Earth and space test 2: dark matter/energy and constellations

what are the stars of the 13 zodiacs/constellation?

(capat/gcllv/sos) 1. Capricorn 2. Aquarius 3. Pisces 4. Aries 5. Taurus 6.Gemini 7.Cancer 8.Leo 9.Virgo 10.Libra 11.Scorpio 12.Ophiuchus 13. Sagittarius

STATE THE FOLLOWING DEFINITION: what is dark matter?

(first mentioned by Fritz Zwicky) a mysterious, invisible substance that makes up the universe. It doesn't absorb,reflect or emit light. Dark matter is made up of non-baryonic matter and makes up approx. 27% of the universe.

EXPLAIN THE FOLLOWING TYPE OF GALAXY elliptical

(the largest type of galaxy) galaxies that have an elliptical (round) shape. they are more 3D shape, without much structure, and their stars are in random orbits around the center.

we know that the likelihood of star collision is about zero when 2 galaxies collide. But the space in between is full of gas and dust. What do you think will happen when during the merger?

1. Dust & gas will gather because of gravity 2. the bigger clusters will form stars because of fusion 3.smaller clusters will form planets 4.the result is a solar system

what are the autumn constellations??

1. andromeda 2. aquarius 3.capricorn 4.pegasus 5.pisces

what are the summer constellations??

1. aquila 2. cygnus 3. hercules 4. lyra 5. ophuicus 6. sagittauris 7. scorpious

what are some of the ideas/theories of dark matter?

1. dark matter consist of a new subatomic particle that we haven't discovered yet 2. dark matter is a quantum defect from the birth of the universe, extra-dimensional mass, and even a modified form of gravity

give two reasons why its necessary to identify stars in the "olden days"

1. farmers use the stars to identify the season for harvesting 2. sailers used stars to guide & give directions

how can you find the big and little dipper in the sky??

1. the big dipper has two parts- a bowl & a handle 2.look @ the outer two stars in the bowl of the big dipper (merek and dubhe). These stars are called the "pointers" b/c they point to the north star (polaris) 3. once you've spotted polaris, you know that the polaris is the last star in the handle of the little dipper

1. what is (weak) gravitational lensing? 2. what is weak gravitational lensing used for?

1. the distortion of light from more distant galaxies by the mass within the cluster 2. weak gravitational lensing is used to map the diff materials in a bullet cluster. it does so by bending light from background objects in a small,measurable way

what are the spring constellations??

1.bootes 2.cancer 3.crater 4.hydra 5.leo 6.virgo

what are the winter constellations??

1.canis major 2.cetus 3.eridanus 4.gemini 5.orion 6.perseus 7.taurus

name 5 circumpolar constellations

1.draco 2.cassaphelia 3.ursa major 4.ursa minor 5.cephius

what is the approx. diameter of our own Galaxy (Milky Way)

100,000 light years

the speed of light in a vacuum is...

300,000 km/sec

The period of halley's Comet is (in years) about...

76 years

If all the "dark matter" in the Universe were to be, somehow, instantaneously removed, which of the following would not happen? A) The Solar System would fly apart. B) The Milky Way would fly apart. C) Clusters of galaxies would fly apart. D) The Universe would expand forever. E) all of the above

A) The Solar System would fly apart.

Why do we believe 90 percent of the mass of the Milky Way is in the form of dark matter? A) The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo. B) Although dark matter emits no visible light, it can be seen with radio wavelengths, and such observations confirm that the halo is full of this material. C) Theoretical models of galaxy formation suggest that a galaxy cannot form unless it has at least 10 times as much matter as we see in the Milky Way disk, suggesting that the halo is full of dark matter. D) Our view of distant galaxies is sometimes obscured by dark blotches in the sky, and we believe these blotches are dark matter located in the halo.

A) The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo.

Gravitational lensing occurs when A) massive objects bend light beams that are passing nearby. B) massive objects cause more distant objects to appear much larger than they should and we can observe the distant objects with better resolution. C) dark matter builds up in a particular region of space, leading to a very dense region and an extremely high mass-to-light ratio. D) telescope lenses are distorted by gravity.

A) massive objects bend light beams that are passing nearby.

Which of the following is an example of baryonic matter? A) you B) the particles produced by physicists in particle accelerators C) electrons and positrons produced by pair production D) WIMPs E) neutrinos

A) you

as we added dark matter in every case, what did this do to the speeds of the inner and outer stars??

All stars sped up, but the outer ones gained the most.

