article_snippet: From seafloor to outer space, a distance of about 30 miles (50 kilometers), the grains spend a few months to a few years in transit, otherwise the grains would grow much larger.
article_snippet: Gravity science results published in 2014 strongly suggested the presence of a 6-mile- (10-kilometer-) deep ocean beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick.
highlights_snippet: Ocean is deeper than previous estimates — more than 30 miles deep .
  