Unit 4 -Final Exam Review - AST 102
the first satellite to measure and confirm the cosmic microwave background was the
cobe (cosmic background explorer)
chemically the process leading to life on earth began with lots of liquid water and
hydrocarbons
the cosmological principle in astronomy
is confirmed by many observations done by hubble and many other astronomer since
one of the things that our current standard model of the big bang theory doesn't explain is
why the temperature of the cosmic background is so uniform throughout all of space
we receive a radio message from civilization around a star 40 light years from earth if we reply right away how long will it be between the time they sent the message and the time they receive our reply?
80 years
according to our textbook roughly what percent of the mass and energy contents of the universe is made up of dark matter plus energy
95 percent
in the very distant future, given our best model of the accelerating universe, what will the universe look like
all of the stars will die and the galaxy will be dark
scientists think that the life we have on earth today originated some time between 3.5 and 3.8 billion years ago. yet the solar system and the earth are known to be at least 4.5 billion years old. which of the following is one reason life as we know it had to wait until 3.5 to 3.8 billion years ago to get going
before 3.8 billion years ago the earth was experiencing a period of heavy bombardment when giant chunks of rock and ice left over from planet formation kept hitting out planet and making it uninhabitable
some astronomers searching for what the mysterious dark matter might be made of have pinned their hopes on MACHO's what do they think these MACHO's are
black holes, brown dwarfs, and white dwarfs in the regions outside the main disk of our galaxy
today we believe that only a small number of elements were actually formed during the big bang. which of the following was not one of these
carbon
scientists are impressed with extremophiles, life forms that can survive under what seems to humans to be extremely unpleasant conditions. in which of the following environments have we not found life
conditions resembling the photosphere of the sun
where in space did the expansion of the universe begin
everywhere at once
which of the following is a biomarker that could be used from an observatory around a nearby star with the right equipment to identify the earth as a planet with life
free oxygen in the earths atmosphere
astronomers believe that the large elliptical galaxies formed
from the collision and merger of many smaller fragments
what do the surveys of the three-dimensional distribution of groups of galaxies reveal about how groups and clusters of galaxies are organized
galaxy groups are organized into huge filaments with great voids between them -- something like the structure one would seen taking a cross-section of some soap bubles
which of the following spacecraft is not leaving the solar system
galileo
what does the fermi paradox say
given all the time since the big bang and all the stars, why has some form of intelligent life in the galaxy not established a network throughout the galaxy and visited us
which of the following is the earth not located in
globular cluster m-13
scientists looking at an observation of physics today understand that there are four forces that govern all action in the universe. these four forces are the strong nuclear force, the weak nuclear force, the elctro-magnetism and
gravity
what makes the earth different from other worlds that might have life in the solar system is that only earth
has a biosphere on its surface where photosynthesis can take place
to map out how clusters of galaxies are distributed in the universe, astronomers needed to know where each cluster was in the sky and
how far away from us each cluster was
if you wanted to find a type of atom in your little finger that has been in its present form since the beginning of the universe, which element should you look for
hydrogen
one reason that some scientists think that there may be life under the ice-crust of jupiters moon europa is that
life has been found on earth at the bottom of the ocean deriving its energy from sunlight but from hot mineral-laden vents coming from deeper inside out planet; something similar could happen at the bottom of the ocean on europa
what recent observations have confirmed the universe is isotropic on the large scale
measurements of the 3-degree cosmic background radiation
astronomers have discovered a planet orbiting proxima centauri the star closest to the sun. this is a star of spectral type m, with 12% the mass of the sun and 15% the size of the sun. the habitable zone around this star would be
much closer to the star than the suns
photosynthesis once it was planet-wide, changed the atmosphere on earth by introducing a significant amount of
oxygen
photosynthesis releases a particular gas as a byproduct this gas is
oxygen
the two scientists who first discovered the cosmic microwave background radiation were
penzias and wilson
the satellite that has given us the most precise measurements of the characteristics of the cosmic background radiation is
planck
the first search for radio messages from extraterrestrial civilizations was called
project ozma
which band of the electromagnetic spectrum do astronomers suggest is likely to be the best for communication between civilizations around different stars
radio waves
which of the following is a recent discovery that confirms the key idea of the copernican principle
that planets around other stars are common
