ASTR 101 Final - Flashcards

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Scientific notation is used in science because...	It makes it easy to write big or small numbers all astronomical distances are expressed in metric units it makes conversions between units easy ALL OF THE ABOVE
The average distance from the Earth to the sun is..	I AU
The sun is...	A star; I AU from earth; more than 100 times the diameter of earth; ALL OF THE ABOVE
A galaxy contains:	gas, dust, stars, and a lot of dark matter
The Milky way Galaxy...	Contains about 100 billion stars
2.9 x 10^7 is the same as...	29 million
Arrange the following in order from smallest to largest...Kilometer, light-year, yard, AU	Yard, Kilometer, AU, Light-year
It takes 1.3 seconds to travel from the moon to earth and 8 minutes to travel from the sun to the earth. Which of the following statements is true?	The sun is 370 time further from earth than the moon
If light takes 8 min to travel from the sun to earth and 5 hr to travel from the sun to pluto, what is the distance from the sun to pluto?	37.5 AU
The speed of light is 3.0x10^5 km/sec, and it takes 1.0 sec for light to travel from the moon to earth. From this information, what is the distance to the moon?	390,000 km
If the distance to nearest star is 4.2 light-years, then	The light we see left the star 4.2 years ago
The Milky way galaxy is...	A spiral galaxy; part of a cluster of galaxies, about 75,000 light years in diameter; ALL OF THE ABOVE
Which sequence is correct from smallest to largest: earth, galaxy clusters, milky way, solar system	Earth, solar system, milky way, galaxy clusters
How is a planet different from a star	Planets reflect light while stars produce their own
If the distance from the sun to the earth is roughly 15 meters, then the distance from the earth to the moon would be...	smaller than your hand
Seen from the northern latitudes, the star Polaris..	is always above the northern horizon
The celestial equator is	a line around the sky directly above Earth's equator; the dividing line between the north and south celestial hemispheres; A AND B
The ______ is the point on the celestial sphere directly above any observer	Zenith
Constellations names are in...	Latin
Most star names, such as Aldebaran and Betelgeuse are..	Arabic
The magnitude scale	can be used to indicate the apparent intensity of a celestial object
The apparent visual magnitude of a star is a measure of the star's...	intensity
The star Vega has an apparent magnitude of .03 and the star HR 4347 has an apparent magnitude of 4.87. It has been determined that both are the same distance from earth. What does this tell us?	Vega must produce more energy than HR 4374
The ______ of an object depends on the diameter of the object and the distance to the object	apparent diameter
An observer's nadir is...	the point directly opposite the observer's zenith
A(n) _____ is one-3,600th of a degree	second of arc/arc-second
The Big Dipper is...	an asterism
Procession of the rotation axis of earth is caused by...	the force of gravity from the sun and moon on earth's equatorial bulge
An observer in the northern hemisphere watches the sky for several hrs. Due to the motion of earth, this observer notices that the stars near the north celestial pole appear to move...	counter clockwise around the celestial pole
You live at a latitude of 73*N. What is the angle between the northern horizon and the north celestial pole?	73*
You live at a latitude of 39*S. What is the angel b/w the southern horizon and the south celestial pole?	39*
If the north celestial pole appears on your horizon, what is your latitude/	0*
which star on the right would appear brightest to an observer?[TABLE]	alpha CMa
Based on the info int he table to the right, what is the ratio of the intensity of Delta Dra to that of Nim? [TABLE]	100
Which star in the table would not be visible to the unaided eye of an observer on earth?	Nim
Star A has an apparent visual magnitude of 13.4. Star B = 15.4. Star A is _____than star B	6.3 times brighter
Polaris is a 2nd magnitude star, and Phi Pegasi is about 16 times fainter. What is magnitude of Phi Pegasi?	5
Which of the following correctly describes the relationship between stars and constellations?	Every star is located in a constellation
How much of the night sky is north of the celestial equator?	Exactly 1/2
If the sun passes directly overhead on at least one per day per year, then,	you are within 23.5* latitude of the equator
If you are standing at the earth's north pole, which of the following would be located at the zenith?	The north celestial pole
For stars in the same constellation, they	may actually be very far away from each other
During June the north celestial pole points towards polaris but during the Dec it points	still towards polaris
If the earth's period of rotation is doubled, but the period of revolution stayed the same...	the night would be half as long
The [DIAGRAM] shows 3 app. locations along western horizon. Which indicates sunset on 12-21 at a latitude of 48*S?	1
[DIAGRAM] sunset on 6-21 for 37*N	3
[DIAGRAM] sunset 6-21 at latitude 77*N	The sun will not set on June 21 at the latitude
[DIAGRAM] sunset at vernal equinox at 48*S	2
The ecliptic is...	The centerline of the zodiac; the projection of earth's orbit on the sky; the apparent path of the sun around the sky; ALL OF THE ABOVE
At what two celestial locations do the celestial equator and ecliptic coincide?	Vernal equinox autumnal equinox
On the vernal equinox, the sun is...	on the celestial equator and moving north wrt the equator
A solar or lunar eclipse will occur..	when the sun is near the line of nodes of the moon and the moon is new or full
The sideral period of hte moon...	is about 27.32 days long; is the period of time for the moon to orbit earth wrt the stars; BOTH A AND B
without the moon, which of the following are true?	...
