Astronomy Quiz 4

Io is a moon of which planet? a) Mars. b) Jupiter. c) Saturn. d) Neptune. e) Pluto.

B: Jupiter

Which of the following planets has only been visited by one spacecraft? a) Mercury. b) Saturn. c) Uranus. d) Neptune. e) Answers c and d above.

E: answers C and D, so Uranus and Neptune

Four basic designs of telescopes

Newtonian, Cassegrain, Prime Focus, Coude

why the terrestrial planets have different densities than the Jovian planets

Terrestrial planets have higher density because they are made of heavier elements. Jovian are low density because they are gaseous

which planets and moons have unusual spins or orbits

Venus and Tritan

Which wavelengths of light get through the Earth's atmosphere?

Visible and radio

Reflection

The bouncing back of a wave when it hits a surface through which it cannot pass.

Oort Cloud

a spherical region that surrounds the solar system, that extends from the Kuiper Belt to almost halfway to the nearest star, and that contains billions of comets

Diffraction

a change in the direction of a wave when the wave finds an obstacle or an edge, such as an opening

diffraction grating

a device made of thousands of closely spaced slits through which light is passed in order to produce a spectrum

concave mirror

a mirror with a surface that curves inward

Ceres

largest object in the asteroid belt between Mars and Jupiter

Differentiation

the process by which gravity separates materials according to density in a planet (heavier metals go to core)

Chromatic abberation

the rainbow effect when light is dispersed through lens

brown dwarf

"Failed" star; Star not massive enough to sustain nuclear fusion.

planet

A large body in space that orbits a star and does not produce light of its own

convex mirror

A mirror with a surface that curves outward

Light Gathering Power (LGP)

A relative measure for comparing the ability of different telescopes to collect light.

What is the sidereal day of Venus? a) 243 days. b) 23 hours 56 minutes. c) 24 hours 37 minutes. d) 17 hours. e) 10 hours.

A: 243 days

The Messenger spacecraft targeted: a) Mercury. b) Venus. c) Mars. d) Jupiter. e) Pluto.

A: Mercury-Messenger

The ETSU radio telescope has a diameter of about 3 meters, similar in diameter to the Infrared Telescope Facility (IRTF) on Mauna Kea, in Hawaii, a telescope used for short-wavelength infrared observations, and the 3 meter optical telescope on the Canary Islands. The relative resolutions of these three telescopes are: a) best: Canary Islands; next: IRTF; worst: ETSU radio telescope. b) best: IRTF; next: Canary Islands: worst: ETSU radio telescope. c) best: ETSU radio telescope; next: IRTF; worst: Canary Islands. d) best: ETSU radio telescope; next: Canary Islands; worst: IRTF. e) best: Canary Islands; next: ETSU radio telescope; worst: IRTF.

A: best to worst: Canary, IRTF, ETSU

Eris is: a) A dwarf planet. b) A Galilean Moon. c) A moon of Mars. d) A planet orbiting alpha Centaurus. e) A small moon of Pluto.

A: dwarf planet

Comets: a) Mostly orbit the Sun out of the plane of the ecliptic. b) Are likely pieces of planets that broke apart during collision with other planets. c) Are rocky objects. d) Mostly orbit the Sun between the orbits of Earth and Mars. e) Are extremely young objects, compared to the age of the rocks on the surface of the Earth.

A: orbit sun outside of ecliptic plane

Which of the following best describes the rotation of Venus, compared to the rotation of Earth? a) Much slower, and in a backwards direction. b) Much faster, and in a backwards direction. c) Much slower, in the same direction as Earth's. d) Much faster, in the same direction as Earth's. e) Tidally locked to the Sun, so that it spins once on its axis for each orbit around the Sun.

A: slower and backwards direction

interferometer

An astronomical interferometer is an array of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, nebulas and galaxies by means of interferometry.

dwarf planet

An object that orbits the sun and is spherical, but has not cleared the area of its orbit. PLuto

Audible sound has wavelengths of approximately 1 meter, while visible light has wavelengths of about 5 X 10-7 meters. Therefore: a) Sound travels much faster than light. b) With a door about a meter in size, diffraction is much more significant for audible waves than visible waves. c) Light never bends around corners, but sound does. d) Light does not travel through a vacuum, but sound can. e) Light and sound are exactly the same thing, except they have different frequencies and wavelengths.

B: Diffraction is more significant for sound than visible

The Earth has an average density of 5.5 g/cm3, while the average density of rocks on its surface is about 3 g/cm3 and the density of water is 1 g/cm3. What conclusion can be reached about the Earth's interior based on these observations? a) the interior is composed of mainly hydrogen and helium, like the Universe as a whole. b) it contains a lot of material denser than rock, probably metals. c) it consists of lower density material than rocks. d) it is mainly water. e) it is mainly rocks, like those on the surface.

