Exposing PseudoAstronomy

September 4, 2008

More Reasons Why Comets Do NOT Prove Creationism

Filed under: comets,creationism — Stuart Robbins @ 11:30 pm
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This post is in regards to the Institute for Creation Research’s September 6, 2003 program about Comets. You can listen to the audio here.

Even though this episode of ICR radio was produced before my previous post on comets and creationism, I’ve opted to write about it second because the claims in it are more subtly incorrect.

The first comment on this episode is really more of a nit-pick (@ 4 min): The scientist on the program claims, “The famous Shoemaker-Levy [9] comet, which broke up into 9 pieces and crashed into the surface of Jupiter …”

Now this claim really isn’t used to try to prove creationism, but another purpose of this blog is to help propagate good astronomy when there is bad astronomy being stated. There are two problems with the above statement. The first is that the comet in question did not break into 9 pieces, but rather it broke into 21 main fragments, labeled A through W. Also, Jupiter really doesn’t have a “surface” in the traditional sense. It may have a rocky core, but we don’t know that for certain. What we do know is that its atmosphere is huge, extending at least 5 times Earth’s radius, and the comet fragments that crashed through the jovian atmosphere would have been crushed by the pressure well before they reached any “surface.”

About 6 min 30 sec into the broadcast, we get the first bit of real pseudo-astronomy: One of their scientists is talking about how comets tend to fragment, they lose some of their material during their orbit, and they’re somewhat fragile if they come really close to a large, massive object (like a planet or star). But he then states, “This has been a problem for evolutionists for a long time because comets just don’t last, and they certainly don’t last over the supposed age of the solar system.”

Again there’s that “evolutionist” label … somehow because I’m an astronomer who uses “real” science I’m now an evolutionist, too. Regardless of this snub, this is the same argument that I talked about in my previous post on comets: Comet nuclei were not all “launched” into close-Sun-passing orbits at the beginning of the solar system. They effectively “lie in wait” in the frigid outer regions until they collide amongst themselves or a passing massive body causes their orbits to change, bringing a few into the inner solar system. This effectively sets their internal “clocks” at a zero-age in terms of losing material, and so it really has nothing to do with “proving” the solar system was created a matter of a few thousand years ago. This is NOT “good evidence that the Universe isn’t billions of years old,” as the narrator states.

The next argument is closely related (about 7 min 45 sec in): Dr. Ross Humphreys is a physicist for the ICR and says, “There’s (sic) some comets called ‘short-period comets’ that come around so frequently that they could not have been in our solar system longer than 10,000 years. … Halley’s comet is acknowledged by scientists to not have been in the solar system longer than 90,000 years.” (emphasis mine)

So this is the same argument as above which I’ve already addressed. However, there’s a new wrinkle. This person claims that these comets aren’t even in the solar system until recently. This simply doesn’t make sense. People who do modeling have shown that it’s nearly impossible to have objects line up just right such that two bodies that were not gravitationally bound to begin with (a comet being “in” our solar system, in other words) can be captured. I believe their physicist meant to say “in the inner solar system,” which could be more correct. But this is a pretty obvious mistake to make, and if you’re going to make an argument from authority (the guy being a physicist) you would hope their authority knows that comets didn’t magically appear from beyond the solar system.

There are a few more misstatements and fallacious arguments in the next few minutes episode, but they are pretty much the same as those I have addressed below and in my other comet post (not believing in the Oort Cloud simply because they can’t see it). Oh, and apparently I’m now a “Big Bang Theorist” because I know about comets and agree with the evidence supporting the Kuiper Belt and Oort Cloud. Maybe I could write a grant to NASA to study comets because I’m a Big Bang Theorist.

The last argument they make that I want to address is the claim the Kuiper Belt “can’t” be a source of short-period comets (about 10 min into the program). The evidence they point to is that the objects in the Kuiper Belt are generally redder in color than comets. They claim this means they’re two entirely different classes of objects, and that evolutionists (honestly, how the heck do they equate studying comets with being an evolutionist?) have tried all sorts of ways to get Kuiper Belt Objects (KBOs) to “lose” their red.

This is actually a fairly easy problem. Without getting into chemistry, spectroscopy, and physics, the basic idea is weathering. Even though there’s no air, water, etc. in space, there are particles that are constantly interacting with KBOs, and those particles mainly come from the solar wind. They have the ability to chemically alter the material they come into contact with, but only the very upper surface. When the objects are weathered, they become redder. Once a KBO is nudged into a sun-grazing orbit, however, the crust sublimates (turns from a solid directly into a gas). What is sublimating? The upper surface of the KBO … the surface that was weathered. So after a first-close-pass with the Sun, the object can easily lose that red color and look like an ordinary comet.


A final comment goes to the nature of science. On this program, as on the comet one I discussed below, the fall-back is something to the effect of, “Creationism has a much simpler answer than all this Oort Cloud, Kuiper Belt, and other stuff. It’s that the Solar System was created by God recently.”

That is faith. Plain and simple. It is NOT science. Science makes testable, potentially falsifiable hypotheses about the way things work. If you pass everything off to God as your explanation, that is perfectly legitimate faith, but it has nothing to do with science because it is not testable nor falsifiable. The explanations I have given may seem “materialistic,” but that is the nature of science; by definition, it does not accept faith-based explanations.

And I must add that, so far, the materialist explanation has worked perfectly fine for explaining the apparently unexplainable features of comets.

Why Comets Are NOT Evidence for a Young Solar System

Filed under: comets,creationism — Stuart Robbins @ 4:47 am
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This post is in regards to the Institute for Creation Research’s February 4, 2006 program about Comets.  You can listen to the audio here.

