Re: Pluto Debate Continues to Continue
- From: Bryan Derksen <bryan.derksen@xxxxxxx>
- Date: Mon, 18 Aug 2008 07:28:02 GMT
Zombie Elvis wrote:
I noticed a pretty interesting article on Astrobiology Magazine about
a debate between Neil deGrasse Tyson and Mark Sykes of the Planetary
Science Institute about the IAU's demotion of Pluto as a planet. The
most interesting quote for me from this article is this one:
"It's good for people to know that debate in science is the norm,"
Sykes said. "Science is dynamic. Science is argumentative. Science is
continual testing and challenging. Science is not about something
everyone has to memorize because some organization has given it its
blessing."
http://astrobio.net/news/modules.php?file=article&sid=2844
Sykes says "If Pluto were half the mass of Uranus, it would still not be
a planet! And if the Earth traded places with Jupiter, Earth would not
be a planet." But here are the numbers for the Stern-Levison parameters
of these hypothetical situations (normalized with Earth=1):
For a 1/2-Uranus-mass Pluto:
(((7.25 earth mass)^2) / (248 years)) / (((1 earth mass)^2) / (1 year))
= 0.211945565
For Earth in Jupiter's orbit:
(((1 earth mass)^2) / (11.9 years)) / (((1 earth mass)^2) / (1 year)) =
0.0840336134
Compare these to Mars' normalized Stern-Levison parameter, 0.0061. They
are both much more capable of clearing objects from their orbits than an
object (Mars) that is already defined as a planet. The article at
<http://space.newscientist.com/article/dn14540-great-planet-debate-ends-in-stalemate.html>
indicates that Sykes is also making the argument that Earth placed in
the Kuiper belt wouldn't be a planet; in a thread here on this newsgroup
a month back I calculated that it would have about half the
orbit-clearing oomph of Mars. I wish I knew what method he was using to
make these determinations.
.
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