2nd Semester Astronomy Final Vocabulary

Flashcard maker : Daniel Thompson
Johannes Kepler
Astronomer who in the 1600’s, discovered that objects in the universe all orbit each other in elliptical paths, not perfect circles. Developed three mathematical laws of elliptical planetary motion
Kepler’s 1st Law
Objects in the universe that orbit other objects, follow elliptical paths. The object being orbited resides at the “focus” of the ellipse.
Kepler’s 2nd Law
As an object moves around another object in its orbit, it sweeps out equal areas in equal times
Kepler’s 3rd Law
P2 = a3. The square of the period of an object’s orbit around another object is equal to the cube of the semi-major axis of the orbit.
Eccentricity
A ratio of the degree of elongation of an elliptical orbit. E = C/a. Values fall between 0 and 1
Aphelion
The distance from the object being orbited at the focus (M1) to the farthest point on the ellipse
Perihelion
The distance from the object being orbited at the focus (M1) to the closest point on the ellipse
Semi-major axis
Half the length of the major axis in an ellipse
Semi-minor axis
Half the length of the minor axis in an ellipse
Focus
An imaginary point within an elliptical orbit where the object being orbited resides. Referred to as “M1”
Ellipitical Path
The path an object takes as it orbits another object following an elliptical orbit
Isaac Newton
English scientist who in the 1600’s, developed the Laws of Motion, the Laws of Gravity and Calculus. Considered one of the greatest minds who ever lived.
Inverse Square Law
One of Newton’s laws of Gravity stating that the gravitational force between two objects varies inversely with the square of the distance between them
6.67 x 10-11
The mathematical value of the Gravitational Constant, “G”
Fg = G*M1*M2/D2
The formula for Newton’s complete law of gravity.
Fg = ?
Newton’s 1st Law of Motion
An object in motion or at rest will remain in motion or at rest, until acted upon by an external force
Newton’s 2nd Law of Motion
Force = mass x acceleration
Newton’s 3rd Law of Motion
For every action, there is an equal but opposite reaction
32 ft/sec2
The numerical value of the acceleration due to gravity at Earth’s surface (in ft/sec2)
K-T Impact
The name given to the asteroid strike that slammed into Earth 65 million years ago, and killed 70% of all life on Earth
Extinction Level Event
An event that may happen on Earth causing such severe damage to the environment that a large number of species go extinct
Iridium
A rare element on Earth that is common in asteroids. Found mixed in with an ash covering most of Earth called the K-T Boundary, proving that an asteroid strike caused the death of the dinosaurs and most life on Earth
K-T Boundary
A layer of iridium and ash found over the entire planet that is evidence for a meteor impact around the time of the mass extinction of the dinosaurs.
Chicxulub
The name of the crater left by the asteroid that struck Earth 65 million years ago, causing a mass extinction
Asteroid
A space rock formed 4.6 billion years ago during the initial formation of the solar system. Trillions of them are found in a belt between Mars and Jupiter
Comet
A ball of space dust, rock and ice formed 4.6 billion years ago during the initial formation of the solar system. Trillions of them are found in two belts called the Kuiper Belt and the Oort Cloud
Near Earth Objects Program
A program instituted by NASA in the late 1990’s to search the sky for asteroids or comets that might be on a collision course with Earth
Meteor
An asteroid that has entered Earth’s atmosphere and is beginning to burn up
Meteorite
An asteroid that has passed through Earth’s atmosphere and has struck the ground
Meteor Shower
A cluster of small space rocks and ice that become meteors and enter Earth’s atmosphere. Occurs when Earth on its orbit around ther sun passes through an old comet tail in space
Tail
The stream of melted gas, water and rocks that trail from a comet as it nears the sun in its orbit. It always points away from the sun.
Nucleus
The main rocky/icy part of a comet
Coma
A ball of melted gas, water and rocks that are blasted off the surface of a comet from the heat of the sun. Forms as the comet gets closer to the sun in its orbit
Halley’s Comet
The name of a famous period comet on a long elliptical orbit that returns to the vicinity of Earth every 76 years.
