ASTR combine 3
What is the theory of evolution?
A scientific theory supported by extensive evidence
Fossil evidence suggests that life on Earth arose...
About a billion years before the rise of the dinosaurs
What did the Miller experiment create?
Amino acids
Why is DNA important to a cell?
Because DNA contains the information necessary to make all of the molecules required by the organism, and it contains the information necessary for the cell to reproduce itself
How long a segment would represent the 3 million year history of human life?
0.67 mm
Which of the following spectral types would have the largest mass (assume all are on the main sequence)
03
If we represent the history of Earth by a line 1 m long, how long a segment would represent the 400 million years since life moved onto the land?
8.9 cm
We receive a radio message from civilization around a star about 40 light years from Earth. If we reply away, how long will it be between the time THEY sent the message and the time they receive our reply?
80 years
What is ALH 84001?
A meteorite that shows evidence for life evolving on Mars
An offspring born with altered DNA due to radioactivity, cosmic rays, or errors in reproduction is called what?
A mutant
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
What is Project Phoenix?
A project to search millions of radio channels for possible messages from intelligent civilizations around a thousand nearby stars
The first complex life appeared on Earth about 0.5 billion years ago during what period?
Cambrian Period
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 our atmosphere
Which of the following is a bio-marker 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 Earth's atmosphere
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?
In the Drake equation, suppose that the term flife = 1/2. What would this mean?
Half of the habitable worlds in the galaxy actually have life, while the other half don't
What is the Fermi Paradox?
It asks, if intelligent life is common out there, how come they have not contacted us?
What are plants and animals?
Just two small branches of the diverse "tree of life" on Earth
One reason that some scientists think that there may be life under the ice-crust of Jupiter's moon Europa is that...
Life has been found on Earth, at the bottom of the ocean, deriving its energy not from sunlight but from hot mineral-laden vents coming from deeper inside our planets; something similar could happen at the bottom of the ocean on Europa
According to current understanding, a key requirement for life is what?
Liquid water
Current searches for extraterrestrial intelligence use radio telescopes to do what?
Listen to many frequencies at the same time
In a globular cluster, astronomers (someday) 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 SETI antennas and search for radio signals from an advance civilization?
No, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it
According to current scientific understanding, the idea that the Milky Way Galaxy might be home to a civilization millions of years more advanced than ours is...
One reasonable to the Fermi's Paradox
The first search for radio messages from extraterrestrial civilizations was called
Project Ozma
What type of life would we expect to find on Titan?
Since lots of liquid Methane and Ethane lakes are there, they may hold extremophiles
Which of the following is a good summary of what most astronomers think about UFO reports?
So far there is no scientific evidence that UFOs have anything to do with life outside the Earth
The key piece of technology that makes the major new search for signals from civilizations around other stars possible is what?
Software and hardware that can search billions of radio channels at once
In the early 1950s, Stanley Miller and Harold Urey conducted a series of pioneering laboratory experiments involving simulations of the early Earth. What did these experiments reveal?
That adding the energy of lightning to some of the gases in the early Earth's atmosphere could lead to the synthesis of some of the building blocks of life
Which of the following worlds is NOT considered a candidate for harboring life?
The Moon
Which of the following events in cosmic history is the most recent?
The formation of life on Earth
For the complex biochemical reactions of life (as we know it) 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 message 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
Why do all known life forms use carbon?
We need long molecules to store information, and carbon helps build the really long molecules
According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth?
about 3.5 billion years
One way in which the ozone layer is useful for life forms on the Earth's surface is that it
absorbs ultra-violet light, preventing much of it from reaching the surface
Which of the following is a way we believe that the early atmosphere of the Earth differed from the atmosphere we have today?
all of the these
After a star like the sun exhausts hydrogen in its core and starts to become a Red Giant, it
becomes cooler and more luminous
If no one has ever visited the core of the Earth, how do we know that it is made of metals?
circulating liquid metals in the core set up a large (measurable) magnetic field
Astronomers now understand that the dark regions visible in parts of our Milky Way that are otherwise crowded with stars are caused by
clouds with a considerable amount of dust that blocks the light out of the stars behind them
Which part of the Earth has the greatest density?
core
Atoms of cool hydrogen emit 21-cm radiation when the
electrons change their spin
stars are born in
giant molecular clouds
What makes the Earth different from the other worlds that might have life in the solar system (and easier to detect from far away) is that only Earth
has a biosphere on its surface where photosynthesis can take place
If you wanted to find a type of atom in your little finger that has been in its present form (been the same element) since the beginning of the universe, which element should you look for?
hydrogen
Measurements show a certain star has a very low luminosity (1/100 times the sun's) while its temperature is quite hot (35,000 K). How can this be?
it must be small in size
How long a star remains on the main sequence depends strongly on
its mass
At what stage of its evolutionary life is the sun?
