Now figure out what we know the circumference of Earth to be today, using the known radius of 6,371 km, remembering πΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆπΆ=2βππβπΆπΆ.
How close was Eratosthenes?
2)[20] a) It took astronauts 3 days to reach the moon, which is 384,400 km from Earth. Going at the same speed, how much longer would it take astronauts to reach Mars, which is 0.524 AU from Earth. b)How about to Alpha Centauri, the nearest star, which is 4.4 light-years from Earth?
c)What does this tell us about the relative difficulty of sending astronauts to other stars compared to sending them to the Moon or even Mars?
1 Astronomical Unit (AU) = 1.496×108 km1 light-year = 9.46×1012 kmd)[5] Scientific Methoda.In a discussion of what holds airplanes aloft, a classmate offers this hypothesis: βAirplanes are held up by an undetectable force field produced by invisible magnets.β Which word in this statement is most likely to keep the statement from satisfying the criteria for a scientific hypothesis? Why?
b.During class, a fellow student explains the result of an experiment that solves the homework problem assigned. When asked how they solved the problem, they said the answer came to them in a dream. You wish to find the answer in the same fashion, but even though this answer ends up being correct, why would this not be a scientific experiment?