... Tonight's Sky . ... Ancient channels discovered on Mars . ... These images show buried channels draining from the giant Valles Marineris canyon into the wide area of the north, according to NASA. ... But after studying HiRISE images of light-toned layered deposits on the plains surrounding Valles Marineris, Weitz and her co-authors concluded that equatorial regions might have remained wet for a much longer period. ... Only registered members of Astronomy.com are allowed to comment on this article. ...