Astronomy test 3 quizzes

The ___________ galaxy is the closest big galaxy to our milky way

Andromeda

_______ forces that caused the gas in the thin disk to fragment into clouds or clumps with masses like those of star clusters

Gravitational

T or F In general theory of relativity, the Einstein field equations relate the geometry of space-time with the distribution of matter within it

True

T or F a globular cluster is spherical collection of stars that orbits a galactic core

True

the very strong source of radio waves at the center of our Galaxy is called a. Sagittarius A b. Cygnus X-1 c. the Crab Nebula d. Milky Way CC1 e. Benford G1

a. Sagittarius A

to predict whether a star will ultimately become a black hole, what is the key property of the star we should look at a. mass b. surface temperature c. color d.distance e. diameter

a. mass

where in the sun does fusion of hydrogen occur a. only in the core b. only near the photosphere(its visible surface layer) c. pretty much throughout the entire body of the sun d. only in the layer where there is a lot of convection going on e. nowhere

a. only in the core

which type of galaxy is observed to contain mostly older stars a. spiral b. elliptical c. dwarf elliptical d. irregular e. none of the above

b. elliptical

Our Milky Way is what type of galaxy. a. elliptical b. spiral c. dwarf elliptical d. irregular e. none of the above

b. spiral

at the end of the p-p chain of nuclear fusion in the sun, hydrogen nuclei have been converted into a. carbon dioxide b. heavy hydrogen nuclei c. antimatter and nothing else d. a helium nucleus e. a lithium nucleus

d. a helium nucleus

in the sun when a positron and an electron collide they will produce a. a deuteron b. a neutron c. hydrogen d.a neutron e. energy in the form of a gamma-ray

e. energy in the form of a gamma- ray

when a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called a. nuclear fusion b. nuclear binding c. the p-p chain d. equilibrium breaking e. nuclear fission

e. nuclear fission

Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us the a. brighter it looks b. bluer its color c. the later in its life we are seeing it d. the larger its halo is e. the faster it is moving away from us

e. the faster it is moving away from us

______ equilibrium says that there is a balance between two forces at every point within a star. one force is the inward force of gravity. the other forces is the pressure in the gas caused by its temperature

hydrostatic

A large explosion that takes place at the end of a star's life cycle is called _______

super nova

T or F the bubbles in the galaxy may be evidence that the supermassive black hole at the center of our galaxy was a quasar a few million years ago

true

T or F dwarf elliptical galaxies are elliptical galaxies that are smaller than ordinary elliptical galaxies

True

T or F energy is generated in the core by the fusion of hydrogen to form helium

True

T or F gravitational forces caused gas in the thin disk to fragment into clouds or clumps with masses like those of star clusters

True

T or F luminosity is an absolute measure of radiated electromagnetic power(light) the radiant power emitted by a light-emitting object

True

after several decades of observation, astronomers have concluded that quasars are a. very powerful and compact sources of energy at the centers of distant galaxies b. projectiles shot out of our own galaxy and moving out into intergalactic space c. energetic collisions of comets in the Oort Cloud d. anti-matter stars in the halo of the milky way galaxy e.a completely baffling mystery with no

a. very powerful and compact sources of energy at the centers of distant galaxies

physicist Kelvin and Helmholtz in the last century proposed that the source of the sun's energy could be a. radioactive rocks b. a slow contraction c. meteorites falling in d. the annihilation of antimatter e. nuclear fusion

b. a slow contraction

Which of the following is NOT a characteristic of a spiral galaxy a. most of its material is in the shape of a flattened disk b. it has quite a bit of gas and dust in it c. it has young stars and bright emission nebulae d. when we take spectra of its stars they have far less of the heavier elements than the sun e. the bright stars in it can be seen organized into distinct spiral arms

b. it has quite a bit of gas and dust in it

what happens to the positron created during the p-p chain of nuclear reactions inside the sun a. it merges with a proton to become a deuterium( heavy hydrogen) nucleus b. it quickly collides with an electron and turns into gamma-ray energy c. it ultimately forms an anit-helium nucleus d.it turns quickly into a neutrino which can escape the sun e. it just sits there at the top of the sun for billions of years unable to interact

b. it quickly collides with an electron and turns into gamma-ray energy

in the first direct detection of gravitational waves by LIGO in 2015 the waves came from a. the collapse of a nearby star into a white dwarf b. a supernova explosion in a nearby galaxy c. the merger of two black holes d. the rapid motion of three hot jupiter planets around a nearby star e. the dashed hopes of all the people in the U.S. who want their government to work well for them