B: Lot of material denser than rock, probably metals.

Which of the following is least useful to astronomers? a) an ground-based optical telescope (i.e., one located on the surface of the Earth). b) a ground-based X-ray telescope. c) a ground-based radio telescope. d) an optical telescope in space. e) an X-ray telescope in space.

B: a ground-based X-ray telescope.

The diffraction of light is: a) the bending of light when it passes from one medium to another. b) the bending of light waves around corners. c) the reflection of light waves. d) the minimum separation between two stars in the sky where an observer can just distinguish two independent stars. e) thermal radiation.

B: bending of light waves around corners

The resolution of a 1 meter space telescope is: a) twice that of a 0.5 meter space telescope. b) half that of a 0.5 meter space telescope. c) four times that of a 0.5 meter space telescope. d) one quarter that of a 0.5 meter space telescope. e) 16 times that of a 0.5 meter space telescope.

B: half that of a 0.5 meter

Asteroids are probably: a) pieces of a planet that broke up. b) left-over planetesimals from the formation of the early solar system. c) pieces of Jupiter that broke off. d) the same composition as comets, but in the inner solar system rather than further out. e) alien spacecraft.

B: left over planetesimals

Which spacecraft orbited Mercury? a) Viking. b) Messenger. c) Cassini. d) New Horizon e) None.

B: messenger

How many spacecraft have visited Triton and its planet? a) none. b) one. c) two. d) four. e) five.

B: one

. The Very Large Array is a collection of 27 radio telescopes, each with a diameter of 25 meters, spread out in a Y-shaped array with a diameter of 22 miles in New Mexico. This telescope: a) Has a light gathering power equal to that of a single 22 mile diameter telescope. b) Has a resolution equal to that of a single 22 mile diameter telescope. c) Has both a resolution and a light gathering power equal to that of a single 22 mile diameter telescope. d) Has a resolution equal to that of a single 25 meter diameter telescope, but a light gathering power equal to that of a 22 mile diameter telescope. e) Has a light gather power and a resolution equal to that of a single 25 meter diameter telescope.

B: resolution equal to single 22 mile diameter telescope

The reason that you can hear but not see a person standing outside the classroom door is: a) Sound waves are much shorter than visible light waves, and so travel farther. b) Sound waves are longer than visible light waves, and so bend more when they go through a doorway. c) Light never bends around corners, but sound does. d) Sound travels faster than light. e) Light does not travel through a vacuum.

B: sound waves are longer than light, and bend through a doorway

The spacecraft that landed successfully on Venus: a) were all NASA spacecraft. b) survived for only short amounts of time before failing, but sent back pictures. c) unfortunately were not able to send back any pictures, so we have never seen the surface of Venus close-up. d) spacecraft have orbited Venus, but none has landed successfully. e) no spacecraft has visited Venus.

B: survived only a short time, but sent back pictures

The main reason for combining many widely-separated telescopes together into an interferometer is: a) To collect more radiation from very faint sources. b) To obtain much sharper images of sources. c) To ensure that observations are uninterrupted by the failure of one telescope. d) To avoid light pollution. e) To track objects as they move across the sky.

B: to obtain sharper images of sources.

Refraction

Bending of light

Relationship between resolution, wavelength, and telescope size

Bigger telescope, higher resolution. Shorter wavelengths, higher resolution.

How many moons are larger than Mercury? a) 0. b) 1. c) 2. d) 7. e) 22.

C: 2

How many moons does Mars have? a) none. b) 1. c) 2. d) 29. e) 39.

C: 2

How many moons in the solar system are larger than Mercury? a) none. b) 1. c) 2. d) 7. e) 16.

C: 2

. Which of the following spacecraft orbited Saturn? a) Messenger. b) Global Surveyor. c) Cassini. d) The Europa Orbiter. e) Pathfinder.

C: Cassini- SSaturn

Which moon in our solar system is closest in diameter to its planet? a) Phobos. b) Titan. c) Charon. d) The Moon. e) Ganymede.

C: Charon

What is the name of the rover operating on the surface of Mars right now? a) Magellan. b) Cassini. c) Curiosity. d) Viking. e) Messenger.

C: Curiosity

The sixth largest object in our solar system is (in terms of diameter) (counting the Sun as number 1): a) Ganymede b) Titan c) The Earth d) Uranus e) Neptune

C: The Earth

Which of the following types of radiation are blocked by the Earth's atmosphere? a) Optical, parts of the infrared. b) Ultraviolet, Radio, parts of the infrared. c) Ultraviolet, X-ray, Gamma-ray, parts of the infrared. d) Radio, Optical. e) X-ray, Radio, parts of the infrared.

