Astronomy Ch. 5 - 10
The angular resolution of a ground-based telescope is usually set by:
Atmospheric seeing
Auroras do not happen on the Moon, because the Moon:
Does not have a strong magnetic field and does not have an atmosphere
Earth's interior is heated by:
Radioactive decay and tidal effects
The part of the human eye that acts as the detector is the
Retina
Since angular momentum is conserved, an ice-skater who throws her arms out will do what?
Rotate more slowly. This is an expression of the conversation law of angular momentum
Scientists can learn about the interiors of terrestrial planets from:
Seismic waves Satellite observations of gravitational fields Physical arguments about cooling Satellite observations of magnetic fields
Oblateness is a property of a planet's __________; obliquity is a property of a planet's __________.
Shape; Orbit
What does Earth's magnetosphere do?
Shields us from the solar wind Is essential to the formation of auroras Extends far beyond Earth's atmosphere
Volatile material
Sometimes called ice. Material that remains gaseous at moderate temperature.
If your body were not in hydrostatic equilibrium with the air, it would:
Swell or contract until equilibrium was reached.
As depth increases, _____ and ______ increase, causing changes in the chemical composition of clouds in the atmospheres of the giant planets
Temperature and pressure
Neptune's existence was predicted because:
Uranus did not obey Newton's laws of motion. -Neptune's gravitational effect on the orbit of Uranus
Venus is hot and Mars is cold primarily because:
Venus has a much thicker atmosphere.
Rank these planets where the atmospheric greenhouse effects are the strongest (to weakest):
Venus, Earth, Mars, Mercury
Which of the following causes the biggest problem in detecting infrared photons from an astronomical object?
Water Vapor
Earth's atmosphere is much different in composition than Venus's atmosphere because:
Water is a liquid on the surface of Earth
The atmosphere of Mars is often pink-orange because:
Wind lifts dust into the atmosphere.
When extrasolar planets were first discovered, they were surprising, and astronomers had to:
Modify the theories of the formation of stellar systems.
As a blackbody becomes hotter, it also becomes_____ and ______.
More luminous; bluer
Which of the following can be observed from Earth's surface?
Radio waves
Geologists can find the actual age of features on a world by:
Radioactive dating of rocks retrieved from the world and Comparing cratering rates on one world to another
Arpeture
The clear diameter of a telescope's objective lens or primary mirror
Astronomers put telescopes in space to
Avoid atmospheric effects
Over the past 800,000 years, Earth's temperature has closely tracked:
Carbon dioxide levels in the atmosphere
Extrasolar planets have been detected by the:
- Gravitational lensing method/Microlensing -Transit method -Direct imaging method -Spectroscopic radial velocity method
The following steps lead to convection in the atmospheres of giant planets. Place the steps in order.
1. Gravity pulls particles toward the center. 2. Particles fall toward the center, converting gravitational energy to kinetic energy. 3. Friction converts kinetic energy to thermal energy. 4. Thermal energy heats the material. 5. Warm material rises and expands. 6. Expanding material cools.
Place in chronological order the following steps in the formation and evolution of Earth's atmosphere:
1. Hydrogen and helium are captured from the protoplanetary disk. 2. Hydrogen and helium are lost from the atmosphere. 3. Volcanoes, comets, and asteroids increase the inventory of volatile matter. 4. Life releases CO2 from the subsurface into the atmosphere. 5. Plant life converts CO2 to oxygen. 6. Oxygen enables the growth of new life-forms.
What is the surface temperature of a star that has a peak wavelength of 290 nm?
10,000 K
At what wavelength does your body radiate the most energy?
10^-5 meter / microwave
Equilibrium temperature of the Earth (with atmosphere)
288 K
The light-gathering power of a 4-meter telescope is _______than that of a 2-meter telescope.
4 times larger
The large feature spanning the surface of Mars in the figure above is _________ and probably was created by _________.
A canyon; a rapid cooling of the crust
Chromatic Abberation
A detrimental property of a lens in which rays of different wavelengths are brought to different focal distances from the lens
Spectrograph
A device that spreads out the light from an object into its component wavelengths (a.k.a spectrometer)
Accretion Disk
A flat, rotating disk of gas and dust surrounding an object, such as a young stellar object, a forming planet, a collapsed star in a binary system, or a black hole
Imagine a giant planet, very similar to Jupiter, that was ejected from its solar system at formation. (Such objects exist and are probably numerous, although their total number is still uncertain.) This planet would almost certainly still have:
A magnetosphere Its original composition Thermal energy
Metallic hydrogen is not:
A metal that acts like hydrogen -In Jupiter, the magnetic fields are generated within deep layers of metallic hydrogen
Bohr Model
A model of an atom, proposed by Niels Bohr, in which a small positively charged nucleus is surrounded by orbiting electrons, similiar to a miniature solar system
Hadley circulation
A simplified, and therefore uncommon, atmospheric global circulation that carries thermal energy directly from the equator to the polar regions of a planet
The Great Red Spot on Jupiter is:
A storm that has been raging for more than 300 years
The spectroscopic radial velocity method of planet discovery measures a motion that is most like the motion of what?
