How did Ptolemy explain the retrograde motion of Venus?
What will be an ideal response?
Question 2
Which of the following is not a possible solution to the Fermi Paradox?
A) There is a galactic civilization, but we are currently unable to detect or recognize it.
B) We are the only intelligent civilization to have ever arisen in the Milky Way.
C) Given the current age of our galaxy, there has not been enough time for a galactic civilization to develop.
D) There is a galactic civilization, but it is being actively hidden from us.
E) Of all of the intelligent civilizations in the Milky Way, none has chosen to create a galactic civilization.