Friday, 7 December 2007

Mooning over creationists

I don't usually like their way of deciding the answers, but creationists sometimes ask very thought-provoking questions.

I was checking the website of our very own Edinburgh Creation Group, and found a link to a site asking How did the Moon get into orbit? It's a fun little simulation. Try it out.

I love games based on orbital motion.

Now, the fact is that the Moon did get into orbit. But it's still worth asking why.

The simulation on the site is quite simple, and seems to involve some fairly straightforward orbital mechanics. And it seems to be impossible to get the moon into orbit unless it's already in orbit.

So tell me, what is the answer? Wikipedia's article on the Moon confirms that "Computer simulations modelling this impact are consistent with measurements of the angular momentum of the Earth–Moon system, as well as the small size of the lunar core." So what (if anything) is wrong with the simulation the creationists point to?

I confess, I'd rather accept a scientist's assertions over a creationist's any day. But better than simply accepting, and what separates thoughtful from dogmatic Humanists (or thoughtful from dogmatic people in general), is to simply accept nothing - to actually ask for the proof, and think about it.



    The following link is interesting. It has animations of simulations run by Robin M. Canup, Ph.D. in Astrophysics, Planetary and Atmospheric Sciences, University of Colorado etc.

    She seems to favour giant impact theory. Her animations are much more advanced than the ones on the creationist web site.

    However interestingly to the casual observer they seem to show the same thing. An impact produces a projectile that crashes back into the Earth at the same place that it was ejected from. I think this was the point the creationist was making was that this was the best that he thought was possible with Newtonian physics. i.e. any orbit will return to the place it starts.

    So I think there is something worth looking into. Wikipedia is not much help:

  2. I found that values of 8 and 10 get it in to orbit, but you have to wait for it to go off screen and come back on before it starts orbiting and it does just graze the ground once on each cycle - though if you fiddle with the values a bit, where it does this can vary.

    Of course, the simulation is a simplification. Other effects such as asteroids striking the moon and even the heat of the sun could shift things. I also wonder if it takes into account the fact that not only does the earth exert force on the moon, but also vice versa.


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