Questions and Answers of An Introduction To The Solar System

Show how the radii of the planetary bodies vary with density.
On the graph you have prepared for Question 1.1, try to identify groupings of the objects. Identify these groupings on your graph. For example, you could identify the icy moons, terrestrial planets
Using the density values of ocean floor crust and a mantle xenolith given in Question 2.1, what would be the density of material at 2900 km depth (where Earth’s core begins) if we could assume that
(a) The mass of the Earth has been determined as 5.973 7 × 1024 kg. Calculate the Earth’s bulk (i.e. mean) density. You should assume the Earth is a sphere with a radius of 6371 km. Quote your
(a) Using the data provided in Table 2.2 , complete Table 2.3 by calculating the relative concentration (concrel) values for (i) mantle (peridotite) rocks, (ii) oceanic crust rocks, and (iii)
Estimate how many planetary embryos of mass 5 × 1022 kg would have been required to assemble:(a) Mercury, and(b) Earth. The mass of each planet is available in AppendixA, TableA1.Table A1 Table Al
Referring back to the completed spider gram (Figure 2.28 ), can you now offer an explanation as to why iron and nickel should be depleted in both crustal and mantle material relative to chondrite
The current rate of heating generated within the Earth by tidal distortion is estimated at 3.0 × 1019 J yr−1. Given the mass of the Earth is approximately 6.0 × 1024 kg, determine the rate of
(a) What proportion of the original 40K and 232Th currently remains since the formation of the Earth? (Using the data in Table 2.6, determine how many half-lives of 40K and 232Th have expired since
(a) By completing Table 2.7, indicate which of the following list of Earth’s layers are defined seismically, and which by other means. What properties do the differences between these layers
(a) What changes will occur over time in the thickness of the lithosphere of a planetary body in which the dominant heat source is radiogenic decay?(b) Giving reasons, discuss whether the same
(a) Given what you have already learned in Chapter 2, discuss the likely heat budgets(especially heat sources) within:(i) A young Earth-like planet with a stabilized crust, fully formed core, and
(a) Does the chemical composition of lunar and Martian basalts (Table 3.1) follow the pattern of element-portioning behaviour expected during the partial melting of peridotite? What does this
Before reading further, note down what sort of volcanism you might expect to find evidence for on Mars. Think in terms of its sources of heat, thermal evolution, and the likelihood of lava and
Because the pit is so tiny, the meteorite was clearly a very small one. Its small size means that its speed must have been severely limited by atmospheric drag. Thus, it more nearly resembles a
Aside from the actual crater, a heat pulse and shock wave will affect the immediate environment. Large impacts will have regional, or even global effects that may kill off many organisms, or even
The proportion of elliptical craters is negligible. Given the wide range of possible impact angles, this shows that the process of cratering favours the production of circular craters over elliptical
Starting in the centre of the image, a small cluster of yellow/green can be seen. Moving out from there, most of the floor of the crater is red, with blue dominating in the terraces and beyond the
Truly diagnostic impact signatures in layers of rock that might be distant from the impact site, are shocked quartz containing planar deformation features, and tektites.Chemical analyses of the
Examine Figure 4.25. Does either of the images reveal a saturated surface? What can you say about the relative ages of the two surfaces illustrated?Figure 4.25 Figure 4.25 Images of planetary
Comment on the use of mass spectrometry and of gas chromatography in analyzing a mixture of CO2, O2, N2, C2H2and C2H4. Assume that these molecules are composed of the most abundant isotopes (12C,
Which of the following substances could be detected remotely by infrared spectroscopy: CO, H2 and HCl?
Estimate the values of the column mass for Venus and Mars, then compare the column masses of the three terrestrial planets, Earth, Venus and Mars. Venus: P, = 92 bar; g = 8.90 ms 2 Mars: P, = 6.3
The solar flux density (amount of energy coming from the Sun) at the radius of the Earth’s orbit is 1.38 × 103Wm－2. A major internal heat source for Earth today is radiogenic heating and this,
If the Earth, with a surface temperature of 288 K, radiates as a black body, at what wavelength will the maximum energy of the emission spectrum be, usingWien’s displacement law (Equation 5.9 )? In
Triton, the largest moon of Neptune, has a high albedo. What does this indicate about its surface? Given that it is a long way from the Sun, is its low surface temperature of 38K surprising?
The release into the Earth’s atmosphere of chlorofluorocarbons (CFCs), which were once commonly used as aerosol propellants, introduces substances that absorb infrared radiation in a different part
Using Figure 5.32, determine whether CO2 would condense as a solid or a liquid on Mars at its average surface temperature.Figure 5.32 partial pressure/bar 10 10 10 10-1 10-2 10 liquid+ gas Esolid +
What speed, relative to the surface, will a piece of atmosphere gain by the Coriolis effect in travelling on Venus from the equator to 30° N? In which direction will the wind produced by this effect
Venus has a core containing molten material but only a very small or no magnetic dipole field. This is thought to be because of the slow rotation of the planet.Some astronomers have speculated that
In the early 20th century, it was assumed that the detected CO2 on Mars was a small fraction of the atmosphere, the bulk being nitrogen as on Earth. Why was it possible to take this point of view
It has been suggested that the transport to Mars of sufficient greenhouse gases would eventually make the planet able to support life. How would you expect the greenhouse gases to transform the
The temperature in the polar regions of the Earth can be very low. Would carbon dioxide freeze out if the temperature dropped to −80 °C (193 K)? (The partial pressure of carbon dioxide on Earth is
How do(a) The ozone layer and(b) The magnetic field aid the continued existence of life on Earth?