C: Ultra, x-ray, gamma, parts of infrared

Our best images of Neptune and its moons came from: a) Pioneer 10. b) Mariner 10. c) Voyager 2. d) Viking 2. e) the Messenger spacecraft.

C: Voyager 2

Which of the following spacecraft visited all four Jovian planets? a) Messenger. b) Viking 2. c) Voyager 2. d) Galileo. e) Cassini.

C: Voyager 2

Which of the following objects often do NOT orbit the Sun in or near the ecliptic? a) The asteroids. b) Uranus and Venus. c) The comets. d) Mars. e) Neptune.

C: comets

Asteroids: a) Mostly orbit the Sun out of the plane of the ecliptic. b) Are likely pieces of a planet that broke apart during a collision with another planet. c) Are likely left-over planetesimals. d) Mostly orbit the Sun between the orbits of Earth and Mars. e) Are extremely young objects, compared to the age of the rocks on the surface of the Earth.

C: left over planetesimals

Which of the following is true about asteroids? a) they are not usually found in the ecliptic. b) they are chunks of about half ice and half rock. c) they are probably left-over planetesimals from the formation of the solar system. d) they are the same thing as comets, but are found in the inner part of the solar system while comets are found in the outer part. e) they are pieces of a planet that broke apart during a collision with another planet.

C: left over planetesimals

Which of the following does NOT happen when an interstellar cloud becomes a solar system? a) the young star has a very strong stellar wind, which blows out left-over gas and dust. b) the cloud flattens to a disk. c) the spin rate of the cloud slows down as the cloud contracts. d) the planets are semi-molten when they are first formed. e) planetesimals collide to produce bigger objects

C: spin rate slows down as cloud contracts

Which of the following is the correct order of the densities of the different types of planets? a) densest: terrestrial; next dense: Jovian; lowest density: Pluto. b) densest: Jovian; next dense: Pluto; lowest density: terrestrial. c) densest: terrestrial; next dense: Pluto; lowest density: Jovian. d) densest: Jovian; next dense: Pluto; lowest density: terrestrial. e) densest: Jovian; next dense: terrestrial; lowest density: Pluto

C: terrestrial, Pluto, Jovian

Which of the following planets has the slowest spin rate? a) The Earth. b) Mars. c) Venus. d) Jupiter. e) Saturn.

C: venus

What type of light travels easily through our atmosphere, so ground-based astronomy is possible at these wavelengths? a) Only visible. b) Visible, UV, and X-rays. c) Visible and radio. d) Gamma rays, X-rays, and visible. e) All types.

C: visible and radio

Which of the following moons is orbiting around its planet in the reverse direction from most of the motions the solar system? a) The Moon. b) Callisto. c) Ganymede. d) Titan. e) Triton.

E: Triton

Ranking the known planets, dwarf planets, and moons in our solar system in order by size, from largest to smallest, Pluto is ranked: a) Ninth. b) Tenth. c) Sixteenth. d) Seventeenth. e) Thirty-first.

D: 17th

How long is a sidereal day on Mercury? a) 23 hours 56 minutes. b) 24 hours. c) 24 hours 37 minutes. d) 58.7 days. e) 249 years.

D: 58.7 days

How many moons in the solar system are bigger than Pluto? a) none. b) one. c) two. d) seven. e) thirty-nine.

D: 7

According to the recent IAU definition, which of the following is a dwarf planet? a) Titan. b) Mercury. c) the asteroids. d) Eris. e) Europa.

D: Eris

Which of the following moons are bigger than Mercury? a) The Moon, Io. b) The Moon, Ganymede. c) Titan, Triton. d) Ganymede, Titan. e) Europa, Io

D: Ganymede, Titan

Which of the following objects has the smallest diameter? a) Ganymede b) The Moon c) Europa d) Pluto e) Triton

D: Pluto

The SECOND largest moon in our solar system (in terms of diameter) is: a) The Moon. b) Callisto. c) Ganymede. d) Titan. e) Triton.

D: Titan

Which spacecraft has visited Neptune? a) Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2. b) 23 spacecraft, about half from the U.S., half from the Soviet Union, and one from the European space agency. c) Just Mariner 10. d) Just Voyager 2. e) None.

D: just voyager 2

As an interstellar gas cloud gravitationally contracts in the process of forming into a star and planets: a) its spin rate stays the same, as does its shape. b) its spin rate stays the same, and it flattens to a disk. c) its spin rate decreases, and it flattens to a disk. d) its spin rate increases, and it flattens to a disk. e) its spin rate increases, and it expands from a disk into a spherical shape.

