Today, astronomers can measure distances directly to worlds like Venus, Mars, the Moon, or the satellites of Jupiter by
A) bouncing radar beams off them
B) using x-ray telescopes
C) using the Hubble Space Telescope to triangulate with
D) using Cepheid variable stars that lie behind the planets
E) sending graduate students out with very long tape measures

Question

Quizplus · Accepted Answer

Astronomers can measure distances directly to nearby worlds like Venus, Mars, the Moon, or the satellites of Jupiter by bouncing radar beams off them. This method is known as radar ranging and uses the time delay between transmitting and receiving the radar signal to calculate distance.

Today, Astronomers Can Measure Distances Directly to Worlds Like Venus