Is it possible to squeak planetary motion? Obviously, you can rotate the earth about the sun by repositioning the earth's rotation center to the center of the sun, but what about moving the moon about the (rotating) earth? If a sketch's rotation center had its x,y location exposed as tiles then there could possibly be an elegant solution, but otherwise...?
While conducting another workshop with the Girl Scouts last night, Charlie, my co-worker, came up with another scheme which I liked, to approximate circular motion. It consisted of: earth turn toward sun earth turn by 90 forward
I liked this idea of a simple "tangent" and, if it worked as hoped, you could extend it to the moon-earth too. However, we see that it's not exactly an "instantaneous tangent" :) http://poincare.uits.iupui.edu/~heiland/squeak/planets
Ideas? Thanks, Randy
Btw, I had a quick look at Randall Caton's excellent Squeak pages, http://www.pcs.cnu.edu/~rcaton/extrasolar/students.html , but didn't see anything that addressed this topic -- or maybe I just didn't dig deep enough.
Am 16.02.2006 um 16:43 schrieb Randy Heiland:
Is it possible to squeak planetary motion?
Yes. You have to embed the moon into the earth (you find "embed" in the halo menu). Then, when you move the earth, the moon already moves with it.
Here's an example:
http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ Sonne-Erde-Mond.001.pr
- Bert -
Wow, this looks promising! I thought I knew embedding, but apparently not. In my sun-earth-moon project, I have the earth away from the sun but its rotCenter inside the sun and when I bring up the earth's embed submenu, I see 'sun' (not 'moon'). However, when do the analogous thing with the moon/earth, all I see in the moon's embed submenu is 'PasteUpMorph' and 'SketchMorph' - no 'earth' or 'sun'. What's up? Currently these sketches live in the World, not in a playfield.
--Randy
-----Original Message----- From: Bert Freudenberg [mailto:bert@impara.de] Sent: Thursday, February 16, 2006 1:08 PM To: Mailinglist Squeakland Cc: Randy Heiland Subject: Re: [Squeakland] sun-earth-moon
Am 16.02.2006 um 16:43 schrieb Randy Heiland:
Is it possible to squeak planetary motion?
Yes. You have to embed the moon into the earth (you find "embed" in the halo menu). Then, when you move the earth, the moon already moves with it.
Here's an example:
http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ Sonne-Erde-Mond.001.pr
- Bert -
Alan Kay has also done some very nice "falling body" simulations -- perhaps we can send a few around. Kim
At 1:40 PM -0500 2/16/06, Randy Heiland wrote:
Wow, this looks promising! I thought I knew embedding, but apparently not. In my sun-earth-moon project, I have the earth away from the sun but its rotCenter inside the sun and when I bring up the earth's embed submenu, I see 'sun' (not 'moon'). However, when do the analogous thing with the moon/earth, all I see in the moon's embed submenu is 'PasteUpMorph' and 'SketchMorph' - no 'earth' or 'sun'. What's up? Currently these sketches live in the World, not in a playfield.
--Randy
-----Original Message----- From: Bert Freudenberg [mailto:bert@impara.de] Sent: Thursday, February 16, 2006 1:08 PM To: Mailinglist Squeakland Cc: Randy Heiland Subject: Re: [Squeakland] sun-earth-moon
Am 16.02.2006 um 16:43 schrieb Randy Heiland:
Is it possible to squeak planetary motion?
Yes. You have to embed the moon into the earth (you find "embed" in the halo menu). Then, when you move the earth, the moon already moves with it.
Here's an example:
http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ Sonne-Erde-Mond.001.pr
- Bert -
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