Astronomy for the Common Folk

Saturn partially in shadow
Full Story and expanded caption: As Saturn's rings orbit the planet, a section is typically in the planet's shadow, experiencing a brief night lasting from 6 to 14 hours. However, once approximately every 15 years, night falls over the entire visible ring system for about four days. This happens during Saturn's equinox, when the sun is directly over Saturn's equator. At this time, the rings, which also orbit directly over the planet's equator, appear edge-on to the sun. During equinox, light from the sun hits the ring particles at very low angles, accenting their topography and giving us a three-dimensional view of the rings. Seen from our planet, the view of Saturn's rings during equinox is extremely foreshortened and limited. But in orbit around Saturn, Cassini had no such problems. From 20 degrees above the ring plane, Cassini's wide angle camera shot 75 exposures in succession for this mosaic showing Saturn, its rings and a few of its moons Aug. 12, 2009, beginning about 1.25 days after exact Saturn equinox, when the sun's disk was exactly overhead at the planet's equator. Credit: NASA/JPL/Space Science Institute
Stargazing by xkcd

Love this comic by xkcd. They titled it “Stargazing“. I think I prefer “Astronomy for the Common Folk”.

On a related note, I was recently up at 2am with our son taking a walk in a nearby park to help him ease a persistent cough in the cool air and we were talking about the stars, Saturn’s rings and other bodies in our cosmic neighbourhood.

I bought the Star Walk 2 app (and, before that, Star Walk) and it is a great augmented reality app that gives you a sort of overlay over the stars you point your phone or tablet at. Great app to identify the things we see in the night sky. Another option is the Star Walk for Kids app which has more cartoonish imagery for kids.

Image credit: A Long Night Falls Over Saturn’s Rings from the NASA Goddard Space Flight Center, licensed CC BY 2.0

By Paul

Enthusiast, writer, Happiness Engineer at Automattic. I take photos too. Passionate about my wife, Gina and #proudDad.


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