Complete List of Terms and Definitions for Astronomy - Section Vocabulary

Terms Definitions
Constellation Star groupings
Davidson Latitude 35.5
Burning helium Red Giants
Normal Matter % 4%
voyager 1 and 2 jupiter
Loess Thick, wind-blown silt deposits
ecliptic path the sun follows
Types of Eclipses Solar and lunar
the suns average density 1.409 g/cm^3
main sequence diagonal pattern of stars
orbit Earth's path around the sun.
chromosphere middle layer of sun's atmosphere, gives of faint red glow
MACSJ0717.5+3745 where four separate galaxy clusters have been involved in a collision, the first time such a phenomenon has been documente;About 5.4 billion light years
thermonuclear process Nuclear reactions, highly energetic processes involving subatomic particles found within the nuclei of atoms, exist in two general forms.
Galileo Galilei Italian astronomer and mathematician who was the first to use a telescope to study the stars. (1564-1642.)
hydrogen fusion (hydrogen burning) the thermonuclear fusion of hydrogen to produce helium.
electromagnetism which is stronger, electromagnetism or gravity?
1645 to 1715 solar inactivity Maunder Minimum
Umbra where sunlight is completely blocked, full shadow
13.7 billion years age of the universe
capricorn the Goat, a zodiacal constellation between Sagittarius and Aquarius.
Ptolemy The great Geometer and Stronomer of the late Classical Age in Alexandria, based his estimate on stellar measurements, observations by marinus of Tyre, gave a circumference of 28,800 km, this is about 72% smaller than the correct circumference. This smaller value of the Earth will be important in sending Columbus on his journey
spiral galaxy a galaxy having a spiral structure
Galileo The greatest Italian scientist of the Renaissance, his most important contributions were his descriptions of the behavior of moving objects using telescope he constructed.
The most abundant molecule in molecular clouds is... H2 (Hyrdogen)
Planet Any big, round celestial body, that orbits the sun
meridian An imaginary line on the celestial sphere passing through the north and south poles and the observer's zenith.
nebula an immense cloud of gas (mainly hydrogen) and dust in interstellar space
Aristarachus distance and size of sun, S=10E!, heliocentric earth
outer planet The large gas planets. Jupiter, Saturn, Neptune and Uranus.
Revolution The movement of one object around another. It takes Earth one year to completely revolve around the sun
What is an equilateral bulge caused by? gravity
Refracting Telescope Uses a lens to gather/bend starlight
Io moon with active sulfur volcanoes due to tidal heating
distance indicator Object whose luminosity or diameter is known. Used to find the distance to a star cluster or galaxy. (p. 287)
solvency solvent condition; ability to pay all just debts.
photosphere -the part we see
-sunspots let us see rotation
-sunspots have a strong magnetic pull
87 Earth days for Mercury to orbit the Sun
The energy that reaches the Earth from the sun in one day is enough energy to meet the world energy demand for 30 years True
Spectroscope A tool used by astronomers to analyze the electromagnetic radiation and determine the composition, movement, and distance of stars in the universe.
Europa The jovian satellite that has an icy crust surrounding an ocean of water
99% The two most abundant elements in the Sun make up ___ of its composition
Retrograde Motion A periodic backward, or westward, loop made by a planet in front of the background of constellations
weight one of the factors used to determine gravity, A measure of the force of gravity on an object
Cassegrain focus an optical arrangement in a relecting tepescope in which light rays are reflected by a secondary mirror through a hole in the primary mirror
Convection Zone Outermost layer of the Sun's interior that forms gas loops
An iron meteorite with the crystals
known as Widmanstaetten figures is an
example of a
processed meteorite
phases one of the different shapes of the moon as on earth.
background radiation radiation left over from the beginning of the universe
apparent brightness is its brightness as seen from Earth
synchronous rotation rotation for which the period of rotation is equal to the period of revolution
electromagnetic spectrum pulsars emit pulsed radiation in many parts of the electromagnetic spectrum
How do astronomers calculate a telescope's light collecting area (A)? (where r = radius of the telescopes mirror or lens, and B is "pi" or 3.14159) A = Br2
pixel the smallest element of an image that can be individually processed in a video display system.
crater chain line of craters along the surface of an astronomical body
self propagating star life cycle of star generates next generation
