The best candidate for a binary crater on Earth today is the Lockne crater in Sweden and a smaller crater nearby called Målingen. “We dated these structures very exactly and saw that they formed at exactly the same age,” about 450 million years ago, says Jens Ormö from the Astrobiology Center in Spain, who led analysis of the craters published in 2014. One other promising candidate pair is known, the Kamensk and Gusev craters, but their location—on the border between Russia and Ukraine—makes them difficult to study in the current global climate.
On Mars, craters can remain visible for billions of years. So using high-resolution images of the surface taken
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