when we determine the age of the universe using the hubble time, what important simplifying assumption goes into our calculations
that the expansion of the universe has been happening at the same rate neither speeding up or slowing down
after the big big in order for the universe to become transparent to light and other electromagnetic radiation what had to happen
the density of the universe had to decrease
one place that astronomers think might have had life long ago is mars. which of the following is not a discovery that we have made on mars so far
the discovery of organic material but spacecrafts that have landed
what recent series of discoveries has made astronomers more optimistic about out prospects of finding life out there
the discovery of planets around thousands of stars in our galaxy
which of the following events in cosmic history is the most recent
the formation of life on earth
when they talk about the copernican principle, philosophers and astronomers mean that
the idea there that is nothing special about our place in the unverse
the mode of the universe that involves an enormous increase of scale during a very short time in the early universe is called
the inflationary universe model
what is the strongest known force in the universe
the strong nuclear force
the rich galaxy cluster that is closest to our local group of galaxies is the
virgo cluster
for the complex biochemical reactions of life to happen a solvent is required what is that solvent for life on earth
water
which of the following questions is not part of what astronomers call the cosmic haystack problem in receiving messages from other civilizations in space
we don't know how to receive signals in the wavelength range that is the most likely for interstellar communications
what new technology has made it possible for astronomers to do optical set - searching for signals for extraterrestrial civilization, not in the radio band of the spectrum but in the visible-light band
we have developed the ability to make laser pulses that are briefly brighter than the sun
in which of the following places have astronomers not found evidence for the building blocks of life
we have found evidence for such materials in all of the above sites
which of the following can we not learn from studying the doppler shifts in the spectrum of galaxies beyond our local group
whether they have Jupiter mass planets around many of their stars
from a scientific perspective which of the following statements about life elsewhere in the universe is best supported by current evidence
while we have evidence of the building blocks of life elsewhere in the universe, we have no definite evidence about life around other stars at this time
at first right after the big bang the universe was too hot for nuclei and electrons to combine into the kinds of neutral atoms that are familiar to us today. how soon after the beginning did it become cool enough for neutral atoms to form
a few hundred thousand years
how do astronomers know that there aren't significant amounts of dark matter within our solar system
a lot of dark matter would affect the motions of our spacecraft as the move through the solar system, and we see no such effect
factoring in everything we currently know about the history of the universe, our best estimate for the age of the universe is
about 13.8 billion years
roughly how many galaxies make up our local group?
about 60 or so
according to our modern bottom-up model of the formation of large structure sin the universe, the structures that formed first were about the mass of a
large globular cluster or a small galaxy
the first scientists to propose a scientific model for the big bang was
lemaitre
at about 1 second after the beginning of the universe, one type of particle was able to start traveling freely though the universe. these particles are still with us, but they are extremely hard to detect. they are called
neutrinos
in globular clusters astronomers discover a star with the same mass as our sun, but consisting entirely of hydrogen and helium. is this star a good place to point our antennas and search for radio signals from an advanced civilizations?
no because such star would not have the heavier elements that we believe are necessary to star life as we know it
which of the following is not a a way that astronomers can find how much dark matter there is in a cluster of galaxies
observe the radio waves coming from all dark matter; from the strength of the radio waves from each cluster, estimate the amount of dark matter needed to produce them
which of the following is pretty good evidence that the universe began with a big bang
the 3-degree cosmic microwave background radiation
the reciprocal of the hubble constant is rough measure of the
the age of the universe
which of the following statements about our modern ideas of how spiral galaxies form and develop is true
the central bulge of spiral galaxies formed first and their disks formed later
if you wanted to write a complete cosmic address for yourself including every location or structure you live in, which of the following would not be part of that address
the coma cluster
some scientists speculate that our universe is not the only universe that exists, but the only one we can gather evidence about. this idea is called
the multiverse theory
the drake equation allows astronomers to estimate
the number of civilizations out among the stars with which we might communicate
the fastest speed at which we might communicate with another technological civilization among the stars is
the speed of light
when did Einstein introduce the cosmological constant into the equations of his general theory of relativity when describing the universe?
