Early Scientists
What did Eratosthenes discover?
Using simple mathematics and shadows cast by sticks, Eratosthenes calculated the true circumference of the Earth.
Approximately how long ago did humans emerge as a species?
Two million years ago
What is the term for the trapping of the Sun's energy by gases in the Earth's atmosphere?
The greenhouse effect
Describe Mars 3 & Mars 6.
Two failed Soviet landers on Mars.
What did Kepler discover?
Among other things, Kepler laid out the three laws of planetary motion, including the idea that planets orbit the sun in ellipses, not circles.
Fill in the blank: ________ is the process by which genetic _________ in an organism's ___ cause changes in a species over generations.
Evolution; mutations; DNA
What is the term devised by Charles Darwin to describe the way advantageous traits persist through generations of organisms?
Natural selection
Describe Voyager 1 & Voyager 2.
Two space probes sent out to observe the gas giants and now travelling through interstellar space; the most and third-most [likely second-most later this year!] distant human-made objects from Earth
What did Newton discover?
Among other things, Newton discovered the force of gravity, which affirmed Kepler's laws of planetary motion and the Copernican heliocentric model.
What three places does Sagan highlight as important intellectual centers?
The Library of Alexandria, Holland, and Ionia
The samurai crab is the example Sagan uses to illustrate what phenomenon?
Artificial selection
Describe Viking 1 & Viking 2.
Two successful NASA landers on Mars.
What incorrect theory is Lowell remembered for?
Percival Lowell is remembered for his speculation about artifically-made water-carrying canals on Mars.
Why does Sagan suggest that early humans developed the pseudoscience of astrology?
It was natural, Sagan suggests, to presume that the stars impacted human personality, destiny, etc., since other celestial objects (e.g. Sun, Moon) affect our lives in so many other ways (weather, seasons, agriculture, animal migrations, etc.).
What is the Local Group?
our "galactic neighborhood" i.e. the group of galaxies that includes the Milky Way.
Describe Projects Orion & Daedelus.
Proposed nuclear-powered (fission and fusion respectively) starships.
What are the names of the four Galilean satellites, and which planet do they orbit?
Io, Europa, Ganymede, and Callisto are four of Jupiter's largest moons.
Name two examples Sagan gives of science clashing with religious/superstitious thinking.
Some possible answers:
- Kepler's mother being tried for witchcraft due to the publication of Kepler's "science fiction" book
- The millennia-long suppression of heliocentrism in favor of the Ptolemaic model of the Earth as the singular world at the center of the universe (persecution of Copernicus, Galileo, Bruno, etc.)
- The persistence of astrology
- The Pythagoreans ("religious" dogmatic belief in a separate "world" of mathematics as a means of deriving natural laws [rather than observation and experimentation])
Explain Einstein's theory of special relativity.
The laws of physics (including the speed of light) are the same no matter where they are observed.
According to the theory of relativity, if a spaceship traveled from the Earth to the center of the Milky Way at the speed of light, how much time would pass for people in the spaceship? How much time would pass on Earth?
21 years (spaceship); 30,000 years (Earth)