Sun Stereo Jan15_2013FEA

Sun Blows Earth A Kiss – Will She Blush?

Three views over 2 1/2 hours of a coronal mass ejection or CME as it burst off of the sun headed for Earth this morning Jan. 13, 2013. The images were captured by NASA’s Solar Terrestrial Relations Observatory (STEREO). Credit: NASA/STEREO

The sun hurled a coronal mass ejection (CME) in Earth’s direction this morning at 1:24 a.m. (CST). This proton-electron particle spray may reach us within 1 to 3 days and possibly make the Arctic sky blush with auroras. We’ll have to wait and see.

Since this CME left the sun at only 275 miles per second, it’s not likely to kick up a big storm. The biggest blasts can send particles our way at nearly ten times that. If they succeed in connecting with Earth’s magnetic envelope, the magnetosphere, electrons and occasionally protons spiral down along magnetic field lines into our atmosphere to produce auroras. We don’t have to worry about these guys hitting us directly on the ground; we’re protected by the planetary magnetic field and the air above us.

Saturn’s tiny moon Daphnis (the point of light) clears the 26-mile-wide Keeler Gap, named after 19th century American astronomer James Keeler, in Saturn’s rings. The gravity of the moon also creates the ripples seen along either side of the vacancy. Credit: NASA/JPL-Caltech SSI

One of my favorite things to do is dig through image archives looking for gems to share. A recent photo of Saturn’s 5-mile-diameter moon Daphnis raising sawtooth-like waves in Saturn’s Keeler Gap caught my eye. The picture, taken by the Cassini spacecraft last August and released in late December 2012, shows a lovely series of ripples on either side of the Keeler Gap, a debris-free zone about 26 miles wide near the outer edge of Saturn’s A-ring.

Closeup of Daphnis and its gravitational wake photographed by Cassini on July 5, 2010 from a distance of 45,000 miles.  Click to enlarge. Credit: NASA/JPL/SSI/ color composite by Gordan Ugarkovic

As it circles the planet on an inclined orbit, Daphis’ gravity tugs on the icy ring particles to clear a gap and create the ripples. The rings are only about 33 feet thick despite their vast extent and consist primarily of individual chunks of ice in their own slightly different but unique orbits about the ringed planet.

Although difficult to see in the picture, the ripples rise up about 1 mile above the ring plane. Notice there are two sets. Material along the inner edge of the gap orbits faster than the moon, so that the ripples precede Daphnis in its orbit. Material on the outer edge moves slower than the moon, creating a set of trailing waves.

Nature has many sculptors and tools with which to fashion the most delightful of cosmic structures. Put a smidge of a moon in the right place and it’s not long before something marvelous happens.

7 Responses

  1. Edward M. BOll

    Comet Panstaars was a possibility to rival Venus, but in January the brightening has slowed a lot. I am still hoping for an Arcturus brightness but if this one slows it’s brightening even more ,Lemmon might be quite a spectacle. A magnitude 2 or 3 is still possible but we won’t pick it up till late April when it would have faded to 4 or more. ISON should be an amazing sight if it is made of the same material as the daylight comet in 1680.

    1. astrobob

      Hi Edward,
      I’ve seen some predictions putting L4 PANSTARRS closer to mag. 1 at max. brightness. C/2012 F6 Lemmon will unfortunately be very poorly placed for northern hemisphere observers when near maximum brightness of ~3rd magnitude. But again, we won’t know for sure until we get closer to those dates.

  2. Bob Crozier

    So did we ever actually see aurora or any other effects from this flare? I checked space weather a couple of times and all seemed seemed very calm.

    1. astrobob

      Activity shot up around 2-3 p.m. CST today, so northern Europe was favored. Right now, as you say, activity is low to moderate. I’m keeping my eyes peeled.

      1. Giorgio Rizzarelli

        BobC, a brief note to tell you that a few days ago I replied to your questions about my perihelion home experiment and the perturbation on Sun by other planets. Sorry for the late but I had to think about it and find the time. Since the post is old and I think you’re not getting notifications, I left this note. Here’s for your convenience the link

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