WQ #30

Photosynthesis releases a particular gas as a byproduct. This gas is: a. carbon dioxide b. oxygen c. water vapor d. methane e. DNA

a. carbon dioxide

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? a. radio waves b. x-rays c. ultra-violet d. infrared e. gamma rays

a. radio waves

Which of the following spacecraft is NOT leaving the solar system? a. Voyager 1 b. Voyager 2 c. Galileo d. Pioneer 10 e. Pioneer 11

c. Galileo

Photosynthesis, once it was planet-wide, changed the atmosphere of the Earth by introducing a significant amount of a. oxygen b. carbon dioxide c. methane d. ammonia e. vibranium

a. oxygen

We receive a radio message from a civilization around a star about 40 lightyears 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? a. 40 years b. 80 years c. 400 years d. 20 years e. it depends on the speed of the radio wave; so it can't be calculated from the information given

b. 80 years

Which of the following is, to the best of our knowledge, in the habitable zone of its star: a. a "hot Jupiter" taking 4 days to orbit a G-type main sequence star b. a planet about 1.05 AU from a G-type main sequence star c. a Jupiter-mass planet taking 15 years to orbit a K-type main sequence star d. a planet in an orbit the size of the Earth's around a red giant star e. all of the above

b. a planet about 1.05 AU from a G-type main sequence star

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 a. much larger (wider) than the Sun's b. much closer to the star than the Sun's c. in about the same place as the Sun's asteroid belt d. much more narrow (small) than the diameter of any planet e. the source of all the UFO's that have been reported by UFO believers on Earth

b. much closer to the star than the Sun's

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? a. observing what looks like dried up river channels from orbiting spacecraft b. the discovery of organic materials (the chemical building blocks of life, such as amino acids) by spacecraft that have landed c. the discovery that Mars long ago had plenty of flowing water, from the composition and layering of some of the rocks examined by Mars rovers d. the discovery of mudstone on Mars, which indicates that ancient Mars may have been more habitable than Mars today e. the discovery of significant amounts of frozen water on Mars, under the surface

b. the discovery of organic materials (the chemical building blocks of life, such as amino acids) by spacecraft that have landed

One reason that some scientists think that there may be life under the ice-crust of Jupiter's moon Europa is that: a. Europa is unusually warm on its surface; in some places the climate resembles Hawaii on Earth. b. Life has already been found on Io, Jupiter's inner-most large moon c. Life has been found on Earth, at the bottom of the ocean, deriving its energy not from sun-light but from hot mineral-laden vents coming from deeper inside our planet; something similar could happen at the bottom of the ocean on Europa d. meteorites blasted off Europa have been found on Earth and we detect the building blocks of life inside these meteorites from Europa e. we are receiving intriguing radio messages from Europa that indicate some form of intelligence lives there

c. Life has been found on Earth, at the bottom of the ocean, deriving its energy not from sun-light but from hot mineral-laden vents coming from deeper inside our planet; something similar could happen at the bottom of the ocean on Europa

If alien beings found one of the Voyager spacecraft in a million years, what would they find aboard? a. a container with a concentrated sample of the most common Earth bacteria b. a flag from the Soviet Union c. an audio and video record d. a human skull done in bronze e. a video tape with every episode of the original "Star Trek" TV series

c. an audio and video record

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? a. supernovae were exploding near the Sun's location every year back then b. the Sun was so much cooler when the Earth formed, that the Earth's oceans (and even Mars' oceans) were frozen over for billions of years c. 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 our planet and making it uninhabitable d. experiments like the one done by Miller and Urey show that life on Earth could not form until plants produced a lot of oxygen for our atmosphere e. the early solar system was filled with dark matter, and life could not form with so much dark matter around

c. 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 our planet and making it uninhabitable

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 a. has liquid water on it; no other world in our solar system has water b. has temperatures in some places where chemical change is possible c. has a solid surface d. has a biosphere on its surface where photosynthesis can take place e. has the chemical ingredients from which life might begin

d. has a biosphere on its surface where photosynthesis can take place

Photosynthesis was a great step forward in the evolution of life on Earth, because with photosynthesis a. we have the way in which life on Earth and life on Mars resemble each other b. life could, for the first time, reproduce (make copies of itself) c. we have the common ancestor that gave rise to every species of life now on Earth d. life could extract chemical energy from sunlight e. life did not have to evolve any further

d. life could extract chemical energy from sunlight

Which of the following questions is NOT part of what astronomers call the "cosmic haystack problem" in receiving messages from other civilizations in space? a. we don't know what star might have planets with intelligent life b. we don't know what channel they may be using to send messages c. we don't know whether the signal is always on (continuous) or only for a brief time every cycle d. we don't know how to receive signals in the wavelength range that is the most likely for interstellar communications e. we don't know how other civilizations might encode messages in the carrier wave they send

d. we don't know how to receive signals in the wavelength range that is the most likely for interstellar communications

From a scientific perspective, which of the following statements about life elsewhere in the universe is best supported by current evidence? a. we have good evidence that life exists on many planets around other stars b. we only have evidence that life exists around three other stars c. the government has evidence (which it is not releasing) that there is at least one other intelligent life form on a planet orbiting another star d. 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 e. there is no evidence for intelligent life anywhere, even on Earth

d. 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

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: a. temperatures near or below the freezing point of water b. temperatures near or above the boiling point of water c. very acid environments d. conditions where the radiation dosage is high e. conditions resembling the photosphere of the Sun

e. conditions resembling the photosphere of the Sun

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? a. the Hubble Space Telescope was put into orbit b. radio and TV signals have gone silent as much of the US adopts cable c. astronomers have developed adaptive optics to deal with the twinkling of the stars d. astronomers have built radio telescopes that can pick up the 3-degree microwave background e. we have developed the ability to make laser pulses that are briefly brighter than the Sun

e. 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 (organic compounds)? a. Earth b. comets c. meteorites d. clouds of interstellar gas and dust e. we have found evidence for such materials in all of the above sites

e. we have found evidence for such materials in all of the above sites

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? a. ammonia b. methane c. water d. carbon dioxide e. diet Coke or diet Pepsi

c. water

Which of the following is a recent (last few decades) discovery that confirms the key idea of the Copernican Principle? a. that the Earth has a Moon b. that gravity waves exist c. that planets around other stars are common d. that 65 million years ago a large asteroid hit the Earth e. that people from Eastern Europe are pretty smart

c. that planets around other stars are common

The Drake Equation allows astronomers to estimate a. the age of the universe b. the location of the Sun within the Milky Way Galaxy c. the number of civilizations out among the stars with which we might communicate d. the rate at which the universe expands e. the number of ducks that we in the United States use for food each year

c. the number of civilizations out among the stars with which we might communicate