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Webb snaps infrared picture of Uranus

Uranus as seen in the infrared by Webb
Click for original Webb false-color image.

In a follow-up to a recent Hubble Space Telescope optical image of Uranus, scientists have now used the Webb Space Telescope to take a comparable picture in the infrared of the gas giant.

Both pictures are to the right, with the Webb picture at the top including the scientists’ annotations.

On the right side of the planet there’s an area of brightening at the pole facing the Sun, known as a polar cap. This polar cap is unique to Uranus – it seems to appear when the pole enters direct sunlight in the summer and vanish in the fall; these Webb data will help scientists understand the currently mysterious mechanism. Webb revealed a surprising aspect of the polar cap: a subtle enhanced brightening at the center of the cap. The sensitivity and longer wavelengths of Webb’s NIRCam may be why we can see this enhanced Uranus polar feature when it has not been seen as clearly with other powerful telescopes like the Hubble Space Telescope and Keck Observatory.

At the edge of the polar cap lies a bright cloud as well as a few fainter extended features just beyond the cap’s edge, and a second very bright cloud is seen at the planet’s left limb. Such clouds are typical for Uranus in infrared wavelengths, and likely are connected to storm activity.

The Webb image also captures 11 of Uranus’s 13 rings, which appear much brighter in the infrared than in the optical.

Unlike all other planets in the solar system, Uranus’s rotation is tilted so much that it actually rolls as it orbits the Sun, a motion that is obvious by comparing these pictures with Hubble’s 2014 optical picture.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.

The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News


  • Icepilot

    “Uranus’s rotation is tilted so much” – But not nearly as much as Venus. Which (bizarrely to me) never gets much discussion wrt Solar System formation, etc.

  • Ray Van Dune

    To clarify, Venus’s polar inclination is approximately 177 degrees, so it rotates “upside down” as compared to Earth.

    Since the designation of a planet’s North Pole is determined by the direction of its rotation in accordance with the “*right-hand rule”, in a sense it is more clearly descriptive to say that Venus “rotates backwards” compared to Earth.

    In the same sense, it is more clearly descriptive to say that Uranus “rolls”, because it’s polar axis is tilted to nearly the same as the orbital plane, even though it is technically true that Venus is inclined to a greater number of degrees.

    * Right-hand rule: if the fingers of the right hand point in the direction of the planet’s rotation, the thumb indicates that the planet’s North Pole is “up”. Since the Venus rotation is roughly opposite to Earth’s, we have to turn our right hand almost completely over to get our fingers to point that way, and our thumb now points down! Thus, Venus’s North Pole is about where our South Pole is!

  • Star Bird

    Uranus also has virtacle Ring simular to Saturn’s but no signs of Romulans unless their using their Cloaking Device

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