c. the merger of two black holes

Edwin Hubble developed a classification scheme for galaxies. By what characteristic did he classify galaxies a. their brightness b. their overall color c. their shape d. their abundance of the element iron e. their Doppler Shift

c. their shape

compared to the mass of our own milky way galaxy the total mass we estimate for the andromeda galaxy is a. a lot smaller b. a little bit smaller c. exactly the same d. somewhat bigger e. not something we can measure

d. somewhat bigger

Which of the following statements about the nuclear bulge of our Galaxy is FALSE a. it is significantly thicker than the disk of the Galaxy b. it typically consists of older stars c. it is difficult for us to see with visible light because of cosmic dust d. the best way to learn more about it is to observe higher energy radiation such as ultraviolet and x-rays e. there is evidence that it is not exactly spherical, but elongated

d. the best way to learn more about it is to observe higher energy radiation such as ultraviolet and x-rays

once a black hole forms the size of its event horizon is determined only by a. the size(diameter) of the star that collapsed into the black hole b. the mass inside the event horizon c.the time since the black hole formed d. the commotion of the material that formed the black hole e. you can't fool me; every black hole has an event horizon of the same size

d. the commotion of the material that formed the black hole

If a nearby galaxy still acts like a quasar today, what is the most likely explanation? a. the galaxy was formed recently, and is just now going through its adolescence b. the galaxy must have an enormous doppler shift and must have traveled here from a large distance away c. the galaxy must be made entirely of very massive stars; very few low mass stars exist in it d. the galaxy must be undergoing a collision with another galaxy that is providing fresh fuel for its central black hole e. the dark matter in the galaxy must be undergoing a transformation into matter we can see

d. the galaxy must be undergoing a collision with another galaxy that is providing fresh fuel for its central black hole

how do quasars demonstrate that the universe evolves with time a. there were very few quasars long ago and their numbers have been growing since b. quasars began emerging only about a billion years ago and how there are many more than ever c. quasars have been around since the big bang but the radiation they give off gets stronger and stronger as time in the universe goes on d. the number of quasars reached a maximum some time ago and now the numbers have been declining e.quasars actually don't demonstrate any evolution; the number has been pretty constant for the entire history of the universe

d. the number of quasars reached a maximum some time ago and now the numbers have been declining

T or F nuclear fusion: a nuclear reaction in which atomic nuclei of high atomic number fuse to form a heavier with the release of energy

False

why do astronomers think that there are fewer quasars today then there were billions of years ago a. quasars are seen when the supermassive black hole at the center of a galaxy has a lot of food to eat (stars and gas) and the amount of available food tends to decrease with time b. quasars are supermassive black hole at the centers of galaxies and such black holes are constantly losing mass and thus getting less and less able to pull on anything c. quasars tend to merge all the time and so there are fewer and fewer of them as time goes on d. quasars are caused by many supernovae going off at the same time and massive stars only exploded in the early history of the universe they don't explode today e. no one has the slightest idea on how to answer this question it is completely unsolved

a. quasars are seen when the supermassive black hole at the center of a galaxy has a lot of food to eat (stars and gas) and the amount of available food tends to decrease with time

for galaxies that have supermassive black holes at their centers how do astronomers find that the mass of the host galaxy and the mass of the black hole are related a. the more massive the galaxy the more massive the central black hole b. the more massive the galaxy the less massive the central black hole c. all supermassive black hole has roughly the same amount of mass d. once the mass of a galaxy reaches a certain size it is not possible to form a black hole in the center at all only galaxies smaller than this limit can have central black holes e. none of the above

a. the more massive the galaxy the more massive the central black hole

Herschel was right about a. the shape of our system but wrong about where the sun lies within the disk b. where the sun lies within the disk but wrong about the shape of our system c.the shape of our system and where the sun lies within the disk d. none of the above

a. the shape of our system but wrong about where the sun lies within the disk

which of the following objects is considered useful to astronomers as a standard bulb for determining distances a. type Ia supernovae b. planets that resemble earth c. K-type stars d. the brightness of the bulge in a galaxy center e. the size of the largest diameter open cluster in a galaxy

a. type Ia supernovae

what observations in astronomy made AFTER the discovery of quasars was a big help to astronomers in figuring out what quasars really were a. the understanding that most stars become white dwarfs when they die and white dwarfs are much smaller than main-sequence stars b. the discovery that the milky way galaxy has a black hole at the center with enough mass for 4 million suns c. the discovery that the galaxies mostly show a redshift d. the discovery of exoplanets(planets orbiting other stars) throughout the galaxy e. the discovery of Herbig-Haro objects around newly forming stars

b. the discovery that the milky way galaxy has a black hole at the center with enough mass for 4 million suns

