Astronomy 105 Flashcards

Terms Definitions
Diurnal Motion
Moon: Radius
1700 km
metallic hydrogen core
rejected aristotle's geocentric world
Discovered the Doppler effect.
Jocelyn Bell
rapid radio pulses
rapidly rotating object
cannot exist above 3 solar masses (Oppenheimer Volkoff limit)
italian mathematician and philosopher; used/invented telescopes to make observations of the sky; firm believer in the heliocentric solar system
the brightest stars are
blue giants
buildings in which professional astronomers who use optical telescopes are being housed
Term meaning "Of the sky"
a scarlet, gaseous envelope surrounding the sun outside the photosphere, from which enormous quantities of hydrogen and other gases are erupted.
facing North, see Big Dipper; constellation near western horizon
black dwarf
the star is now dead
outer planets
Jupiter, Saturn, Uranus, & Neptune
Polish astronomer who produced a workable model of the solar system with the sun in the center
Highland regions other than Aphrodite Terra include:
Isthar Terra
Alpha Region
Beta Region
Created Massive observatories, Made thier own calendar.
Mayan Civilization
an object which revolves around another object in space
first step in synthesis of elements
the Twins, a zodiacal constellation between Taurus and Cancer containing the bright stars Castor and Pollux
intercloud gas
a low-density region of the interstellar medium that fills the space between interstellar clouds
electromagnetic radiation
light. traveling disturbance in the electric and magnetic fields caused by accelerating electric charges
light year
electromagnetic waves traveling at a sonstand speed, a light year is the distance these waves travel in one earth year
name a type of coude focus
keck observatory
Other features of the cloud layers: typical colors-bright yellow, orange and red; the great red spot- a hurricane on Jupiter that is stable and always present
study of earthquakes, also tells us details about the interior
Nova explosions involve a white dwarf in a binary system.
critical density
the density corresponding to a universe in which gravity acting alone would be just sufficient to halt the present expansion
3.1st quarter
1/2 of sunlit side is seen
An enormous explosion of a giant star
Olympus Mons
mars, largest mountain in solar system, shield volcano
1 proton + 1 neutron (+1 electron)
TF the cosmological redshift is a direct measure of the expansion of the universe.
What method do astronomers use to measure the distances to nearby stars
Region around a planet where charged particles are trapped by the planets magnetic field:
jovian planets
gian gaseous planets similar in overall compostition to jupiter: jupiter, saturn, uranus, neptune
the study of the moon, stars, and other objects in space.
flares and prominences
bursts of energy from suns surface
great circle from the north point of the horizon, to the zenith, to the south point of the horizon, to the nadir, to the north point of the horizon
absolute magnitude
the actual brightness of a celestial object
reds and violets do not syncronize "picture is blurry"
chromatic aberration
Celestial Sphere
A hypothetical sphere of very large radius centered on the observer; the apparent sphere of the night sky.
Waxing Gibbous
Rising later in the afternoon, second week since new moon has passed
the distance that light travels in one year (p104)
Barnard's star
-One of closest stars to earth
-has largest proper motion (10.3"/year)
The earth appears to set in this direction.
a year
period of one orbit around the sun
How much better resolution would a 60 mm objective lens have than your eye's 6 mm exit pupil?
arms of galaxies
where are Population I stars located?
Greenhouse Effect
The trapping of heat from the atmosphere
Elliptical Galaxies
Galaxies that look like round or flattened balls
(adj) daily [motion of an object in the sky]
(of the moon) pertaining to the period during which the visible surface of the moon decreases
Newtonian telescope
reflecting telescope with a mirror at the prime focus so you don't have to stick your head in. you would have to stick your head into a prime focus telescope.
sun spot
one of the relatively dark patches that appear periodically on the surface of the sun and affect terrestrial magnetism and certain other terrestrial phenomena.
Kuiper Belt
the region of the solar system outside the orbit of Neptune that is occupied by small, icy, cometlike bodies
Irregular Galaxy
These galaxies do not hae a well defined shape or structure. The stars in these galaxies are all so young which causes the blue tint.
event horizon
a region inside of which nothing can escape; if something crosses this, it will be pulled into the black hole
The rise and fall of the level of water in the ocean.
