In this talk I will show many pictures from various cameras that show evidence of past rivers, lakes, and an ocean on Mars. Many images will be from HiRISE. Most of these probably formed billions of years ago.
Early evidence for rivers was first found in Mariner 9 photos from 1971. A feature, later named Nirgal Vallis, had the curves of rivers on Earth; Warrego Valles in the Thaumasia quadrangle displayed branched channels (dendritic drainage pattern). Also, huge streamlined shapes indicated great floods in the past--floods that may have been as large as any that the Earth has experienced.
Past lakes have been proposed for over two hundred craters including Gale Crater, Jezero Crater, Columbus Crater, Holden Crater, Ritchey Crater, Hellas Basin, and Argyre Basin. Some portions of Valles Marineris may have contained lakes. The Eridania Lake may have held 9 times as much water as all of the Great Lakes combined. Besides showing features which usually form in water like deltas, many proposed lakes contain mineralogical evidence for water in the form of clay and hydrated sulfates that require water for their formation.
An ocean on Mars has been debated for decades. Much evidence supports its existence, including observations suggesting tsunamis struck the ocean and left marks on the landscape. Some of the photos and information for this talk can be found in Marspedia articles: https://marspedia.org/RiversonMars and https://marspedia.org/OceansonMars
The 24th Annual International Mars Society Convention is Thursday-Sunday, October 14-17, 2021. This convention presents a unique opportunity for those interested in the planet Mars to come together and discuss the science, technology, social implications, philosophy and a multitude of other aspects of Mars exploration.
You can register on the main website http://www.marssociety.org After you register, you can access the convention's main application Attendify at http://convention.marssociety.org using code "TakingFlight".
More info and session listings are in the hub world, code PDK958
This meeting is interactive. Most of the time the speakers and members are appearing on a Zoom screen. You will be able to grab the mike so you can talk to the people in Zoom.