Complete List of Terms and Definitions for Astronomy Exam 6

Terms Definitions
ecliptic ...
Nuclear Fusion ...
Dwarf Planet Pluto
Jupiter Great Red Spot
the big dipper Ursa Major
Kepler's Third Law a^3/p^3= c
Autumnal Equinox Summer >>> Winter
Galaxy A huge collection of stars
the lower the number the brighter
Does Mercury have an atmosphere? no
apparent magnitude brightest of a star
increasing mass uranus, neptune, saturn, jupiter
Each successful Apollo mission landed how many astronauts on the Moon? 2
4 jovian planets Jupiter, Saturn, Uranus, Neptune
Mars temperature 50k cooler than on earth
Astronomy the scientific study of the universe.
Meteor any of the small solid extraterrestrial bodies that hits the earth's atmosphere
Kepler discovered the planets orbits were: Ellipses.
How are stars powered? Nuclear energy (fusion)
What are Maria dark, lava-filled impact basins
Astronomers can measure magnetic fields on the sun using the ? effect? Zeeman effect
Martian Surface Features Impact craters with heavy erosion
Large deserts
Chaotic Terrain: highlands and broken hills
Volcanoes: The Tharsis and Elysium regions, Olympus Mons largest volcano.
Canyons
Which of Saturn's moons was discovered to have active gysers in 2005? Enceladus
Mars red color, rocky, white polar caps, once had water
phases lighted portion of the moon we see
invisble...rarified chromosphere and corona are what to the eye?
synodic period the time interval between successive similar alignments of a celestial object with respect to the Sun
Satellite Any celestial body orbiting around a planet or star.
Spectrum wavelengths of visible light that are separated when a beam of light passes through a prism; range of wavelengths of electromagnetic radiation. result of refraction.
Sunspots Relatively cool spots on the Sun's surface
Perihelion closest to the sun; occurs January 3
Corona outermost, largets layer of the Sun's atmosphere; extends millions of kilometerrs into space and has temperatures up to 2 million Kelvins.
Summer solstice- (occurs around June21) when the Northern hemisphere is tipped most directly toward the Sun; Tilt axis facing directly towards Sun.
Frequency f; Number of cycles/second. SI Unit: Hertz, Hz
small compared to other outer planets Uranus OUTTA
Halo Stars Move in randomly oriented, elongated orbits out of the Galactic plane
Asterism - group of stars within a constellation
Aphelion point when earth is furthest from the sun (arround July 4)
aristotle thought the earth was the center of the universe and everything revolved around it
Noting the turnoff mass in a star cluster on an H-R diagram allows you to determine its age
Axis of Rotation what a celestial body spins on
all jovian cores are _____X the mass of earth 5
Earth third planet from the sun; has an atmosphere that protects life and surface temperatures that allow water to exist as a solid, liquid, and gas
Sunset the daily event of the sun sinking below the horizon. When the uppermost part of the sun apperars below the horizon.
Spectral Classification classification of stars based on their spectral characteristics; stars of similar temps will have similar spectra
Thermal energy the total kinetic and potential energy of all the particles in a substance. Depends on temperature AND density
light-year the distance traveled by light in a year, at a speed of about 300,000 kms a second
Magnitude The name for the brightness of a star.
Compound A substance that is composed of atoms of two or more different elements that are chemically combined
type II Cepheid different cepheids can have very different pulsating periods
baryonic matter Refers to ordinary matter made from atoms
false TF according to the Big Bang theory, matter is expanding into pre-existing space
Black Hole After a supernova explosion, the core remains so massive, that without the energy created by nuclear fusion to support it, the core is swallowed up by its own gravity. The gravity is so strong that not even light can escape. The core has become a cosmic vaccum
Heliocentric A sun centered model of the planets. In a system, Earth and the other planets revolve around the sun.
Positional Astronomy Branch of astronomy based on finding location of objects on the celestial sphere
Red Shift a shift in the spectra of distant galaxies toward longer wavelengths
On what date does the sun shine directly over the tropic of capricorn? December 21st.
Angular diameter (angular size) The arc angle across and object
the sun a ball of burning gas that fuses hydrogen into helium at its core
the magnetized realm in, around, and above bipolar sunspot groups...the seat of unrest on the sun solar active region
Revolution same as orbit, the path a planet takes as it travels once around the sun, for Earth a revolution takes 365 1/4 days.
