AIG: Comets Prove the Universe Is Young

The creation scientists at Ken Ham’s Answers in Genesis (AIG) — described in the Cast of Characters section of our Intro page — never give up. They keep recycling their ancient clunkers.

They’ve been posting a series of articles under the general heading of “10 Best Evidences From Science That Confirm a Young Earth,” most of which we’ve ignored. Today’s offering is #8 Short-Lived Comets. It’s not much, but it’s in their Top Ten, so it’s a good example of the best they can do. Here are some excerpts, with bold font added by us:

A comet spends most of its time far from the sun in the deep freeze of space. But once each orbit a comet comes very close to the sun, allowing the sun’s heat to evaporate much of the comet’s ice and dislodge dust to form a beautiful tail. Comets have little mass, so each close pass to the sun greatly reduces a comet’s size, and eventually comets fade away. They can’t survive billions of years.

That’s true. If a comet’s orbit regularly passes close to the sun, its ice will eventually evaporate. Their article continues:

Given the loss rates, it’s easy to compute a maximum age of comets. That maximum age is only a few million years. Obviously, their prevalence makes sense if the entire solar system was created just a few thousand years ago, but not if it arose billions of years ago.

Gasp! Our professors lied to us! Well, maybe not. This creationist claim has been around for a long time. It’s included in the Talk Origins Index to Creationist Claims, where they say:

The comets that entered the inner solar system a very long time ago indeed have evaporated. However, new comets enter the inner solar system from time to time. The Oort Cloud and Kuiper Belt hold many comets deep in space, beyond the orbit of Neptune, where they do not evaporate. Occasionally, gravitational perturbations from other comets bump one of them into a highly elliptical orbit, which causes it to near the sun.

Isn’t that good enough to satisfy AIG? No, they’ve anticipated that answer and they have a response. AIG says:

Evolutionary astronomers have answered this problem by claiming that comets must come from two sources. They propose that a Kuiper belt beyond the orbit of Neptune hosts short-period comets (comets with orbits under 200 years), and a much larger, distant Oort cloud hosts long-period comets (comets with orbits over 200 years).

Yet there is no evidence for the supposed Oort cloud, and there likely never will be.

Well! How about that? Do the creationists win? Is the universe really young? Perhaps not. TalkOrigins has a response to that also, which you can see here. It says:

As of June 2000, more than 250 objects in the Kuiper Belt have been observed directly (Buie 2000), and it alone can be the source of short-term comets.

The Oort cloud has not been observed directly (although Sedna, a planetoid discovered in March 2004, might be in the Oort cloud), but its [the Oort cloud’s] presence is well supported based on observations of long-period comets.

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.

So there you are. By the way, although TalkOrigins doesn’t mention it in this context, we ought to point out that there’s more evidence for an old universe than claiming that new comets come from the outer solar system. How does AIG explain the fact that the Earth appears old, and so does the Moon, and Mars, all of the other bodies in the solar system? And then there are the stars, billions of light-years away, yet their light has had enough time to become visible to us.

Maybe AIG discusses those things in other articles. As we said, we haven’t been paying much attention. We’re confident, however, that their arguments are no better than what they have to say about comets. Given a whole universe of evidence, we won’t worry too much about AIG’s Top Ten list.

Copyright © 2012. The Sensuous Curmudgeon. All rights reserved.

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19 responses to “AIG: Comets Prove the Universe Is Young

  1. Speaking of AIG clunkers, Dad had a white ’64 Mercury Comet.
    Perhaps Ken would like to use (ok fine, push) it whenever he decides
    to take his winnings and head for Australia to wait out the Dec 21 cataclysm. He can look at its beautiful tail all the way across Nevada.
    Its YEC and dated by scientists at 47 years old Ken!

  2. A Saturn booster hooked up to that thing would make the trans-Pacific crossing a breeze .

  3. No chance that AIG is a parody site like Landover Baptist?

  4. Charles Deetz ;)

    @anevilmeme ever hear of Poe’s Law? Makes your question even funnier 🙂

  5. Comets have little mass, so each close pass to the sun greatly reduces a comet’s size, and eventually comets fade away. They can’t survive billions of years.

    Agreed: current mass divided by current rate of loss = time.

    Given the loss rates, it’s easy to compute a maximum age of comets. [emphasis added]

    How is it easy — or even possible — if the comet’s original mass isn’t known?

    Is there a scientific consensus regarding the maximum mass of a comet?

    Is there a secret Fudge Factor™ missing from the equation?

    This inquiring, totally befuzzled mind wants to know!

  6. anevilmeme: “No chance that AIG is a parody site like Landover Baptist?”

    Unfortunately, Ken Ham’s for real, and so is his Creation Museum in Kentucky near Cincinnati, Ohio. (You can see it on Google Earth.)

  7. gnome de net asks, “Is there a scientific consensus regarding the maximum mass of a comet?”

    Good question. Being just an amateur astronomer, I can’t answer that off the top of my head, but it’s a moot point since objects in the Kuiper Belt (and the Oort Cloud as well) are too far from the Sun to evaporate much, if at all.

    There are some pretty large objects in the Kuiper Belt that appear to be comet-like in density — Pluto is one of them. Of course, the more massive the object, the more likely it is to remain in its present orbit, and never get kicked in toward the Sun where it would evaporate and form a tail.

    But then, we only call something a comet if it’s falling toward the Sun and forming a tail (or expected to form a tail). Otherwise, it would be called an asteroid, planetoid, minor planet, meteoroid, or even a planet. For instance, Neptune would make one helluva comet if it ever got knocked out of its current orbit and fell in toward the Sun!

