Home > Planets > 08/30/2018 – Ephemeris – Planet controversy again

08/30/2018 – Ephemeris – Planet controversy again

August 30, 2018

Ephemeris for Thursday, August 30th. The Sun will rise at 7:02. It’ll be up for 13 hours and 20 minutes, setting at 8:23. The Moon, 3 days before last quarter, will rise at 10:40 this evening.

Back when I was a kid we used to know what a planet was, and there were 9 of them. Back then there was no real definition for a planet, other than it orbited the Sun. You knew it when you saw it. In 2006 the International Astronomical Union voted to define planets by three criteria, which left Pluto out, so now there are 8. Planetary scientists, who may not consider themselves astronomers, balk at that definition. Alan Stern of the New Horizons mission to Pluto wants a new definition. Basically a planet is any body that’s round, or formally has reached hydrostatic equilibrium. That includes all 9 old planets, many moons like ours, Kuiper Belt objects, and the asteroid Ceres. About 115 at last count.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


For more information go to Ethan Siegel’s Starts with a Bang blog:  You Won’t Like The Consequences Of Making Pluto A Planet Again

Categories: Planets
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