Astronomy 11.1

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Why is Neptune denser than Saturn?
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Why is Neptune denser than Saturn?
It has a different composition than Saturn, including a higher proportion of hydrogen compounds and rocks.
Why do jovian planets bulge around the equator, that is, have a "squashed" appearance?
Their rapid rotation flings the mass near the equator outward.
Which of the following best describes the internal layering of Jupiter, from the center outward?Which of the following best describes the internal layering of Jupiter, from the center outward?
core of rock, metal, and hydrogen compounds; thick layer of metallic hydrogen; layer of liquid hydrogen; layer of gaseous hydrogen; cloud layer
Which of the following does yield information on jovian planet interiors?
Earth-based observations of the mass and size of the planets
laboratory studies and theoretical models
detailed observations of planetary shapes
spacecraft measurements of magnetic and gravitational fields
How does Jupiter's core compare to Earth?
it is about the same size but is 10 times more massive.
Choose the correct description of the interior structure of Jupiter and why it is layered in this way.
Jupiter has a gaseous envelope on the outside where the pressure is low. As we travel downward into Jupiter, the pressure increases and the layers of hydrogen are squeezed closer together, becoming the liquid, and then behaving like a metal.
How do the interiors of the other jovian planets compare to that of Jupiter?
Other jovian planets have similar structures, except for the metallic hydrogen layer. Uranus and Neptune are too small to generate the pressures needed for this layer, while Saturn's layer is smaller than Jupiter's because Saturn does not generate the pressure needed for metallic hydrogen in as much of its volume as Jupiter does.
The items below describe worlds or selected localities on worlds. Based on our current scientific understanding, match these items to the appropriate category below
Likely to be habitable
- underground on Mars
- subsurface ocean on Europa
- moon with atmosphere orbiting jovian planet 1 AU from 1 Msun star

Unlikely
- surface of Mars
- surface of terrestrial planet 10 AU from 0.5 Msun star
- volcanoes on Io
Which statement explains the observations that make it seem possible that Mars could have life underground?
We have detected water ice on Mars, and Mars still has some volcanic heat.
In Part A you found that the terrestrial planet 10 AU from a 0.5MSun star is unlikely to be habitable. Could this planet be habitable if it were in a different orbit around its star?
Yes, but it would have to be less than 0.5 AU from its star.
Which of the following planets cannot be seen with the naked eye?NeptuneWhy does Jupiter have several distinct cloud layers?Different layers represent clouds made of gases that condense at different temperaturesWhat atmospheric constituent is responsible for the blue color of Uranus and Neptune?methaneWhy do some scientists think that Jupiter's existence may have been critical for life to evolve on Earth?It kicked out many comets from the inner solar system through gravitational encounters, thus limiting the number of objects that could potentially hit the inner planets.Listed below are the names, spectral types (in parentheses), and approximate masses of several nearby main-sequence stars. Rank the stars based on the distances to their habitable zones (from the central star), from shortest to longest.Shortest •bernard's star (M4) .2 Msun •61 Cygni A (K5) .7 Msun •Alpha Centauri A (G2) 1 Msun •Sirius (A1) 2 Msun •Spica (B1) 11 Msun LongestConsider again the same set of five stars. This time, rank the stars based on the size (width) of their habitable zones, from smallest to largest.Smallest •bernard's star (M4) .2 Msun •61 Cygni A (K5) .7 Msun •Alpha Centauri A (G2) 1 Msun •Sirius (A1) 2 Msun •Spica (B1) 11 Msun LargestImagine that each of the five stars is orbited by a terrestrial planet at a distance of 1 AU (Earth's distance from the Sun). Rank the stars based on the planet's expected surface temperature (not including any greenhouse effect), from lowest to highest.Lowest •bernard's star (M4) .2 Msun •61 Cygni A (K5) .7 Msun •Alpha Centauri A (G2) 1 Msun •Sirius (A1) 2 Msun •Spica (B1) 11 Msun HighestHigh-mass main-sequence stars have a more distant and wider BLANK than low-mass stars.habitable zoneSky surveys looking for radio signals generated by technology are part of the . BLANKsearch of extraterrestrial intelligenceBLANK is designed as a way of estimating the number of intelligent civilizations in the Milky Way.drake equationThe notion that living organisms with advantages that give them greater reproductive success (in some local environment) will survive while others perish is an example of what Darwin called BLANKnatural selectionOne of the key premises for the BLANK is that living organisms are able to produce far more offspring than their environment can support.theory of evolutionThe different time periods of the BLANK are defined by changes in fossils found from those time periods.GEOLOGICAL TIME SCALE. Incoming ultraviolet light from the Sun can cause a BLANK in a living organism's DNA that can affect its ability to survive and reproduce.MUTATIONHow do typical wind speeds in Jupiter's