The outbursts on Comet 67P/C-G
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The Rosetta science team has released a detailed analysis of the jets and outbursts that they observed coming from Comet 67P/C-G during the comet’s close approach to the Sun.
Brief but powerful outbursts seen from Comet 67P/Churyumov–Gerasimenko during its most active period last year have been traced back to their origins on the surface.
In the three months centred around the comet’s closest approach to the Sun, on 13 August 2015, Rosetta’s cameras captured 34 outbursts. These violent events were over and above regular jets and flows of material seen streaming from the comet’s nucleus. The latter switch on and off with clockwork repeatability from one comet rotation to the next, synchronised with the rise and fall of the Sun’s illumination.
By contrast, outbursts are much brighter than the usual jets – sudden, brief, high-speed releases of dust. They are typically seen only in a single image, indicating that they have a lifetime shorter than interval between images – typically 5–30 minutes. A typical outburst is thought to release 60–260 tonnes of material in those few minutes.
They have also released a new image taken by the navigation camera of Rosetta’s September 30th landing zone.
Please consider donating to Behind the Black, by giving either a one-time contribution or a regular subscription, as outlined in the tip jar to the right. Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
The Rosetta science team has released a detailed analysis of the jets and outbursts that they observed coming from Comet 67P/C-G during the comet’s close approach to the Sun.
Brief but powerful outbursts seen from Comet 67P/Churyumov–Gerasimenko during its most active period last year have been traced back to their origins on the surface.
In the three months centred around the comet’s closest approach to the Sun, on 13 August 2015, Rosetta’s cameras captured 34 outbursts. These violent events were over and above regular jets and flows of material seen streaming from the comet’s nucleus. The latter switch on and off with clockwork repeatability from one comet rotation to the next, synchronised with the rise and fall of the Sun’s illumination.
By contrast, outbursts are much brighter than the usual jets – sudden, brief, high-speed releases of dust. They are typically seen only in a single image, indicating that they have a lifetime shorter than interval between images – typically 5–30 minutes. A typical outburst is thought to release 60–260 tonnes of material in those few minutes.
They have also released a new image taken by the navigation camera of Rosetta’s September 30th landing zone.
Comet 67P loses a couple of Olympic swimming pools of water each orbit, an astronomer said earlier. With burst of 100 tons at a time I’d think it’d be more, but if it’s only every 2.4(?) rotation and mostly only during the short “Summer”, I suppose that it can add up.
China has now begun operating the world’s largest radio telescope! The 500 meter aperture spherical telescope, compared to 53 years old “tiny” Arecibo’s 305 meters. And with other advantages in terms of reflectivity and sky coverage and whatnot. I think it is especially good news that the Chinese are doing good things, science for science sake, like their ambitious interplanetary space program recently announced. I suppose it works as a radar too and can characterize near Earth objects. Arecibo even maps volatilities in Mercury’s polar craters with radar. But as usual info from China is not very easy to find online so I’m not sure about FAST using radar.