How do we know that there is much more mass in the halo of our galaxy than in the disk? A) There are so many globular clusters in the halo that their total mass is greater than the mass of stars in the disk. B) Stars in the outskirts of the Milky Way orbit the galaxy at much higher speeds than we would expect if all the mass were concentrated in the disk. C) Although the question of mass in the halo was long mysterious, we now know it exists because we see so many brown dwarfs in the halo. D) The recent discovery of photinos, combined with theoretical predictions, tells us that there must be a huge mass of photinos in the halo. E) We don't know that there is more mass in the halo; it is only a guess based on theory.

B) Stars in the outskirts of the Milky Way orbit the galaxy at much higher speeds than we would expect if all the mass were concentrated in the disk.

How do we determine the amount of dark matter in elliptical galaxies? A) We measure the orbital velocities of star-forming gas clouds around the outer portions of the galaxy. B) We measure the speeds of stars at different radii from the galactic center and determine how much mass is interior to the orbit. C) We count the number of stars in the galaxy and determine its volume, so that we can calculate the galaxy's density. D) We search for dark lanes of dust and black holes within the galaxy. E) We measure how fast the galaxy rotates as a whole.

B) We measure the speeds of stars at different radii from the galactic center and determine how much mass is interior to the orbit.

The distribution of the dark matter in a spiral galaxy is A) approximately spherical and about the same size as the galaxy halo. B) approximately spherical and about ten times the size of the galaxy halo. C) flattened in a disk and about the same size as the stellar disk. D) flattened in a disk but about ten times larger than the stellar disk. E) predominantly concentrated in the spiral arms.

B) approximately spherical and about ten times the size of the galaxy halo.

there are two reasons on how galaxies formed (bottom-up or top-down) explain the theory in which you prescribe to

BOTTOM UP: this theory states that once small galaxies are formed, they attract each other by gravity and combine to form larger galaxies. The larger galaxies then combine to form clusters. Thus, gravity is the mechanism to form larger and larger structures.

In which of these galaxies would Newtonian motion (outer stars slowing down father away from the nucleus) be best approximated? A) spiral with about 50% visible, 50% dark matter. B)An irregular with 10% visible, 90% dark matter. C)An elliptical with almost no gas, dust, or dark matter. D)It does not matter. In all galaxies, the same Newtonain physics applies, and the outer stars must trail behind.

C) An elliptical with almost no gas, dust, or dark matter

Why do we call dark matter "dark"? A) It emits no visible light. B) We cannot detect the type of radiation that it emits. C) It emits no or very little radiation of any wavelength. D) It blocks out the light of stars in a galaxy.

C) It emits no or very little radiation of any wavelength.

Recent measurements of the expansion rate of the universe reveal that the expansion rate of the universe is doing something astronomers did not expect. What is that? A) The measurements show that the universe may not be expanding at all. B) The measurements show that the universe may be shrinking rather than expanding. C) The measurements show that the expansion is accelerating, rather than slowing under the influence of gravity. D) The measurements indicate that the universe is at least 30 billion years old, meaning that more than 10 billion years passed between the Big Bang and the formation of the first stars and galaxies. E) The data show that the expansion rate varies widely in different parts of the universe.

C) The measurements show that the expansion is accelerating, rather than slowing under the influence of gravity.

The term Zodiac refers to A) the light from Saturn's rings. B) a method for making astrological predictions. C) a group of constellations lying near the ecliptic. D) the head of the Celestial Empire. E) all constellations named after animals.

C) a group of constellations lying near the ecliptic.

if the universe is dominated by dark energy, then the rate of expansion of the universe is A)slowing down B) zero, the universe is neither expanding or contracting C) accelerating D) exactly constant with time

C) accelerating

Which of the following methods used to determine the mass of a cluster does not depend on Newton's laws of gravity? A) measuring the orbital velocities of galaxies in a cluster B) measuring the temperature of X-ray gas in the intracluster medium C) measuring the amount of distortion caused by a gravitational lens D) none of the above

C) measuring the amount of distortion caused by a gravitational lens

Which of the following particles are baryons? A) electrons B) neutrinos C) protons D) quarks E) photons

C) protons

What is meant by "dark energy"? A) the energy associated with dark matter through E=mc2 B) any unknown force that opposes gravity C) the agent causing the universal expansion to accelerate D) highly energetic particles that are believed to constitute dark matter E) the total energy in the Universe after the Big Bang but before the first stars

C) the agent causing the universal expansion to accelerate

Why isn't space expanding within systems such as our solar system or the Milky Way? A) Hubble's law of expansion applies only to the space between galaxies. B) We are so close to these systems that we don't observe their expansion. C) The universe is not old enough yet for these objects to begin their expansion. D) Their gravity is strong enough to hold them together against the expansion of the universe.

