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Oort cloud and Kuiper belt are ad-hoc fantasies of astronomers (Talk.Origins)
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- The Kuiper Belt and Oort Cloud have never been observed. They have been proposed merely as an ad hoc explanation for a source of comets.
- Brown, Walt, 1995. In the Beginning: Compelling evidence for creation and the Flood.' Phoenix, AZ: Center for Scientific Creation, p. 69.
CreationWiki response: (Talk.Origins quotes in blue)
1. As of June 2000, more than 250 objects in the Kuiper Belt have been observed directly, and it alone can be the source of short-term comets.
They are called trans-Neptunian objects (TNOs) but there is a trend toward calling them Kuiper Belt objects in the hope that they are that predicted source of short period comets. However TNOs are more like Pluto than comet nuclei.
Most of the objects found are hundreds of kilometers in diameter, while known comet nuclei are less then 20 km in diameter and most are less than 2 km. Even if some TNOs are as small as comet nuclei, it would be odd if only the extremely small ones became comets. And the larger one would last longer, which would balance out the fact that small ones would tend to outnumber large ones. Furthermore, many TNOs are both brighter and redder than comet nuclei.
None of the comets with a maximum age of about 10,000 years go out as far as Neptune. Those that do have a maximum age of about 100,000 years. The only way of placing a comet from the so-called Kuiper Belt into an orbit deep within aphelion deep inside the solar system would be by a slingshot encounter with Jupiter or one of the other planets. Not only is such an event too improbable to be likely to occur before the comet evaporates, but the only such encounter ever known to have occurred resulted in the destruction of the comet. The Kuiper Belt theory predicts that because of the rarity of the needed encounter and the short life expectancy of such comets, most short period comets should have aphelion beyond Neptune's orbit. However, about 60 percent have aphelion of 4-6 AU or about the vicinity of Jupiter.
Just because the supporters of a particular theory give a label to something that is based on that theory does not make it what is predicted by the theory. In this case there are reasons to doubt the interpretation.
- The Kuiper Belt
- The Sizes of Comet Nuclei
- Comet Halley Nucleus
- Trans-Neptunian Objects
- How Comets Move
The Oort cloud has not been observed directly (although Sedna, a planetoid discovered in March 2004, might be in the Oort cloud),
Sedna is 1,770 km across, way too big for a cometary body. Calling it an Oort cloud object is a stretch even assuming the Oort cloud exists.
but its presence is well supported based on observations of long-period comets.
The Oort cloud theory is based on observations of long-period comets, so this is Circular Reasoning.
2. If there were no source for new comets to come from, all comets would have the same age. They do not. Some are young and have lots of gasses; others are little more than gravel heaps.
This assumes that comets all start out with about the same composition. Talk.Origins is assuming a particular theory of their origin, and then projecting an age estimate based on that.