Meteors everywhere

With the June Bootids just round the corner and comet C/2009 McNaught R1 laying down a trail in full binocular view, meteors seem to be filling the skies of the newsphere at the moment.

Meteor storms happen because comets and the like leave behind trails of dust that the Earth can later plough into. Sometimes these things drift, the Earth’s orbit alters a little and we move in and out of the denser areas of the trail, altering the number of meteors that take aim at the Earth. The Draconids are one such example, peaking about once every thirteen years and next year’s October shower is expected to be one of these peaks. NASA are responding by making plans to turn the International Space Station and the Hubble Space Telescope so their most vulnerable areas have some level of protection, but other satellites and networks may be tested by the shower.

For us on the ground, so long as we’re not using a system that falls prey to this (should any do so), then the only effect we need to look out for is that of dozens of shooting stars in the night sky. Of course, there will probably be a twitter meteorwatch arranged for this, but October 2011 is a little far off, so you’ll have to make do with the Perseids in about two months time. More information at the new official meteorwatch website.

But Earth-based meteors aren’t all that have been in the sights of observers. Observations with the Hubble space telescope of the site of the 3rd of June flash seen and imaged by two independent observers have shown no impact debris. The debris is normally formed when an object enters the cloud layer and explodes. Debris clouds were associated with many (but not all) of the 1994 Comet Shoemaker-Levy 9 impacts on Jupiter and a debris cloud was spotted as the only sign of a recent asteroid impact on Jupiter in July 2009. The fact that this more recent flash hasn’t left anything to see probably indicates that the impactor was a high altitude, energetic meteor that sent out a shockwave that then lit up the atmosphere. A shooting star on a wandering star. But the observations also revealed something else, a chance to have a good look at the site of Jupiter’s missing southern equatorial band (it really is missing, I checked last night, I can confirm NASA’s assumptions…). The missing cloud belt is doing just fine, it happens to be overlaid with another belt of cloud, this one white ammonia ice crystals not unlike our own NLC displays. These intruder clouds are already showing signs of preparing to clear away, with dark downdraft vortices forming on the southern edge. It is likely Jupiter will start to get its belt back in a few months or so.


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