Einstein's equations required the universe to expand or contract; he could not image or accept it doing either one so he put a factor in to stop it from moving
if you want to check on what conditions were like in the universe a few hundred thousand years after the big bang, what sort of instrument would it be best to use
a satellite with infrared and microwave telescope on board
when astronomers have examined rich clusters of galaxies with their instruments they have found that these clusters
are more likely to contain giant elliptical galaxies than poor clusters
according to the models of the universe we discussed in this course why do the galaxies move apart?
as a result of the big bang, space itself is stretching, and this stretching carries the galaxies away from each other
in our modern view of the expansion of the universe, we understand that space is stretching; individual galaxies don't speed away from each other as if they were rocket. in that case why do galaxies show a red shift
as space stretches the waves of radiation in space also stretch and their wavelength increases
which of the following statements about dark matter is false
astronomers have a pretty good idea of what dark matter is made of
according to the cosmological principle, the universe
is isotropic and homogeneous
in describing the universe using his equation of general relativity, Einstein assumed that it was
isotrop
which of the following is not true about the local group of galaxies?
it has about a thousand member galaxies
based on many surveys of the average density of matter in the universe astronomers now conclude that the average density of the universe is
less than the critical density
which of the following did not happen during the first few minutes after the big bang
some very massive early stars formed
in the early 1950s stanley miller and harold urey conducted a series of pioneering laboratory experiments involving simulations of the earth earth. what did these experiments reveal
that under the conditions on the early earth, they could synthesize some of the building blocks of life in a laboratory
how do astronomers currently think the amount of detectable matter in the universe compares to the amount of dark matter and dark energy
the amount of detectable matter is far less than the amount of dark matter and energy
scientists speculate that the the properties of the universe must be the way there are because if they were significantly different we would not be here to think about them. this idea is called
the anthropic principle
according to the most recent data from satellites making precise measurements of the properties of the cosmic background radiation
the dark energy makes up just a little less than 70% of the density of the universe, making it the most significant constituent of the mass-energy
astronomers have measured that there is more helium in the universe than can be explained by the fusion in stars over the last 13 billion years. how do they think the extra helium got into the universe?
the extra helium was made during the first few minutes of the big bang, when the entire universe was hot enough for fusion to occur briefly
recent observations indicate that the universe is expanding faster today than it was a few billion years ago. what kind of observations have led astronomers to this surprising conclusion
the measurement of galaxies distances using type la supernovae
according to our modern theories the geometry of the entire universe may be curved or warped this is a pretty bizarre notion what other discovery in astronomy has helped us believe that space may be able to curve or wrap
the properties of black holes
in which of the following domains of the universe have astronomers not found evidence for the presence of dark matter today
the solar system
if alien beings found one of the voyager spacecraft in a million years what would they find aboard?
an audio and video record
think for a moment about an atom of the element lead inside the radio that you listen to in the morning. in which of the following places has this atom probably not been during the course of its existence
the sun
which of the following is to the best of our knowledge in the habitable zone of its star
a planet about 1.05 AU from a g-type main sequence star
by examining rich clusters of galaxies such as the coma clusters astronomers have discovered that spiral galaxies
are found mostly in the outer regions of such cloisters not in the middle
which of the following statements about the early universe is false
at the very beginning the energies were so great that the universe was actually contracting for a while
how does a period of extremely fast inflation very early in the history of the universe explain the observation that the geometry of the universe looks flat to us
inflation increases the size of the universe so much that the resulting universe looks flat from any point of view
if we include the effects of deceleration in our calculations for the age of the universe the age we get is
less than the hubble time
photosynthesis was a great step forward in the evolution of life on earth, because of photosynthesis
life could extract chemical energy from sunlight
when do astronomers now think that the dark energy began to accelerate the expansion of the univser
several billion years after the big bang
which of the following is a good summary of what most astronomers think about UFO reports in the popular media
so far there is no scientific evidence that ufos have anything to do with life outside the earth
the sloan digital sky survey
takes images and spectra of millions of objects to find the positrons and redshifts of as many galaxies and quasars are possible
when astronomers say that the groups of galaxies are distributed isotropically they mean that
the way galaxies are arranged in space looks the same in all directions
what discovery about saturns moon enceladus has encouraged astronomers to think of that moon as a possible place where life might exist
there are plumes of salty vapor coming from cracks in enceladus surface
the standard bulbs that made is possible for astronomers to discover the acceleration in the expansions of the universe were
type la supernovae
according to astronomers which of the following places in the outer parts of our solar system might be a reasonable place for life to exists
under the ice of jupiters moon europa
the great voids that astronomers studying galaxies are finding are
very large regions of intergalactic space, where relatively few galaxies or galaxy clusters cana be found
