Astro Geol Flashcards
A type of halo that forms when light passing through an ice crystal bends 22 degrees.
22-degree Halo
A type of halo that forms when light passing through an ice crystal bends 46 degrees.
46-degree Halo
A rotating disk of gas orbiting a star, formed by materials falling toward the star.
Accretion disk
Thermal energy resulting from bolide impacts upon the surface of an object.
Accretionary heating
A rare, stony meteorite that lacks chondrules and resembles terrestrial rocks.
Achondrites
Refers to the brightness of an object in space, measured on a scale from 0 to 1, where 0 is completely dark.
Albedo
The angle an object makes with the horizon, also known as elevation.
Altitude
A type of Solar Eclipse where the New Moon covers the Sun’s center, leaving the outer edges visible as a “ring of fire.”
Annular Solar Eclipse
The latitude 64°34′ S, with all of the area below being part of the Antarctic Circle.
Antarctic Circle
The opposite of the Prime Meridian, located at 180° longitude.
Antimeridian
Two points on the surface of a celestial body that are diametrically opposed to each other.
Antipodes
The lighter part of a shadow that forms when the umbra tapers to a point, involved in annular solar eclipses and planet transits.
Antumbra
The point on Earth’s elliptical orbit farthest away from the Sun.
Aphelion
A landform on Venus that straddles its equator for over 10,000 km, made up of four smaller highlands.
Aphrodite Terra
A spring tide that occurs during a Micromoon, with smaller variation between high and low tides.
Apogean spring tide
Asteroids that cross the Earth’s orbit.
Apollo asteroids
The latitude 64°34′ N, with all of the area above being part of the Arctic Circle.
Arctic Circle
A pattern of stars recognizable from Earth, such as The Big Dipper, which is part of Ursa Major.
Asterism
A rocky object orbiting the Sun, with sizes ranging from a few meters to hundreds of kilometers.
Asteroid
The orbital zone between Mars and Jupiter where most of the Solar System’s asteroids are located.
Asteroid belt
A method to measure the four seasons of a year using the dates of equinoxes and solstices.
Astronomical Season
The darkest of the three twilight phases, occurring during the earliest dawn and latest dusk.
Astronomical Twilight
The time it takes Earth to complete a full orbit around the Sun, also known as Tropical or Solar Year.
Astronomical Year
The layer of gases that surrounds a planet, retained by its gravity.
Atmosphere
A natural electric phenomenon creating bright and colorful light due to charged particles interacting with Earth’s magnetosphere.
Aurora
Also known as Southern Lights, auroras that occur in the Antarctic Circle.
Aurora Australis
Also known as Northern Lights, auroras that occur in the Arctic Circle.
Aurora Borealis
An equinox that occurs during September in the Northern Hemisphere, marking the start of Autumn.
Autumnal Equinox
The angle of tilt of an object from its orbital plane, also known as Obliquity.
Axial Tilt
The imaginary line that an object, usually a planet, rotates around.
Axis
An object’s cardinal direction, specified as the horizontal angle it makes with a reference direction, such as true north.
Azimuth
An upland dome on Venus.
Beta Regio
The areas of a planet that encompass all of its living things.
Biosphere
A celestial object with a gravitational pull so strong that not even light can escape it, formed when a star with more than 20 solar masses collapses.
Black Hole
A Seasonal or Monthly event that occurs as a Full Moon.
Blue Moon
The largest known structure on Mercury, formed from an asteroid impact.
Caloris Basin
Long, sinuous forms on Venus and Mars, preserved in regions of subdued relief.
Canali
Chondrites made up of undifferentiated silicates with compounds of carbon and water, representing primordial Solar System material.
Carbonaceous chondrites
A gap or space observed between the A and B segments of Saturn’s rings.
Cassini Division
The projection of a reference object’s equator onto the celestial sphere.
Celestial Equator
The imaginary horizontal line separating two hemispheres.
Celestial Horizon
Imaginary lines that trace a reference object’s axis in space.
Celestial Pole
An imaginary sphere made up of the upper hemisphere and the lower hemisphere.
Celestial Sphere
A stony meteorite containing spherical granules, called chondrules, made of minerals like olivine and pyroxene.
Chondrite
The region of the solar atmosphere between the photosphere and the corona, with temperatures ranging from 4500 K to 8500 K.
Chromosphere
Stars that never set below the horizon due to their proximity to the celestial pole.
Circumpolar Stars
The brightest of the three twilight phases, when the Sun is below the horizon but still lights up the sky.
Civil Twilight
A roughly spherical region of diffuse gas surrounding the nucleus of a comet.
Coma
Frozen leftover pieces from the formation of the Solar System, composed of dust, rock, and ice, with a glowing head and tail.
Comet
A phenomenon where two astronomical objects appear close to each other in the sky.
Conjunction
A traditionally defined group of stars identified through patterns, now defined by the International Astronomical Union as a two-dimensional area in space.
