Dramatic Change in Jupiter ’ s Great Red Spot

Introduction: Jupiter’s Great Red Spot (GRS) is one of its most distinct and enduring features, having been continuously observed since the 1800’s. It currently spans the smallest latitude and longitude size ever recorded. Here we show analyses of 2014 Hubble spectral imaging data to study the color, structure and internal dynamics of this long-live storm. Physical Dimensions: The GRS’s red edges have contracted from a longitude length of ~21° during the Voyager flybys in 1979 to ~15.5° in Hubble data acquired in 2012, shrinking on average 0.19°/year over the modern era [1]. Amateur observers documented a sudden decrease in longitudinal extent in early 2014, faster than the average rate of contraction, and Hubble Space Telescope time was granted to characterize the current state of the storm. In the 2014 Hubble data, the red edges of the spot span about 14.1° in longitude, a decrease of 1.4° (1760 km) in 21 months, a rate of change four times greater than typical since 1979. The GRS’s latitudinal size has been much more constant, historically spanning between 10.5° and 11°, and is currently 9.4°, the smallest size measured to date. There has been a slight overall trend toward latitude shrinkage of 0.04°/year, significantly slower than in the longitude dimension, but the fastest change of 0.7° occurred between 2012 and 2014. Though the storm has a clearly diminishing length-to-width aspect ratio, from 1.8 in the Voyager era (and much greater historically) to 1.5 currently.