A glimpse into the future of space
exploration.
In 2021, a new spherical dwarf planet was discovered in our solar system in
a large elliptical orbit past Pluto. It was given the name of Ajax, and a robotic space probe
containing a seismometer was launched in 2022 to explore it. This space probe contained special
explosive charges that were detonated on Ajax’s surface to examine the internal structure of
this dwarf planet my tracking the seismic waves from the explosion. The seismic wave data from this
experiment is shown in the two tables below.
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1.
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Examine the information in Ajax Data Table 01 and 02 to answer this
question. At what depth was the first anomaly discovered, and what evidence is there that the
rock was solid at this depth?
a. | The first anomaly was at a depth of 150 km. Since S-Waves were able to propagate
through this substance, it must have been solid rock. | b. | The second anomaly was at a depth of 150 km.
Since both P-waves and S-Waves were able to propagate through this substance, it must have been solid
rock. | c. | The first anomaly was at a depth of 750 km. Since P-Waves were able to propagate
through this substance, it must have been solid rock. | d. | The first anomaly was at a depth of 1000 km.
Since S-Waves were not able to propagate through this substance, it must have been liquid rock.
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2.
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Examine the information in Ajax Data Table 01 and 02 to answer this
question. At what depth was the second anomaly discovered, and what evidence demonstrated that
the rock at this depth is not molten (magma).
a. | The second anomaly was at a depth of 750 km. Since S-Waves were able to propagate
through this substance, it could not be magma. | b. | The second anomaly was at a depth of 750 km.
Since P-Waves were able to propagate through this substance, it must have been solid rock.
| c. | The second anomaly was at a depth of 1200 km. Since S-Waves were not able to
propagate through this substance, it must have been liquid rock. | d. | The second anomaly
was at a depth of 900 km. Since the speed at this depth was an even number for both P and S-Waves, it
could not have been magma. |
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3.
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Examine the information in Ajax Data Table 01 and 02 to answer this
question.
What was the thickness of the second layer of rock revealed by the seismic wave data
from Ajax, and which of the following diagrams is the best model of this dwarf planet?
a. | The second layer was 450 km thick. Model Three is the best diagram. | c. | The second layer
was 600 km thick. Model Two is the best diagram. | b. | The second layer was 150 km thick. Model One
is the best diagram. | d. | The
second layer was 600 km thick. Model Four is the best diagram. |
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4.
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How did seismologists determine that the Earth has multiple internal layers,
and what did analysis of S-wave data demonstrate that one layer inside is the Earth is
liquid?
a. | They analyzed data from seismometers, and they observed that S-waves were unable to
penetrate one of the layers inside the Earth. | b. | They chemically analyzed rocks from Earth and
Mars. The results of this analysis showed that all rocks in our solar system are made of elements
from the periodic table. | c. | They tracked the speed of seismic waves
propagating through the Earth, and they compared this to patterns in the way celestial objects move
in our solar system. | d. | They examined the atomic structure of igneous,
sedimentary, and metamorphic rock. Then they used seismometers to determine the number of layers
inside the Earth. |
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Use the following data tables to help you
answer question 5 to 10.
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5.
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Examine the information in Seismic Data Table 02 to answer this
question. Speed changes and refraction has been observed in seismic wave data as the waves
travel through different substances with different densities. What is one location where this
is revealed in Seismic Data Table 02, and what best explains this phenomenon?
a. | At a depth of 50 kilometers the S-Waves slowed from 5 km/s to 4 km/s. This
occurred as the wave hit the boundary of the crust and the mantle. | b. | At a depth of 5200
kilometers the S-Waves slowed from 7.5 km/s to 0 km/s. This occurred because S-Waves are unable to
travel through liquid rock. | c. | At a depth of 50 kilometers the S-Waves
increased speed from 4 km/s to 5 km/s. This occurred as the wave hit the boundary of the inner core
and the outer core. | d. | At a depth of 5200 kilometers the S-Waves
slowed from 14 km/s to 8 km/s. This occurred as the wave hit the boundary of the crust and the
mantle. |
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6.