main sequence middle aged star
The largest part of the Earth is its
mantle
An important way that scientists have been able to study the interior of the Earth is by:
measuring how seismic waves are transmitted through the Earth
In terms of numbers, the most common life-forms on Earth are
microscopic creatures, too small to see with our eyes
The amount of time a low mass M type star (1/2 the mass of our star) will spend as a main sequence star is
more time than the sun
The most abundant gas in Earth's atmosphere is
nitrogen
In a globular cluster, astronomers (someday) 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 SETI antennas and search for radio signals from an advanced civilization?
no, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it
Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best (cheap, little competition from nature, penetrates atmospheres) for communication between civilizations around different stars?
radio waves
According to the theory of plate tectonics,
slow motions within the mantle of the Earth move large sections of the crust around
In 1980, scientists suggested that the great mass extinction of 65 million years ago (which ended the reign of dinosaurs) may have been caused by a large impact from space. What discovery gives a big boost to this idea?
the discovery of a buried crater (about 200 km across) near Chicxulub, Mexico
Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth s layers to happen?
the early Earth must have been so hot it was like a liquid and heavier things sank to the middle
When they talk about the Copernican principle, philosophers and astronomers mean that:
the idea that there is nothing special about our place in the universe
If you were to take one kilogram of material from the surface of the sun and one kilogram taken from the center which of the following statements would be true
the kilogram from the surface would contain more hydrogen that the one from the center
The region around the Earth where charged particles are trapped and spiral around is called:
the magnetosphere
When plotted on an H-R Diagram, the majority of stars fall into the region astronomers call
the main sequence
Which of the following statements about the rate of stellar evolution is true
the more massive the original star, the faster the evolution
The Drake Equation allows astronomers to estimate
the number of civilizations out among the stars with which we might communicate
The process of convection involves
the slow upward flow of warmer material and downward flow of cooler material
The fastest speed at which we might communicate with another technological civilization among the stars (according to our present understanding of science) is
the speed of light
The smallest mass that a star can have is about 1/12 the mass of the sun. The reason for this is that
the temperature in the core of a contracting protostar less than 1/12 solar masses does not get high enough for nuclear reactions to start
In which region of the Earth's atmosphere have you spent most of your life?
the troposphere
We know that Red Giant stars are larger in diameter than the sun because
they are cooler but have about the same luminosity
Which of these did the June 1908 impact event in Siberia and the 2013 event in the Russian city of Chelyabinsk have in common?
they both exploded high in the atmosphere and produced a shock wave that reached the ground
A spot where magma rises to the surface can be seen as a
volcano
The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?
water vapor and gases like carbon dioxide in the atmosphere cause a greenhouse effect
What new technology has made it possible for astronomers to do "optical SETI" - searching for signals for extra-terrestrial 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
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
When the sun dies it will become a
white dwarf
Life on Earth is based on what?
Carbon chemistry
In which of the following places have astronomers NOT found evidence for the building blocks of life (organic compounds)?
Clouds of interstellar gas and dust, Earth, comets, and meteorites
Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best for communication between civilizations around different stars?
Radio Waves
What recent series of discoveries has made astronomers more optimistic about our prospects of finding life out there?
The discovery of planets around more than a hundred nearby stars
Which of the following is a reason why early living organisms on Earth probably could not have survived on the surface?
The lack of an ozone layer
The fastest speed at which we might communicate with another technological civilization among the stars (according to our present understanding of science) is what?
The speed of light
What evidence do scientists have about how life on Earth originated?
They have no direct evidence about the first life forms on our planet
We receive a radio message from a civilization around a star about 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
Which of the following is the molecule within a cell that actually assembles proteins from amino acids?
RNA
Why are massive main-sequence stars not likely to have planets that contain life?
These stars are on the main sequence for too short a time to allow life to evolve
What evidence do we have that Europa has subsurface liquid matter?
Tidal heating may allow water to exist under its icy surface. The expansion caused by this may explain all the cracks on Europa's surface
When the outer layers of a star expand, and it becomes a giant, which way does it move on the H-R diagram?
toward the upper right
which of the following types of star has the lowest surface temperature
M
Why would we expect aliens to look very different from humans?
Because an alien species would form from an entirely different biochemical foundation, so it's unlikely they would have two arms, two legs, etc.
The most likely region of the radio spectrum for communication with other civilizations is the water hole, the part of the spectrum between what?
Between the radio emissions of hydrogen and OH
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
How does the habitable zone around a star of spectral type G compare to that around a star of spectral type M?
It is closer to its star
What are the implications of our never hearing from alien life?
It would tell us that life is unique and that we need to keep intelligent life safe
Photosynthesis was a great step forward in the evolution of life on Earth, because with photosynthesis...
Life could extract chemical energy from sunlight
Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best (cheap, little competition from nature, penetrates atmospheres) for communication between civilizations around different stars?
Radio Waves
The number of communicative civilizations in our galaxy is limited by what?
The survival of technological societies
How could Titan now or in the future harbor life?
There are many organic compounds there and frozen water
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
One place that astronomers think might have had life start long ago is Mars. Which of the following is not a discovery that we have made on Mars so far?
the discovery of organic materials (the chemical building blocks of life, such as amino acids) by spacecraft that have landed
