How Cool is This?! STEREO-A Spacecraft Spots Comet Ison Swimming Through the Solar Wind

By Tom Yulsman | November 22, 2013 1:57 pm
Comet Ison Comet Encke STEREO

An animation from NASA’s STEREO-A spacecraft shows Comet ISON entering its field of view on Nov. 21, 2013. (Source: Karl Battams/NASA/STEREO/CIOC)

Looking all the world like sperm cells whipping their tails to propel themselves toward an egg, comets Encke and Ison are seen in this animation of spacecraft images swimming through the solar wind toward the sun.

This is actually the first view of Comet Ison from one of NASA’s two STEREO spacecraft. The dark, cloud-like features coming in from the right are actually denser concentrations of the particles streaming outward from the sun that comprise the solar wind. This is what’s causing Encke’s tail to ripple and whip back and forth.

As you’ve probably heard, Ison will be rounding the sun on Nov. 28, 2013, passing within a mere 700,000 miles of it. Considering that the sun is about 870,000 miles across, this will be a very close encounter — and Ison may not survive it intact.

Encke orbits the sun every 3.3 years. But for Comet Ison, this is its first trip around the sun. And that’s really significant, according to NASA, because it means that:

. . . it is still made of pristine matter from the earliest days of the solar system’s formation, its top layers never having been lost by a trip near the sun. Scientists will point as many ground-based observatories as they can and at least 15 space-based assets towards the comet along the way, in order to learn more about this time capsule from when the solar system first formed.

Comet Ison is now visible to the naked eye — in the east before sunrise. Over the next few days it should get brighter, but probably increasingly difficult to spot because of the light from the sun. To help you find it, use this chart from Discover’s sister publication, Astronomy Magazine.

You also may want to check out this recent Google Hangout with Astronomy editors and Corey Powell, editor at large for Discover (and the magazine’s “Out There” blogger).

Stay tuned! More images of Ison to come…

CATEGORIZED UNDER: Astronomy, select, Top Posts
  • stephanie magnin

    ‘Ultimate Coolness’. Thank you for such extraordinary totally brilliant imagery!

    • Tom Yulsman

      Thank you Stephanie! Make sure to come back. Compelling imagery is what ImaGeo is all about.

      • stephanie magnin

        I never stray too far away from the rare and essential things that once in a blue moon manage to fuel my enthusiasm.


    Is that a sperm?

    • stephanie magnin

      And much more :) High five!

  • Krammer

    If the solar wind is coming from the right, and the comets are entering from the left, moving to the right toward the sun, why is the orbit of Mercury OUTSIDE (to the left) of that of the Earth?

  • Aakriti Ghai

    it is so brilliant man. high five. I just lov what NASA does. see
    NASA’s partnership with Planetary resources



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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