Ch 12
The rare-Earth hypothesis would predict that the factor f life, in the Drake equation should be close to
0
Given that life on Earth appears to have arisen quite easily and rapidly suggests that the factor f life, in the Drake equation could be close to
1
Suppose there are a million habitable planets in our galaxy, that one in ten are habitable, that one in a hundred civilizations that has ever existed is in existence now. Given this, how many civilizations are in existence now?
1
a SETI search using the 300-meter diameter Arecibo radio telescope can pick up a 10 million Watt at a distance of 1,000 ly. If we were ti detect a similar signal coming from 10,000 ly away, how powerful would the alien antenna have to be?
1 billion Watts
If the communication lifetime of civilizations in our galaxy is 10,000 years and our galaxy is 13 billion years old, what is the chance of us detecting another intelligent civilization now
1 in 1,300,000
If the communication lifetime of civilizations in our galaxy is 100 million years and our galaxy is 13 billion years old, what is the chance of us detecting another intelligent civilization now?
1 in 1300
Approximately how soon might we expect an immediate response from a civilization that received the signal we sent to the globur cluster M13 (21,000 ly away. in 1974?
42,000 years
Given that there are several hundred billion stars in the Milky Way Galaxy and preliminary data from exoplanet studies suggest that as many as one in five star systems may have one or more habitable planets, then a reasonable estimate for the number of habitable planets could be about
100 billion or more
Which of the following is a prime number
13
Suppose that there are 10 billion (10,000,000,000,000. habitable planets in our galaxy, that 1 in 5 habitable planets have life, that 1 in 100 civilizations that have ever existed is in existence now. How many civilizations would exist at present?
2,000,000
Given that our galaxy has a volume of approximately 8 10^12 ly^3, what is the average distance between civilizations if there are currently 1 million intelligent civilizations in our galaxy?
200ly
If you arrange the following 15 bits (111001111100111. into 5 rows of 3 bits starting with the first bit, what number does it spell out?
3
Given that our galaxy has a volume of approximately 8 10^12 ly^3, what would be the average minimum amount of time to exchange messages between civilizations if there are currently 125,000 intelligent civilization in our galaxy?
800 years
Which Lagrange points in the Earth -- Moon system are stable?
L4 and L5
the most likely method of interstellar communication is similar to which type of communication on Earth?
Morse code
In the simplified Drake equation, the total number of life-bearing planets in our galaxy is given by
NHP x flife
Which of the following factors in the simplified Drake equation is best known?
Nhp, the number of habitable planets in our galaxy
Which scientist built a radio transmitting tower at the turn of the 20th century and claimed that he was receiving interplanetary communications with it?
Nikola Tesla
What type of civilization can life on Earth currently be classified as?
Type I
What type of civilization would be able to construct a "Dyson Sphere" around its parent star to capture its radiation?
Type II
In the novel Contact by Carl Sagan, an extremely advanced civilization has constructed a labyrinth of wormholes throughout the galaxy. A civilization capable of such a feat would most likely be classifies as what kind of civilization?
Type III
How is intelligence defined in the Drake Equation?
a civilization willing and able to communicate over interstellar distances
If we were to intercept a signal from civilization that was sent to another of its colonies on the other side of the galaxy, this would be an example of
a signal used communication between a civilization's home world and another star system
If we were to detect radio and TV signals that had leaked out into space from another civilization, this would be an example of
a signal used for local communication in the world where the intelligent beings exist
An organism with and Encephalization Quotient (EQ of 4 is expected to be of
above-average intelligence
In the simplified Drake equation, a value of f life = 1 would imply that
all habitable planets in the galaxy have life
The 1420 MHz (21 cm radio line generated by neutral hydrogen a toms is a good choice for interstellar communications because
all intelligent civilizations should be aware of its universal significance and would probably also think of sending and receiving signals at this frequency
Which type of electromagnetic radiation is able to carry the most information?
all types have equal ability
If we were to intercept a strong radio signal at 1420 MHz in binary format from another civilization, this would be an example of
an intentional signal beacon
Which of the following kinds of signal so we currently have the best chance of detecting with currently technology?
an intentional signal beacon
a UFO is
an unidentified object seen in the sky
Which of the following cases in the Drake equation would be the minimum necessary condition fro us to be the only intelligent civilization currently in our galaxy?
any one of the factors to be zero
Approximately what proportion of people in the United States believe we have been visited by extraterrestrials?