As gas blob spirals in from accretion disk into a black hole the ____ _____ varies as the orbit loops around the hole. Luminosity varies.
energy flux the amount of energy emitted from each square meter of an object's surface per second
refracting telescope a telescope that uses convex lenses to gather and focus light
order the following chemicals from most refractory to least or equivalently from least volatile to most iron, silread, pneumonia, hydrogen
James Webb Space Telescope successor the Hubble Space Telescope; it is planned to study the evolution of galaxies, the production of elements by stars, and the process of star and planet formation
constellation A group of stars that form a pattern in the sky
great circle a circle that bisects a sphere. the celestial equator and the ecliptic are answers
Big Idea #1 Neither Matter or Energy can be created nor destroyed all energy is either stored or released (Kinetic, Potential)
absorption line A dark line in a spectrum. Produced by the absence of photons absorbed by atoms or molecules. (p. 110)
dwarf star a low-mass star that emits low to average amounts of light that burn their hydrogen slowly over a long life span
forces that support cold hydrogen clouds rotation, magnetic field, internal pressure
Solar Eclipse shadow cast by the moon falls on the Earth
Surface Features of Venus 1. Maxwell Montes- largest mt on Venus; shield volcano 2. Aphrodite Terra- largest highlands 3. Isthar Terra- Highland containing Maxwell Montes
• A gas heated to millions of degrees would emit mostly X rays
Using Hubble's Law, what is the upper limit on the age of the Universe? 15 billion years
white dwarf the hot, but dim stars in the H-R diagram
crescent phase the phase of the moon at whichonly a small, crescent shaped portion of the near side of the moon is illuminated by sunlight, crescent phase occurs just before and after new moon
What does surface gravity measure? The gravitational attraction at a planet's or star's surface.
what is the average live span of a star 10 billion years
a is 4 times more distant than b = it receeds how many times faster 4
where are most asteroids found between mars and jupier in the asteroid belt
Newton's Law of Universal Gravitation Between any two objects anywhere in space there exists a force of attraction that is in direct proportion to the product of their masses and min inverse proportion to the square of the distance between them
series of ten radio dishes from the carribean to hawaii; only works as one radio telescope which can map 100x more detail than best photos very long baseline interferometer VLBA
what is the main sequence? a diagonal band that runs from the upper left to the lower right of the chart. contains hot,blue, bright stars in the upper left and cool, red,dim stars in the lower right. yellow, main sequence stars, like the sun, fall in between.
List 2 factors that cause seasons Revolution of earth around the sun, and tilt of warth on axis (23.5°)
evolutionary path of a low mass star nebula, protostar, main sequence, red giant, yellow giant, red supergiant, white dwarf/ planetary nebula
What are the layers of the sun, in order from inner to outer? Core, Photosphere, chromosphere, and corona
The angular resolution of a telescope is defined as the smallest angle or distance by which we can tell two objects are separated
E. rotation periods comparable to the Sun's. Neutron stars do not have
A. masses greater than 1.4 solar masses.
B. sizes comparable to large cities.
C. strong magnetic fields.
D. large surface gravities, compared to the Sun.
E. rotation periods comparable to the Sun's.
How does a low-mass star die? Ejection of H and He in a planetary nebula leaves behind an inert white dwarf.
what role does centrifugal force play in tides? it pulls the other side of the earth's oceans causing a bubble effect
How massive can a black hole be? Any size as long as all the mass is within the Schwarzschild radius for that mass value
scarps mercury
Rutherford Atomic Struture
penumbral shadow light shadow
Canis major declination 30* south
moon Major geologic activity:
impact cratering
Doppler Effect wavelength has shifted
2 factors that affect gravity -mass
-distance
atmosphere a protective layer of air
star color related to star temperature
Saturn 6th planet well developed rings
electromagnetic radiation radiation consisting of electromagnetic waves, including radio waves, infrared, visible light, ultraviolet, x-rays, and gamma rays.
meteorite a meteoroid that actually reaches earth's surface
brown dwarf small star that has died
Photosphere The photosphere of an astronomical object is the region from which externally received light originates.
Plato argued that the perfect geometrical figure is a sphere; First principle says that since the heavens were perfect therfore it must be made up of spheres
Sirius the brightest star in Canis Major
guasar A enormously bright, distant galaxy with a giant black hole at its center.
Meteor showers are associated with ________ . comets
penumbra the partial or imperfect shadow outside the complete shadow of an opaque body, such as a planet, where the light from the source of illumination is only partly cut off
Radio Galaxy Very bright, often giant, elliptical galaxy that emits as much or more energy in the form of radio wavelengths as it does wavelengths of visible light.
What elusive particles are created by the sun that, when detected and their number estimated, allowed astronomers to figure out what nuclear fusion reaction powers it? Neutrinos
neutrinos product of the nuclear fusion of hydrogen into helium
crater a circular depression on a celestial body caused by the impact of a metroid asteroid or comet or by a volcano
Seasons The lengths separated into four and caused by the tilt of the earth
Sir Arthur Eddington calculated the temperature and pressures in the center of the Sun if it were made of pure hydrogen: T~15.000,000 K
revolve to move around another object. earth revolves around the sun. the moon revolves around earth.
What photon has the highest energy? Gamma rays.
Chromesphere layer of Sun above the photosphere, temperature 50,000K
telescope a magnifier of images of distant objects
Radio telescopes Collect radio waves - valuable information about size, composition and movement of stars and galaxies
chromosphere middle layer of the sun's atmosphere, "color sphere"
41. What gravitational lens was actually one object but appeared to have 5 identical dots ? Einstein’s Cross
hydrostatic equilibrium balance between gravity and the pressure of the hot gases in the stars core
Light Year the distance light travels in one year
arc minute An angular measure; each degree is divided into 60 arc seconds
Rocket Propulsion Newton's third law, you are lifting off the earth with more force than gravity can pull you down with
name two types of optical telescopes refracting and reflecting
blue This is the color of the hottest stars
horizon The junction between the earth and the sky
gas giants the four massive planets with huge gravity
Ejecta Blanket the ring of material surrounding a crater that was ejected during the crater-forming impact. **the moon.
