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trinitree88
2010-Apr-08, 09:37 PM
What could be better for an Irishman (I'm mongrel Irish/Swedish/German), than a physics paper about potatoes? This guy gives a size limit for small asteroids to convert from roughly potato-shape to spherical with a new limit. neat. SEE:http://arxiv.org/ftp/arxiv/papers/1004/1004.1091.pdf :clap::dance::wall: pete

Argos
2010-Apr-08, 09:42 PM
Pete, you might like to clean up the link. ;)

http://arxiv.org/ftp/arxiv/papers/1004/1004.1091.pdf

01101001
2010-Apr-09, 02:32 AM
Abstract: The Potato Radius: a Lower Minimum Size for Dwarf Planets; Charles H. Lineweaver, Marc Norman (http://arxiv.org/abs/1004.1091)


Summary: Gravitational and electronic forces produce a correlation between the mass and
shape of objects in the universe. For example, at an average radius of ~ 200 km – 300 km, the
icy moons and rocky asteroids of our Solar System transition from a rounded potato shape to
a sphere. We derive this potato-to-sphere transition radius -- or “potato radius” -- from first
principles. Using the empirical potato radii of asteroids and icy moons, we derive a constraint
on the yield strength of these bodies during their formative years when their shapes were
determined. Our proposed ~200 km potato radius for icy moons would substantially increase
the number of trans-Neptunian objects classified as “dwarf planets”.

slang
2010-Apr-11, 10:40 AM
Boil 'em, mash 'em, stick 'em in 'n orbit! (annoying flash (http://www.nothingtodo.co.uk/view/768/potatoes-boil-em-mash-em-stick-em-in-a-stew.html). I warned.)

Interesting (from the discussion section)


Our derivation of the ~ 200 km – 300 km potato radius is related to the fact that on Earth,
earthquakes away from subduction zones are confined to depths less than ~ 30 km. This is
because plastic or ductile deformation of the rocks below 30 km is enough to relieve the
deviatoric stress, or pressure differences – the same ductile deformation that allow potatoes,
as they increase in mass, to become spheres.

grapes
2010-Apr-11, 12:10 PM
Does it really talk about electronic forces?

ETA: I see their reference is Thompson's 1917 On Growth and Form, maybe that's where they get it. I have my copy around here somewhere...

Jerry
2010-Apr-12, 03:45 AM
I think in this case, the 'electronic' is in reference to all physical forces other than gravity.

Spoons
2010-Apr-12, 05:40 AM
I heard Charlie Lineweaver this morning (about 11:20am local time) on local ABC radio - he's quite a character! Very refreshing to hear someone talk with such enthusiasm on the radio.

Very interesting stuff!

trinitree88
2010-Apr-13, 09:27 PM
I heard Charlie Lineweaver this morning (about 11:20am local time) on local ABC radio - he's quite a character! Very refreshing to hear someone talk with such enthusiasm on the radio.

Very interesting stuff!

Spoons. Agreed. I've read a number of his papers. He's good. pete