geolindon
20-11-2016, 11:51 PM
G day,
I always enjoy Phil Miles' excellent planet postings, in today's Uranus post he included a longitude grid which set me off searching www for understanding. Rather than high-jacking his thread i thought i'd post here - maybe other newbies will share my awe.
it took me a while to realise (and i hope i'm correct in this) that his N for north annotation is indicating the junction of the longitude lines.
the diagram at the top of this article shows Uranus' rotation, orbit and seasons; https://www.ssec.wisc.edu/planetary/uranus/science/
2016 is approx halfway from 2007 to 2028 with the N pole swinging towards Sun and Earth.
the much brighter band to the right/south in Phil's image might be residual from 42 years of sunlight around the 1986 solstice, and still waning even post equinox due to 'the long radiative time constant' caused, its thought by Uranus' particularly low internal heat generation ;) which is further guessed to be due to extra heat being dissipated by the collision with an Earth sized proto planet that knocked it sideways. though it could be due to a layer of liquid diamond insulating and keeping the heat internal :question:
because all the New Horizons' images i have seen for Pluto are projected North to page top re solar system rather than re Pluto, i need to do this exercise for Pluto to help me understand eg Sputnik Planitia's ice but NASA scientists now think the whole crust has rotated as one tectonic plate :rolleyes:
awesome!!
L
I always enjoy Phil Miles' excellent planet postings, in today's Uranus post he included a longitude grid which set me off searching www for understanding. Rather than high-jacking his thread i thought i'd post here - maybe other newbies will share my awe.
it took me a while to realise (and i hope i'm correct in this) that his N for north annotation is indicating the junction of the longitude lines.
the diagram at the top of this article shows Uranus' rotation, orbit and seasons; https://www.ssec.wisc.edu/planetary/uranus/science/
2016 is approx halfway from 2007 to 2028 with the N pole swinging towards Sun and Earth.
the much brighter band to the right/south in Phil's image might be residual from 42 years of sunlight around the 1986 solstice, and still waning even post equinox due to 'the long radiative time constant' caused, its thought by Uranus' particularly low internal heat generation ;) which is further guessed to be due to extra heat being dissipated by the collision with an Earth sized proto planet that knocked it sideways. though it could be due to a layer of liquid diamond insulating and keeping the heat internal :question:
because all the New Horizons' images i have seen for Pluto are projected North to page top re solar system rather than re Pluto, i need to do this exercise for Pluto to help me understand eg Sputnik Planitia's ice but NASA scientists now think the whole crust has rotated as one tectonic plate :rolleyes:
awesome!!
L