Astronomy Terms

40 questions · Answers revealed below each question · Print this set

1.Which astronomy term is the average Earth-Sun distance?
- A. the penumbra
- B. apparent magnitude
- C. the astronomical unit
- D. the Oort Cloud
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the astronomical unit
Did you know? One astronomical unit is about 150 million kilometers.
2.Which cosmology term is the unseen pressure driving cosmic acceleration?
- A. dark energy
- B. the observable universe
- C. Hubble's law
- D. the age of the universe
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dark energy
Did you know? Dark energy makes up most of the universe's content.
3.Which observation term reads starlight's dark lines to reveal chemistry?
- A. a circumpolar star
- B. spectroscopy
- C. right ascension
- D. SETI
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spectroscopy
Did you know? Spectroscopy tells us what stars and planets are made of.
4.Which spaceflight term is the weightless state of free-falling orbit?
- A. the Kessler syndrome
- B. apogee
- C. microgravity
- D. the Hohmann transfer
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microgravity
Did you know? Orbiting crews are not beyond gravity — they are falling around Earth.
5.Which astronomy term is the darkest central part of a shadow?
- A. the saros
- B. the astronomical unit
- C. the umbra
- D. stellar parallax
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the umbra
Did you know? Total solar eclipses happen when the umbra sweeps across Earth.
6.Which cosmology term is the cooled afterglow of the early universe?
- A. dark matter
- B. the Big Crunch
- C. the Hubble constant
- D. the cosmic microwave background
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the cosmic microwave background
Did you know? The CMB fills the sky in every direction.
7.Which observation term is the 29.5-day cycle of the Moon's phases?
- A. SETI
- B. spectroscopy
- C. the synodic month
- D. the Messier catalog
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the synodic month
Did you know? The synodic month runs one full set of moon phases.
8.Which spaceflight term keeps an astronaut breathing outside a craft?
- A. cosmic rays
- B. a spacesuit
- C. a spacewalk
- D. apogee
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a spacesuit
Did you know? A spacesuit is a personal spacecraft in miniature.
9.Which astronomy term powers stars by joining light nuclei together?
- A. the Roche limit
- B. nuclear fusion
- C. the giant-impact hypothesis
- D. orbital resonance
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nuclear fusion
Did you know? Stars fuse hydrogen into helium in their cores.
10.Which cosmology term are the two elements the early universe first forged?
- A. redshift
- B. a fast radio burst
- C. hydrogen and helium
- D. the Fermi paradox
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hydrogen and helium
Did you know? Stars later cooked up every heavier element.
11.Which observation term is the sky point that Earth's spin axis points toward?
- A. right ascension
- B. SETI
- C. the celestial pole
- D. light pollution
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the celestial pole
Did you know? The north celestial pole sits close to Polaris.
12.Which spaceflight term is the conventional edge of space at 100 kilometers?
- A. the Hohmann transfer
- B. the Kármán line
- C. perigee
- D. a launch window
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the Kármán line
Did you know? The Kármán line sits at 100 kilometers above sea level.
13.Which astronomy term is the icy ring of bodies beyond Neptune?
- A. the Kuiper Belt
- B. orbital resonance
- C. a molecular cloud
- D. the solar nebula
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the Kuiper Belt
Did you know? Pluto, Haumea, Makemake and Arrokoth all belong to the Kuiper Belt.
14.Which cosmology term ties a galaxy's distance to its recession speed?
- A. Hubble's law
- B. the accelerating expansion
- C. cosmic inflation
- D. the Hubble constant
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Hubble's law
Did you know? Hubble's law showed the universe is expanding.
15.Which observation term is a sky map for finding constellations?
- A. a star chart
- B. light pollution
- C. zodiacal light
- D. spectroscopy
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a star chart
Did you know? Star charts are drawn for specific dates and latitudes.
16.Which spaceflight term is the ocean landing of a returning capsule?
- A. microgravity
- B. a spacesuit
- C. the Kessler syndrome
- D. splashdown
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splashdown
Did you know? Apollo capsules ended their flights with a splashdown.
17.Which astronomy term is the short span when an eclipse is fully total?
- A. a Cepheid variable
- B. the astronomical unit
- C. a Lagrange point
- D. totality
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totality
Did you know? Totality at a solar eclipse rarely lasts beyond a few minutes.
18.Which cosmology term asks why no aliens have shown up if the galaxy is old?
- A. the Fermi paradox
- B. the Drake equation
- C. the cosmic microwave background
- D. Laniakea
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the Fermi paradox
Did you know? The Fermi paradox contrasts big numbers with empty skies.
19.Which observation term is a domed theater projecting the night sky?
- A. the synodic month
- B. a planetarium
- C. the meridian
- D. light pollution
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a planetarium
Did you know? Planetariums replay the sky for any date or place.
20.Which spaceflight term is an astronaut working outside a spacecraft?
- A. splashdown
- B. perigee
- C. a spacewalk
- D. a launch window
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a spacewalk
Did you know? Spacewalks are also called extravehicular activity.
