title: Key science questions from the second conference on early Mars: geologic, hydrologic, and climatic evolution and the implications for life.
abstract: In October 2004, more than 130 terrestrial and planetary scientists met in Jackson Hole, WY, to discuss early Mars. The first billion years of martian geologic history is of particular interest because it is a period during which the planet was most active, after which a less dynamic period ensued that extends to the present day. The early activity left a fascinating geological record, which we are only beginning to unravel through direct observation and modeling. In considering this time period, questions outnumber answers, and one of the purposes of the meeting was to gather some of the best experts in the field to consider the current state of knowledge, ascertain which questions remain to be addressed, and identify the most promising approaches to addressing those questions. The purpose of this report is to document that discussion. Throughout the planet's first billion years, planetary-scale processes-including differentiation, hydrodynamic escape, volcanism, large impacts, erosion, and sedimentation-rapidly modified the atmosphere and crust. How did these processes operate, and what were their rates and interdependencies? The early environment was also characterized by both abundant liquid water and plentiful sources of energy, two of the most important conditions considered necessary for the origin of life. Where and when did the most habitable environments occur? Did life actually occupy them, and if so, has life persisted on Mars to the present? Our understanding of early Mars is critical to understanding how the planet we see today came to be.
authors.affiliation: Mars Program Office, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109-8099, USA. David.Beaty@jpl.nasa.gov
authors.forename: David W
authors.initials: DW
authors.lastname: Beaty
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Clifford
authors.forename: Lars E
authors.initials: LE
authors.lastname: Borg
authors.forename: David C
authors.initials: DC
authors.lastname: Catling
authors.forename: Robert A
authors.initials: RA
authors.lastname: Craddock
authors.forename: David J
authors.initials: DJ
authors.lastname: Des Marais
authors.forename: Jack D
authors.initials: JD
authors.lastname: Farmer
authors.forename: Herbert V
authors.initials: HV
authors.lastname: Frey
authors.forename: Robert M
authors.initials: RM
authors.lastname: Haberle
authors.forename: Christopher P
authors.initials: CP
authors.lastname: McKay
authors.forename: Horton E
authors.initials: HE
authors.lastname: Newsom
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Parker
authors.forename: Teresa
authors.initials: T
authors.lastname: Segura
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Tanaka
mesh_terms: D019419:Evolution, Planetary; D005118:Extraterrestrial Environment / Q000737:chemistry; D005843:Geography; D055593:Geological Phenomena; D005844:Geology; D019369:Life; D018535:Mars; D008685:Meteorological Concepts; D014867:Water
chemical_list: D014867:Water