Sunspots are known to be magnetic phenomena because
a. Doppler shifts in spectral lines are observed.
b. the Zeeman effect is observed in sunspots.
c. collisional broadening is observed in spectral lines.
d. infrared observations indicate that the sunspots are cooler than their surroundings.
e. observations during eclipses reveal a very extensive photosphere.
Question 2
The greatest inaccuracy in Copernicus's model of the solar system was that the planets
a. traveled in circular orbits with uniform motion.
b. traveled on epicycles whose centers followed orbits around the Sun.
c. traveled in elliptical orbits.
d. were allowed to travel backwards in their orbits.
e. orbited the Sun.