26
U-238
I-129
Mn-53
U-238
One credible explanation for why the planets near the Sun are composed mainly of rock and iron is that:
the Sun's gravity only acts on solid materials, and only iron and rock condensed into a solid.
the Sun is made mostly of iron, so gas ejected from its surface cooled and condensed to form iron-rich planets.
the high temperatures in the inner part of the Solar System prevented ices and gases from condensing near the Sun.
the Sun's magnetic field attracted all the iron in the young Solar System into the region around the Sun.
The high temperatures in the inner part of the Solar System prevented ices and gases from condensing near the Sun.
If the moon were twice as massive as it presently is, its orbital period around Earth would:
double.
quadruple.
be halved.
be quartered.
remain unchanged.
Remain unchanged
Rank the following in terms of decreasing semi-major orbital axis:
Mercury, Mars, Pluto, Uranus, Jupiter
Pluto, Uranus, Jupiter, Mars, Mercury
Mercury, Mars, Uranus, Jupiter, Pluto
Jupiter, Uranus, Mars, Mercury, Pluto
Pluto, Uranus, Jupiter, Mars, Mercury
If the moon was twice as distant from the Earth as it presently is, its gravitational attraction to Earth would:
double.
quadruple.
be halved.
be quartered.
remain unchanged.
be quartered
Which orbital property is most strongly responsible for Earth's seasons?
Axial tilt
Period
Eccentricity of orbit
Counter-clockwise rotation
Axial tilt
Let's try an escape velocity problem - what velocity would Earth's moon need to attain in order to break free from orbiting Earth? Note: this is not the same calculation as what velocity an object on the surface of the Moon would need to escape the gravitational force of the Moon. Also, we are not considering also escaping the Sun (which would require more speed and a more complex equation...that would be called escape from the Earth-Sun system). Just free the Moon from the Earth.
Use these numbers:
Moon orbital period: 27.3 days
Moon orbital path length: 2,418,000 km (assume it's circular for convenience)
Hint: first calculate the orbital speed of the Moon in km/s
2.38 km/s
11.2 km/s
1.03 km/s
1.45 km/s
1.45 km/s
Kepler's third law:
relates the duration of a planet's orbit to the size of its orbit
relates a body's mass to its gravitational attraction.
allowed him to measure the distance to nearby stars.
allowed him to predict when eclipses occur.
Relates the duration of a planet's orbit to the size of its orbit
Which of Kepler's laws explains why comets on high eccentricity orbits spend most of their orbital period far from the Sun?
First Law
Second Law
Third Law
None of them; this is unrelated to Kepler's laws
Second Law
Which number best represents the percent mass of the Solar System contained by the Sun?
10
50
99
100
99
What region of the Sun is considered its surface?
Corona
Chromosphere
Photosphere
Convective Zone
Radiative Zone
Photosphere
Which is not the result of a solar storm?
aurora on Earth
magnetic field lines
coronal mass ejections
solar flares
Magnetic field lines
Which best defines the solar wind?
An expanding low density plasma moving outward from the Sun
Convective currents in the Chromosphere that create zonal jets in the solar mid-latitudes
Currents focused where magnetic field lines emerge from the solar interior
Random ion motion in the Radiative Zone
An expanding low density plasma moving outward from the Sun
The temperature of the Sun's Photosphere is approximately:
5500 K
50,000 K
2 million K
15 million K
5500K
The 'solar cycle' is:
The amount of time it takes the Sun to complete a full rotation on its axis
A roughly 11-year period of sunspot variation in location and intensity
Periodicity associated with known comets entering the inner Solar System
A 22-year cycle in which the Sun's magnetic poles flip
A 22-year cycle in which the Sun's magnetic poles flip
The primary hazard geomagnetic storms pose to humans as a result of solar activity is to:
skin and eyes due to intense radiation at the surface.
electrical and communication systems.
intensifying weather patterns and inducing extreme precipitation.
ecosystem disruptions due to effects on migratory animals that rely on magnetic navigation.
