Astronomy Week 8
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 years
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
Which of the following spacecraft is NOT leaving the solar system?
Galileo
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
If alien beings found one of the Voyager spacecraft in a million years, what would they find aboard?
an audio and video record
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????
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
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?
on the surface of some of the smaller members of the Kuiper Belt
Photosynthesis, once it was planet-wide, changed the atmosphere of the Earth by introducing a significant amount of
oxygen
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
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
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
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:
the fact that most of our atmosphere is made of nitrogen
Which of the following events in cosmic history is the most recent?
the formation of life on Earth
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 (according to our present understanding of science) is
the speed of light
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 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
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
