Below is the online edition of In the Beginning: Compelling Evidence for Creation and the Flood,
by Dr. Walt Brown. Copyright © Center for Scientific Creation. All rights reserved.
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Summarized below are the hard-to-explain details which any satisfactory theory for the origin of comets should explain.
Formation Mechanism. Experimentally verified explanations are needed for how comets formed and acquired water, dust particles of various sizes, and many chemicals.
Ice on Moon and Mercury. Large amounts of water-ice are in permanently shadowed craters near the poles of the Moon, and planet Mercury.
Crystalline Dust. Comet dust is primarily crystalline.
Near-Parabolic Comets. The observed near-parabolic comets are falling toward the Sun for the first time—and from all directions. Why are so many comets represented by the tall red bar in Figure 174?
Random Perihelion Directions. Comet perihelions are scattered on all sides of the Sun.
No Incoming Hyperbolic Orbits. Although a few comets leave the solar system on hyperbolic orbits, no obvious incoming hyperbolic comets are known. That is, no comets are known to come from outside the solar system.
Small Perihelions. Perihelions of long-period comets are concentrated near the Sun, in the 1–3 AU range, not randomly scattered over a larger range.
Orbit Directions and Inclinations. About half the long-period comets have retrograde orbits (orbiting in a direction opposite to the planets), but all planets, and almost all short-period comets, are prograde. Short-period comets have orbital planes near Earth’s orbital plane, while long-period comets have orbital planes inclined at all angles.
Two Separate Populations. Why are long-period comets so different from short-period comets? Even millions of years and many gravitational interactions with planets would rarely change one kind into the other.
Jupiter’s Family. How did Jupiter recently collect its large family of comets, each with a short life expectancy of only about 12,000 years?24 [See Figure 171 on page 307.]
High Loss Rates of Comets. Comets are being destroyed, diminished, or expelled from the solar system at high rates that are difficult for some theories to explain.
Composition. Comets are primarily water, silicate dust (such as olivine), carbon dioxide, sodium,79 and combinations of hydrogen, carbon, oxygen, and nitrogen. Comets also contain limestone, clays, methane, and the amino acid glycine that is almost exclusively produced by life on earth. Surprisingly, one compound in comets, cubanite, is produced only in scalding hot liquid water. Comet 67P has molecular oxygen (O2) dissolved in its ice.
Heavy Hydrogen. The high concentration of heavy hydrogen in most comets means comets did not come from today’s known hydrogen sources—in or beyond the solar system.
Small Comets. What can explain the strange characteristics of small comets, including their abundance and nearness to Earth, but not to Mars? Small comets have never been seen impacting Mars, but there have been many sketchy reports of flashes of light on the Moon.80
Missing Meteorites. Meteor streams are associated with comets and have similar orbits. Meteorites are concentrated in Earth’s topmost sedimentary layers, so they must have fallen recently, after most sediments were deposited.81 [See "Shallow Meteorites" on page 41.] Comets may have arrived recently as well.
Recent Meteor Streams. As comets disintegrate, their dust particles form meteor streams which orbit the Sun. After about 10,000 years, solar radiation should segregate particles by size. Because little segregation has occurred, meteor streams, and therefore comets, must be recent. [See "Poynting-Robertson Effect" on page 42.]
Crater Ages. Are the ages of Earth’s impact craters consistent with each comet theory?