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Headshot of Emily Lakdawalla

Scale comparisons of the solar system's major moons

Posted By Emily Lakdawalla

10-07-2013 6:05 CDT

Topics: pretty pictures, amateur image processing, scale comparisons, presentation slides, the Moon, Jupiter's moons, Io, Europa, Ganymede, Callisto, Saturn's moons, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus, Uranus' moons, Neptune's moons, Triton

Here's a presentation slide I've been meaning to put together for a while. It shows the major moons of the eight planets, to scale with each other. Below is a labeled version. You can download one without text here, and if you scroll down I've got a couple of alternative layouts.

Note: it's been pointed out to me that the Callisto image is from Voyager, not Galileo. I'll fix the text on the image eventually. --ESL

The Solar System's Major Moons

Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other moons data: NASA/JPL. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

The Solar System's Major Moons
The Solar System contains 18 or 19 natural satellites of planets that are large enough for self-gravity to make them round. (Why the uncertain number? Neptune’s moon Proteus is on the edge.) They are shown here to scale with each other. Two of them are larger than Mercury; seven are larger than Pluto and Eris. If they were not orbiting planets, many of these worlds would be called “planets,” and scientists who study them are called “planetary scientists.”

Here are some alternative unlabeled versions:

The Solar System's Major Moons (sorted by location)

Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other moons data: NASA/JPL. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

The Solar System's Major Moons (sorted by location)
The Solar System's Major Moons (scattered)

Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other moons data: NASA/JPL. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

The Solar System's Major Moons (scattered)

For the next one, I used a different Iapetus image, because it's adjacent to the Uranian moons Oberon and Ariel for which we don't have good lower-phase (fuller) global views; putting in the higher-phase one I used above made it look too big. Ganymede looks a little small for the same reason, and also because Titan's atmosphere makes it look bigger than it actually is.

The Solar System's Major Moons (ordered by size)

Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other moons data: NASA/JPL. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.

The Solar System's Major Moons (ordered by size)
 
See other posts from July 2013

 

Read more blog entries about: pretty pictures, amateur image processing, scale comparisons, presentation slides, the Moon, Jupiter's moons, Io, Europa, Ganymede, Callisto, Saturn's moons, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus, Uranus' moons, Neptune's moons, Triton

Comments:

Mark Adler: 07/10/2013 10:09 CDT

Beautiful!

William McKinnon: 07/10/2013 02:42 CDT

For shame! You should include Charon! See today's announcement from New Horizons!

Dave Rothery: 07/10/2013 04:23 CDT

Bill is quite right. if Proteus, Mimas, Enceladus are 'major moons', then Charon surely is too (it is immaterial that Pluto is not a planet).

Alson Wong: 07/11/2013 01:40 CDT

A beautiful montage. Every other image I've seen comparing satellites to scale shows Titan with its atmosphere as being smaller than Ganymede, which is incorrect. Are the images corrected for relative brightness? The Moon (Luna) has a lower albedo than Callisto, but it appears brighter in these montages.

Guillermo Abramson: 07/11/2013 03:26 CDT

Buenísimo!

AlgebraWinter: 07/11/2013 04:07 CDT

These are inspiring!! Are they available as posters?

Mean & Anomalous: 07/11/2013 07:16 CDT

Nicely done!

Michael Teoh: 07/12/2013 12:04 CDT

Phobos and Deimos of Mars are both left out?

Alson Wong: 07/12/2013 12:32 CDT

Michael, Phobos and Deimos aren't "major moons": large enough for self-gravity to make them round.

David Salo: 07/12/2013 03:09 CDT

In my opinion, we don't have images of Charon that would be appropriate for inclusion in this sort of slide. Hopefully we can revisit that question in 2015.

Emily Lakdawalla: 07/14/2013 04:56 CDT

I'm glad people like these! @Bill: If you travel to the future and bring me a New Horizons photo of Charon that I can use in this poster, I'll add it. Otherwise, you'll have to wait. In 2015 I plan to make a slightly different poster, "The Not-Planets," which will include all of these objects plus Ceres, Pluto, and Charon, with a companion version that includes outlines for a few of the better-known TNOs. (There are approximately 200 TNOs of this size.) Alson: I did not make any real effort to do correct relative brightness. The Moon, Titan, and Iapetus should all be darker, for sure. I may attempt a version that attempts this some time in the future. AlgebraWinter: I have learned to wait for people to notice errors before setting up posters for sale.

John Hartwell: 07/15/2013 06:12 CDT

Very nice, indeed. Why is Mars excluded? Surely good pictures must exist...

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