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From: steve@jplgodo.UUCP (Steve Schlaifer x3171 156/224)
Newsgroups: net.space
Subject: Re: Uranus's axis
Message-ID: <569@jplgodo.UUCP>
Date: Sun, 9-Feb-86 20:22:09 EST
Article-I.D.: jplgodo.569
Posted: Sun Feb  9 20:22:09 1986
Date-Received: Wed, 12-Feb-86 21:38:27 EST
References: <111@valid.UUCP> <161@ucdavis.UUCP>
Distribution: net
Organization: Jet Propulsion Labs, Pasadena, CA
Lines: 33
Summary: Uranus 'year' is 84 years not 144

In article <161@ucdavis.UUCP>, u553691091ea@ucdavis.UUCP (Tim Underwood) writes:
> > I know that Uranus's axis of rotation is tilted ~90 degrees from the
> > normal, perpendicular-to-ecliptic axis.  This means that the axis
> > lies in the plane of the ecliptic, but which way does it point?  
> > ............
> 
> Uranus' pole points towards the earth/sun at this time.  In about 44 years ( I
> think it's orbital period is about 176 years) 

The orbital period is more like 84 years not 176 so the 44 above should be 21.

> , it's pole will point tangent to it's orbit (i.e. it's pole, like ours, 
> points towards some point in space reguardless of it's position in it's 
> orbit). In 88 years Uranus' other pole will point towards the earth. 

Same here.  The 88 should be 42.

> As an extra, What is the Ulysses probe? Will it also go to Jupiter?

Ulysses is a rename of the (joint ESA/NASA I think) International Solar Polar
Mission (ISPM).  It was originally designed as two spacecraft which would pass
over the Sun's north and south poles at the same time but funding constraints
eliminated one of the spacecraft.  The current design calls for a single
spacecraft to pass over the Sun's south pole.  To get out of the ecliptic plane
and over the pole, the mission design calls for a Jupiter gravity assist
(flyby).
-- 

...smeagol\			Steve Schlaifer
......wlbr->!jplgodo!steve	Advance Projects Group, Jet Propulsion Labs
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