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An atmosphere is held in place around a celestial object by the object's gravitational pull.
Answer: True
Explanation: The gravitational pull of a celestial object is the fundamental force responsible for retaining its atmosphere, counteracting the tendency of gases to disperse into space. Stronger gravity and lower temperatures facilitate longer atmospheric retention.
The word 'atmosphere' is derived from Latin roots meaning 'air' and 'sphere'.
Answer: False
Explanation: The term 'atmosphere' is derived from Ancient Greek roots: 'atmós' (meaning 'vapour' or 'steam') and 'sphaîra' (meaning 'sphere'), not Latin.
Astronomical objects typically acquire their atmospheres solely through volcanic outgassing occurring late in their formation.
Answer: False
Explanation: Astronomical objects generally acquire their atmospheres during their early formation stages through accretion of surrounding matter and/or outgassing of volatile substances from within. Volcanic outgassing is a contributor, but not the sole mechanism, nor exclusively late-stage.
According to the nebular hypothesis, planets form secondary atmospheres primarily through the accretion of gas from the surrounding disk.
Answer: False
Explanation: The nebular hypothesis posits that primary atmospheres are formed through the accretion of gas from the protoplanetary disk. Secondary atmospheres are typically formed later via outgassing from the planet's interior.
A primary atmosphere is formed later in a planet's history through outgassing, while a secondary atmosphere is accreted during formation.
Answer: False
Explanation: This statement reverses the definitions. A primary atmosphere is accreted during formation, while a secondary atmosphere is typically formed later through processes such as outgassing.
The frost line is important because it marks the boundary where planets can only form rocky cores, not accrete gas.
Answer: False
Explanation: The frost line is significant because it is the boundary beyond which volatile compounds can condense into ice. This allows planets forming beyond the frost line to accrete large amounts of gas and ices, leading to the formation of gas and ice giants, not just rocky cores.
A secondary atmosphere is formed when a planet's gravity retains gas accreted during its initial formation.
Answer: False
Explanation: This describes a primary atmosphere. A secondary atmosphere is typically formed later in a planet's history, often through outgassing from its interior.
What is the primary force responsible for holding an atmosphere in place around a celestial object?
Answer: Gravitational pull
Explanation: The gravitational pull of a celestial object is the fundamental force that retains its atmosphere, counteracting the tendency of gas molecules to disperse into space.
From which ancient languages does the word 'atmosphere' derive its roots?
Answer: Ancient Greek and Greek
Explanation: The term 'atmosphere' originates from Ancient Greek, derived from 'atmós' (vapour/steam) and 'sphaîra' (sphere).
Which of the following is a primary mechanism by which astronomical objects acquire their atmospheres during formation?
Answer: Accretion of surrounding matter and internal outgassing
Explanation: During formation, astronomical objects acquire atmospheres primarily through the accretion of surrounding gas and dust, and through the outgassing of volatile substances from their interior.
In the context of the nebular hypothesis, what is the origin of a planet's *secondary* atmosphere?
Answer: Outgassing of volatile substances from the planet's interior
Explanation: Secondary atmospheres are typically formed after initial accretion, primarily through the release of volatile compounds from a planet's interior via processes like volcanic activity.
In our Solar System, Mercury is the only planet lacking a substantial atmosphere.
Answer: True
Explanation: While Mercury possesses an extremely tenuous exosphere, it is generally considered to be the planet in our Solar System lacking a substantial atmosphere, unlike Venus, Earth, Mars, and the gas/ice giants.
The gas giants possess atmospheres primarily composed of nitrogen and oxygen, similar to terrestrial planets.
Answer: False
Explanation: The gas giants (Jupiter, Saturn, Uranus, Neptune) possess atmospheres primarily composed of hydrogen and helium, not nitrogen and oxygen, which are characteristic of some terrestrial planets like Earth.
Exoplanets cannot possess atmospheres, as they orbit stars outside our solar system.