Equinox - southern or northern hemisphere is s_____ tilted t___ or a__ the/away sun slightly, tilted, away
heliocentric cosmology a theory of the formation and evolution of the solar system with the sun at the center
Mercury the closest planet to the sun, has chortest period of revolution, named after the swift messenger of the Greek gods
Solar Wind Rapidly moving atoms and ions that escape from the solar corona and blow outward through the solar system
Ellipse A elongated circle, or oval shape, the shape of the planets orbit.
dark matter matter that does not give off electromagnetic radiation
Umbra It is cone-shaped and is the darkest part of the shadow during an eclipse.
our familiar constellations would look the same (shape wise) if we viewed them from
mars?
pluto?
a planet obiting a star on the other side of the milky way galaxy? 		true, true, false
A hot, low-density gas will emit what type of spectrum? Emission
solar flares eruptions of gas on the sun into space
Wien's Law Using this you will find that cool objects like cars, plants, and people radiate most of their energy in the infrared. Very cold objects radiate mostly in the radio band.
vernal equinox occurs in march and marks at the beginning of spring in the northern hemisphere
neutron star a tiny star that remains after a supernova explosion
Critical density the average amount of matter per cubic meter needed to close the universe
light years time is takes for light to reach us
Use of Doppler effect to tell how stars are moving
Waxing the changing phases of the moon as it becomes more fully illuminated between new moon and full moon as seen from earth
nebula a large cloud of gas and dust spread out in an immense volume
What is a planet? A "Moderately large" object that orbits a star. It can be rocky, icy, or gaseous. Has to be large enough to be spherical due to self-gravity
circular velocity The velocity an object needs to stay in orbit around another object
What is the formula for a change in an object's momentum/per unit of time? F=ma
potential energy the energy stored in an object as a result of it location in space
Additional information used to test these models is obtain from helioseismology (the study of vibrations on the Sun as a whole)
What is an Emission nebulae? Are sources of radiation--note the characteristic reddish glow from hydrogen emission.
falling stars or shooting stars Meteors are also called ______________ or _______________
Solar Nebula a rotating cloud of gas and dust that gave rise to Earth's early solar system.
suppose you put two protons near each other because of the electromagnetic force the two protons will repel each other
How are stars classified? Stars are classified by their size, temperature, brightness and color.
atrophy a wasting away of the body or of an organ or part, as from defective nutrition or nerve damage.
Jupiter and Saturn's magentic fields are closely aligned with the _______ axis and centered on the _______ center. rotation, planetary (caused by Dynamo effect)
What is maria? Maria are the dark, flat areas of the moon. These are hardened rock from lava flows that occurred billions of years ago.
How big is the universe? The observable universe is 14 billion light-years in radius and contains over 100 billion galaxies with a total number of stars comparable to the number of grains of sand on all of Earth's beaches
Absortion and emission of photons Light is absorved by atoms in gas
196,000 mps; 300,000 kps What is the speed of light in miles per second or kilometers per second?
what is the difference between a meteoroid, meteor, and meteorite? when asteroids break into fragments and fall to earth they're called meteroids. when they burn up in the atmosphere and produce a streak of light they're called meteors. when they collide with the ground they're called meteorites
How do you get the Stellar lifetime? stellar mass divided by stellar luminosity
What is inferred to be the source of the Sun's energy now? fusion reactions in the core
The original nebular hypothesis was ruled out early
on because 		the Sun rotates more slowly than was
expected
Why do astronomers think the Earth ended up with so little CO2 compared with Mars and Venus? Plant life and abundant water have removed most of the CO2, locking it into rocks and the oceans.
A (type II) supernova is believed to occur when the core of a massive star collapses
The reason why Jovian planets are believed to possess rocky cores is because C. otherwise they would be more oblate than they are
The reason why Jovian planets are believed to possess rocky cores is because A. they have strong magnetic fields
B. they are very massive
C. otherwise they would be more oblate than they are
D. they emit more heat than they receive from the Sun
E. otherwise they would become stars like the Sun
What happens at the end of a protostar stage? the protostar ignites and blows away the cocoon and becomes a star.
How does Mercury's rotation relate to the Sun? C. Its rotation rate is 2/3 as long as its year, due to tidal resonances with the Sun
How does Mercury's rotation relate to the Sun? A. It always keeps one face tidally locked toward the Sun, as our Moon does with Earth.
B. Its year is much shorter than Earth's
C. Its rotation rate is 2/3 as long as its year, due to tidal resonances with the Sun.
D. Mercury's rotation is retrograde
E. It does not spin at all, being stopped by the solar tidal forces