Mercury
Closest planet to the sun. hard rocky world covered in craters, with a long day and a long night
Venus
2nd planet from the sun. A hellish world with a dense crushing atmosphere, 900 degree heat, acid clouds and a rugged rocky landscape. CO2 atmosphere causes a runaway greenhouse effect
Earth
3rd planet from the sun. Our home world covered in 70$ oceans, with land continents, teeming life and a protective atmosphere
Mars
4th planet from the sun. A small parched world with a very thin CO2 atmosphere, strong UV radiation at the surface, no surface water and rocky terrain. Was volcanic at one time. Does have weather (dust storms and wind)
Jupiter
5th planet from the sun. Our solar system’s largest world. A gas planet with dense bands of striped clouds and a huge great red spot. Strong gravity holds 63 moons in orbit, with some moons having erupting volcanoes, and/or conditions possible for life to exist
Saturn
6th planet from the sun. A huge gas world with a striking ring of dust, rock and ice surrounding it. Has 62 moons. Its largest moon has a thick atmosphere and liquid lakes of methane
Uranus
7th planet from the sun. A huge gas world with a pale blue color caused by hydrogen and methane atmosphere. Has 27 moons
Neptune
8th planet from the sun. A huge gas world with a deep blue color caused by hydrogen and methane atmosphere. Has visible clouds and 13 moons. Its cloud temperatures are the coldest in the solar system.
Ceres
1st dwarf planet from the sun. A spherical rocky world 580 mi in diameter, orbiting between Mars and Jupiter. It was named a dwarf planet in 2006.
Vesta
A large asteroid in the Asteroid Belt. Is one of the destinations of Dawn, a space probe sent to explore the Asteroid Belt
Makemake
A Pluotoid dwarf planet named after a god of Easter Island. A rounded world with a 310 year elliptical orbit
Haumea
A Pluotoid dwarf planet named after a god of Hawaii. A rounded world with a 283 year elliptical orbit positioned beyond Pluto. It has two moons.
Pluto
The original 9th planet from the sun. Re-designated a Dwarf Plant in 2006. An icy, rocky world with no atmosphere, orbiting beyond Neptune. Has four moons, the largest being Charon.
Sol
The latin name given to our sun. A giant ball of hydrogen gas undergoing nuclear fusion it its core, it provides the heat and light bathing our solar system. 865,000 mi in diameter, it is a stable yellow dwarf star
Core
The center of the sun. Site of hydrogen fusion in the sun
Radiation Zone
Area outward from the sun’s core, it is a dense layer of the Sun in which energy is transferred to the outer layer.
Convection Zone
The outer layer of the sun, Made of vast churning hot gases that rise and eventually cool as they approach the surface. Its top surface is called the Photosphere
Photosphere
The top surface of the sun (convection zone). Where all light, radiation and solar wind escapes the sun. At a temperature of about 12,000 degrees F.
Chromosphere
The inner atmosphere of the sun nearest the surface. Consists of rapidly moving hot hydrogen gas, influenced by strong magnetic fields.
Corona
The sun’s outermost layer of gas, held in place by the sun’s gravity. Visible during a solar eclipse. The gases in this region are very hot from being excited and fed by enormous solar eruptions.
Deimos
One of the two moons of Mars. Named after a Greek figure in mythology, it is a slightly rounded small rock (15 km dia) that orbits Mars further out than Phobos, the other moon of Mars. Most likely a captured asteroid.
Phobos
One of the two moons of Mars. Named after a Greek figure in mythology, it is a rounded small rock (24 km dia) that orbits Mars closer in than Deimos, the other moon of Mars. Most likely a captured asteroid
Luna
The Latin name given to our moon.