atmosphere compare to typical wind speeds on Earth?They are much faster than hurricane winds on Earth.Suppose you read on the internet this statement: Abraham Lincoln reported seeing "flying saucers." Based on what you read in the Extraordinary Claims essay, what should you believe this statement? Why or why not?It is probably false because the idea of flying saucers was not popularized until 1947Which accurately reflects what a good scientist would say about a group of people who claim to have seen a UFO on some particular night?They have probably seen something but we do not know exactly whatOne of the best-known claims of UFO enthusiasts is that an alien spacecraft crashed in Roswell, New Mexico, in 1947, and that the government recovered alien bodies that they have been hiding ever since at Area 51 in Nevada. Which of the following make scientists skeptical of this claim?It seems unlikely that the government could keep such a thing secret for more than 70 years; no independent evidence supports the idea that anything of non-human origin crashed in RoswellWhy is Jupiter denser than Saturn?The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn.Why does Neptune appear blue and Jupiter red?Methane in Neptune's atmosphere absorbs red light.How do astronomers think Jupiter generates its internal heat?by contracting, changing gravitational potential energy into thermal energyOverall, Jupiter's composition is most like that ofthe sunHydrogen exists as a gas, liquid, and solid within Jupiter.trueWhy do some scientists say that the Moon may have been important for the evolution of human life?it stabilized Earth's axis tilt and prevented large climate changes.Why is Saturn almost as big as Jupiter, despite its smaller mass?Jupiter's greater mass compresses it more, thus increasing its densitySort each of the planetary properties below based on whether they apply to some, all, or none of the four jovian planets in our solar system.Jupiter and Saturn only: -interior is mostly liquid or metallic hydrogen -composed mostly of hydrogen and helium Uranus and Neptune only: -blue color because of methane -composed mostly hydrogen compounds all four jovian planets: -approximately 10 Earth-mass core -orbited by rings of ice and rock -magnetic field stronger than Earth's -strong atmospheric winds and storms no jovian planets: -solid surface under a thick atmosphereChoose the correct explanation, whether the discovery should be considered reasonable or surprising.This is unlikely. A Jupiter-mass planet might be larger if it were hotter, but we know of no mechanism that would make such a planet much smaller than Jupiter's size.How do astronomers think Saturn generates its internal heat?by raining dense helium droplets from higher to lower altitudes, resembling the process of differentiationWhich of the following places is generally considered a potential home for life in our solar system?Titan Mars EuropaWhy do Uranus and Neptune have blue methane clouds but Jupiter and Saturn do not?Methane does not condense into ice in the warmer atmospheric temperatures of Jupiter and SaturnWhich of the following statements best describes the general pattern of composition among the four jovian planets?Uranus and Neptune contain relatively more rock and hydrogen compounds than Jupiter and Saturn.Look at the average densities of the jovian planets given in Figure 1. Can you identify a trend in jovian planet densities with mass or distance from the Sun?There is no clear trend in the densities with mass or distanceWhich of the following statements best explains why the densities of Uranus and Neptune are higher than that of Saturn, even though Saturn is much more massive?They have a higher proportion of hydrogen compounds and rock.Which of the following best explains why Jupiter's density is higher than Saturn's?Jupiter is more massive than Saturn.Based on the leading scientific theory of solar system formation, which of the following statements best explains why Uranus and Neptune have a significantly different composition than Jupiter and Saturn?Jupiter and Saturn captured more gas from the solar nebula than Uranus and NeptuneProcess of Science: A prediction based on Newton's theory of gravity led to the discovery of Neptune.trueAs the mass of the central star increases, the distance to the habitable zone __________ and the size (width) of the habitable zone __________.increases/increasesSuppose that our Sun was cool enough to include Mercury in its habitable zone. Which of the following would be true in that case?Only Mercury would be in the Sun's habitable zone.Scientists think it is very unlikely that complex and large forms of life could evolve on planets that orbit stars that are much more massive than the Sun. Why?The expected lifetime of a massive star is too short to allow for the evolution of complex lifeThe belts and zones of Jupiter are) alternating bands of rising and falling air at different latitudes.Jupiter's Great Red Spot is a low-pressure storm like a hurricane on Earth.falseHow many more times is the atmospheric pressure in Jupiter's core greater than the atmospheric pressure at Earth's surface?100 millionWhy do the jovian planet interiors differ?accretion took longer further from the Sun, so the more distant planets formed their cores later and captured less gas from the solar nebula than the closer jovian planets.