An ice-skater spinning his partner. Spectroscopic radial-velocity measurements pick up the Doppler shift of a star being tugged by its orbiting planet, much like a very small Chihuahua tugs on its owner when being walked
A stellar occultation occurs when:
An object, such as a planet, moves in front of a distant star.
Impacts on the terrestrial worlds and the Moon:
Are less common than they used to be
If scientists want to find out about the composition of the early Solar system, the best object to study are:
Asteroids and comets. -Asteroids and comets are made almost exclusively of the pristine material out of which the solar system formed
To survive passage through the Earth's atmosphere without burning or breaking up before it hits the ground, an asteroid must be:
At least 100 meters in size
Beam 1 has half the wavelength of beam 2. How do their frequencies compare?
Beam 1 has two times the frequency of beam 2
Robotic landers are more common than simple-return spacecraft because:
Carrying enough fuel to get back to Earth makes sample return expensive
All large astronomical telescopes are reflectors because:
Chromatic aberration is minimized, they are not as heavy as refracting telescopes, they can be shorter than refracting telescopes
Clumps grow into planetesimals by:
Colliding with other clumps. -This series of colliding with other clumps helped form the planets we see today. In the early solar system, collisions between particles and clumps cause them to stick together and grow in size.
Planetary systems in the Milky Way Galaxy are probably:
Common (many stars have planets) -Planet formations and star formation seem to go hand in hand
The different colors of clouds on Jupiter are primarily a result of:
Composition
If crater A is inside crater B, we know that:
Crater B was formed before Crater A
A stellar occultation can be used to measure the:
Diameter of a planet
What is the process by which heavier molten material sank deeper into the planetary core, leaving the outer layers made of lighter material?
Differentiation
Lava flows on the moon and Mercury created large, smooth plains. We don't see similar features on Earth because:
Earth has plate tectonics and erosion that modify the surface
Earth has fewer craters than Venus. Why?
Earth's surface experiences more erosion
The magnetic fields of the giant planets:
Extend far into space
(T/F) During summer in the northern hemisphere of Mars, the polar ice cap melts and liquid water flows outward from it in rivers.
False
(T/F) Impact cratering no longer affects the terrestrial planets.
False
(T/F) On Mars, water ice is present primarily at its polar ice caps.
False
(T/F) The cores of the giant planets are all similar.
False
(T/F) The current atmosphere of the terrestrial planets were formed when the planets formed
False
(T/F) The interior of the Earth is hot mainly because of the pressure induced by the weight of the material above it
False
Permanent magnetism in the Earth's solid iron core is the source of Earth's magnetic field.
False
The geological processes that shape a planet have ceased on Earth.
False
The temperature differences between night and day on the Moon and Mercury are very small because they have so little atmosphere.
False
(T/F) A giant planet has a solid surface that marks an abrupt change from the a gaseous atmosphere
False -As one travels into the interior of a giant planet, the atmosphere becomes denser, transitioning fairly smoothly into a liquid or solid core
One of the reasons why the hubble space telescope has better spatial resolution than a 4-m ground based telescope is that it has large mirror
False Also: not the largest telescope built & there is no blurring due to the atmosphere
(T/F) Chromatic aberration is a problem that limits the image quality of reflecting telescopes
False Chromatic aberration is associated with refracting telescopes
(T/F) Cooler objects emit more of their total light at shorter wavelengths than hotter objects
False (backwards!)
Imagine that you are rock collecting in Arizona and you find rock containing shock-modified quartz. You immediately know the rock:
Formed during an impact
Two stars are of equal luminosity. One is twice as far from the other, the closer star appears:
Four times brighter (Farther away, 1 / d^2 as bright)
Jupiter and Saturn have compositions similar to the sun and are called:
Gas giants
Auroras are caused by:
Gases fluorescing in the atmosphere due to collisions with solar wind particles
Refracting Telescope
Glass lens is curved, light at the outer edges of the lens is refracted more than light near its center. Concentrates the light rays entering the telescope, bringing them into a sharp focus. Lets in light and magnifies image.
What could have caused the planets to migrate through the Solar System?
Gravitational pull from other planets
Place the following events in the order they occur during the formation of planetary system:
Gravity collapses a cloud of interstellar gas A rotating disk forms Dust grains stick together by static electricity Small bodies collide to form larger bodies Primary atmosphere form A stellar wind "turns on" and sweeps away gas and dust Primary atmosphere is lost Secondary atmospheres form
Earth experiences long-term climate cycles spanning _____ of years.