Io
One of the four Galilean moons of Jupiter. Larger than our moon, it is close to Jupiter and has over 300 active volcanoes, due to gravitational flexing from Jupiter’s gravity. Yellowish in color from volcanic sulfur coating its surface.
Ganymede
One of the four Galilean moons of Jupiter. The largest moon in the solar system, it is spherical and larger than the planets Mercury and Pluto. Made of rock and ice, its surface is streaked with groves.
Callisto
One of the four Galilean moons of Jupiter. A spherical rock and ice world, its surface is covered in dense craters, suggesting an encounter with a huge asteroid field billions of years ago.
Europa
One of the four Galilean moons of Jupiter. It is spherical and is made of rock and ice. Its surface is mostly ice and is streaked with hundreds of ice groves. It is believed to contain an ocean of salty water under its thick surface ice layer, that may possess the conditions for life to exist.
Enceladus
A major moon of Saturn, it is a rounded ice covered world that was recently discovered to eject geysers of liquid water periodically. Geologically heated from gravitational tidal flexing with Saturn.
Titan
Saturn’s largest moon and 2nd largest moon in our solar system. A round rocky world covered in a thick dense atmosphere made mostly of nitrogen gas with significant amounts of methane. Has liquid lakes/seas of hydrocarbons (ethane and methane) on surface. Possible candidate for lifeforms in the solar system.
Triton
The largest moon of Neptune. A round rocky world covered extensively in frozen nitrogen ice. Erupts liquid nitrogen geysers. One of the coldest places in the solar system, with temperatures below -400 degrees F
Titania
The largest moon of Uranus. A spherical world of rock and ice. Eighth largest moon in solar system
Pan
A small rocky moon of Saturn. Closest moon to Saturn, it orbits within Saturn’s rings, and has cleared out a path within the rings.
Pioneer
The first space probes to be sent to fly by the gas giant planets. Launched in the early 1970’s by the U.S., two such spacecraft (10 and 11) photographed Jupiter and Saturn. They are now on a trajectory to leave the solar system.
Voyager
Two space probes launched in the late 1970’s by the U.S. to fly by the gas giant planets. Two such spacecraft (1 and 2) photographed and measured Jupiter, Saturn, Uranus, Neptune and many of their moons. They are now on a trajectory to leave the solar system.
Mariner
A space probe sent to photograph Mercury in the 1970’s. First spacecraft to to visit Mercury.
Spirit
The name given to a spacecraft rover sent in 2003 U.S. to land on Mars. Landed in Gusev Crater, it explored the surface of Mars very successfully until it got stuck in sand in 2010.
Opportunity
The name given to a spacecraft rover sent in 2003 U.S. to land on Mars. Landed on a flat ancient sea sedimentary plain called Meridiani Planum, it has explored the surface of Mars very successfully and is still operational.
Apollo
The name given to the U.S. program to land men on the moon. Consisted of 17 separate spacecraft, six of them successfully landed men on the moon in the 1960’s-1970’s.
Apollo 11
The specific Apollo mission that landed the first men on the moon in July 1969.
Neil Armstrong
American Astronaut (1930 – ). Commander of the Apollo 11 mission, he was the first man to walk on the moon.
Buzz Aldrin
A crewman of Apollo 11 with Neil Armstrong, he was the 2nd man to walk on the moon.
Michael Collins
The pilot of Apollo 11 with Neil Armstrong and Buss Aldrin, he piloted the Apollo Command Module while Armstrong and Aldrin walked on the moon.
Galileo
17th century Scientist and Astronomer. Invented the refractor telescope, discovered the major moons of Jupiter. A space probe named after this scientist, that orbited and studied Jupiter and its moons in the 1990’s
Cassini
A space probe launched by the U.S. in 1997, it was sent to orbit Saturn and study several of its moons. Carried a probe named Huygens which it launched to successfully land on Saturn’s moon Titan
Rock, dust, ice
The three major constituents of planetary rings
Huygens
A small space probe carried by the Cassini spacecraft to Saturn, it was released by Cassini in 2004 to successfully land on Titan, Saturn’s largest moon.
