Astronomy Cosmos Practice Exam

Question 1 Astronomy Cosmos

What is the North Star?

When the Moon is too far to fully cover the Sun, leaving a bright ring. Combining observations of light, gravitational waves, neutrinos, and cosmic rays. Polaris, near the north celestial pole. Mercury, Venus, Earth, Mars.

Question 2 Astronomy Cosmos

What is the brightest planet in the sky?

A similar deep image by JWST, capturing the early universe. The process by which stars create heavier elements through fusion. Venus. Defunct human-made objects orbiting Earth.

Question 3 Astronomy Cosmos

What is a supercluster?

A vast structure of galaxy clusters; e.g., the Laniakea Supercluster. The Red Planet, due to iron oxide on its surface. NASA spacecraft (Voyager 1 and 2, 1977) studying the outer planets and now in interstellar space. Observatories detecting gravitational waves.

Question 4 Astronomy Cosmos

When did Apollo 11 land on the Moon?

July 20, 1969. A nearly massless, weakly interacting subatomic particle. A space telescope launched in 1990, orbiting Earth. A succession of methods used to measure distances on different scales.

Question 5 Astronomy Cosmos

What is space weather?

Conditions in space affecting Earth, e.g., from solar wind. Zones of energetic charged particles trapped by Earth's magnetic field. The rate of expansion of the universe (~70 km/s/Mpc). The total energy emitted by a star per unit time.

Question 6 Astronomy Cosmos

What is microlensing again (cosmology)?

NASA spacecraft that flew by Pluto in 2015. Regular pulses from rotation, useful for timing experiments. ~1.44 solar masses; the maximum mass of a stable white dwarf. Brief brightening of a star as a compact object passes in front.

Question 7 Astronomy Cosmos

What is the International Space Station (ISS)?

A small rocky body orbiting the Sun, mostly in the asteroid belt. How bright a star appears from Earth. A constant in Einstein's equations representing energy density of empty space. A modular space station in low Earth orbit, occupied since 2000.

Question 8 Astronomy Cosmos

What is an eclipsing binary?

A pulsating star whose period correlates with luminosity, useful as distance indicator. A binary star where one passes in front of the other from our view. A small rocky body orbiting the Sun, mostly in the asteroid belt. A circle of 12 constellations along the ecliptic.

Question 9 Astronomy Cosmos

Where is JWST located?

Polaris, near the north celestial pole. Weakly interacting massive particles (WIMPs), axions, etc. Defunct human-made objects orbiting Earth. At Earth-Sun Lagrange point L2, about 1.5 million km from Earth.

Question 10 Astronomy Cosmos

What is Mars sometimes called?

Sagittarius A* (Sgr A*). The Sun's outermost atmosphere, far hotter than the surface. The Red Planet, due to iron oxide on its surface. Olympus Mons on Mars.

Question 11 Astronomy Cosmos

What is redshift?

The CMB discovery, fitting the Big Bang model. A stable position in a two-body gravity system where small objects can remain stationary relative to the bodies. About 13.8 billion years. The lengthening of light wavelengths from receding objects.

Question 12 Astronomy Cosmos

How old is the Sun?

About 4.6 billion years. A planet orbiting a star other than the Sun. The shortening of light wavelengths from approaching objects. In the Orion Arm, about 26,000 light-years from the galactic center.

Question 13 Astronomy Cosmos

How old is the universe?

Cooler, darker regions on the Sun's surface caused by magnetic activity. About 5,500 °C (5,778 K). A nearly massless, weakly interacting subatomic particle. About 13.8 billion years.

Question 14 Astronomy Cosmos

What is a galaxy cluster?

The bubble of space dominated by the Sun's plasma and magnetic field. Using a planet's gravity to alter a spacecraft's trajectory and speed. Galaxy chains connecting clusters in the cosmic web. A bound group of hundreds to thousands of galaxies.

Question 15 Astronomy Cosmos

What is a neutrino?

The group of about 80 galaxies including the Milky Way and Andromeda. The idea that our universe is one of many. A region between Mars and Jupiter populated by small rocky bodies. A nearly massless, weakly interacting subatomic particle.

Question 16 Astronomy Cosmos

What is space debris?

A bound group of hundreds to thousands of galaxies. Defunct human-made objects orbiting Earth. The Sun's apparent path across the sky. A succession of methods used to measure distances on different scales.

Question 17 Astronomy Cosmos

What are the inner rocky planets?

How bright a star would appear at 10 parsecs. A sudden, intense burst of radiation from the Sun. Mercury, Venus, Earth, Mars. About 13.8 billion years.

Question 18 Astronomy Cosmos

What is the Drake equation's main factors?

