180 likes | 374 Views
Life on Other Planets. Life on Mars – Presence of Water. Mars presently has polar ice caps that contains significant quantities of frozen water. Life on Mars – Presence of Water (2). There is abundant evidence for flowing water (very large rivers) in the ancient southern hemisphere of Mars.
E N D
Life on Mars – Presence of Water • Mars presently has polar ice caps that contains significant quantities of frozen water.
Life on Mars – Presence of Water (2) • There is abundant evidence for flowing water (very large rivers) in the ancient southern hemisphere of Mars Possible dendritic stream network
Life on Mars – SNC Meteorites • Allen Hills (ALH84001) meteorite – blasted free from the surface of Mars millions of years ago by an asteroid impact
SNC Meteorites – A Mars Connection • Trapped gases within these meteorites match the isotopic composition of the Martian atmosphere (determined by the Viking probes).
SNC Meteorites – Evidence of fossils • A SNC meteorite fro the Allen Hills area of Antarctica has possible bacterial-like forms preserved in semispherical calcite, vug-like pockets
ALH84001 – Bacterial Forms • The “bacteria-like_ forms are very small compared to fossilized terrestrial bacteria • Examples of very ancient (>3.2 Ga fossilized terrestrial bacteria)
ALH84001 – Possible Bacterially Produced Magnetite bacteria produced Magnetite
ALH84001 – Organic Compounds • ALH84001 contains polcyclic aromatic hydrocarbons (PAHs) – these may have an inorganic or inorganic origin • No DNA or RNA compounds have been identified in the SNC meteorites
Life on Europa • The surface of Europa has an “ice pack” appearance and limited amounts of impact cratering
Life on Europa • Recent Galileo imaging and geophysical measurements provide strong evidence that this moon of Jupiter has a relatively thin crust of ice, which is underlain by a very deep ocean of liquid water.
Life on Europa • The ocean exists, in part, due to tidal heating produced by Jupiter and other nearby moons.
Life on Europa • The combination of liquid and magmatic heat may provide an ideal breeding grounds for life. Similar environments are found at “black smokers” located deep beneath the earth’s oceans
“Black Smokers on Earth” • Hot, nutrient-laden fluids can support life in area region, devoid of sunlight and abundant oxygen
“Black Smokers on Europa” • Conditions similar to the submarine “black smokers on Earth may exists in the deep submarine environment of Europa. Future space probes are being planned, which will search for life on Europa