D) Their gravity is strong enough to hold them together against the expansion of the universe.

when we look over very large size scales in space, what is the distributions of galaxies and clusters of galaxies? A) They are smoothly distributed throughout space. B) The density of these objects in space gets to be less the farther you go away from Earth in any direction. C) They form the centers of large spheres of completely empty space. D) They lie on the surfaces of gigantic, intersecting bubbles. E) They all lie along one long line that connects back to the center of the universe.

D) They lie on the surfaces of gigantic, intersecting bubbles.

our current understanding of how structures formed in the Universe in the presence of dark matter shows that structures of different sizes should have formed in what order? A) largest first, smallest (top down) b) smallest first,largest last (bottom up) C)all size scales formed at the same time (simultaneous) D)the models make no prediction about this

D)the models make no prediction about this

If there is no dark matter in the Milky Way Galaxy, what is the best alternative explanation for the observations? A) We are not measuring the orbital velocities of atomic clouds and stars properly. B) We are not measuring the distances to atomic clouds and stars properly. C) We are not attributing enough mass to the visible or "bright" matter. D) We are not observing all the visible or "bright" matter in the galaxy. E) Our understanding of gravity is not correct for galaxy-size scales.

E) Our understanding of gravity is not correct for galaxy-size scales.

What might be causing the universe to accelerate? A) WIMPs B) neutrinos C) white-dwarf supernovae D) dark gravity E) We don't know!-but we call it "dark energy."

E) We don't know!-but we call it "dark energy."

Which of the following are candidates for dark matter? A) brown dwarfs B) Jupiter-size objects C) WIMPs D) faint red stars E) all of the above

E) all of the above

Which of the following is not evidence for dark matter? A) the flat rotation curves of spiral galaxies B) the broadening of absorption lines in an elliptical galaxy's spectrum C) X-ray observations of hot gas in galaxy clusters D) gravitational lensing around galaxy clusters E) the expansion of the universe

E) the expansion of the universe

what galaxies are the oldest? Explain

ELLIPTICAL GALAXIES are the oldest because... 1.looks redder which means it contains older stars and have low rates of star formation 2.all available gases & dust is already used up in the past & all that remains are old red stars 3.the shape tells you its old

what made fritz Zwicky predict the existence of dark matter?

Fritz Zwicky believed that our spiral galaxy was spinning too fast for its mass & that with it constantly spinning, all of the stars should've flung outwards. Thus, some unknown mass must be holding everything in place (dark matter)

what are galaxies?

Galaxies are huge collections of stars, dust and gas. They usually contain millions to trillion stars and can range in size from a few thousand to several hundred thousand light-years across.

what constellation does our sun belong to??

None because the earth travels around the sun. as a result,the sun moves in in the sky relative to the stars and through the constellations of the zodiac

what galaxy is our solar system in & what is the closest galaxy to ours? be specific

Our galaxy is the Milky Way GALAXY which is a spiral galaxy. The closest galaxy to ours is the Andromeda galaxy which is about to collide with us soon

What evidence suggests that the Milky Way contains dark matter? A) We observe clouds of atomic hydrogen far from the galactic center orbiting the galaxy at unexpectedly high speeds, higher speeds than they would have if they felt only the gravitational attraction from objects that we can see. B) We see many lanes of dark material blocking out the light of stars behind them along the band of the Milky Way. C) We see many dark voids between the stars in the halo of the Milky Way. D) When we observe in different wavelengths, such as infrared or radio, we see objects that don't appear in visible-light observations. E) When we look at the galactic center, we are able to observe a large black hole that is composed of dark matter.

We observe clouds of atomic hydrogen far from the galactic center orbiting the galaxy at unexpectedly high speeds, higher speeds than they would have if they felt only the gravitational attraction from objects that we can see.

STATE THE FOLLOWING DEFINITION: electromagnetism

a force that holds atoms together and prevents you from falling to the ground.

STATE THE FOLLOWING DEFINITION: dark energy

a force that repels gravity and makes up 68% of the universe. people believe that because of dark energy, the universe is expanding faster as time goes by.

