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.
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.
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.