Hubble Space Telescope
Earth’s largest space-based optical telescope. Launched in 1990 into high Earth Orbit, its 8′ primary mirror and high-resolution instruments have taken spectacular images of the universe. Still in operation. Named after the astronomer who first discovered the nature of galaxies and the expansion of the universe
Spitzer Space Telescope
A large space telescope launched by the U.S. in 2003 and placed into a heliocentric solar orbit, it photographs the sky in Infrared wavelengths.
Chandra Space Telescope
A large space telescope launched by the U.S. in 1999 and placed into a very high Earth orbit, it photographs the sky in X-Ray wavelengths.
COBE space telescope
The initials for the Cosmic Background Explorer, a space telescope launched by the U.S. in 1989 and placed into Earth orbit to measure the faint microwave background radiation that permeates space and is thought to be remnants of the big Bang.
Asteroid Belt
The area of asteroid and rocks that orbit the sun between Mars and Jupiter. Contains billions of asteroids of various sizes
Kuiper Belt
An area of trillions of asteroids and comets that orbit the sun beyond the orbit of Neptune, but near the orbit of Pluto.
Oort Cloud
An area of trillions of comets that orbit the sun far beyond the orbit of Pluto. Its outer regions extend almost 1 light year from the sun, making it the outer reaches of the solar system
Liquid ocean
What scientists suspect may exist deep under the surface ice of Europa, a moon of Jupiter
Water geysers
What is ejected from Enceladus, one of the moons of Saturn
Liquid Nitrogen geysers
What is ejected from Triton, one of the moons of Neptune
Craters
Circular holes made in the rocky surface of planets, dwarf planets and moons, caused by asteroid and comet impacts onto the surface.
Orpheus
One of two names given to the Mars-sized planet suspected of colliding with Earth over 4 billion years ago. The rubble from that collision was thrown up into orbit and formed our moon. The other name for the object is “Theia”
Earth Mark 1
The name given to primitive Earth, prior to its collision with Orpheus/Theia
Earth Mark 2
The name given to primitive Earth, after its collision with Orpheus/Theia
Collision Theory
The current theory of the moon’s formation, theorizing that another smaller planet hit our primitive Earth shortly after their formation. The collision destroyed the smaller planet, severely changed Earth, threw debris into Earth orbit that cooled and coalesced by gravity to form our moon.
Capture Theory
A discarded theory of moon formation suggesting that gravity from primitive Earth captured a small passing planet that began orbiting Earth as our moon.
Sibling/Fusion Theory
A discarded theory of moon formation suggesting that a rapidly spinning primitive Earth formed a bulge of material that was thrown off the planet into an orbit that became our moon.
Co-Formation Theory
A discarded theory of moon formation suggesting that both the primitive Earth and our moon formed together in their current orbits at the same time from the original nebula that formed the solar system.
Total Eclipse
A solar eclipse during which the sun becomes fully blocked by the disk of the moon or planet
Lunar Eclipse
The blocking of sunlight to a moon that occurs when a planet such as Earth is directly between the sun and the moon
Solar Eclipse
The blocking of sunlight to a planet that occurs when a moon is directly between the sun and the planet
Sputnik 1
The first artificial satellite to be launched into orbit by man. Was launched by the Soviet Union in 1957
Explorer 1
The first artificial satellite to be launched into orbit by the U.S. Was launched in 1958
Mercury Friendship 7
The first manned mission of the U.S. to place an Astronaut into Earth orbit. Carried Astronaut John Glenn into orbit in 1962, for three orbits. Currently on display at the Smithsonian Museum in Washington, DC
Mercury Freedom 7
The first manned mission of the U.S. to place an Astronaut into space. Carried Astronaut Alan Shepard into sub-space on a quick 15-minute up/down ballistic trajectory in 1961. Currently on display at the U.S. Naval Academy at Annapolis, MD
Alan Shepard
Astronaut who made the first United States’ suborbital rocket-powered flight in 1961 (1923-1998)
Yuri Gagarin
Soviet cosmonaut who in 1961 was the first person to be launched into space (1934-1968)
John F. Kennedy
American President who in 1961, made a famous speech which directed America to build a rocket that could land men on the moon. Was assassinated in 1963.