Hundreds of thousands (140,000)
Uranus and Neptune are called:
Ice giants
Out of the four processes that shape the surface of the terrestrial world, the one with the most potential for catastrophic re-arrangement is:
Impact cratering -Other processes: volcanism, tectonism, & erosion
______,_______, and _________ build up structures on the terrestrial planets, while in general, ________ tears them down.
Impacts, tectonism, volcanism; erosion
Consider a northward-traveling particle of gas in Jupiter's northern hemisphere. According to the Coriolis effect, which way will this particle of gas turn?
In the direction of rotation
What makes carbon dioxide a highly effective greenhouse gas?
It easily absorbs infrared radiation.
The kepler mission telescope observes primarily in visible light. this telescope is located in space because
It is above atmospheric distortion
If the radius of an object's orbit is halved, what must happen to the speed so that angular momentum is conserved?
It must be doubled
If the radius of an object's orbit is halved, what must happen to the speed so that the angular momentum is conserved?
It must be doubled. Since angular momentum L=mvr, we see that if the distance r is halved, the speed v must be doubled
Mercury has (essentially) no atmosphere because:
It's small
The amount of angular momentum in an object depends on what?
Its radius, mass, and rotation speed
Which of the following planets still has its primary atmosphere?
Jupiter. -Rememer that the "primary" atmosphere is the one the planet formed with; the terrestial planets all lost their soon after formation
Which is NOT a reason for the large size of volcanoes on Mars as compared to Earth's smaller volcanoes?
Lack of atmosphere; therefore no erosion
The spectroscopic racial velocity method preferentially detects...
Large planets close to the central star
Reflecting Telescope
Light from an object enters the telescope tube and is reflected off a curved mirror at the end of the tube.
______ are compressional, while ______ oscillate perpendicular to the line of travel.
Longitudinal and P waves; transverse and S waves
Scientists learn about the interior structure of planets by using- (choose all that apply)
Observing of seismic waves Model of Earth's interior Observations of magnetic fields
If a radioactive element A decays into radioactive element B with a half life of 20 seconds, then after 40 seconds:
One-quarter of element A will remain
Uncertainties in climate science are dominated by uncertainty about:
Physical causes
Consider an external solar system in which there are three terrestrial planets. All are located far from other objects so tidal forces aren't significant. If planet A has a radius of 1 Earth radius, and planet B has a radius of 2 Earth radii, and planet C has a radius of 3 Earth radii, which planet has the highest chance of having at least a partially liquid core and a detectable magnetic field?
Planet C
The discovery of "hot Jupiter" planets close to their central star led to the theoretical model of what?
Planet migration
One telescope has an aperture of 20 cm and one has an aperture of 30 cm, which should you choose and why?
The 30cm because the light-gathering power will be better
The Moon has a diameter that is approximately one-fourth that of Earth. If these objects' interiors are heated by radioactive decays, and the total amount of energy in decays is proportional to the object's volume, then how does the amount of heat the Moon has compare to that of Earth?
The Moon has 1/64th = 0.016 times that of Earth's
Weather on Earth is driven by __________; weather on Jupiter is driven by_________.
The Sun; internal energy
Doppler Effect
The change in a wavelength of sound or light that is due to the relative motion of the source toward or away from the observer
The concept of disk instability was developed to solve the problem that:
The early solar nebula likely dispersed too soon to form Jupiter. -The disk instability theory proposes that a disk could break up into large planet-like components which happens very rapidly, as opposed to the slow process of accretion
Oblateness
The flattening of an otherwise spherical planet or star caused by its rapid rotation
Zonal winds on the giant planets are stronger than those on the terrestrial planets because:
The giant planets rotate faster
Obliquity
The inclination of a celestial body's equator to it's orbital plane (tilted axis)
Unlike the giant planets, the terrestrial planets formed when:
The inner Solar System was hotter than the outer Solar System -The planets closer to the sun were hotter and as a consequence captured less gas as the Solar System was forming.
Auroras are the result of:
The interaction of particles from the Sun and Earth's atmosphere
How do scientists know the history of Earth's magnetic field?
The magnetic field freezes into rocks, and plate tectonics spreads them out
Geologists can find the relative age of impact craters on a world because:
The ones on the top must be younger
Heisenberg Uncertainty Principle
The physical limitation that the product of the position and the momentum of a particle cannot be smaller than a well-defined value, Planck's constant (h).