Measuring distances to nearby stars. Star formation rate, fraction with planets, fraction habitable, fraction with life, fraction intelligent, fraction communicating, lifetime. A plot of stars' luminosity vs. temperature, organizing them by evolution. Observatories detecting gravitational waves.

Question 19 Astronomy Cosmos

What are spectral classes of stars?

Mercury, Venus, Earth, Mars. O, B, A, F, G, K, M (from hottest to coolest). The era ~380,000 years after the Big Bang when electrons combined with nuclei and the universe became transparent. A massive, luminous sphere of plasma generating energy by fusion.

Question 20 Astronomy Cosmos

Who first detected gravitational waves?

LIGO in 2015, from a binary black hole merger. A NASA mission flying closer to the Sun than any prior spacecraft. Gravitational and inertial mass are equivalent (gravitational and accelerating frames look the same). A 35,786 km circular orbit where satellites match Earth's rotation.

Question 21 Astronomy Cosmos

Which planet has the most prominent rings?

Over 5,000 confirmed as of 2024. Saturn. Galactic rotation curves, gravitational lensing, CMB anisotropies, structure formation. The Sun's outermost atmosphere, far hotter than the surface.

Question 22 Astronomy Cosmos

What is a white dwarf?

NASA's Mars Science Laboratory rover, landed 2012. A millisecond-duration radio pulse from extragalactic sources. A NASA mission flying closer to the Sun than any prior spacecraft. The compact remnant of a low- to medium-mass star after shedding outer layers.

Question 23 Astronomy Cosmos

Why is Venus called Earth's twin?

The Tsiolkovsky equation relating velocity to mass and exhaust velocity. Similar size and mass, though with a hostile atmosphere. A G-type main-sequence yellow dwarf star at the center of our Solar System. Defunct human-made objects orbiting Earth.

Question 24 Astronomy Cosmos

What is parallax?

Any object orbiting another; in everyday use, human-made spacecraft. The apparent shift in an object's position due to observer movement; used to measure stellar distances. Yuri Gagarin, in 1961. A celestial body orbiting the Sun, large enough to be round but not having cleared its orbit.

Question 25 Astronomy Cosmos

What is a constellation?

A bound group of hundreds to thousands of galaxies. A weaker tide when Sun and Moon are at right angles relative to Earth. A pattern of stars in the sky, often named after mythological figures. The large-scale structure of the universe — filaments, walls, voids of galaxies.

Question 26 Astronomy Cosmos

What is a star?

A disk-shaped region beyond Neptune containing icy bodies, including Pluto. A vast cloud of gas and dust in space, often a stellar nursery. A massive, luminous sphere of plasma generating energy by fusion. Charged particles from the Sun interacting with Earth's magnetic field and atmosphere.

Question 27 Astronomy Cosmos

What is an active galactic nucleus (AGN)?

A galactic core emitting unusually high amounts of energy from a central black hole. The process by which gravity built galaxies and clusters from primordial fluctuations. A small rocky body orbiting the Sun, mostly in the asteroid belt. Galactic rotation curves, gravitational lensing, CMB anisotropies, structure formation.

Question 28 Astronomy Cosmos

What is radial velocity method?

Detecting exoplanets by measuring stellar wobble caused by orbital pull. A star that has exhausted hydrogen in its core and expanded. Sunlight and solar wind pushing gas and dust away from the comet. Saturn.

Question 29 Astronomy Cosmos

What is a geomagnetic storm?

Arno Penzias and Robert Wilson, 1964. A plot of stars' luminosity vs. temperature, organizing them by evolution. A disturbance of Earth's magnetosphere from solar activity. Total eclipses fully cover the Sun; partial only some of it.

Question 30 Astronomy Cosmos

What is parallax used for?

The leading theory that the universe began ~13.8 billion years ago from a hot, dense state and expanded. Earth's axial tilt of about 23.5°. A constant in Einstein's equations representing energy density of empty space. Measuring distances to nearby stars.

Question 31 Astronomy Cosmos

What is a transit method?

Detecting exoplanets by observing dips in stellar brightness as they pass in front. A small rocky body orbiting the Sun, mostly in the asteroid belt. The radius of the event horizon of a non-rotating black hole. Uranus and Neptune.

Question 32 Astronomy Cosmos

What is the Hubble constant?

Measuring distances to nearby stars. A pattern of stars in the sky, often named after mythological figures. The apparent shift in an object's position due to observer movement; used to measure stellar distances. The rate of expansion of the universe (~70 km/s/Mpc).

Question 33 Astronomy Cosmos

What is luminosity?

Yuri Gagarin, in 1961. A vast structure of galaxy clusters; e.g., the Laniakea Supercluster. A stream of charged particles flowing from the Sun. The total energy emitted by a star per unit time.