Answer: False
Explanation: Exoplanets, planets orbiting stars outside our solar system, can and do possess atmospheres, which are detectable through various astronomical methods.
A stellar atmosphere is the dense, inner core of a star where fusion occurs.
Answer: False
Explanation: A stellar atmosphere refers to the outer layers of a star, above the photosphere. The dense inner core where fusion occurs is distinct from the stellar atmosphere.
Both Venus and Mars have atmospheres principally composed of hydrogen and helium.
Answer: False
Explanation: Venus and Mars have atmospheres principally composed of carbon dioxide, nitrogen, and argon. Hydrogen and helium are the dominant gases in the atmospheres of the gas giants.
Earth's dry atmosphere contains approximately 78% oxygen and 21% nitrogen.
Answer: False
Explanation: Earth's dry atmosphere is primarily composed of approximately 78% nitrogen (N2) and 21% oxygen (O2), with nitrogen being the more abundant gas.
Jupiter's atmosphere is rich in nitrogen and oxygen, characteristic of a terrestrial planet.
Answer: False
Explanation: Jupiter's atmosphere is predominantly composed of hydrogen and helium, characteristic of a gas giant, not nitrogen and oxygen, which are found in terrestrial planets like Earth.
Titan, a moon of Saturn, and Triton, a moon of Neptune, are known to have significant atmospheres primarily composed of nitrogen.
Answer: True
Explanation: Titan and Triton are notable for possessing significant atmospheres, both primarily composed of nitrogen. Titan's atmosphere also contains methane.
Jupiter and Saturn are classified as ice giants due to their atmospheres being primarily composed of water ice.
Answer: False
Explanation: Jupiter and Saturn are classified as gas giants, with atmospheres predominantly composed of hydrogen and helium. Uranus and Neptune are classified as ice giants, characterized by significant amounts of water, ammonia, and methane ices.
The cloud layers of Uranus and Neptune are identical to those of Jupiter and Saturn, consisting solely of ammonia ice.
Answer: False
Explanation: While Uranus and Neptune share similar cloud layer structures with Jupiter and Saturn, their uppermost cloud layer is composed of methane ice particles, not solely ammonia ice.
A 'hot Jupiter' is an exoplanet that orbits far from its star, resulting in extremely low atmospheric temperatures.
Answer: False
Explanation: A 'hot Jupiter' is an exoplanet that orbits very close to its host star, leading to extremely high atmospheric temperatures, not low ones.
Brown dwarfs are objects less massive than Jupiter that can fuse hydrogen in their cores.
Answer: False
Explanation: Brown dwarfs are objects more massive than Jupiter, capable of fusing deuterium but not hydrogen in their cores.
Photosynthesis has played a role in increasing the oxygen content of Earth's atmosphere over geological time.
Answer: True
Explanation: Photosynthesis by organisms on Earth has been a primary driver for the significant increase in atmospheric oxygen content over geological timescales.
Uranus and Neptune are classified as ice giants because their atmospheres are primarily composed of hydrogen and helium, with minimal amounts of water, ammonia, or methane.
Answer: False
Explanation: Uranus and Neptune are classified as ice giants precisely because their atmospheres contain significant proportions of water, ammonia, and methane ices, in addition to hydrogen and helium.
Venus has a surface air pressure significantly lower than Earth, approximately 0.9% of Earth's pressure.
Answer: False
Explanation: Venus has a surface air pressure significantly higher than Earth, approximately 90 times greater than Earth's pressure.
Titan's atmosphere is primarily composed of methane and nitrogen, making it unique as the only moon with a dense atmosphere and a methane cycle.
Answer: True
Explanation: Titan's atmosphere is primarily composed of nitrogen and methane, and it is unique as the only moon known to possess a dense atmosphere and a methane cycle analogous to Earth's water cycle.