Hadley circulation is broken into zonal winds by:
The planet's rapid rotation
Deep in the interiors of the giant planets, water is still a liquid even though the temperatures are tens of thousands of degrees above the boiling point of water. This can happen because:
The pressure inside the giant planets is so high
Absorption
The process by which an atom captures energy from a passing photon
Emission
The production of a photon when an atom decays to a lower energy state
If photons of blue light have more energy than photons of red light, how can a beam of red light carry as much energy as a beam of blue light?
The red beam must contain more photons to carry the same total energy
Protoplanetary Disk
The remains of the accretion disk around a young star from which a planetary system may form
Which of the following factors does NOT directly influence the temperature of a planet?
The size of the planet Factors that DO influence: Distance from the planet to the sun The albedo (reflective properties) of the planet The luminosity of the Sun
Diffraction
The spreading of a wave after it passes through an opening or beyond the edge of an object
Comparative planetology
The study of planets through comparison of their chemical and physical properties.
The terrestrial planets and the giant planets have different composition because:
The terrestrial planets are closer to the sun. - The hotter planets in the inner Solar System collected less gas than cooler, outer planets.
Planet Migration
The theory that a planet can move to a location away from where it formed, through gravitational interactions with other bodies or loss of orbital energy from interaction with gas in the protoplanetary disk.
The difference in climate between Venus, Earth, and Mars is primarily caused by:
The thickness of their atmospheres
Convection
The transport of thermal energy from lower (hotter) to the higher (cooler) layers of a fluid by motions within the fluid driven by variations in buoyancy.
The planets in the inner part of the Solar System are made primarily of refractory materials; the planets in the outer Solar System are made primarily of volatiles. The reason for the difference is that:
There were no volatiles in the inner part of the accretion disk. -Volatiles are easily evaporated or broke up with heat, and it was too hot in the inner solar system for these compounds to be present
Spacecraft are the most effective way to study planets in our Solar System because:
They can collect more information than is available just from images
The major advantage CCDs have over other imaging techniques is that:
They have a higher quantum efficiency They have a linear response to light They yield output in digital format They operate at visible and near-infrared wavelengths
Large worlds are geologically active longer than smaller worlds because:
They have more radioactive fuel and they lose heat at a slower rate
Convection in the ______ causes weather on Earth
Troposphere
(T/F) All the giant planets have clouds and belts.
True
(T/F) Life is responsible for the presence of oxygen in Earth's atmosphere
True
(T/F) Radio telescopes are often used in interferometric arrays to increase light-gathering power
True
(T/F) Storms on giant planets last much longer than storms on Earth.
True
(T/F) The atmospheric greenhouse effect occurs on Earth, Venus, and Mars
True
(T/F) The fraction of CO_2 in Earth's atmosphere is at the highest level measured in the last 450,000 years.
True
(T/F) The temperature of Earth has measurably risen over the past 100 years.
True
(T/F) Uranus has extreme seasons because its poles are nearly in the plane of the Solar System.
True
(T/F) Water never forms visible clouds in the atmospheres of giant planets.
True
(T/F) Wind erosion is an important process on Venus.
True
(T/F) The solar system formed from a giant cloud of dust and gas that collapsed under gravity.
True. - All starts and most planetary systems are made this way. The same can be said for all stars, too.
(T/F) Volcanism has been present on all terrestrial planets. How do we infer that volcanism was a process that was present on other terrestrial worlds (mercury, mars, the moon)?
True. -Relatively smooth expanses of crust
(T/F) Volatile materials are solid only at low temperatures.
True. -This is why the inner planets collected less gas in their atmosphere than the outer planets. -Volatile materials turn into liquids and vapors at moderate to high temperatures.
Is a molecular cloud held together by gravity?
True. -Any cloud of gas will be bound by gravity
(T/F) A cloud of interstellar gas is held together by gravity
True. -Aside form chemical bonds that hold together rock or chunks of metal, almost everything in the universe that is held together is done so by gravity.
(T/F) Gravity and angular momentum are both important in the formation of the planetary system.
True. -Gravity is what causes the cloud to collapse and what allows larger planetariums to grow. Angular momentum spins up the protoplanetary disk as it contracts which increases the rate of collisions of small particles, allowing them to grow into planetesimals.
(T/F) Microlensing similar to the transit method in that both require the planet to pass in front of a bright object.
True. -The differnce between microlensing and transits is that in the latter the bright obejct is dimmed; while in the former the object becomes brighter
(T/F) Blue light has more energy than red light.
True. Blue light has a higher frequency, therefore has more energy.
The ozone layer protects life on Earth from:
Ultraviolet radiation (the Sun's rays)
Studying climate on other planets is important to understanding climate on Earth because:
Underlying physical processes are the same on every planet Other planets offer a range of extremes to which Earth can be compared Comparing climates on other planets helps scientist understand which factors are important Other planets can be used to test atmospheric models
Momentum is a product of:
mass & velocity
