Researchers at the California Institute of Technology (Caltech) have discovered evidence for an ancient delta on Mars where a river might once have emptied into a vast ocean.
This ocean, if it existed, could have covered much of Mars's northern hemisphere—stretching over as much as a third of the planet.
"Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun," says Mike Lamb, an assistant professor of geology at Caltech and a coauthor of the paper describing the results. The paper was published online in the July 12 issue of the Journal of Geophysical Research.
Although the new findings are far from proof of the existence of an ancient ocean, they provide some of the strongest support yet, says Roman DiBiase, a postdoctoral scholar at Caltech and lead author of the paper.