The Sun's atmosphere is mainly composed of heavier elements like iron and silicon, reflecting its stellar nature.
Answer: False
Explanation: The Sun's atmosphere, like its interior, is overwhelmingly composed of hydrogen and helium. Heavier elements are present in much smaller quantities.
Which planet in our Solar System notably lacks a substantial atmosphere?
Answer: Mercury
Explanation: Mercury possesses an extremely tenuous exosphere but is generally considered the planet in our Solar System lacking a substantial atmosphere.
What are the primary atmospheric components of the gas giants (Jupiter, Saturn, Uranus, Neptune)?
Answer: Hydrogen and helium
Explanation: The gas giants are characterized by atmospheres predominantly composed of hydrogen and helium, reflecting their formation conditions and large gravitational influence.
Which method is commonly used to detect atmospheres on exoplanets?
Answer: Transit spectroscopy
Explanation: Transit spectroscopy is a primary method used to detect and analyze the atmospheres of exoplanets by observing how starlight is filtered as it passes through the planet's atmosphere during a transit.
What distinguishes a stellar atmosphere from a planetary atmosphere?
Answer: Stellar atmospheres are the outer regions of stars, above the photosphere.
Explanation: A stellar atmosphere refers to the outer layers of a star, extending above its photosphere, and can contain complex molecules in cooler stars, distinct from planetary atmospheres.
Which terrestrial planet has the densest atmosphere, approximately 80 times that of Earth's?
Answer: Venus
Explanation: Venus possesses the densest atmosphere among the terrestrial planets, with a surface pressure approximately 80-90 times that of Earth's, largely due to its thick carbon dioxide composition.
What are the two most abundant gases in Earth's dry atmosphere by volume?
Answer: Nitrogen and Oxygen
Explanation: Earth's dry atmosphere is primarily composed of approximately 78% nitrogen (N2) and 21% oxygen (O2).
Which moon in our Solar System is noted for having a significant atmosphere primarily composed of nitrogen and methane?
Answer: Titan (moon of Saturn)
Explanation: Titan, Saturn's largest moon, possesses a dense atmosphere primarily composed of nitrogen, with methane also being a significant component.
What defines a 'hot Jupiter' exoplanet?
Answer: A Jupiter-like planet orbiting very close to its host star.
Explanation: A 'hot Jupiter' is a type of exoplanet, similar in mass to Jupiter, that orbits very close to its host star, leading to extremely high atmospheric temperatures.
What is a brown dwarf primarily distinguished by?
Answer: Its capacity to fuse deuterium but not hydrogen.
Explanation: Brown dwarfs are distinguished by being more massive than Jupiter but incapable of sustaining hydrogen fusion, though they can fuse deuterium.
What are Uranus and Neptune classified as, and why?
Answer: Ice giants, due to significant amounts of water, ammonia, and methane ices.
Explanation: Uranus and Neptune are classified as ice giants because their atmospheres contain substantial proportions of water, ammonia, and methane ices, in addition to hydrogen and helium.
What is the approximate surface pressure of Venus compared to Earth?
Answer: About 90 times greater than Earth's pressure
Explanation: Venus has a surface air pressure approximately 90 times greater than Earth's, owing to its dense carbon dioxide atmosphere.
How does the composition of Earth's atmosphere relate to the evolution of life?
Answer: The atmosphere's composition has been significantly altered by biological processes like photosynthesis.
Explanation: Biological processes, particularly photosynthesis, have profoundly altered Earth's atmospheric composition over geological time, notably increasing oxygen levels, which in turn influenced the evolution of life.
The troposphere is the outermost layer of a terrestrial planet's atmosphere, where gases can escape into space.
Answer: False
Explanation: The troposphere is the lowest layer of Earth's atmosphere, where most weather occurs. The exosphere is the outermost layer, from which gases can escape.
The ozone layer in Earth's stratosphere absorbs visible light, causing the temperature to decrease with altitude.