EXPLAIN THE FOLLOWING TYPE OF GALAXY irregular

a galaxy that does not have a distinct shape. Irregular galaxies may contain abundant amounts of gas and dust.

what is a galaxy?

a huge group of stars, dust and gases held together by gravity

STATE THE FOLLOWING DEFINITION: what is an ecliptic

a path that the sun,moon and planets travel through the sky as teh earth rotates.

the global clusters a) are concentrated near the edge of a galaxy b) are present only in our galaxy c) are concentrated in spiral arms d) are concentrated in gigantic nucleus e) are spherically distributed about the galactic centre

a) are concentrated near the edge of a galaxy

scientist hypothesize the existence of dark matter because. a) the outer & inner parts of a galaxy rotates at teh same speed b) the outer portion of a galaxy rotates at te same speed c) the inner portion of a galaxy rotates faster than the outer portion d) none of the above

a) the outer & inner parts of a galaxy rotates at teh same speed

FILL IN THE BLANKS _________were the first to describe over half of the ______constellations recognized by______________ (IAU) today

ancient greeks, 88, international atronomical union

dark matter was created a)at the time of the big bang b) during the inflation period c) inside galactic centres c) inside the CMBR

at the time of the big bang

the theory that most of the mass of the universe is invisible "dark matter" was proposed partially because of a) the difficulty observing the centre of earth's galaxy b) the shape of spiral galaxies c) the observation of black holes d)the difficulty observing galaxies than our own

b) the shape of spiral galaxies

_________________is an irregular galaxy that is believed to have collided with the Milky Way and is expected to merge with the Milky Way in the future. a)The Andromeda galaxy b)The Small Magellanic Cloud c)M87 d)The Virgo cluster e)The Whirlpool

b)The Small Magellanic Cloud

An elliptical galaxy could... a) evolve into an irregular galaxy when it has used up all of its gas and dust. b)be formed from the collision and merger of spiral galaxies. c)evolve from a single spiral galaxy when the spiral has used up all of its gas and dust. d)become a starburst galaxy if it were to move through the hot intergalactic medium of a cluster. e)evolve from an S0 galaxy if the S0 galaxy were to increase its rotation rate.

b)be formed from the collision and merger of spiral galaxies.

which component of our galaxy contains the largest amount of mass? a) Population I stars b) Halo c) Dark Matter d) Disk e) Nuclear Bulge

c) Dark Matter

we would expect a galaxy with many bright blue stars a) to contain no life b) to have little or no dust or gas c) too have much dust and gas d) to have no old stars e) to contain no stars liek the sun

c) too have much dust and gas

which of the following statements about dark matter is FALSE? a) it is observed to be a major part of the milky way b) it is observed to be present in other groups of galaxies c)astronomers have a pretty good idea what the dark matter is made of d) we can detect its gravity, even though we can't see it e)it may make up even more of the universe that the matter we can see

c)astronomers have a pretty good idea what the dark matter is made of

which is not a piece of evidence for dark matter? a)visual data b)gravitational lenses c)increased gravity d)mass calculations

c)increased gravity

Which of the following is one of the two basic postulates of Einsteins special theory of relativity? A) the wavelength of light is shifted when the source is viewed by an observer B)the total energy of a system stays constant c)light is measured to move at the same speed, no matter how fast or in what direction you are moving relative to the light source when you measure it d)the momentum of an obj. remains constant unless the object is acted upon by a force

c)light is measured to move at the same speed, no matter how fast or in what direction you are moving relative to the light source when you measure it

Based on the galaxies found in the Local Group of galaxies, the most common type of galaxy in the universe is expected to be a)the spiral galaxies. b)the barred spiral galaxies. c)the dwarf elliptical galaxies. d)the irregular galaxies. e)the giant elliptical galaxies.

c.)the dwarf elliptical galaxies.

STATE THE FOLLOWING DEFINITION: galaxy clusters

collection of hundreds of galaxies,containing large amounts of stars, planets and gases. Galaxy clusters are also 90% dark matter

EXPLAIN THE FOLLOWING TYPE OF GALAXY spiral

consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. ex. the milky way (our galaxy) is a spiral galaxy

STATE THE FOLLOWING DEFINITION: constellations

constellations aren't real and are mad eup by farmers to identify stars needed to tell them the season they're in for harvesting. Each month has a different constellation.

