Week 8
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? Select one: 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
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?
80
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 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
The first search for radio messages from extra-terrestrial civilizations was called
Project Ozma
What discovery about Saturn's 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
Which of the following is a good summary of what most astronomers think about UFO reports in the popular media? Select one: a.it is now clearly established that alien spacecraft have crashed on Earth; we have the bodies of the aliens who flew them here
a
If alien beings found one of the Voyager spacecraft in a million years, what would they find aboard?
an audio and video record
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: Select one: a.the presence of a large moon around the Earth b.the abundance of micro-organisms in the deserts of the Earth c.the fact that most of our atmosphere is made of nitrogen
c
Which of the following spacecraft is NOT leaving the solar system? Select one: a.Voyager 1 b.Voyager 2 c.Galileo d.Pioneer 10 e.Pioneer 11
c
Photosynthesis, once it was planet-wide, changed the atmosphere of the Earth by introducing a significant amount of
oxygen
What recent series of discoveries has made astronomers more optimistic about our prospects of finding life out there?
the discovery of planets around thousands of stars in our Galaxy
The Drake Equation allows astronomers to estimate
the number of civilizations out among the stars with which we might communicate
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
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 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
Which of the following is, to the best of our knowledge, in the habitable zone of its star: Select one: a.a planet about 1.05 AU from a G-type main sequence star b.a Jupiter-mass planet taking 15 years to orbit a K-type main sequence star c.all of the above
a
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
According to astronomers, which of the following places in the outer parts of our solar system might be a reasonable place for life to exist? Select one: a.in the core of the planet Saturn b.in the rings of Neptune c.in the mountains of Pluto d.on the surface of some of the smaller members of the Kuiper Belt
d
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 more narrow (small) than the diameter of any planet
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 of the following events in cosmic history is the most recent? Select one: a.the birth of the universe b.the formation of our Galaxy c.the formation of the Sun d.the formation of life on Earth e.you can't fool me, all of the above happened at roughly the same time
d
Which of the following questions is NOT part of what astronomers call the "cosmic haystack problem" in receiving messages from other civilizations in space? Select one: 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
