Seasons on Ceres

Seasons on Ceres
Seasons on Ceres This short animation shows how the illumination of the northern hemisphere changes as Ceres’ axial tilt changes from 2 to 12 to 20 degrees. (In each frame, the lighting is shown on the summer solstice, when the sun reaches its greatest northern latitude.) We have discussed the orientation of the dwarf planet’s axis before. As we saw, it is tipped only 4 degrees, causing much more modest changes in lighting throughout each Cerean year (which is 4.6 terrestrial years) than Earth (and perhaps your planet) experiences. However, the gravitational tugs of Jupiter and Saturn, despite their distance, tip the axis. The angle can change from as little as 2 degrees to as much as 20 degrees in only about 12,000 years, which astronomers consider to be very fast. (Earth’s axis is tilted 23.5 degrees and is stabilized by the moon. Mars, which lacks a sizable moon, also goes through dramatic changes in axial tilt, although much more slowly than Ceres.) The angle of the sun near the poles is an important factor for where ice might accumulate. The animation shows the regions that would stay in shadow throughout every Cerean day of a full Cerean year, with blue for 2 and 12 degrees and red for 20 degrees. (The blue at 12 degrees is difficult to see.) When the sun goes farther north, it shines deeper into craters, illuminating and warming locations that would remain in shadow if the sun could not rise as high in the sky. Full image and caption. NASA / JPL-Caltech / UCLA / MPS / DLR / IDA

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