Answer: False
Explanation: The ozone layer in Earth's stratosphere absorbs ultraviolet (UV) radiation, not visible light, causing the temperature to increase with altitude in this layer.
The mesosphere acts as a heat sink because gases like water vapor and carbon dioxide radiate energy into space, causing temperatures to rise with altitude.
Answer: False
Explanation: The mesosphere acts as a heat sink because gases like water vapor and carbon dioxide radiate energy into space, causing temperatures to decrease with altitude in this layer.
Above the homopause, heavier gases tend to dominate the upper atmosphere due to molecular diffusion.
Answer: False
Explanation: Above the homopause, molecular diffusion leads to the separation of atmospheric constituents by weight, with lighter gases diffusing upward and heavier gases tending to settle lower, not dominate the upper atmosphere.
The thermosphere is a layer of the atmosphere above the mesosphere.
Answer: True
Explanation: The thermosphere is indeed the atmospheric layer situated above the mesosphere.
The exosphere is characterized by extremely high pressure, preventing any gas molecules from escaping.
Answer: False
Explanation: The exosphere is characterized by extremely low pressure, and it is the layer from which gas molecules can escape into space.
The Kármán line is defined as the altitude where atmospheric pressure becomes extremely high, preventing gas escape.
Answer: False
Explanation: The Kármán line is defined as the boundary marking the edge of space, typically at 100 km altitude, where conventional flight becomes impossible due to thin atmosphere, not where pressure is high.
The stratosphere on Earth is characterized by decreasing temperatures with increasing altitude due to ozone absorption of UV radiation.
Answer: False
Explanation: The stratosphere on Earth is characterized by increasing temperatures with increasing altitude due to the absorption of ultraviolet (UV) radiation by the ozone layer.
Which layer of a terrestrial planet's atmosphere is known for containing the ozone layer and experiencing a temperature increase with altitude?
Answer: Stratosphere
Explanation: The stratosphere contains the ozone layer, which absorbs ultraviolet radiation, causing the temperature to increase with altitude in this atmospheric layer.
In the mesosphere, temperature decreases with altitude primarily because:
Answer: Gases like CO2 and water vapor radiate heat into space.
Explanation: In the mesosphere, gases such as carbon dioxide and water vapor efficiently radiate thermal energy into space, leading to a decrease in temperature with increasing altitude.
What phenomenon occurs above the homopause layer in a planet's atmosphere?
Answer: Molecular diffusion leads to the separation of gases by weight.
Explanation: Above the homopause, molecular diffusion becomes the dominant process, causing atmospheric constituents to separate based on their atomic or molecular weights.
The thermosphere experiences rising temperatures with altitude due to its absorption of what type of solar radiation?
Answer: X-rays and extreme ultraviolet (EUV) radiation
Explanation: The thermosphere's temperature rises with altitude due to its absorption of high-energy X-rays and extreme ultraviolet (EUV) radiation from the Sun.
Which layer is the outermost part of a planetary atmosphere, where gas molecules can escape into space?
Answer: Exosphere
Explanation: The exosphere is the outermost layer of a planetary atmosphere, characterized by extremely low pressure and density, where gas molecules can achieve escape velocity and drift into space.
The Kármán line is significant because it marks:
Answer: The edge of space, where conventional flight becomes impossible.
Explanation: The Kármán line, typically defined at 100 km altitude, is recognized as the boundary between Earth's atmosphere and outer space, beyond which conventional aerodynamic flight is not feasible.
A celestial body is more likely to retain its atmosphere if it has weak gravity and high surface temperatures.
Answer: False
Explanation: A celestial body is more likely to retain its atmosphere if it possesses strong gravity and maintains low surface temperatures, as these factors counteract atmospheric escape.
The solar wind can strip away a planet's atmosphere, but a magnetosphere offers no protection against this process.