Saturn V
Massive rocket built by the U.S. in the 1960’s to launch spacecraft capable of reaching the moon . Was used to launch the Apollo spacecraft, Skylab and others
Command Module
The part of each Apollo spacecraft that carried three astronauts to and from the moon. It orbited the Moon while 2 astronauts descended to the moon in the LM. Since it was the only part of the spacecraft with a heat shield able to withstand re-entry, it was the only part to return to Earth.
Service Module
The part of each Apollo spacecraft that housed the rocket engine, fuel, oxygen tanks and major instruments. Was jettisoned above Earth prior to reentry of the Astronauts
Lunar Module
The part of each Apollo spacecraft consisting of an Ascent stage and Descent stage, that descended to the moon carrying two astronauts then returned them back to the Command Module in orbit. The Descent stage remained on the moon, where six of them sit today.
Apollo 13
One of the manned missions to the moon that had an explosion in route, forcing it to return the crew to Earth without landing.
Skylab
America’s first space station launched in the 1970’s. crews of 3 stayed in space for weeks studying the sun. It fell out of orbit and burned in 1979
John Glenn
First American to orbit the earth in 1962
Mare Tranquillitatus
The location on the moon of the Apollo 11 landing. Means “Sea of Tranquility” in English. A flat volcanic lava plain
Sea of Tranquility
The location on the moon of the Apollo 11 landing. Means “Mare Tranquillitatus” in Latin. A flat volcanic lava plain
Mir
A space station placed in Earth orbit in 1986 by the Soviet Union. Served as a research station for crews in space for over 20 years. Eventually fell out of orbit in 2001.
International Space Station
A massive research space station placed in Earth orbit in 1998 by the U.S., with assistance from several European and Asian countries. Modules have been added to it over the years. Most expensive object ever built by man (over $150 billion and counting).
Space Shuttle
A reusable spacecraft fleet of six craft designed to carry cargo, astronauts, and satellites to and from space. First one was launched in 1992. Over 135 missions to space were conducted. All craft retired and program ended in 2011
Challenger
One of the Space shuttle fleet, it made numerous flights into space, carrying astronauts and cargo. Exploded during a launch in 1986 and was lost, with its crew.
Columbia
First Space Shuttle launched into space. Made numerous flights into space, carrying crew and cargo. Burned up during reentry in 2003 and was lost with its crew.
Discovery
One of the Space shuttle fleet, it made numerous flights into space, carrying astronauts and cargo. Was retired from service in 2011
Atlantis
One of the Space shuttle fleet, it made numerous flights into space, carrying astronauts and cargo. Was retired from service in 2011
Endeavor
One of the Space shuttle fleet, it made numerous flights into space, carrying astronauts and cargo. Was retired from service in 2011
Space Junk
Refers to all the pieces of debris that have fallen off rockets, satellites, space shuttles, and space stations and remain floating in space.
Kepler Space Telescope
A large optical space telescope launched in 2009 by the U.S. to search for planets around other stars. Has discovered numerous planets and planet candidates to date.
Cosmos 1
A unique spacecraft designed by the Planetary Society to be launched into space and powered by sailing on beams of sunlight. Was launched in 2005, but the rocket crashed during launch and the spacecraft was destroyed.
Eris
The largest dwarf planet of our solar system. It is bigger than Pluto. Was designated the first dwarf planet. a rock and ice world that orbits on a large elliptical orbit beyond Pluto. Its discovery led to the concept of dwarf planets.
Charon
Pluto’s major moon. Almost 1/2 the size of Pluto. Orbits with Pluto around a common center of mass (barycenter).