The moon has an angular diameter of .5*. What is the moon's angular diameter in minutes of arc?	30
If the plane of the earth's equator were not tilted wrt to the ecliptic plane...	the daylight period of earth would be the same year-round; there would be no seasonal changes; earth's poles wold not experience six month long nights; ALL OF THE ABOVE
The phase of the moon on a particular night is determined by...	the relative positions of th sun, earth, and moon
On a clear night when an observer in LA sees a 1st quarter moon, an observer in london would see...	a first quarter moon
The moon's angular diameter in our sky is measured to be .5*. From this we can find...	diameter of the moon if we know the moon's distance
The lowest amount of solar energy per square meter is incident upon the surface of earth in the northern hemisphere on or about...	December 21, the winter solstice
Which of the following did not accept a heliocentric model for the universe?	Tycho
Parallax is...	the apparent motion of an object due to the motion of the observer
The copernican system was no more accurate than the ptolemaic system in predicting the positions of the planets because...	the copernican system included uniform circular motion
Galileo's telescopic discoveries of mountains on the moon and spots on the sun were controversial because they suggested that the sun and moon...	were not perfect spheres
Tycho's universe was the same as the copernican universe except that...	earth did not move
Tycho brahe's greatest contribution to astronomy was...	his 20 years of careful observations of the planets
When we say that the gravitation is universal, we mean that...	it is a property of all matter
Newton concluded that some force had to act on the moon because...	a force is needed to pull the moon away from straight-line motion
Kepler's second law implies that...	a planet should move at its greatest speed when it is closest to the sun
Kepler's first law of planetary motion implies that...	the distance between the planet and the sun changes as the planet orbits the sun
Gravity obeys an inverse square relation. This statement implies that the force due to gravity between two masses...	will decrease as the square of the distance b/w the two masses increases
The force due to gravity between two objects depends on...	I & III; the mass of each object; the distance b/w the two objects
An object has been located orbiting the sun at a distance from the sun of 65 Au; what is the app. orbital period?	524 years
Saturn is on average 10 AU from the sun. What is the app orbital period of saturn?	32 years
In pre-copernican astronomy, it was almost universally believed that...	the earth was the center of the universe
When mars is located directly behind the earth wrt the sun in its orbit, it is...	at the midpoint in the sky bewteen east and west at midnight
The greatest inaccuracy in copernicus' model of the solar system was that the planets...	travel in circular orbits with uniform motion
Which of the following statements describes Kepler's 3rd law of planetary motion?	The larger the orbit, the longer its orbital period
_____ has wavelengths that are longer than visible light	Infrared radiation
____ have wavelengths that are shorter than visible light?	I, II, IV; Gamma-rays, ultraviolet light; x-rays
The energy of a photon	is inversely proportional to the wavelength of the light
Long wavelength visible light	will appear red in color to the average human eye
Photons of blue light	have a greater energy than photons of red light
A nanometer is...	a unit of length
What is the relationship between color and wavelength for light?	wavelength increases from blue light to red light
In which way does a photon of blue light NOT differ from a photon of red light?	speed
The neutral hydrogen atom consists of	one proton and one electron
The process of removing an electron from a stable nucleus is known as...	ionization
The two most abundant elements in the sun are...	hydrogen and helium
Which of the following can be determined by using the Doppler effect?	I, III, IV; the speed at which a star is moving away from an observer; the radial velocity of a star; the speed at which a car is traveling toward an observer
[DIAGRAM] shows a light source, gas cloud, and 3 diff straight lines. Which line would you see an absorption spectrum?	3
The [TABLE] shows spectral types of five stars; which would have the lowest surface temp?	Cet
The [TABLE] lists spectral types. Which star would have the greatest surface temp?	Per
