Scientists have discovered what they believe to be the largest impact crater in the entire solar system, with scars covering a large part of Jupiter’s largest moon, Ganymede.
The scientists behind the new study wanted to reconsider observations of a host of previous NASA missions studying the massive moon, which is larger than Mercury, the smallest planet in our neighborhood. In particular, they were fascinated by a set of features called furs, which appear on some of the oldest sites of the moon.
Earlier researchers pointed to these furrows as evidence of a large impact that was powerful enough to leave scars all over Ganymede. But when looking at the structures, the scientists behind the new study believe that it is an underestimation, and that the furs represent an impact so great that it affects the entire moon.
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The researchers began collecting data collected by NASA’s twins Voyager missions, each flying past the Jupiter system in 1979, and through NASA Missy Galileo, who spent eight years in the late 1990s and early 2000s studying the massive planet and its neighbors.
The scientists then reanalyzed observations covering what is called the Dark Terrain, which includes the oldest surfaces on Ganymede. By the Dark Terrain, according to the new modeling, the furrows all wrinkle from one point – even those on the opposite side of the moon.
The researchers suggest that the furs provide indicators of an impact event affecting whole Ganymede, not just the one hemisphere previously identified as reformed in such an event, although positively identifying an impact site takes more than suspected rings.
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But if an impact was to blame, a very large asteroid – at least 30 miles (50 kilometers) over and possibly more than 90 miles (150 km) over) – could have been involved in that collision, causing a bolleye series of rings and fractures left over the moon that, after millennia of geological processes, have become the furrows and troughs that scientists now see, according to a statement about the new research.
If that model work is correct, scientists say, they have found the largest impact choice in the solar system, with a radius as large as 4,800 miles (7,800 km) – that is a radius about twice the length of the Mississippi River. Today’s largest known intrusion system, named Valhalla Crater and found on another Jupiter moon, Callisto, pale in comparison, with a radius of 1200 kilometers (1,900 km).
The scientists behind the new study hope that new data will help them to better interpret Ganymede’s furrows and understand exactly what formed them. The European Space Agency is working on building a spacecraft named the Jupiter Icy Moons Explorer (JUICE), which it intends to launch in 2022. The mission will concentrate on Ganymede, Callisto and Europe, arriving nearby in 2029 and operating there for at least three years.
The research is described in a study July 15 published in the journal Icarus.
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