The orbital period P of a moon of Saturn, Enceladus, is 1.370 days and its average distance a from Saturn is 238 000 km. Assuming that the mass of Saturn MSat is much greater than that of Enceladus
Outline the reasons why the element mercury (Hg) is not a suitable candidate for the material responsible for producing the magnetic dipole fields in the four giant planets. (The relative abundance
By considering the effect of self-compression only, an approximate value of the pressure at the center of a planet, Pc is given by:where G is the gravitational constant (6.67 ×10－11N m2 kg－2),
Jupiter generates a heat flux of about 7 watts per square meter of surface at the 1 bar level. The decay of 40K and other radiogenic isotopes produces 4.8 × 10－12Wkg－1 of heat in the Earth
Measurements of the gravitational field of Saturn indicate that the hydrogen/helium ratio in the molecular hydrogen layer is roughly solar and that helium is not depleted. Does this fit in with the
Outline reasons why it might be difficult to detect neon, Ne, in the atmospheres of the giant planets by remote methods.
At the 0.42 bar level on Jupiter, the number density (i.e. the number of molecules per unit volume) is 2.4 × 1025 m－3. Use this information to estimate the temperature at this level. (Note that
Methane is a relatively abundant molecule in the atmospheres of Jupiter and Saturn. However, no methane cloud layers are predicted there. What might be the reason for this?
Jupiter has a radius (at the 1 bar level) of 71 490 km at the equator. Its period of rotation is 0.412 days. At what speed (with respect to a non-rotating observer in space, moving with Jupiter in
Some of the wind velocities in Figure 6.14 are shown as negative and yet the entire atmosphere is rotating in the same direction. Explain this.Figure 6.14 latitude 70 60 50 40 30 20 10 0 -10 -20 -30
Describe the interaction that produces the bow shock of the magnetosphere for Jupiter.
Laboratory work on a mixture of icy materials at very high pressures (around 2 × 106 bar = 2 Mbar) has led to a suggestion that Uranus and Neptune do not have rocky cores at all but are composed
No oxygen-containing molecules have been detected in the atmosphere of Uranus, but this does not mean that there is no oxygen in Uranus. Why not?
Until the Voyager encounter, there was no direct evidence for the magnetic field of Uranus.If the planet did not have a magnetic field, what would its magnetosphere be like?
The average density of Jupiter is very similar to that of Rhea, an icy moon of Saturn. Rhea is thought to be composed of one-half rocky and one-half icy materials. How is the same average density
Nitrogen molecules in the atmosphere of Titan were detected by the UV spectrometer on Voyager 1. Why would it be difficult to detect the nitrogen molecules using ground based instruments on Earth?
List some observations on heat sources and heat transport on Jupiter that must be taken into account when developing theories to explain the pattern of winds.
The Earth is protected from harmful energetic particles by its magnetosphere. Is the same true for Jupiter?
Before the Voyager 2 mission reached Uranus and Neptune, it was suggested that Uranus had a hot, molten, rocky core, which gave rise to a magnetic field, but that the core in Neptune was solid and so
Given the composition of the atmospheres of Uranus and Neptune, which atoms might give rise to auroral emissions on these planets?
Pluto has a semimajor axis of 39.48 AU and an eccentricity of 0.249 . What are Pluto’s perihelion and aphelion distances?
Neptune has a semimajor axis of 30.07 AU and an eccentricity of 0.009 . What are Neptune’s perihelion and aphelion distances?
Considering your answers to Questions 7.1 and 7.2, is Pluto always further from the Sun than Neptune?Data from question 7.1 Pluto has a semimajor axis of 39.48 AU and an eccentricity of 0.249. What
Mercury has a semimajor axis of 0.39 AU. What is Mercury’s orbital period?
In the following cases, decide whether the moon might undergo tidal heating.(a) Anewly formed moon that is in a circular orbit, and has a rotation period that is much less than its orbital period.(b)
At what semimajor axis value would you expect to find a gap in the asteroid belt semimajor axis distribution corresponding to a 3 : 1 resonance with Jupiter?
If you travelled to the distance from the Sun equal to the semimajor axis associated with a Kirkwood Gap, might you find any asteroids there? ( think about the effect of orbital eccentricity.)
Look at Figure 7.15, the image of the 58 km × 23 km asteroid, (243) Ida. Remembering the types of craters that you met in Chapter 4, how would you describe the craters on Ida?Figure 7.15 Figure 7.15
Imagine an asteroid of diameter 1 km, of unknown taxonomic class, is about to hit the Moon. Will it make any difference to the impact crater produced, whether the asteroid was S-type, or C-type?