21.Which astronomy term is the thin gas and dust between the stars?
- A. the interstellar medium
- B. a molecular cloud
- C. a protostar
- D. totality
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the interstellar medium
Did you know? The interstellar medium is the raw stock of new stars.
22.Which cosmology term mirrors matter with opposite electric charge?
- A. antimatter
- B. Laniakea
- C. the age of the universe
- D. hydrogen and helium
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antimatter
Did you know? When matter meets antimatter, both turn into energy.
23.Which observation term describes how much the atmosphere blurs star images?
- A. the Arecibo message
- B. seeing
- C. the CCD
- D. precession
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seeing
Did you know? Twinkling stars are a sign of poor seeing.
24.Which spaceflight term are high-energy particles streaming from space?
- A. the Kessler syndrome
- B. a spacewalk
- C. the Kármán line
- D. cosmic rays
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cosmic rays
Did you know? Cosmic rays from deep space strike the atmosphere constantly.
25.Which astronomy term is the lighter outer fringe of a shadow?
- A. the astronomical unit
- B. the Kuiper Belt
- C. the parsec
- D. the penumbra
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the penumbra
Did you know? Observers in the penumbra see only a partial eclipse.
26.Which cosmology term is the brightest kind of explosion known?
- A. a gamma-ray burst
- B. the Hubble constant
- C. the Fermi paradox
- D. a fast radio burst
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a gamma-ray burst
Did you know? Gamma-ray bursts flash from distant dying stars.
27.Which observation term is the point straight overhead?
- A. the zenith
- B. the Wow! signal
- C. a planetarium
- D. the CCD
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the zenith
Did you know? Stars cross the zenith at their highest.
28.Which astronomy term is the Sun's apparent yearly path across the sky?
- A. the penumbra
- B. the ecliptic
- C. totality
- D. the Hertzsprung-Russell diagram
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the ecliptic
Did you know? The planets track close to the ecliptic plane.
29.Which cosmology term stretches light from galaxies speeding away?
- A. antimatter
- B. redshift
- C. the age of the universe
- D. a gamma-ray burst
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redshift
Did you know? Greater redshift means a more distant, earlier universe.
30.Which observation term is the band of constellations along the Sun's yearly path?
- A. the zodiac
- B. the celestial pole
- C. the CCD
- D. declination
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the zodiac
Did you know? The Sun spends a month in each zodiac constellation.
31.Which astronomy term keeps one face of a moon turned toward its planet?
- A. the Roche limit
- B. the astronomical unit
- C. tidal locking
- D. the interstellar medium
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tidal locking
Did you know? Tidal locking is why we mostly see one side of the Moon.
32.Which cosmology term measures about 13.8 billion years?
- A. the age of the universe
- B. about 1 billion years
- C. about 4.6 billion years
- D. about 100 billion years
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the age of the universe
Did you know? The universe's age comes from mapping the cosmic microwave background.
33.Which observation term is the ancient brass instrument for measuring star heights?
- A. zodiacal light
- B. SETI
- C. interferometry
- D. the astrolabe
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the astrolabe
Did you know? Astrolabes let navigators and astronomers read the sky for centuries.
34.Which astronomy term is the cold dense gas cloud where new stars are born?
- A. the saros
- B. the ecliptic
- C. the Roche limit
- D. a molecular cloud
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a molecular cloud
Did you know? Molecular clouds are often called stellar nurseries.
35.Which cosmology term is the 1998 finding that the universe speeds up?
- A. the accelerating expansion
- B. a gamma-ray burst
- C. redshift
- D. a fast radio burst
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the accelerating expansion
Did you know? The accelerating expansion earned a Nobel Prize in 2011.
36.Which observation term washes out the stars above bright cities?
- A. spectroscopy
- B. the Dunhuang Star Chart
- C. a star chart
- D. light pollution
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light pollution
Did you know? Dark-sky parks protect views of the Milky Way.
37.Which cosmology term are ripples in spacetime from colliding massive bodies?
- A. redshift
- B. antimatter
- C. gravitational waves
- D. the accelerating expansion
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gravitational waves
Did you know? LIGO first detected gravitational waves in 2015.
38.Which observation term is the search for signals from other civilizations?
- A. declination
- B. the Arecibo message
- C. SETI
- D. the zenith
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SETI
Did you know? SETI projects scan radio bands for artificial patterns.
39.Which astronomy term is how bright a star looks from Earth?
- A. apparent magnitude
- B. the parsec
- C. the solar nebula
- D. the Oort Cloud
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apparent magnitude
Did you know? Lower magnitude numbers mean brighter stars.
40.Which cosmology term is the number measuring the universe's expansion rate?
- A. dark energy
- B. the accelerating expansion
- C. the Hubble constant
- D. the cosmic web
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the Hubble constant
Did you know? Teams still debate the Hubble constant's exact value.

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