Electrical and communication systems.
Roughly, what is the projected lifetime of the Sun?
5 billion years
7 billion years
12 billion years
20 billion years
12 billion years
Which are the key tenants of the Faint Young Sun paradox?
The early Sun was dimmer than now, but yet the Early Earth was still warm enough to have liquid water.
The early T-Tauri Sun was more energetic than now, yet the early Earth was a frozen ice world.
The early Sun was brighter than it is now, yet Earth was still habitable for simple small organisms.
The early Sun was nearly extinguished, and yet the early Earth escaped a permanent snowball existence.
The early Sun was dimmer than now, but yet the Early Earth was still warm enough to have liquid water.
Which of the following is not a consideration when modeling the Sun's interior?
The Sun's total mass
The Sun's overall luminosity
The Sun's average density
The Sun's surface temperature
All of the above contribute to modeling the Sun's interior.
All of the above contribute to modeling the Sun's interior.
Mercury's average density is about 1.5 times greater than that of Earth's Moon, even though the two bodies have similar radii. What does this suggest about Mercury's composition?
Mercury must have a uranium core.
Mercury's interior is much richer in iron than the Moon's.
Mercury's greater mass has prevented its gravitational attraction from compressing it as much as the Moon is compressed.
Mercury contains proportionally far more rock than the Moon.
Mercury's interior is much richer in iron than the Moon's.
How do we know the Caloris Basin is younger than other parts of the Mercury surface?
The densest population of crater features are found in its center.
It used to be filled with water.
It contains fewer craters than other parts of Mercury.
It contains unusual rippled highland terrain.
It contains fewer craters than other parts of Mercury.
The scarps that cut across the surface of Mercury probably were:
Formed when the crust buckled as Mercury cooled.
Cut by flowing lava.
Produced by impacts pushing portions of the crust outward.
formed when crustal plates ran together during a plate tectonic phase.
Formed when the crust buckled as Mercury cooled.
Mercury's core is unusual in that:
it is partially molten.
it has a high density.
it contains iron.
it is relatively large compared to Mercury's size.
It is relatively large compared to Mercury's size
What evidence is there that the surface of Venus was covered by giant flows of lava a few hundred million years ago?
There are relatively few impact craters on Venus.
The number of cracks in the lava indicate how old it is.
The surface is still hot.
Radioactive dating was used to determine when it cooled.
There are relatively few impact craters on Venus.
Why are images of the surface of Venus produced by NASA represented in false color?
The visible color of the Venus surface is so monochromatic that it is more useful to highlight elevation differences with false color
The surface of Venus is obscured by clouds in the visible part of the EM spectrum.
Satellite instrumentation lacks the ability to detect light in the visible region of the EM spectrum.
Scientists would rather use color saturated images when conducting research.
The surface of Venus is obscured by clouds in the visible part of the EM spectrum.
Our knowledge of the composition of Earth's core comes from
gravitational waves that pass through Earth.
analysis of the material erupted by volcanoes.
samples obtained by drilling deep holes.
analysis of earthquake waves.
Analysis of earthquake waves.
The slow shifts of our planet's crust are thought to arise from
the Earth's magnetic field drawing iron in crustal rocks toward the poles.
heat from the interior causing convective motion, which pushes on the crust.
the great weight of mountain ranges forcing the crust down and outward from their bases.
the gravitational force of the Moon pulling on the crust.
Heat from the interior causing convective motion, which pushes on the crust.
Where would you expect to find the oldest oceanic crust on Earth?
At the North Pole, in the Arctic ocean.
At seamounts (underwater mountains)
In the trenches by subduction zones.
Between the ridges of the Mid-Ocean Ridge.
In the trenches by subduction zones.
What happens when two continents collide?
One plate subjects beneath the other and volcanism occurs.
Mountains are formed.
The edges of the two continental plates are pushed downward, forming a depression between them.
One remains stationary and the other slips past along a giant transform fault.
Mountains are formed.
