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The Sciences

Jupiter, looking sharp


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This weird-looking image is the sharpest picture of Jupiter ever taken from the ground. Taken with a device called -- are you ready for this? -- the Multi-Conjugate Adaptive Optics Demonstrator (or MAD, in an acronymic stretch), it has a resolution better than Hubble's! The Earth's atmosphere roils and waves, distorting ground-based views of the sky. That's one of the reasons we launch telescopes into space, to get above all that mess. But if you can observe a point-like object such as a star at the same time you observe your target object, it's possible to compensate for the distortion by taking extremely rapid fire snapshots and measuring the way the star image changes. You then apply a correction to the image, and presto! It's cleaner. However, you can only do this for the area near the star. Distortions change across a telescope's field of view, making this technique somewhat limited. That sort of tech has been around a while. The European Southern Observatory's MAD is a big advance, though, in that it can use multiple test objects instead of just one. That means it can measure the atmospheric nastiness across a much larger area of the sky, allowing images of Jupiter like this one to be taken, where the entire planet enjoys a nice thorough cleaning. Moreover, the astronomers making the observation were able to keep it together for two hours, so they made a way cool movie of Jupiter's rotation. The image colors are odd because this is an infrared picture. The telescope and detector observed Jupiter at wavelengths of about 2 microns, about three times redder than the human eye can see. At those wavelengths, hydrogen and methane are strong absorbers, meaning they block the light coming from deep down in Jupiter's atmosphere. What you're seeing here is light reflecting off of high haze, above the clouds we see in the usual jovian vistas. See the bluish stuff at the poles? That's probably made up of haze particles even higher in the atmosphere, where they can interact with Jupiter's magnetic fields, causing them to emit more infrared light at shorter wavelengths. Using this new method, scientists can track all sorts of weather on Jupiter better than they could before. That means we'll understand weather in general better, which is one reason why we study other planets: we learn more about the Earth. But we also do it because, after all, we love this stuff!


Jupiter, looking sharp and hot

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