Two stars of the same spectral class must have the same...	temperature
The radiation emitted from a star has a maximum intensity at a wavelength of 300 nm. What is the temp?	10,000 K
At what wavelength would a star radiate the greatest amount of energy if the star has a temp of 60,000 K	50 nm
The sun has a temp of app 5800 K. At what wavelength does the max energy radiated by the sun occur?	520 nm
One star has a temp of 30,000 K and another 60,000K. How much more energy/sec will the hotter star radiate?	625 times
One star has a temp of 10,000K and another 5,000K. How much more energy/sec will the hotter star radiate?	16 times
How much energy is radiated each second by one square meter of a star whose temp is 10000 K?	5.67x10^8 J
The H delta line has a wavelength of 410.2 nm in the lab. If it appears in a star spectrum at 410.0, what is the radial velocity?	146 km/sec toward the observer
The H[delta] line has a wavelength...	146 km/sec TOWARD observer
The Hy line has a wavelength...	346 km/sec AWAY from observer
What is the order of star colors with increasing temperature	Red, yellow, blue
Each element has its own set of characteristic absorption lines because	electron energy levels differ for each element
The Doppler effect states that the motion of any object can...	shift the wavelength of spectral lines
Granulation is caused by	rising gas below the photosphere
Most of the light we see coming from the sun originates in the	photosphere
The sun creates its energy by the process of	nuclear FUSION
The chromosphere of the sun	is hotter than the photosphere
The diagram at the right shows a plot of temp of the sun...	2300 km; other question is 9000 K
Sunspots	are cooler than their surroudings
The ___ is/are the hot gases that are the moving extension of the sun's corona	Solar wind
If a sunspot=4500 K and surroundings=5800, how many times brigther?	2.8
If the spectrum of a sunspot shows that it has a maximum at 650 nm, waht is temp of sunspot	4600 Kq
What are three layers of suns atmosphere, in order of increasing distance from the surface?	Photosphere, chromosphere, corona
A star's luminosity depends only on the star's	temperature and diameter
In an HR diagram, stars with smallest radius are found in the ___ of the diagram	lower left
We know that giant stars are larger in diameter than the sun because	they are more luminous but have the same tempreautre
Which star in the diagram is most like the sun?	HR 5337
Which star in the diagram has the greatest surface temp?	Alnilan
Which of the stars in the diagram has the largest absolute visual magnitude?	Sirius B
Which of the following stars in most dense?	a white dwarf
If a star has a parallax of .02 sec of arc, then its distance is...	50 pc
If a star with an absolute mag of -5 has an apparant mag of +5, then its distance is..	1000 pc
Which star in the table above would appear the faintest in the night sky?	65 Tau
Which star in the table above has the greatest luminosity	58 Ori
Which star in the table above is closest to the earth?	HR 2491
Which star in the table above has the greatest surface temperature?	HR 4621
If you compare two stars...	the one with the smaller absolute magnitude will always have greater luminosity
Interstellar gas clouds may collapse to form stars if they..	encounter a shock wave
The average star spends ___ of its lifetime on the main sequence	90%
What causes the outward pressure that balances the inward pull of gravity in a star?	the outward flow of energy
The free-fall contraction of a molecular cloud...	can be initiated by shock waves from supernovae
Which of the following is not evidence of the existence of an interstellar medium?	molecular bands in the spectra of cool stars
Due to the dust in the interstellar medium, a star will appear to an observer on earth to be..	fainter and cooler than it really is
The extinction of starlight due to the interstellar medium...	I & IV; is the greatest in the ultraviolet, is caused by dust particles
Stars are born in	dense molecular clouds
while on the main sequence, a star's primary energy source comes from	nuclear FUSION
What force(s) are responsible for the collapse of an interstellar cloud?	gravity
Why do higher mass stars live shorter lives on the main sequence than lower mass stars?	high mass stars burn through their nuclear fuel faster
As a star exhausts hydrogen in its core, it..	becomes cooler and more luminous
A Type Ia supernova is believed to occur when..	a white dwarf exceeds the chandrasekhar limit
A type-II supernova..	C&D; is characterized by a spectrum that shows hydrogen lines; occurs when the iron core of a massive star collapses