  8. AiG said:

    That maximum age is only a few million years.

    That’s still much longer than 6000 or 10,000 years, Ham. Make up your mind.

  9. Ceteris Paribus

    @gnome de net – The fudge factor is that it doesn’t matter how big the original mass is, all we need care about is the percentage loss per orbital pass near the sun.

    So just for grins assume a mass loss of 1 percent per orbit, and (using some snazzy logyrithm arithmetic tricks) the original mass can be calculated to be reduced by one half in just about 70 orbits.

    Since AIG says it’s favorite Kuiper Belt comets all have orbits under 200 years, their longest lived comets would be half gone in just 14,000 years, or not much more than the 10,000 years which seems to be their upper bound on the age of the universe.

    But when comets lose sufficient mass, they break up. And David Rives, the noted astrologer astronomer, tells us that “falling stars” are actually debris from failed comets. It all neatly works out according to God’s plan. http://www.youtube.com/watch?v=R-_xvYFlkNk

  10. “The comets that entered the inner solar system a very long time ago indeed have evaporated.”
    How long ago is “a very long time ago”? Sounds longer ago than when men became competent astronomers. If these comets sompletely evaporated then, how do we know they existed in the first place?

  11. @ doodlebugger

    Speaking of AIG clunkers, Dad had a white ’64 Mercury

    Well, my dad had a blue Mercury and drove the family on route 66 across the US in 1959 from LA to Princeton, New Jersey. We lived in the US for 3 years, just great, but sorry you have ol’ Hambo (gee, he needs a shave and should be riding a comet) over there. What a clown and I’ll let you know if the world ends on Dec 21 being always tomorrow here underside.

  12. @Ceteris Paribus

    That makes sense only if you (and AIG) are assuming that current cometary mass is 50% of the original.

  13. Carl Segnit says, “…and I’ll let you know if the world ends on Dec 21 being always tomorrow here underside.”

    Uh, Carl? How ya gonna do that, Ol’ Chap? You’ll be DEAD. And you’ll be dead before we are. Unless, of course, Australia gets special dispensation.

  14. Today, Nov. 29, I read an article stating that the universe has slowed its production of starts because the amount of matter used in start-making is getting low. Seems to me that’s more like a sign of age rather than youth!

  15. Ceteris Paribus

    @gnome de net: There is no need to know the actual “original” mass. All that matters is that we assume exponential decay at some constant percentage rate. The math is actually nothing more than the “rule of 70” used for back-of-an-envelope approximations of compound interest.

    If the annual interest rate on money is 1 percent, then the original investment will double in 70/1 years, or 70 years. If the annual interest rate is 7 percent, then the money will double in 70/7 or 10 years. Doesn’t matter if the original investment was 10 cents or 10 million dollars – what we are looking at is doubling times.

    Works the other way also. If you are given a pile of gold coins and decide to spend 1% of what you have remaining each year, after 70 years half the gold will be gone.

    So lets make a first guess approximation that a comet will come apart after half of its mass has evaporated. If the comet loses 1 percent of its mass each orbit, it will have lost half its mass after 70 orbits, and fall apart. Doesn’t matter if the original comet mass was 10 kg or 10 Tg.

    The “rule of 70” works for doubling or halving. If you want to change the assumption of final mass loss that would cause the comet to disintegrate, then you would just set it up as a standard exponential equation and solve for those assumptions. Handling the exponent requires taking the log (or natural log depending on how you set it up) of both sides of the equation, but is pretty much just 11th grade algebra in US.

  16. @Ceteris Paribus

    I agree with everything you have written because you have shown how to calculate that which has yet to occur — i.e., in the future.

    I see nothing that allows the calculation of original starting conditions — i.e., in the past — because that calculation requires either mass or time be known.

    So lets make a first guess approximation that a comet will come apart after half of its mass has evaporated.

    What is magical about one half? Why would a 10 Tg comet disintegrate at 5 Tg and not continue evaporating until its mass is further reduced to 10 Kg?

    Continue with your “pile of gold coins” example: given “x” (the size of the pile today), please show how to calculate the original size without knowing when that pile was created.

  17. @Ceteris Paribus

    Yes, “the ‘rule of 70’ works for doubling” as well. But after you’ve doubled the mass of a comet, why stop? Why not double that mass again and again? What do we know about comets that tells us what their original masses were? Is there an accepted maximum mass?

  18. Ceteris Paribus

    @gnome de net:

    You question: “What is magical about one half? Why would a 10 Tg comet disintegrate at 5 Tg and not continue evaporating until its mass is further reduced to 10 Kg?”

    I’m only offering a back of the envelope estimate. If you want better estimates, you will need to consult an astrophysicist who specializes in comets.

    But consider that by definition a comet of any size does not have sufficient gravity to stick itself together. Otherwise there would be neither a water tail nor a mineral tail. So what is holding the comet together is most likely the ice acting as “glue”.

    Water ice has a density on the order of 5% of the density of rocky stuff. So even if happened that the mass lost in the tails of each of these two components was the same, the density difference argues that a lot more of the ice glue would have evaporated from the comet than the rocky stuff.

    So as first approximation we might expect that there is a greater chance that a comet would disintegrate before 50% of the original mass has been lost, than the chance that disintegration would continue to hold off until more than 99% of the mass has been lost.

    But that is all conditional on just how sticky the ice glue really is. Maybe comet ice acts like superglue, and one little drop can hold a ton of rocky stuff together. So you really do need to ask an astrophysicist who specializes in comets.

  19. gnome de net

    @Ceteris Paribus

    And your response to “please show how to calculate the original size (of a pile of coins or a comet) without knowing when that pile (or comet) was created” is…