the Andromeda Galaxy (our nearest spiral neighbor) has spectral lines that show a blue shift. From this we may conclude that: a. the universe is no longer expanding b. this particular nearby galaxy is moving toward us c. this galaxy has merged with the milky way and is now part of it d. this particular nearby galaxy is moving away from us e. this galaxy has a number of very bright and hot O type stars in it

b. this particular nearby galaxy is moving toward us

which of the following objects do many astronomers believe is a black hole a. the nebula in Orion where new stars are seen to form (from dark dust clouds) b. the crab Nebula c. Cygnus X-1 d. the open cluster called the Pleiades e. Bayonne, new jersy

c. Cygnus X-1

which type of galaxy is very difficult to see but (astronomers recently realized) may be very common a. spiral b. elliptical c. dwarf elliptical d. irregular e. none of the above

c. dwarf elliptical

if you are in a freely falling elevator near the top of a tall building as the elevator falls your weigh would be: a. the same as your usual weight b. a little bit less than your usual weight c. equal to zero-- you would be weightless d. a little more than usual weight e. so great that you would be pressed to the floor in great pain

c. equal to zero-- you would be weightless

where would you look for the youngest stars in the Milky Way Galaxy a. in the halo b. where there is dark matter c. in the disk d. in the nuclear bulge e. you can't fool me; my chances of finding a very young star are the same, wherever in the Galaxy I look

c. in the disk

what method would astronomers use to find the distance to a remote quasar a. parallax b. Cepheid variables c. measuring the size of its dark matter halo d. finding the redshift and using Hubble's law e. the turnoff point of the main sequence on an H-R diagram

d. finding the redshift and using Hubble's law

most spiral galaxies consist of a. flat, rotating disk containing stars b. gas and dust c. gas dust and bulge d. flat, rotating disk containing stars, gas, dust, and bulge

d. flat, rotating disk containing stars, gas, dust, and bulge

what was especially noteworthy about the Sagittarius dwarf galaxy when it was discovered among the small galaxies near the milky way a. it was so large in mass astronomers could not understand how the milky way wasn't flying toward it b. it had a supermassive black hole in the center much larger than the milky way c. it was rotating so quickly that it could not hold together for very long d. it was on a collision course with the milky way and would be swallowed by it eventually e. it was made entirely of dark matter and so could not be seen on any photographs

d. it was on a collision course with the milky way and would be swallowed by it eventually

how are galaxies and quasars related a. quasars can be seen in front of galaxies but they have nothing to do with them b. quasars can only be seen behind galaxies but they have nothing to do with them c. quasars and galaxies are never seen together and they have nothing to do with each other d. quasars are active supermassive black holes at the centers of galaxies e.quasars are a complete mystery so it is not possible to say how they might be related to galaxies

d. quasars are active supermassive black holes at the centers of galaxies

T or F a stellar black hole (or Steller-mass black hole) is a black hole formed by the gravitational collapse of a star

True

T or F elliptical Galaxy: a galaxy with an elliptical shape, little interstellar matter and spiral arms

False

______ is the force resisting the relative motion of solid surfaces fluid layers and material elements sliding against each other

Friction

T or F astronomers us the redshift and using Hubble's Law to find the distance to a remote quasar

True

T or F collapsar is the shortened form to describe a collapsed star. When an old star no longer has enough fuel for significant fusion reactions

True

when astronauts aboard the International Space Station (ISS) in space let go of an orange it just floats there. Why is that a. the ISS is so far from the earth the gravity is essentially zero b. the ISS is falling around the earth and is in free fall, things feel no weight c. spacetime is so different aboard the ISS that time stops and so nothing can fall d.the law of gravity only works on the earth, it doesn't work in space e. this is an unsolved problem in science and so it is fruitless to worry about it

b. the ISS is falling around the earth and is in free fall, things feel no weight

what have we learned from the work of Harlow Shapley and others about the location of the sun in the Milky Way Galaxy a. we are almost exactly in the center of a giant flat pinwheel b. we are very close to the edge of the visible disk of the Galaxy, more than 50,000 LY from the center c. we are high above the disk of the galaxy about as far away as the most distant globular cluster d. we are in the disk of the galaxy about 3/5 of the way from the center e. you can't fool me because of all the dust astronomers still have no idea where our sun is located in the milky way galaxy

d. we are in the disk of the galaxy about 3/5 of the way from the center

which of the following can a black hole NOT eat(swallow) a. a planet b.a cloud of gas and dust c. a star d. another black hole e. you can't fool me black holes can eat anything

e. you can't fool me black holes can eat anything

The type of galaxy that consists almost entirely of old stars and is thus less blue (more yellow and reddish) than the other types is _______

elliptical