Looking Up: Uranus

Oct 10, 2016

Uranus in all its glory
Credit NASA/JPL/STScI

This week on Looking Up Hal tells us exactly where to look to get a peek at the planet Uranus.

Regular listeners to Looking Up might remember that we talked about the planet Uranus about a year ago. And we call it the planet Uranus, because we are not 12. And as we have swung around the Sun again, Uranus is once again perfectly positioned in our night sky for viewing, if you know where to look. 

And it’s most certainly worth a look. Even binoculars may show Uranus to be a tiny disk, and not a single point of light like a star. Currently in the constellation Pisces, Uranus can be located nearly due east of the Pleiades star cluster. If you have difficulty finding it, I recommend you download one of the many terrific night sky maps available for smartphones, most at no cost at all.

Uranus is unique in several ways that make it pretty special. Nearly 2 billion miles from Earth, Uranus was observed many times through history, but until 1781 it was thought to be a star. Using mathematics based on the movement of the other planets, William Herschel was able to actually predict where Uranus ought to be, and he was correct. Thus Uranus was the first planet to be discovered, and not simply observed since antiquity.

It’s also unique because unlike all the other planets, Uranus’s axis is tilted dramatically. Billions of years ago something really big smacked into Uranus and tipped it over, so that today it basically rolls around its orbit around the Sun.

October 2016 is a particularly good month to observe Uranus. If you want to give your eyes a good test, find a dark location outside city lights and try to find Uranus with your naked eye. It’s possible, but quite a challenge. And as you’re looking at it, remember that the light you are seeing took over 2 ½ hours to reach Uranus from the sun, and another 2 ½ to bounce back to your eye. Good thing photons don’t get tired.

If you’d like to take a closer look at Uranus, or any of the other wonderful and amazing things in the sky, please visit CSASTRO.org for a link to information on our monthly meetings and our free public star parties! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!