Author Question: Spacecraft have landed on all the terrestrial worlds except A) Mercury. B) Venus. C) Moon. D) ... (Read 111 times)

james9437 · **on:** Jul 27, 2018

Spacecraft have landed on all the terrestrial worlds except

A) Mercury.
B) Venus.
C) Moon.
D) Mars.
E) Spacecraft have landed on all of the terrestrial worlds.

Question 2

In essence, most of the extrasolar planets discovered to date have been found by

A) closely examining very high-resolution photographs of other star systems.
B) observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet.
C) identifying spectral lines that look like what we expect to see from a planet rather than a star.
D) observing mini-eclipses of a star as an unseen planet passes in front of it.