Answer: False
Explanation: The solar wind can indeed strip away a planet's atmosphere; however, a magnetosphere provides significant protection by deflecting the solar wind.
The atmospheric pressure on Mars is roughly comparable to Earth's atmospheric pressure.
Answer: False
Explanation: The atmospheric pressure on Mars is significantly lower than Earth's, approximately 0.6% of Earth's pressure.
The scale height of an atmosphere increases as atmospheric temperature decreases and gravity increases.
Answer: False
Explanation: The scale height of an atmosphere increases as atmospheric temperature increases and decreases as gravity increases. Therefore, lower temperatures and higher gravity lead to a smaller scale height.
A planet's equilibrium temperature is always warmer than its global mean temperature due to the greenhouse effect.
Answer: False
Explanation: A planet's global mean temperature is often warmer than its equilibrium temperature due to the greenhouse effect trapping heat. The equilibrium temperature is a theoretical calculation based on incoming solar radiation and outgoing thermal radiation.
Atmospheric circulation on planets like Earth, Mars, and Venus is primarily driven by magnetic field fluctuations.
Answer: False
Explanation: Atmospheric circulation on planets like Earth, Mars, and Venus is primarily driven by thermal differences and convection, not magnetic field fluctuations.
Earth's rotation influences atmospheric circulation by inducing the Coriolis force, which causes air masses to move in straight paths.
Answer: False
Explanation: Earth's rotation induces the Coriolis force, which deflects air masses, causing them to move in curved paths, not straight ones.
Zonal flows are atmospheric jet streams that move predominantly along lines of longitude.
Answer: False
Explanation: Zonal flows are atmospheric jet streams that move predominantly along lines of latitude, not longitude.
Lighter gas molecules are retained more easily by a planet's gravity than heavier ones because they move slower.
Answer: False
Explanation: Lighter gas molecules are lost more easily because they move faster at the same temperature, reaching escape velocity more readily than heavier molecules, which move slower.
Wind erosion is a geological process that primarily deposits material, rarely sculpting landscapes.
Answer: False
Explanation: Wind erosion is a geological process that actively sculpts landscapes by transporting and depositing material, wearing down features over time.
Atmospheric pressure is irrelevant for the existence of surface liquids; they can exist stably even at very low pressures.
Answer: False
Explanation: Atmospheric pressure is crucial for the stability of surface liquids; without sufficient pressure, liquids would readily boil away or sublimate, even at low temperatures.
Planets with significant atmospheres typically have surfaces heavily covered in impact craters, similar to airless bodies.
Answer: False
Explanation: Planets with significant atmospheres are protected from impacts, and atmospheric processes like erosion tend to erase impact craters over time, unlike airless bodies which retain them.
Escape velocity is the speed required for gas molecules to remain bound to a celestial body's atmosphere indefinitely.
Answer: False
Explanation: Escape velocity is the minimum speed an object needs to overcome a celestial body's gravitational pull and escape into space. Gas molecules must reach or exceed this velocity to escape the atmosphere.
The presence of a magnetosphere prevents atmospheric escape entirely by deflecting all solar wind particles.
Answer: False
Explanation: While a magnetosphere significantly protects an atmosphere by deflecting the solar wind, it does not prevent atmospheric escape entirely, as other factors like thermal escape still contribute.
The global mean temperature of a planet can be warmer than its equilibrium temperature due to the greenhouse effect.
Answer: True
Explanation: The greenhouse effect traps thermal radiation, causing a planet's global mean temperature to be warmer than its equilibrium temperature.
Convection is the primary driver of atmospheric circulation on planets like Earth, Mars, and Venus, transporting heat efficiently.
Answer: True
Explanation: Convection, driven by thermal differences, is the primary mechanism for efficient heat transport and atmospheric circulation on planets like Earth, Mars, and Venus.
On Earth, the Coriolis force deflects air masses, leading to prevailing winds like the trade winds and westerlies.