We should expect galaxies to collide with each other fairly often because a)a galaxy's size is only a little smaller than the average distance between galaxies. b)galaxies contain large amounts of neutral hydrogen. c)galaxies occur in clusters. d)a and c e)none of the above

d) a and c a galaxy's size is only a little smaller than the average distance between galaxies, and b/c galaxies occur in clusters.

which of the following best describes the density wave theory of how spiral arms are formed and maintained? a) spiral arms are strings of globular clusters,like pearls on a necklace b)spiral arms are paths where friction due to higher gas density is causing materials to spiral down into the centre of the galaxy c)spiral arms are caused by jets shot out of the centre of the galaxy being wound up due to differential rotation d) spiral arms are regions of higher density; the extra gravitational attraction causes passing stars to slow down as they pass through the arm, thus perpetuating the traffic jam e)spiral arms are caused by stars being ejected from the nucleus of a galaxy and pinwheeling out into space

d) spiral arms are regions of higher density; the extra gravitational attraction causes passing stars to slow down as they pass through the arm, thus perpetuating the traffic jam

Our Milky Way Galaxy consists of A) The Sun and its 9 planets b) All the actual stars in the universe c)a compact car formly produced by ford motor company d) system of 100 billion stars held together by their mutral gravitational attraction e) a cluster of about 100,00 stars which orbits about the galactic center

d) system of 100 billion stars held together by their mutral gravitational attraction

in clusters, if the majority of mass is dark matter, how would the galaxies behave? a) the cluster must condense into one huge e 0 galaxy quickly b) the inner members close to the central e 0 giant must move the fastest, just as in our solar system c) all galaxies in the cluster are moving at the same speed driven by the 50/50 mix of light and dark matter d) the outer galaxies are moving so fast, it looks like they must escape the cluster, if there is not a huge amount of dark matter present

d) the outer galaxies are moving so fast, it looks like they must escape the cluster, if there is not a huge amount of dark matter present

Astronomers now speculate that a galaxy's shape depends on all of the following except a.)the rate of star formation. b)the history of past collisions. c)the mass. d)the chemical composition. e)All of the above are important in determining a galaxy's shape.

d)the chemical composition.

through which fundamental force does dark matter interact with normal matter? a) centripedal force b)electromagnetic force c)light d)the gravitational force e)dark matter and normal matter no not interact through any force

d)the gravitational force

the majority of the universe is made up of...

dark energy

this does not produce any light and must be detected indirectly....

dark matter

the universe is made up of dark energy, dark matter and light matter. Dogs live on earth. What percentage of the universe is composed of the substance that makes up dogs?? a) 89% b) 21% c) 75% d) 50% e) 4%

e) 4%

a galaxy consisting primarily of old stars with very little cool gas and dust will be a(n).....

elliptical

the most massive galaxies belong to the type of galaxies known as the....

elliptical

the main classification of galaxies are:

elliptical,spiral,irregular

This effect bends light so objects behind a very large galaxy can be seen.

gravitational lensing

as the universe expands,________________is/are trying to pull it back together

gravity

what did Albert Einstein state about massive objects in the universe??

he stated that massive objects bend and distort light, allowing them to be used as lenses

what does dark energy do?

it causes the universe to expand at an increasing rate

how does a cosmic crash happen??

it happens over the course of billion of years when galaxy clusters attract each other because of their huge masses. When this happens, the dark matter in each galaxy cluster interacts with each other.

what does dark matter do to galaxies??

it seeds up the motion of galaxies inside galaxy clusters.

in the 1930's, it was discovered that galaxies did not have enough___________ to spin as fast as they did.

mass

STATE THE FOLLOWING DEFINITION: what is baryonic matter??

matter that is composed of protons,neutrons and electrons bundled together in an atom. ex. the universe is made up of baryonic matter

dark matter is...

not entirely understood

what occurrence in the universe points to the existence of dark energy?

people believe that because the universe is expanding more as time goes by, even with the force of gravity, the gravity should make the universe smaller. Yet, since the universe is actually expanding, that means there's an external force that opposes gravity= DARK ENERGY

what is precession is what is one consequence of it?

precession is the earth's 3rd motion where the earth "wobbles" around its axis. One consequence of it is a new North Star

whys the earth not in danger of being swallowed by the supermassive blackhole at the centre of the galaxy?

since the earth is far away from the blackhole, gravity & the force of the blackhole isn't strong enough to pull earth is

STATE THE FOLLOWING DEFINITION: what is a precession?

the 3rd motion of the earth that is commonly unknown. It's the motion of the earth "wobbling" slowly completing a circle every 26,000 years

being born in August, I am considered a virgo. Why is it that I can only see it in the spring time?

the sun blocks the view due to earth's rotation

the Principal of Equivalence are used in general relativity says that that an observer cannot tell the difference between acceleration and a)gravity b)time c)decelleration d)a falling elevator e)being inside a black hole

time

TRUE OR FALSE Halley's coment has been observed several times before

true