From Michael Miller:
Re: Series of thumps may have thrown Uranus off-kilter (Oct. 7): About that impact simulation of why the planet Uranus tilts... this simulation explains it better!
Take a wine bottle cork, after of the contents of the bottle have been disposed of, and stick half of a toothpick into the bottom of the cork so that just a small point sticks out, that is to become the center point of gravity for the planet model. Then place the remainder of the toothpick on the top of the cork, sticking up to mark the north pole. Next, screw 3" drywall screws into the cork on all sides, 4 of them, aiming down, so that the whole thing balances on the center toothpick on your fingertip.
Voila... the model tilts at about 20 degrees, much like Mars, Saturn and Earth... one drywall screw (only one) yields Uranus, -4 degrees tilt. So this shows that planets tilt because they are lopsided. Under Uranus's clouds the core is lopsided. That settles it for me. There is nothing wrong with having people (kids too) draw their own conclusions in lieu of any definitive science on the subject. Is there? What we need is a new radar range of the planet Uranus - THAT's real science!
P. S. for kids, I've had it work with marshmallows and straws with tiny mini-marshmallows on the ends of them, but we always run out of marshmallows! Toothpicks are still vital, though it's been know to work well with swizzle sticks...
Michael Miller, Program Coordinator
The Glenfield Planetarium