Lunar Eclipse
The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon
is the measure of the amount of matter in an object.
solar flare
an eruption of gas from the sun's surface that occurs when the loops in sunspot regions suddenly connect
Explain the history of these constellations. How did they come into existence? Why did people group stars into constellations?
Ancient Mesopotamians, Babylonians, Egyptians & Greeks grouped the stars into constellations thousands of years ago so that they could remember the patterns and use the stars to tell time, etc. They chose the patterns and names they did to honor gods, heroes, and animals.
Modern constellations were named to fill in gaps among the ancient constellations, especially in the southern hemisphere's sky since the ancient civilizations from which we get our constellations were all in the northern hemisphere. This may explain why many southern hemisphere constellations are simple shapes instead of elaborate stories.
the spinning motion of a planet on its axis
in terms of absolute numbers the most common galaxies are
dwarf ellipticals
Molecular-Cloud Cores
A dense clump within a molecular cloud that forms as the cloud collapses and fragments. Protostars form from molecular-cloud cores
Project Apollo
final stage of the U.S. space program to reach the Moon, with Apollo II landing on the Moon's surface on July 20, 1969.
Vernal equinox
The start of spring in the northern hemisphere.
convection zone
the outer most layer of the sun's interior-hot gases rise and eventually cool as they approach the top
light-gathering power
the ability of a telescope to collect light - proportional to the area of the telescope's objective lens or mirror
Angular Size
the angle it appears to span in your field of view (does not tell us true size because it depends on distance) (further away objects smaller angular size)
proper motion
the change in the location of star on the celestial sphere
heliocentric model
the sun is the center of the solar system
Missing Red Dwarfs?
Red dwarfs that would be expected fi they existed in sufficient quantities to account for the dark matter in the Galaxy are not found in this highly sensitive observation with the HST.
how long does it take earth to rotate on its axis once?
a day
first surface mirror
Mirror is coated on surface of glass, usually molecules-thick coating of aluminum or silver
white dwarf
What will be the final fate of the sun?
Kepler's 3rd Law
More distant planets orbit the Sun at slower average speeds (p squared equals a cubed), p=a^1.5
supermassive star
a star with a mass more than fifty times the mass of the sun.
Kepler's second law
A line joining the planet and the sun sweeps out equal areas in equal amounts of time. (the woosh law) Planets move faster when near the sun.
Astronomical Unit (AU) - Define:
Equals about 150 million km
Or about 93 million miles.
Average distance between the earth and sun.
about a third of the way down to the center, energy moves outwards primarily in the form of photons of light
radiation zone
The scarps on Mercury were probably caused by
D. the crust cooling and shrinking
The scarps on Mercury were probably caused by
A. tectonic activity
B. meteorite bombardment
C. a tidal bulge
D. the crust cooling and shrinking
E. volcanism
Eccentricity is a measure of
how oval or elliptical the orbit is (highest =1, line) (lowest=0,
perfect circle)
Newton's 1st Law of Motion
Law that states: A body at rest remains at rest, and one moving in a straight line maintains a constant speed and same direction unless it is deflected by a ``force
The altitude of Polaris equals
the latitude of the observer (Use ESRT for Cities in NYS).
What are light years used to measure?
they are used to measure distances outside our planetary system.
spectral type organization (highest temp to lowest)
o, b, a, f, g, k, m.
only bad astronomers forget general known mnemonics
How is the color of a star related to surface temperature?
They are directly related
Newton's 3rd Law of Planetary Motion
For every action there is an equal and opposite reaction.
A solar mass star will evolve off the main sequence when
D. hydrogen has been completely converted into helium in the core
A solar mass star will evolve off the main sequence when
A. it completely runs out of hydrogen
B. it expels a planetary nebula to cool off and release radiation
C. it explodes in a violent nova
D. hydrogen has been completely converted into helium in the core
E. it loses all its neutrons, so fusion must cease
central region of Earth's core are a solid
the pressure at the center raises the melting point
The observed spectral liens of a star are all shifted towards the red end of the spectrum. Which statement is true?
B. This is an example of the Doppler effect
The observed spectral liens of a star are all shifted towards the red end of the spectrum. Which statement is true?
A. This is an example of the photoelectric effect
B. This is an example of the Doppler effect
C. The second law of Kirchhoff explains this.
D. The star is not rotating.
E. The star has a radial velocity towards us
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