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.
Answer:B
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.