Day: May 14, 2010

Ah… this is apparently a regular occurance on Jupiter…

Jupiter has lost a belt! …By Emily Lakdawalla

…referencing Astro Bob here…

Jupiter loses one of its belts

…who tells us the following…

So here’s the surprise. That bad boy south equatorial belt (SEB) has completely faded away. Point your scope at the planet any morning soon and you’ll see only one obvious dark stripe, the North Equatorial Belt. Jupiter with only one belt is almost like seeing Saturn when its rings are edge-on and invisible for a time — it just doesn’t look right.

The SEB is one of the most active areas on the planet for weather changes. Every 3-15 years, the belt, which is normally dark reddish-brown in color and typically divided in two by the south equatorial belt zone, fades from view. After some weeks or months a brilliant white spot forms within that zone and begins spouting dark blobs of material which get stretched into filaments and ovals by Jupiter’s fierce winds into a new SEB. Within a few weeks (or longer) the belt is back and Jupiter presents its familiar dual “tire track” appearance through a telescope.

…seems we can expect the SEB to return to its colourful self in a while. Does make one wonder just what is going on deep down in Jupiter to create such wonders.

The image above is Jupiter seen through a different spectral filter, and as you can see the bands defined by CH4 (methane) absorption are still as prominent as ever. This indicates the change in visible light colours is due to some trace compound that normally colours the clouds – but what?

NB Notice how bright the Great Red Spot is – almost no/almost all methane spectral presence to be so bright? Can anyone tell me what a CH4 filter shows? The presence or absence of methane? Either way that makes the GRS very, very curious.

Jupiter lost a cloud stripe, new photos reveal – Space.com- msnbc.com.

Jupiter’s missing stripe might be related to this…

The impact of a large object with Jupiter in July 2009
Authors: A. Sánchez-Lavega, A. Wesley, G. Orton, R. Hueso, S. Perez-Hoyos, L. N. Fletcher, P. Yanamandra-Fisher, J. Legarreta, I. de Pater, H. Hammel, A. Simon-Miller, J. M. Gomez-Forrellad, J. L. Ortiz, E. García-Melendo, R. C. Puetter, P. Chodas
(Submitted on 13 May 2010)

Abstract: On 2009 July 19, we observed a single, large impact on Jupiter at a planetocentric latitude of 55^{\circ}S. This and the Shoemaker-Levy 9 (SL9) impacts on Jupiter in 1994 are the only planetary-scale impacts ever observed. The 2009 impact had an entry trajectory opposite and with a lower incidence angle than that of SL9. Comparison of the initial aerosol cloud debris properties, spanning 4,800 km east-west and 2,500 km north-south, with those produced by the SL9 fragments, and dynamical calculations of pre-impact orbit, indicate that the impactor was most probably an icy body with a size of 0.5-1 km. The collision rate of events of this magnitude may be five to ten times more frequent than previously thought. The search for unpredicted impacts, such as the current one, could be best performed in 890-nm and K (2.03-2.36 {\mu}m) filters in strong gaseous absorption, where the high-altitude aerosols are more reflective than Jupiter’s primary cloud.