Which of hte following is not a characteristic of hte stars of the disk component of our galaxy?	randomly inclined orbits
Younger stars have more heavy elements because...	the heavy elements were made in previous generations of stars
Radio maps of our galaxy show spiral arms because	the gas in spiral arms is denser
_____ of the milky way contains mostly population II stars and globular clusters	The spherical component
___in other galaxies shoudl contain luminous O and B stars if they are like the milky way	the spiral arms
The period-luminosity relation is useful in determining...	the distance to globular clusters that contain cepheid variables
____is believed to dominate the mass content of the galaxy	dark matter
Population II stars ...	III & IV; are primarily old low mass stars; are located in globular clusters
The orbits of population I stars	I & III; are confined to disk of the galaxy; are nearly circular
The traditional theory states that the galaxy formed...	as a large spherical cloud of gas that was rotating very slowly
A Type-II cepheid has been located in a distant globular cluster with a period of 10 days; what is the abso. mag?	-1
Which of the following can't be associated with the spiral arms of a galaxy?	metal poor stars
What behavior do galactic rotation curves exhibit to suggest the existence of dark matter?	large velocities are seen at large distances from the galactic center
A mega-parsec is equivalent to..	3,260,000 light years
The hubble law is a relation between a galaxy's	distance and recession velcoity
Gravitational lensing	occurs when light passes near a massive object and is deflected by the object's gravitational field
the look-back time is...	a&b; the time it takes for the light from an object to reach earth; numerically equal to the distance in light-years
Most of hte mass of a galaxy is contained in the	dark matter of a galaxy
___galaxies have no obvious spiral arms or nucleus	Irregular
Suppermassive black holes are believed to be located at the center of many galaxies because	the orbital motion of material near the center is very fast and indicates a very massive core
what is the hubble's constant essentially a measure of?	the expansion of the universe
what is the primary factor in determining the classification for an elliptical galaxy?	shape
what distance method is used to calibrate the hubble constant?	supernova observations
the hubble time is	an estimate of the age of the universe based on hubble's constant
when a proton and an antiproton collide	they destroy each other and produce energy in the form of gamma rays
as the universe cooled, it eventually reached a temp....	recombination
what was the temp when the recombination took place?	about 3000 K
In 1998 is was announced that the expansion of the universe is accelerating. what does this imply?	a force exists that we knew nothing about that causes the expansion
the cosmic background radiation comes from a time in the evolution of the universe...	when electrons began to recombine with nuclei to form atons
whether the universe if open,closed, or flat depends on...	density
current evidence suggests that the universe is...	flat, infinite, and accelerating in its expansion
what observational evidence supports the fact that our universe is expanding?	redshift of galaxies
where did the cosmic microwave background (CMB) come from?	photons released when electrons and nuclei combined for the first time
why is the CMB so cold if the early universe was so hot?	the expansion of the universe has redshifted those photons to an effectively cooler temperature
what observation has prompted astronomers to ponder the possible existence of dark energy?	supernovae appear fainter than expected at large redshifts
microlensing refers to	gravitational lensing by stellar object with Einstein rings around microseconds
Plants around stars other than the sun	have been found by astronomers using several different methods
What limitation(s) make it impossible to travel between stars?	II & III; the tremendous distance; the finite speed at which objects travel
how are galaxies distributed in the universe?	they are group in clusters and superclusters, connected by chains, surrounding large empty voids
which of the following is not a method for searching planets around stars other than the sun?	accurate measurement of the temperature of the stars


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ASTR 101 Final - Flashcards

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