According to the nebular theory, how did the Oort cloud form?
A) It consists of objects that fragmented from the protosun during a catastrophic collision early in the formation of the solar system.
B) It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet.
C) It is material left over from the interstellar cloud that never contracted with the rest of the gases to form the solar nebula.
D) It is made of planetesimals that formed beyond Neptune's orbit and never accreted to form a planet.
E) It is made of planetesimals formed in the outer solar system that were flung into distant orbits by encounters with the jovian planets.
Question 2
Spectra for the Cygnus loop and the Orion nebula are shown above. Judging from their spectra, how would these two objects look to the naked eye (assuming they were bright enough for colors to be distinguished)?
A) The Cygnus loop would appear red, and the Orion nebula would appear blue.
B) The Cygnus loop would appear red, and the Orion nebula would appear red.
C) The Cygnus loop would appear blue, and the Orion nebula would appear blue.
D) The Cygnus loop would appear blue, and the Orion nebula would appear red.