The beginning of this program is actually fairly decent, talking about how comets are “dirty icebergs” that orbit the Sun, and when they get too close, they begin to lose material because the Sun’s heat and wind both melt and erode material from its surface.  I don’t know precisely if the number “5%” of it gets removed, but that’s not a huge issue for me (is for them, and I’ll explain why).

The first real mistake in this piece comes at about 2 min 30 seconds in.  The host makes the point that, “Since matter is being stripped away from comets, how long do they survive in the solar system?”  Their expert, Dr. Falkner (not sure on that spelling), replies that most comets are only a few miles across and that each time they come close to the Sun, they may “lose a few feet off of that size.”

This contradicts what they said above about the 5% number.  Let’s say for argument that a comet is 1 mile in diameter (probably fairly small).  And a “few feet” amounts to a generous 10 feet.  If it loses 10 feet off its diameter every pass, it would need to go through about 528 passes of the Sun to disintegrate … not after “probably maybe 100 trips around the Sun it eventually dissipates.”  If comets have orbits of 100 years (as they then generalize), then that’s nearly 53,000 years!  NOT 10,000 years.

Then let’s examine the claim of 5%.  If a comet is again 1 mile in diameter, then it doesn’t simply have to approach the Sun 20 times (20*5 = 100) to die off.  5% is multiplicative.  So the first pass it would have 95% of its original material, but the next pass would reduce it to 90.25% of its original material (0.95*(1-0.5)).  This continues iteratively.  So the third pass would leave it with 85.7375% (0.9025*(1-0.05)), and so on.

But this is again a huge over-generalization, but they use it to say it’s evidence for recent creation.  Well, yes, IF you assume that all comets started orbiting the Sun on orbits that took them close to the Sun when the solar system was formed, IF you assume that all comets have 100-year orbits, IF you assume that all comets are only 1 mile in diameter and lose a few feet or 5% (which are NOT equivalent) of material after every orbit, then sure, this may be evidence for a recent creation.  But this is NOT the case.

And it’s not even the biggest mistake they make.  The host then says that, “Many evolutionists answer this question by hypothesizing that a large cloud of orbiting comets (dirty snowballs) exists in the outer reaches of the solar system.”  So there’s the association fallacy at work, I’m an “evolutionist” and therefore I’m wrong about other things simply by that association.

Well this claim that that’s what astronomers believe is mostly true.  They are referring specifically to the Oort Cloud, a very large (2-light-year-radius) cloud of comets that is believed to contain trillions of bodies in the outer reaches of the solar system, extending half-way to the nearest star (4.3 light-years away).  It is believed to be the source of long-period comets (comets that have a “year” of more than 250 Earth-years).  But there’s another region of comets interior to the Oort Cloud that starts just outside Neptune – the Kuiper Belt.  This is another region of space believed to have billions of comets that is the source for short-period comets (those with years less than 250 Earth years).  The Kuiper Belt was first observed in 1992 (when the first object was discovered in it).  The Oort Cloud remains the subject of theory simply because the objects in it are so far away and so small that they are too faint to be detected with current technology.  But it is still a falsifiable theory.

Now that you have a brief understanding for what these are, on with the ICR claims (at about 4 min in):  [host] “However, there is a small problem with the Oort Cloud Theory.”  [scientist] “All this sounds very complicated, but the bottom line is nobody’s ever seen the Oort Cloud.  We see what looks like an Oort Cloud around other systems, but we don’t see it in our own vicinity.  So I have my doubts that it exists …” [emphasis mine]

So let’s think about this for a bit.  “Nobody’s ever seen the Oort Cloud … so I have my doubts that it exists.”  Alright.  No one’s ever seen gravity, but we see its effects.  No one has ever seen a crater form on a planetary surface, but we have a very good idea of how it happens and we can model it.  No one has ever seen a star explode (this is a good thing) but we have good models that make predictions about what we should see after they explode, which have been observed.

The Oort Cloud is hypothetical, and it is not possible to actually observe it with our technology.  But, it is the best science-based explanation for long-period comets.  The Kuiper Belt was hypothetical, but it was later verified and we have now cataloged many hundreds of members of it.

And they even miss the point that even if the Oort Cloud does NOT exist, then (a) there’s no source for long-period comets, but (b) it STILL does not mean that the solar system was created 10000 years ago or less.  That’s because it’s actually fairly few comets that enter the inner solar system at any given time, the Belt has to be perturbed by a passing object to knock a comet into the inner solar system.  That takes time.  And so any object in the Kuiper Belt today could get knocked into an orbit that takes it close to the Sun and makes it a comet to us.  That starts the clock on that particular comet at 0.  So the fact that we still see comets today says ABSOLUTELY NOTHING about the solar system having been created recently.


The creation scientist then goes on to talk about some other stuff, but around 5 min 30 sec basically sums up the point of the broadcast episode:  “Comets are fragile.  During their orbits around the Sun, they shrink, or melt, some occasionally hit the Sun or Jupiter, and some comets leave the solar system all together.  Yet, there’s the continued presence today of hundreds of known comets … each and every comet is a witness to a supernatural, created solar system that is just thousands of years old, not billions.”

As I have hopefully convincingly shown, this is simply not true.  It is based on gross generalizations, assumptions, and outright disregard for the consensus of the structure of the solar system.

But, it’s difficult to argue with faith, when the announcer says (8 min 30 sec):  “As creationists, we know that comets, along with the rest of the Universe, were made by God on Day 4 of Creation Week.”

This is why I am not trying to convince you that creationism is or is not true.  I am simply illustrating that the scientific claims that creationism makes are flawed, not true, or outright denials of evidence.

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