Answer: True
Explanation: The Coriolis force, induced by Earth's rotation, deflects moving air masses, resulting in the formation of prevailing wind patterns such as the trade winds and westerlies.
According to the source, what two factors are crucial for a celestial body to retain its atmosphere for extended periods?
Answer: Strong gravity and low temperature
Explanation: A celestial body's ability to retain its atmosphere is significantly enhanced by strong gravitational pull and low ambient temperatures, which reduce the kinetic energy of gas molecules.
How does a planet's magnetosphere protect its atmosphere?
Answer: By deflecting the solar wind
Explanation: A planet's magnetosphere acts as a shield, deflecting the charged particles of the solar wind, thereby mitigating atmospheric stripping.
Why can Jupiter retain its atmosphere of hydrogen and helium, while Earth cannot?
Answer: Jupiter has significantly higher gravity and lower temperatures.
Explanation: Jupiter's immense gravity and extremely low temperatures allow it to retain light gases like hydrogen and helium, whereas Earth's lower gravity and higher temperatures facilitate the escape of such gases.
The atmospheric pressure on Mars is extremely low, approximately what percentage of Earth's atmospheric pressure?
Answer: 0.6%
Explanation: The surface atmospheric pressure on Mars is approximately 0.6% of Earth's standard atmospheric pressure.
What does the 'scale height' of an atmosphere represent?
Answer: The altitude change over which pressure decreases by a factor of 'e'.
Explanation: The scale height quantifies the vertical extent of an atmosphere, representing the altitude increment over which atmospheric pressure diminishes by a factor of 'e' (approximately 2.718).
The difference between a planet's equilibrium temperature and its global mean temperature is often due to which atmospheric phenomenon?
Answer: The greenhouse effect
Explanation: The greenhouse effect, where atmospheric gases trap outgoing thermal radiation, typically causes a planet's global mean temperature to be warmer than its equilibrium temperature.
What is the primary driver of atmospheric circulation on planets like Earth, Mars, and Venus?
Answer: Thermal differences and convection
Explanation: Atmospheric circulation on terrestrial planets is primarily driven by thermal gradients, leading to convective heat transport from warmer to cooler regions.
How does Earth's rotation influence its atmospheric circulation?
Answer: It generates the Coriolis force, deflecting air movement.
Explanation: Earth's rotation induces the Coriolis force, which deflects atmospheric movements, shaping large-scale circulation patterns and prevailing winds.
What are zonal flows in planetary atmospheres?
Answer: Jet streams moving predominantly along lines of latitude.
Explanation: Zonal flows refer to atmospheric jet streams that exhibit a predominantly east-west movement along lines of latitude.
Why are lighter gas molecules lost more rapidly from a planet's atmosphere than heavier ones?
Answer: They possess higher kinetic energy at the same temperature.
Explanation: At a given temperature, lighter gas molecules possess higher average kinetic energy, increasing the likelihood that individual molecules will reach escape velocity and leave the atmosphere.
How does the presence of a significant atmosphere affect the appearance of impact craters on a planet's surface?
Answer: Atmospheres protect from impacts and erode existing craters over time.
Explanation: Atmospheres shield planetary surfaces from smaller impacts by burning up incoming objects, and atmospheric processes like wind erosion can gradually degrade existing craters, making them less prominent than on airless bodies.
What crucial role does atmospheric pressure play regarding liquids on a planet's surface?
Answer: It allows liquids to exist stably without boiling away or sublimating.
Explanation: Sufficient atmospheric pressure is essential for maintaining liquids in a stable state on a planet's surface, preventing them from boiling or sublimating prematurely.
Which of the following is NOT listed as a mechanism for atmospheric depletion on planets?
Answer: Gravitational collapse into the planet's core
Explanation: While solar wind sputtering, sequestration, and erosion from impacts contribute to atmospheric depletion, gravitational collapse into the core is not a recognized mechanism for atmospheric loss.