Total Lunar Eclipse This happens when the Moon is completely inside the darkest part of Earth's shadow.
time it takes the moon to travel around the earth is called sidereal month
circumpolar constilations never rise or set. they move around the north star.
asteroid Any of the rocky objects larger than a few hundred meters in diameter (and not classified as a planet or moon) that orbits the Sun.
Gravitational time dilation The stronger the gravity, the slower the pace of time.
Month A division of the year that is based on the orbit of the moon around the Earth
full moon lit-up side of the moon is facing Earth
Barred-spiral galaxies Younger, large amount of gas and dust. Central bar shape, made of stars. Arms spiral out from the elongated center. SB
Partial Solar eclipse- Sun becomes only partially blacked by the disk of the Moon
A T or F. Cobalt (Co) is formed during Silicon (Si) buring.
Sister Maria Chelest What did Galileo's daughter in the nunnery change her name to?
What is an interstellar cloud? what a star stats as
What is Regolith? A thicklayer of dust left by meteorite impacts. It can be found on the moon because the moon has been constantly bombarded with meteoroids and is still hit by "micrometeoroids".
diffraction the spreading of light os it goes in a tiny opening or around a tiny object
GALILEO GALILEI (1564-1642) Used a telescope to study moon, sun, Jupiter, etc. Proposed relativity, studied objects in free fall.
One day The length of time it takes for the earth to rotate on its axis one time.
Reason for Differences in Composition These differences arose because all four planets started from ice-rich planetesimals of about the same size, but captured different amounts of hydrogen and helium gas from the solar nebula
Spiral Galaxies Galaxy that appears to have a bulge in the middle and arms that spiral outward
Eclipsing Binary a binary star system in which one star periodically blocks the light from the other
Neil Degrasse Tyson He is a great science communicator who is known for the demotion of Pluto as a planet.
annular eclipse an eclipse of the sun in which a portion of its surface is visible as a ring surrounding the dark moon.
Black holes, by definition, cannot be observed directly. What observational evidence do scientists have of their existence? Gravitational interaction with other object
plasma the Sun is a ball of ___, a gas with many of the atoms being ionized due to the high temperature; behaves like gas but responds to magnetic fields
What is nuclear fusion? two nuclei sticking together to form a new, heavier nucleus
What is the surface of Mercury like? Rocky, with craters and scarps.
what is the pressure of then sun? 300 billion atmospheric pressure (at the core)
Explain the Capture hypothesis and explain two arguments that contradict this hypothesis The Capture hypothesis states that the sun formed by itself and that its gravity captured passing planets. One problem with this hypothesis is that if the planets were randomly captured, their orbits would be random and sporadic, not perfectly aligned and nearly circular. Also, it is nearly impossible for the sun to capture a planet of any size without means to slow it down, because it would have too much speed and just fly past before the sun could catch it.
How are neutron star binaries different from Supernova binaries? Neutron star binary systems burn much quicklier, hotter and more often.
Kepler's 1st Law of Planetary Motion law of ellipses, The orbit of every planet is an ellipse with the sun at one of the two foci.
Their densities are higher than those of asteroids Which statement about comets is NOT true?
Types of EM radiation. Dec. order of energy (short to long wavelength) Gamma Rays - energetic processes. observed w/ space telescopes cuz ozone absorbs most.

X-rays - energetic processes & absorbed by ozone.

UV radiation - most emitted by energetic processes & hot stars. mostly absorbed by ozone.

Visible rad. - moderate temp stars like sun emit large fraction of their energy @ visible wavelengths. Passes through atmosphere.

IR rad - most emitted by cool stars, most wavelengths absorbed by water vapor in atmosphere.

Radio Waves - smallest eng & longest wavelengths. Most emitted by plasmas associated w/ magnetic fields. Generally pass thru but shorter length radio waves bounce off ionosphere
What are the orbits of most extra solar planets like -- how do they compare to the
orbit of Earth around the Sun?
The orbit of most extra solar planets
Where will a planet in retrograde motion rise? In the east (just like everything else in the sky).
Why is Newton's version of Kepler's third law so useful to astronomers? It can be used to determine the masses of many distant objects.
What was the theory on Venus prior to the 1950's? that is may be home to a lush, tropical jungle-like environment.