Scientists assumed every cave on Mars formed from ancient lava, but a team from Shenzhen University has now found eight that water carved through soluble rock — a process never before confirmed on the Red Planet - Space Daily

For years, the simplest explanation for Martian caves was lava. Mars has enormous volcanic provinces, long lava flows and many pit-like openings that look like skylights into lava tubes. If a cave existed on Mars, the default assumption was often that molten …