ConceptChecks
ConceptCheck 8-1: No. Earth is not an exception to any of the three properties in Table 8-1, and in fact, all the planets are consistent with these properties.
ConceptCheck 8-2: The carbon atoms that make up much of our human bodies and the very oxygen atoms we breathe were made inside of stars. Stars have made most of the atoms other than hydrogen.
ConceptCheck 8-3: Yes. Hydrogen (H) is the first most abundant element, and oxygen (O) is the third most abundant element. Water (H20) is, in fact, quite common even though it is usually frozen.
ConceptCheck 8-4: No. The age of a rock refers to how much time has passed since the rock cooled and solidified. It is not the age of the rock’s atoms, which were made in stars, and possibly different stars at different times.
ConceptCheck 8-5: To be correct, the nebular hypothesis must explain why all the planets orbit the Sun in the same direction and in nearly the same plane. This arrangement is unlikely to have arisen purely by chance.
ConceptCheck 8-6: No. Through Kelvin-Helmholtz contraction, gravitational energy is converted into heat—a lot of heat. The protosun, which formed before nuclear reactions began, had a surface temperature of 6000 K, slightly higher than our present-day Sun. Thus, the solar nebula was warmed by the protosun.
ConceptCheck 8-7: Frozen water helped to make Jupiter large enough to hold onto hydrogen and helium. The closest that a large, Jupiterlike planet could form would be much farther away in a much hotter solar nebula.
ConceptCheck 8-8: Called chemical differentiation, denser, iron-rich materials migrate to the center of a planet while the less dense silicon-rich minerals float to the outside surface before the initially molten planet solidifies in the early solar system.
ConceptCheck 8-9: At Neptune’s present distance, the time to build a planet the size of Neptune is much longer than the time that the protoplanetary disk is around.
ConceptCheck 8-10: In the Nice model, once planetary orbits became unstable, Neptune was deflected to about twice its original orbital distance.
ConceptCheck 8-11: Accretion refers to the gravitational accumulation of matter. Chemical bonds might, or might not, be formed once matter has accumulated.
ConceptCheck 8-12: An extrasolar planet with an orbit that causes a star to wobble side to side will not exhibit any Doppler shifted spectra as seen from Earth because the star will not be moving alternately toward and away from Earth, and therefore the radial velocity method will fail to detect such an orbiting extrasolar planet.