D: spin rate increases and flattens to a disk

Which type of light can travel through the Earth's atmosphere without being absorbed very much? a) X-rays and ultraviolet. b) ultraviolet and X-rays. c) visible, ultraviolet, and X-rays. d) visible and radio. e) visible, radio, and ultraviolet.

D: visible and radio

Which of the following moons orbits its planet in a backwards direction, compared to most of the motions in the solar system? a) The Moon. b) Io. c) Europa. d) Ganymede. e) Triton.

E: Triton

Which of the following objects is larger than Pluto? a) The Earth's Moon. b) Ganymede. c) Europa. d) Triton. e) All of the above.

E: all

The density of water is 1 g/cm3, while the density of rock is 2-3 g/cm3. What is the average density of the Earth? a) 0.1 g/cm3. b) 0.7 g/cm3. c) 1 g/cm3. d) 2 g/cm3. e) 5.5 g/cm3.

E: 5.5 g/cm3

What is the name of Jupiter's largest moon? a) Callisto. b) Io. c) Titan. d) Europa. e) Ganymede.

E: Ganymede

The angular momentum of a spinning object with mass M, spin velocity V, and radius R is proportional to: a) MV/R. b) MV2/R. c) M/(VR). d) M2V3R4. e) MVR.

E: MVR

The largest moon of Neptune is: a) Io. b) Europa. c) Callisto. d) Titan. e) Triton.

E: Triton

The resolution of a telescope: a) increases (gets worse) with increasing wavelength of light. b) increases with increasing diameter of primary mirror or lens. c) increases with decreasing wavelength of light. d) increases with decreasing diameter of primary mirror or lens. e) both a) and d) above.

E: both A and D, so increases (gets worse) with increasing wavelength of light AND increases with decreasing diameter or mirror or lens

When a planet or moon is completely enshrouded by clouds which visible light cannot penetrate, which of the following method or methods can be used to study the surface? a) use X-rays. b) use radar. c) use gamma-rays. d) send a spacecraft to land on its surface. e) both b) and d) above.

E: both B and D, so radar and spacecraft

An interferometer telescope is: a) a telescope in space. b) a telescope that uses a primary lens instead of a mirror. c) a telescope that observes X-ray light. d) a telescope that has both a secondary mirror and a tertiary mirror. e) a collection of several telescopes working together

E: collection of several telescopes working together

Which of the following is a characteristic of terrestrial planets? a) Densities of approximately 1 g/cm3. b) Located in the outer solar system. c) Diameter of 4 or more earth diameters. d) Likely similar to Kuiper Belt Objects. e) Mainly made of materials with high evaporation temperatures.

E: made of materials with high evaporation temps

Which of the following planets has never been visited by a spacecraft? a) Mercury. b) Mercury, Uranus, Neptune, and Pluto. c) Uranus, Neptune, and Pluto. d) Pluto. e) None of the above.

E: none

Which planet orbits the Sun in a direction opposite that of the rest of the planets? a) Mercury. b) Venus. c) Saturn. d) Neptune. e) None.

E: none

Jovian Planets

Jupiter, Saturn, Uranus, and Neptune because they are gaseous

; the primary target(s) of the Messenger, Magellan, Viking, Voyager 1, Voyager 2, Galileo, Cassini, and New Horizons spacecraft

Messenger: Mercury Magellan: Venus Viking: Mars Voyager 1: Jupiter & Saturn Voyager 2: all 4 Jovian planets Galileo: Jupiter Cassini: Saturn New Horizons: Pluto

Planetesimals are

Small bodies from which the planets started from.

terrestrial planets

The name given to the four inner planets: Mercury, Venus, Earth, and Mars

Heliopause

The outer boundary of the heliosphere. Heliosphere, the region surrounding the Sun and the solar system that is filled with the solar magnetic field and the protons and electrons of the solar wind.

how a planet and a dwarf planet differ according to the IAU definitions

They both orbit the Sun, are spherical, but a planet dominates its part of the solar system. A dwarf planet does not.

conservation of angular momentum

as long as there is no external torque, the total angular momentum of a set of interacting objects cannot change

Kuiper Belt Object

one of the hundreds or thousands of small bodies that orbit the sun in a flat belt beyond Neptune's orbit; also includes dwarf planets located in the Kuiper Belt

focal length

the distance from the center of a lens to the focal point

angular momentum

rotational momentum of a spinning or orbiting object

law of reflection

the angle of incidence is equal to the angle of reflection