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Watch for moon and Jupiter before dawn on September 19

Moon with Jupiter in predawn and dawn sky September 19 Read more

Tonight is Sep 18, 2014

Moon Phase Courtesy U.S. Naval Observatory

Watch for the waning crescent moon near the dazzling planet Jupiter during the predawn and dawn hours on Friday morning – September 19, 2014 – and for a morning or two after that. Simply look eastward to behold these two glorious worlds reflecting the light of the sun.

Jupiter is the king planet in our solar system, having the volume of more than 1,300 Earths! Even Jupiter’s famed Great Red Spot is about twice as large as our planet. The Giant Red Spot is a high pressure storm, similar to a hurricane, rotating counter-clockwise in Jupiter’s Southern Hemisphere, taking about 6 days to spin full circle. This storm has been raging on Jupiter at least since humanity first saw it through early telescopes, a few hundred years ago.

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Comparing the size of Earth versus the Great Red Spot on Jupiter. Photo Credit: NASA

Comparing the size of Earth versus the Great Red Spot on Jupiter. Photo Credit: NASA

Contrasting the size of Jupiter (left) with the planet WASP-17b (right) Image credit: Wikipedia

Contrasting the size of Jupiter (left) with the planet WASP-17b (right) Image credit: Wikipedia

Some have asked us which planet is the largest in the Milky Way galaxy. Despite Jupiter’s great size, you can guess that our solar system’s king planet is not our galaxy’s king planet.

At the time of this writing (September 2014), the largest known planet seems to be WASP-17b, with a diameter that’s twice as large as Jupiter’s yet harboring less than half of Jupiter’s mass.

Planet WASP-17b is known as a puffy planet or a hot Saturn because of its low density. Like Saturn, this world could float in water – that is, if you had a large enough ocean to put it in.

The moon will be moving downward in the predawn sky over the next few days.  Watch for it!

The moon will be moving downward in the predawn sky over the next few days. Watch for it!

Bottom line: Take a look at our own solar system worlds – the moon and Jupiter – pairing up together in the predawn and dawn sky on September 19, 2014 and for a day or two after that.

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