around 33% or a third
an organism with an Encephalization Quotient (EQ. of 1 is expected to be of
average intelligence
the range of frequencies that a radio telescope is sensitive to is referred to as its
band
The range of frequencies that are contained in a particular radio signal is referred to as its
bandwidth
an organism with an Encephalization Quotient (EQ of 0.1 is expected to be of
below-average intelligence
The Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence states that the first thing to do after the detection of a possible signal is to
confirm that it is genuine
About 90% of UFO sightings
can be explained by natural phenomena
The adoption of very similar streamlined body shapes by both sharks and dolphins provides evidence for
convergent evolution
The fact that many different organisms on Earth have developed eyesight provides evidence for
convergent evolution
The fact that Encephalization Quotients (EQ of organisms have generally increased with time provides evidence for
convergent evolution toward intelligence
If there around 10,000 transmitting civilizations in the Milky Way, then theoretically the Allen Telescope Array, when it is complete, might be capable of detecting a signal within a few
decades
The organisms with the next highest Encephalization Quotient (EQ ratios after humans are
dolphins
Which term in the simplified Drake equations depends on sociological factors?
f now
Which of the following factors in the simplified Drake equation is least well known?
fnow, fraction of civilization-bearing planets that have intelligent civilizations on them now
Optical SETI is useful for
focused communication over short distances and in particular directions
Why was the global cluster M13 selected as the target fro the 1974 Arecibo message?
globular clusters are densely packed with stars, hence maximizing the probability of interception by an advanced civilization
in 1974 we transmitted a message toward the globur cluster M13 which is 21,000 ly away. What is one reason that we will probably have stopped communicating before we receive and return signal
globur clusters contain, old, low mass stars fewer heavy elements and hence are not ideal places for life
Intelligence may be subject to convergent evolution because it
has survival value
Which of the following signals from an advanced civilization would be easiest to detect?
high intensity, narrow bandwidth
The factor f now, in the Drake equation depends on
how long civilizations survive once they have arisen
The organisms with the highest Encephalization Quotient (EQ ratios are
humans
A Lagrange point in the Earth -- Moon system is a position
in space where the effects of the Earth's and Moon's gravity cancel each other out
the ratio of an animal's brain weight to body weight is though to be roughly proportional to its
intelligence
The Drake equation allows us to estimate the number of
intelligent civilizations capable of communicating in our galaxy now
Which type of signal could carry the largest amount of information?
large bandwidth
A dinosaur like a Brontosaurus with a small head and a large body would be expected to have an Encephalization Quotient (EQ of
less than 1 but greater than zero
On the basis of the scientific method, which of the following would be considered conclusive evidence that we are being visited aliens?
none of these would be conclusive
Due to increasing amounts of terrestrial radio noise, in the future SETI telescopes may be placed
on the far side of the Moon
Sending signals at optical wavelengths might be a viable alternative to radio wavelengths
over relatively short distances where absorption by interstellar matter would not be a problem
Currently in the USA, SETI programs are mostly funded
privately
Why are radio waves probably the most efficient way to communicate between civilizations?
radio waves are easy to produce and are not affected much by interstellar matter in the galaxy
An optical SETI signal would most likely consist of
rapid, short bursts of intense laser light
any reply to a detected SETI signal should
represent a consensus of the Earth's population
It is unlikely that we will be able to detect the signals from civilizations in other galaxies because
signals from other galaxies will be severely weakened by distance, making them far harder fro us to detect
The sweep technique used in SETI programs is also known as a
sky survey
The Inner Galactic Plane Survey conducted with the Allen Telescope Array in northern California is an example of a
targeted search
The search for radio signals from intelligent civilizations on planets around nearby solar-type stars is an example of a
targeted search
The main problem with early attempts to listen for radio signals from space was
that they were conducted at relatively low frequencies which have problems penetrating the Earth's upper atmosphere
One of the most likely places an advanced civilization might leave an artifact for us to find would be
the L4 and L5 points in the Earth -- Moon system
Which of the following physical parameters is NOT under the control of a radio telescope?
the bandwidth
After World War II, the US Government spent two decades investigating UFOs because they
thought that they might be new types of aircraft being developed by the Soviet Union
Encephalization Quotient (EQ values can be estimated for extinct species because
we can estimate their body masses from their fossilized remains and their brain masses from the sizes of their fossilized cranial cavities
In principle, the Drake equation should enable us to calculate the exact number of intelligent civilizations capable of interstellar communication in our galaxy right now. However, currently this is not feasible because
we do not have exact numbers fro any of the factors in the equation
