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Europa and Life

Europa and Life. 5 October 2016. The Galilean Satellites of Jupiter. In 1609, Galileo used his recently invented telescope to look at Jupiter He saw 4 small ‘ stars ’ moving with the planet He concluded that they were moons orbiting Jupiter, like planets circling the Sun

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Europa and Life

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  1. Europa and Life 5 October 2016

  2. The Galilean Satellites of Jupiter • In 1609, Galileo used his recently invented telescope to look at Jupiter • He saw 4 small ‘stars’ moving with the planet • He concluded that they were moons orbiting Jupiter, like planets circling the Sun • Although he called them the ‘Medician’ stars in honor of his patron, Duke Cosimo of Medici, we know them as the Galilean satellites

  3. If we remove water density increases Io 3.57 g/cc Europa 2.97 g/cc Ganymede 1.94 g/cc Callisto 1.86 g/cc Orbital Resonance Io Europa Ganymede Callisto Tidal Heating

  4. Europa: general characteristics • Size: • R = 1560.8±0.5 km • Composition: • silicate rock and H2O ice • Interior: • water-ice crust and probably, subsurface ocean, and an iron–nickel core • Surface: • temperature averages about 110 K (−160 °C) at the equator and only 50 K (−220 °C) at the poles -> water ice acts like rock • Atmosphere: • Tenuous, O2 • Size: • R = 1560.8±0.5 km • Composition: • silicate rock and H2O ice • Interior: • water-ice crust and probably, subsurface ocean, and an iron–nickel core • Surface: • temperature averages about 110 K (−160 °C) at the equator and only 50 K (−220 °C) at the poles -> water ice acts like rock • Atmosphere: • Tenuous, O2

  5. Europa: interior Warm ice..or..liquid water? or some combination?

  6. Europa: surface

  7. Conamara Chaos • mysterious “brown gunk” is probably sea salt baked by radiation -> means underlying ocean is in direct contact with rock and enriched with potentially life-nurturing amounts of minerals

  8. Compare to California’s San Andreas Fault Europa Astypalaea Linea San Andreas Fault

  9. “cycloid” ridges daily fracturing? (120 miles across)

  10. Icebergs? (25 miles across)

  11. Tilted ice blocks look like the Arctic Ocean too…

  12. Europa’s surface shows few craters

  13. Tyremulti-ring impact structure Few large impact craters: -> Suggests 60 Myr surface age. A couple of multi-ringed impacts: -> Penetrated 20 km thick ice!

  14. Few large impact craters: -> Suggests 60 Myr surface age. A couple of multi-ringed impacts: -> Penetrated 20 km thick ice!

  15. Europa: ocean and atmosphere • surface pressure of Europa's atmosphere is 10−12 atm • tenuous ionosphere • H2, O2, O that escapes Europa's gravity form a gas torus in the vicinity of Europa's orbit around Jupiter -> feeds Jupiter’s magnetospheric plasma • A lot of water • periodically occurring plumes of water 200 km high

  16. Europa: potential habitability • one of the top locations in the Solar System in terms of potential habitability and the possibility of hosting life

  17. Discussion Topics • What experiments would you take to Europa to find the water and search for life? Talk with those near you and make a short list. • Would you land on Europa? Why or why not? • Where would you land?

  18. Summary • Many of the icy bodies in the outer Solar System are internally differentiated • Thanks to tidal heating, Europa and Enceladus may have a liquid ocean between the icy crust and the rocky core • Warm rock in contact with water heats it: this starts convection. Hot water can emerge from cracks in the surface: this provides chemical energy for possible life • If Earth life arose at hydrothermal vents, it could happen there, too. Also light can reach into the cracks, possibly allowing temporary photosynthesis

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