Of the three main dynamical classes in the Kuiper Belt (Plutinos, Classical and Scattered Disc), which group of objects are most likely to have close approaches with (or impact) the giant planets?
If a ‘typical’ comet nucleus were to split apart while in the inner Solar System (i.e. when it is undergoing significant heating from the Sun), why might we expect to see an outburst of cometary
It is clear that the inner Solar System is visited by comets from the outer Solar System (i.e. the Kuiper Belt or the Oort cloud), and so these comets could impact the Earth and other terrestrial
If you observed sporadic meteors throughout the night, you would notice that the rate increases significantly after midnight. Why might this be the case?
The kinetic energy of a body of mass m, travelling at a velocity, v, is given by ½mv2. Calculate and compare the impact energies (i.e. the kinetic energies) of a small car travelling at 50 mph, and
In total extent the Pictoris circumstellar dust disc is 1500 AU across. IR observations indicate that its inner edge lies about 20 AU from the star. How well does the suggested extent of this disc
Consider a disc of gas and dust around the protoSun.(a) What would be the relationship between the orbital periods of particles in circular orbits in the inner and outer parts of the disc, if
Why would a rotating Solar Nebula assume the shape of a disc, and what opposes the collapse of this disc?
What processes in the Solar Nebula can account for the Sun’s low angular momentum, and at what stage in the formation of the Solar System did each of these probably occur?
Many chondrules contain small amounts of iron sulfide (FeS) mixed in with the silicate minerals. If we assume that the iron sulfide has not grown within the chondrules subsequently, what constraint
According to the model in Figure 8.14 , what are:(a) the total proportion of ‘icy and rocky’ dust expressed as a ratio of the total material in the Solar Nebula?(b) the ratio between rock-forming
Assume the density of the material forming planetesimals was 3 × 103 kg m−3. How many 10 km diameter planetesimals would it take to form the Earth, which has a mass of approximately 6.0 ×1024 kg?
The simulations in Figures 8.16 and 8.17 both begin with a population of planetesimals between about 1016 and 1017 kg in mass, i.e. about 10 km diameter. The flat tops to the curves for t = 0 show
What factors are responsible for the giant planets being richer than the terrestrial planets in volatiles such as hydrogen and helium?
(a) Data on the Galilean satellites (Io, Europa, Ganymede and Callisto) are included in Appendix A, Table A2. Can you see any systematic trend in their densities?(b) The density of ice is about 1.0
Can you think why inner moons are more vulnerable to impacts than outer ones, and why smaller ones are more likely to break up as a result of an impact?
State four possible origins of planetary satellites, with examples.
If a planetary system is forming at β Pictoris, what stage (if any) do you think it has reached in the sequence suggested in this chapter for the development of our own Solar System, and why?
Assuming that the flux of extraterrestrial material has remained constant over the last billion years, calculate the mass and volume that this extra matter has added to our planet during this time.
A meteorite has been found which is composed of a mixture of iron and silicates. Within the silicate portion there are fragments of materials recognizable as chondrites and achondrites. The meteorite
20 000 meteoroids of mass >0.1 kg arrive at the Earth’s surface each year. On average, what is the frequency with which materials of this size would be encountered in a town with a radius of 5 km?
The chemical composition of CI meteorites is considered to be the same now as it was when they were formed, even though the original minerals have been altered. What can you say about the nature of
Consider the refractory elements Ca and Al shown in Figure 9.12 . What differences in chemical composition exist between CI, CM2 and CV3 meteorites? How would this be reflected in the proportions of
What are the δ17O and δ18O of ocean water? What are the δ17O and δ18O of pure 16O?
Consider for a moment that the dust and gas reservoirs in the solar nebula both had oxygen isotope compositions at G in Figure 9.17. Where would the isotope compositions plot if we mixed small
In general, what are the consequences for the oxygen isotope compositions of planetary bodies for a variation with time in the oxygen isotope composition of the solar nebula?
Different sorts of matrix materials from Murchison have oxygen isotope compositions which, on a plot of δ17O versus δ18O, fall on a line with a slope of about 0.5 . This line is parallel to,
If the majority of organic compounds in Murchison were formed in the solar nebula as a consequence of condensation, how can we interpret the survival of interstellar organic molecules in this
Allende contains carbon mainly in an amorphous form but also as diamonds. How might we try and assess whether these elemental forms of carbon are related?
(a) 26Al decays by positron emission to give stable 26Mg. How could you tell whether a mineral component from a meteorite had once contained 26Al?(b) In what sorts of minerals would the occurrence of
Which mechanisms are most likely to have contributed heat to asteroids?
Some of the observable asteroids, classified as M-type, have a metallic composition.What does this tell us about processes within the asteroid belt?
Kodaikanal is an unusual iron meteorite which has a radiometric formation age of 3.8 Ga. This is within the range recorded in the majority of impact-produced rocks from the Moon (3.8 Ga to 4.0 Ga).