Methane
One of the major gases present in the four gas giants of the solar system, and on Titan, Saturn’s biggest moon. Gives Uranus and Neptune their blue color.
Hydrogen
The most common element in the universe. Major component of the four gas giant planets, and the sun.
Olympus Mons
The largest volcano in the solar system – on Mars – about 27km high.
Valles Marineris
A deep very long canyon on Mars. Formed as a crack on Mars from plate tectonic activity long ago.
11 years
The length in years of our sun’s sunspot cycle
25 days
The approximate rotational period of the sun, in days
4.6 billion years
The approximate age of our solar system, from its initial formation from nebula gases until the present
108
The approximate number of Earths that could fit across the sun from one side to the other
Umbra
The darkest part of the inner shadow of a solar or lunar eclipse
Penumbra
The less dark. larger outer shadow of a solar or lunar eclipse
Prominence
An eruption of superheated gas from the sun that loops upward from the surface, then falls back as a loop; follows magnetic field lines on the sun
Solar Flare
An eruption of superheated gas from the sun that jets upward from the surface and escapes into space
Solar Wind
A steadily blowing “wind” of hot hydrogen gas blown off the sun’s surface and out into space by explosions off the photosphere. Streams from the sun at 1 – 2 million mph.
Aurora Borealis
Colored light display emitted in the northern hemisphere by the atmosphere due to the interaction of the solar wind with the magnetic field and atmosphere of Earth
-400
The number in degrees F representing the temperature of deep space beyond Neptune
CO2
The major gas on Mars and Venus. Causes the Greenhouse Effect. Absorbs solar heat. A contributor to Global Warming on Earth
Mare
Dark-colored, hardened lava flows on the moon that formed from lava welling up and filling in large impact basins. Was originally thought to be water basins on the moon by early Astronomers
Rays
Light colored streaks coming from craters on the moon and other rocky objects in the solar system. Represents dust and rock splatter from the impact of an asteroid
synchronous gravitational lock
An effect that occurs due to gravity between two objects, that forces the same face of a moon or planet to always face the object it is orbiting
Magnetic Field
In Astronomy, the region of space surrounding a rotating star or planet, where electromagnetic forces create lines of force above the rotating star, planet or moon
Radioactive elements
Unstable elements in nature that spontaneously decay/break apart, causing the release of radiation or heat. The primary cause of Earth’s continued internal heat at its core.
Zone of habitation
That area of space where the flux of heat from a star is sufficient to allow liquid water to exist for at least part of a year. Currently, Earth, Mars and Venus are in this zone in our own solar system.
63
The number of moons of Jupiter
Dwarf Planet
An object/planet that is round, orbits the Sun; and has not cleared the region of its orbit of other objects. Our solar system has five such objects currently known, with more suspected
Cassini Division
A large dark gap of mostly empty space between the two largest rings of Saturn.
Great Red Spot
A giant, 400 year old continuous storm on Jupiter
Geocentric Theory
The now disproved theory of medieval scholars and clergy that the Earth is the center of the universe, and everything revolves around it
Heliocentric Theory
The current theory of our solar system proving that the sun is the center of our system, and everything revolves around it
Moon
The only moon of Earth. 1/4 the size of Earth, it is a hard rocky, dry spherical object covered in lava basins, craters and hills. Had a origin as the remains of a giant collision between Earth and another planet billions of years ago
Galilean Moons
The four major moons of Jupiter (Io, Europa, Ganymede and Callisto), named after Galileo, the man who discovered them
Planet
An object/planet that is round, orbits the Sun; and has cleared the region of its orbit of other objects. Our solar system has eight such objects currently known
SETI
The abbreviation for the Search for Extraterrestrial Intelligence
Arecibo Radio Telescope
Earth’s largest radio telescope … located in Puerto Rico.
VLA
Very Large Array of radio telescopes, consists of 27 telescope dishes located in New Mexico

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