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Examine the information in Seismic Data Tables 01 and 02 to answer this
question.
What was the thickness of the layer of liquid rock revealed by Earth’s seismic
data, and which of the following diagrams is the best model of our planet?
a. | Earth’s outer core is about 2300 km thick. Model One is the best
diagram. | b. | Earth’s inner core has a radius of about 1200 km. Model Four is the best
diagram. | c. | Earth’s mantle is about 3000 km thick. Model Three is the best
diagram. | d. | Earth’s crust is about 50 km thick. Model Two is the best
diagram. |
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7.
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Examine the information in Seismic Data Table 02 to answer this
question. P-Waves can travel through both solid and liquid rock. S-Waves, on the other hand,
can only travel through solid rock. What is one location in Seismic Data Table 02 where liquid
rock is revealed by the S-Wave data?
a. | At a depth of 50 kilometers the S-Waves increased speed from 4 km/s to 5 km/s. This
occurred as the wave hit the boundary of the inner core and the outer core. | b. | At a depth of 2900
kilometers the S-Waves slowed from 5 km/s to 4 km/s. This occurred as the wave hit the boundary
of the crust and the mantle. | c. | At a depth of 2900 kilometers the S-Waves
stopped. This occurred because after 2900 km there is a layer of liquid
rock. | d. | At a depth of 5200 kilometers the S-Waves slowed from 14 km/s to 8 km/s. This
occurred as the wave hit the boundary of the crust and the mantle. |
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8.
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Examine the information in Seismic Data Table 01 to answer this
question. Layers of rock inside the Earth have been revealed by analyzing seismic data.
Geologists have observed that seismic waves change speed as they move downward toward Earth’s
center. What is one location where this is revealed in Seismic Data Table 01, and
what best explains this phenomenon?
a. | At a depth of 2900 kilometers the P-Waves decreased speed from 9 km/s to 8
km/s. This occurred as the wave hit the boundary of the outer core and inner
core. | b. | At a depth of 50 kilometers the P-Waves stopped. This occurred as the wave hit
the boundary of the mantle and the outer core. | c. | At a depth of 5200 kilometers the P-Waves
slowed from 11 km/s to 10 km/s. This occurred because P-Waves are unable to travel through solid
rock. | d. | After 5200 km, P-Wave speed was a constant 11 km/s all the way to Earth’s
center. This occurred as the wave moved from the outer core through the inner
core. |
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9.
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Examine the information in Seismic Data Table 02 to answer this
question. Refraction and changes in speed have been observed in seismic wave data as the waves
travel towards the center of our planet. What is one location where this is revealed in Seismic
Data Table 02, and what best explains this phenomenon?
a. | At a depth of 2900 kilometers the S-Waves slowed from 5 km/s to 4 km/s. This
occurred as the wave hit the boundary of the crust and the mantle. | b. | At a depth of 5200
kilometers the S-Waves slowed from 14 km/s to 8 km/s. This occurred as the wave hit the boundary of
the crust and the mantle. | c. | At a depth of 2900 kilometers the S-Waves
slowed from 7.5 km/s to 0 km/s. This occurred because S-Waves are unable to travel through liquid
rock. | d. | At a depth of 50 kilometers the S-Waves increased speed from 4 km/s to 5 km/s. This
occurred as the wave hit the boundary of the inner core and the outer
core. |
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10.
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Examine the information in Seismic Data Table 01 to answer this
question. What is the primary cause of seismic waves, and what pattern do you notice about the
P-Waves as they propagated downward towards the center of our planet?
a. | Seismic waves mainly occur when massive celestial objects impact the Earth. The
P-Waves maintain a constant speed as they the move through our planet. | b. | The primary cause of
seismic waves are explosions from nuclear detonations. P-Waves are unable to travel through
liquids. So, they cannot be detected in oceans. | c. | Seismic waves mainly occur beneath the seas due
to the mass of the water. P-Waves speed up as they travel down towards the center of the
Earth. | d. | Seismic waves mainly result from tectonic plate movement. The P-Waves slow down as
they move through different rock layers within the Earth. |
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