Sometimes all it takes is time to see things with renewed clarity, and so it is with technicians at the SETI Institute in Mountain View, CA who have taken old images of Jupiter's most mysterious moon and given them a digital-age polish that reveals Europa's chaotic surface features in astonishing detail.
Using decades-old snapshots of Europa captured during NASA/JPL's Galileo mission to the immense gas giant in the late '90s, engineers at SETI led by Mario Valenti were able to reprocess a trio of fly-by images of the icy satellite to reveal incredible levels of depth and focus.
All three images were gathered along the same longitude as Galileo streaked past on Sept. 26, 1998 during the intrepid spacecraft's 17th orbit of Jupiter. This was the eighth of Galileo's 11 scheduled Europa flybys.
The refocused set targets areas known as Chaos Transition, Crisscrossing Bands, and Chaos Near Agenor Linea to show long linear ridges, wide dark bands, rounded domes, and regions of frozen blocks traversing Europa's striped surface. These features are most likely formed by Jupiter's powerful gravitational forces as it constantly yanks and tugs at Europa's rearranged crust.
Ridges may form when cracks in the surface open and close repeatedly, causing structures that tower hundreds of yards tall, stretch miles wide, and can span up to thousands of miles.
Locations of haphazard "chaos terrain" showcase massive blocks that have nudged sideways, shifted, rotated, or tilted until finally being refrozen into new configurations and positions.
The main goal of scientists employing hi-tech image processing techniques to transform new photos of the moon's surface is to prepare for the mission parameters of NASA's Europa Clipper probe in 2024, which will be the first spacecraft to return to the frigid moon since Galileo's rendezvous over twenty years ago. The Galilean orbiter intends on completing dozens of Europa flybys to obtain more data on the ocean underneath its icy crust and how it interacts with the surface.
"We've only seen a very small part of Europa's surface at this resolution. Europa Clipper will increase that immensely," explained planetary geologist Cynthia Phillips of NASA's Jet Propulsion Laboratory in Pasadena.
These crystal-clear, enhanced-color images let scientists highlight certain geologic features not normally seen with the naked eye by assigning them different colors. Regions that seem tinted light blue or white are composed of water ice, with reddish areas containing non-ice materials like salts.
With one of the youngest surfaces of any heavenly body in our solar system, Europa, and its updated images, allows planetary scientists to investigate how this relatively young (40-90 million years old) crust was impacted by Jupiter's dominance in preparation for the Europa Clipper mission launching later this decade.