Constellation
The outer 30% of the Sun’s radius where heat is transferred via convection currents.
Convection Zone
The current basis for the 24-hour time zone system, created by the International Meridian Conference in 1884.
Coordinated Universal Time (UTC)
The outermost portion of the Sun’s atmosphere, visible during a Solar Eclipse.
Corona
A small asteroid that orbits a larger asteroid, providing the first evidence that asteroids may have tiny moons.
Dactyl
The transition from night to day as the sky brightens, classified as civil, nautical, and astronomical.
Dawn
The practice of setting clocks forward one hour during summer and back in autumn to utilize natural daylight.
Daylight Saving Time (DST)
The irregularly shaped, dark-colored moon of Mars.
Deimos
A tide cycle where there is only one high tide and one low tide in a day.
Diurnal tide
The transition from day to night as the sky darkens, classified as civil, nautical, and astronomical.
Dusk
A celestial body that orbits a star, has enough mass for a nearly round shape, but hasn’t cleared its orbital path.
Dwarf planet
A dull glow when sunlight reflects off Earth’s surface, illuminating the unlit portion of the Moon, best seen around the New Moon.
Earthshine
The change from high to low tide, also known as an ebb current.
Ebb tide
An astronomical event where one celestial body partially or fully covers another.
Eclipse
The imaginary plane that traces the Sun’s apparent path across the sky or the projection of Earth’s orbit onto the celestial sphere.
Ecliptic Plane
A British astronomer who predicted the return of a comet, later named after him.
Edmond Halley
The angle an object makes with the horizon, also referred to as altitude.
Elevation
A spring tide that occurs during either the Autumnal or Vernal equinox.
Equinoctial spring tide
A phenomenon occurring twice a year when the Sun is directly over the Earth’s equator, making day and night lengths nearly equal.
Equinox
A rare optical phenomenon at dawn or dusk, where sunlight reflects off cosmic dust, creating a hazy light extending from the horizon.
False Dawn
The second primary Moon phase, when the Moon has reached the first quarter of its orbit, with 50% of its surface illuminated.
First Quarter Moon
The change from low to high tide, also known as flood current.
Flood tide
The final primary Moon phase when the entire face of the Moon is lit.
Full Moon
A massive collection of gas, dust, and billions of stars and their solar systems, all held together by gravity.
Galaxy
An Italian mathematician, astronomer, and physicist who first used a telescope to observe celestial bodies, discovering moons of Jupiter, Venus’ phases, and more.
Galileo Galilei
An American astronomer who proposed the Kuiper Belt as the source of short-period comets.
Gerard Peter Kuiper
A spherical group of stars located in the halo of galaxies.
Globular cluster
Energy stored in a system due to the force of gravity.
Gravitational Potential Energy
Any circle formed by a plane passing through the center of Earth, like the equator and meridians.
Great Circle
A conjunction of Jupiter and Saturn.
Great Conjunction
A large, persistent storm on Jupiter, rotating counter-clockwise.
Great Red Spot
The mean solar time at the Prime Meridian, also referred to as GMT.
Greenwich Mean Time (GMT)
A phase of the Moon where 50% of its surface is illuminated, also known as First Quarter or Third Quarter Moon.
Half Moon
A natural phenomenon where ice crystals in the sky refract light, creating a halo around the Sun or Moon.
Halo
The vertical distance from Earth’s surface.
Height
The theory proposed by Nicolaus Copernicus, stating that Earth and the other planets orbit the Sun.
Heliocentric Theory
The highest point a tide reaches.
High tide
A coordinate system used to describe the position of objects in the sky based on altitude and azimuth, ignoring distance.
Horizontal Coordinate System
A 98-inch space telescope in Earth’s orbit, named after Edwin Hubble, equipped with infrared and X-ray sensors.
Hubble Space Telescope (HST)
A rare solar eclipse where an Annular Eclipse transitions to a Total Solar Eclipse, or vice-versa.
Hybrid Solar Eclipse
A depression formed by the impact of a projectile.
Impact crater
An imaginary line that zigzags through the antimeridian, marking the boundary between one day and the next.
International Date Line (IDL)
The gas giant planets of our Solar System: Jupiter, Saturn, Uranus, and Neptune.
Jovian planets
A solstice in June marking the longest day of the year in the Northern Hemisphere and the shortest in the Southern Hemisphere.
June Solstice
A region of icy bodies beyond Neptune, proposed by Gerard Peter Kuiper, where Pluto is located.
Kuiper Belt
Imaginary horizontal lines used to locate points on Earth’s surface, part of the geographical coordinate system.
Latitude
An atmospheric phenomenon where light reflects off ice crystals, forming pillars of light.
Light pillars
A unit of distance defined as the distance light travels in a vacuum in one year, roughly 9.5 trillion kilometers or 6 trillion miles.
Light-year