Question 34 Astronomy Cosmos

What is MOND?

Detecting exoplanets by measuring stellar wobble caused by orbital pull. Modified Newtonian Dynamics — an alternative to dark matter modifying gravity. A plot of stars' luminosity vs. temperature, organizing them by evolution. The Sun's apparent path across the sky.

Question 35 Astronomy Cosmos

What is cosmology?

The study of the universe's origin, evolution, and large-scale structure. The idea that our universe is one of many. A standardizable supernova used as a "standard candle" for cosmic distances. A measure of the change in velocity needed for a spaceflight maneuver.

Question 36 Astronomy Cosmos

What is a Cepheid variable?

A day when day and night are nearly equal in length. A pulsating star whose period correlates with luminosity, useful as distance indicator. GW170817, a neutron star merger in 2017. A millisecond-duration radio pulse from extragalactic sources.

Question 37 Astronomy Cosmos

What is a nebula?

On large scales, the universe is homogeneous and isotropic. A vast structure of galaxy clusters; e.g., the Laniakea Supercluster. A vast cloud of gas and dust in space, often a stellar nursery. Enceladus or Titan, both intriguing for astrobiology.

Question 38 Astronomy Cosmos

What is the Local Group?

The radius of the event horizon of a non-rotating black hole. The group of about 80 galaxies including the Milky Way and Andromeda. A millisecond-duration radio pulse from extragalactic sources. Defunct human-made objects orbiting Earth.

Question 39 Astronomy Cosmos

What is an equinox?

Total eclipses fully cover the Sun; partial only some of it. A measure of the change in velocity needed for a spaceflight maneuver. A day when day and night are nearly equal in length. The shortening of light wavelengths from approaching objects.

Question 40 Astronomy Cosmos

What is a light-year?

The analysis of light by wavelength to determine composition, motion, and conditions. The distance light travels in one year, about 9.46 trillion km. A plot of stars' luminosity vs. temperature, organizing them by evolution. The scientific study of celestial objects, space, and the physical universe.

Question 41 Astronomy Cosmos

How many stars are in the Milky Way?

LEO is faster, lower; GEO is fixed over a point on Earth. An estimated 100–400 billion. Triton. A higher-than-usual tide when Sun, Earth, Moon align.

Question 42 Astronomy Cosmos

How many planets are in our Solar System?

Olympus Mons on Mars. A region between Mars and Jupiter populated by small rocky bodies. Einstein, originally to allow a static universe; later called his "greatest blunder." Eight (since Pluto's reclassification in 2006).

Question 43 Astronomy Cosmos

What is a red giant?

Voyager 1. The bubble of space dominated by the Sun's plasma and magnetic field. The contradiction between high probability of alien life and lack of evidence. A star that has exhausted hydrogen in its core and expanded.

Question 44 Astronomy Cosmos

Name some dwarf planets.

Alan Shepard, in 1961. On large scales, the universe is homogeneous and isotropic. Pluto, Eris, Haumea, Makemake, Ceres. Mercury, Venus, Earth, Mars.

Question 45 Astronomy Cosmos

What is the Drake equation's "L"?

The region around a star where liquid water could exist on a planet's surface. The compact remnant of a low- to medium-mass star after shedding outer layers. The boundary of a black hole beyond which escape is impossible. The expected lifetime of a communicating civilization.

Question 46 Astronomy Cosmos

What is stellar nucleosynthesis?

The process by which stars create heavier elements through fusion. A supermassive black hole. Alan Shepard, in 1961. An estimated 100–400 billion.

Question 47 Astronomy Cosmos

How long does sunlight take to reach Earth?

Hypothesized matter that doesn't emit light but exerts gravity, making up ~27% of the universe. About 8 minutes 20 seconds. NASA spacecraft (Voyager 1 and 2, 1977) studying the outer planets and now in interstellar space. The shortening of light wavelengths from approaching objects.

Question 48 Astronomy Cosmos

What is the Hubble Space Telescope?

Conditions in space affecting Earth, e.g., from solar wind. Voyager 1. Einstein's theory of physics at high velocities, with constant light speed. A space telescope launched in 1990, orbiting Earth.

Question 49 Astronomy Cosmos

What is the Solar System?

The Search for Extraterrestrial Intelligence; observing for signals. Mostly ice particles with rocky and dust components. Sagittarius A* (Sgr A*). The Sun and the gravitationally bound system of planets, moons, and other bodies.

Question 50 Astronomy Cosmos

What is the Tolman-Oppenheimer-Volkoff limit?

The maximum mass of a neutron star, ~2–3 solar masses. A small rocky body orbiting the Sun, mostly in the asteroid belt. Saturn. A pulsating star whose period correlates with luminosity, useful as distance indicator.