On July 9, 2009, was the thirtieth anniversary of the flyby of the Voyager 2 probe past Jupiter.
The picture shown here, taken by Voyager 2 from a distance of 246,000 kilometers, was the first close look ever obtained of Jupiter’s satellite, Europa.
The linear crack-like features had been seen from a much greater distance by Voyager 1, but this image provides a resolution of about four kilometers. The complicated linear features appear even more like cracks or huge fractures in this image. Also seen are somewhat darker mottled regions which appear to have a slightly pitted appearance, due to small scale craters.
No large craters (more than five kilometers in diameter) are easily identifiable in the Europa photographs to date, suggesting that this satellite has a young surface.
Various models for Europa’s structure were tested during analysis of this image, including the possibility that the surface is a thin ice crust overlying water or softer ice and that the fracture systems seen are breaks in that crust. Resurfacing mechanisms such as production of fresh ice or snow along the cracks and cold glacier-like flows were considered as possibilities for removing evidence of impact events.
Photo-ID: JPL P-21758; Raw Image Name: A79-7087; Date: July 9, 1979.
The image here is a scan from a print of the original data, so some image quality is lost.
Image Credit: NASA Ames Research Center/astroarts.orgoff