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----------------------------------------------------------------------------------------------- I would like to get a survey of readers, please respond with any comment, recommendation. I have a complete index of reviews that is easily searched for a particular topic.
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------------ 1874 - Will we likely find life on Exoplanets and Exomoons?
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- Let’s put together a scenario of how life formed on Earth, then, let’s see if the same thing likely happened on some of the over 3,000 exoplanets that have so far been discovered. It is currently estimated that the average is at least one planet per star in the Milky Way Galaxy. We have at least 100,000,000,000 stars, therefore, 100,000,000,000 planets in their own solar systems.
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- Ok, back to Earth . A billion years after formation the Earth was bombarded by large meteorites and comets. Most of these impacts hit the oceans. Water interacted with impact-heated rock to enable synthesis of complex organic organisms The enclosed crater itself became a microhabitat within which life could flourish.
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- The complex organic molecules included glycine, alanine, amino-n-butyni acid, and H2O, plus, the energy required for synthesis of these molecules.
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- Human desire to explore new horizons has been grounded in finding life. As we explore the planets and moons in our Solar System we often use the phrase: “ Life as we know it”. We accept that life as we know it defends on a very friendly environment having very limited variables.
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- Even on planet Earth life as we know it keeps expanding as we discover new life living in extreme conditions. Since the 1900’s when exploration of the Galapagos Rift came across giant volcanic chimneys in the depths of the ocean, alien creatures were surviving and thriving in this abyss. Giant tube worms 10 feet tall. Clams colonized by symbiotic bacteria. New life forms that can replicate photosynthesis using only chemicals, no sunlight. At 16,400 feet deep the ocean was alive with blind shrimp and anemones.
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- This new life is know as extremophiles. If this new life exists here in the bottom of our oceans could it exists in other liquid oceans? Astronomers have found liquid oceans on Saturn’s moons Titan, Enceladus, and Mimas. On Jupiter’s moons Europa, Ganymede and Callisto. Maybe even on the Dwarf Planets Pluto and Ceres. Could these water worlds also support life, extremophiles?
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- Europa, one of Jupiter’s 67 moons, has deep, salty oceans beneath an icy crust. The chemical balance of these oceans are very similar to the ones here on Earth. On Earth our oceans make hydrogen where salty seawater soaks into cracks in the Earth’s crust. The water reacts with minerals to produce hydrogen and heat.
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- Oxygen could form from the frozen water molecules on the icy surface. The molecules cold be split apart by the cosmic radiation. Both the hydrogen and the oxygen could be recycled into the depths of the ocean. The oxidants from the ice are like the positive terminal of a battery, the chemicals from the seafloor, reductants, are the negative terminal. Can the biological processes complete the circuit?
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- To pick one environment most likely it would be the saltwater oceans on Europa. Europa has the geological activity, underwater volcanoes, water vapor plumes. This chemistry could deliver the nutrients for life. The chemical energy could come from the hydrothermal vents.
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- In 1977 Voyager I was the first visitor to Saturn and Jupiter. We witnessed the volcanic blast off the surface of the moon Io. In 1979 Voyager II witnessed the icy surface of Europa with the long, linear cracks crisscrossing its surface. The somewhat eccentric orbits or Io and Europa create varying gravity pulls, tides, from mammoth Jupiter.
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- In 1989 Galileo’s spacecraft made a dozen close flybys of Europa. The images confirmed Europa to be a spinning shell of ice atop a large liquid water ocean. The cracks and fissures were the evidence of a form of plate tectonics. The magnetic field was detected evidence of a salty, global subsurface ocean. Ice alone is not conductive enough to support a magnetic field.
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- Much more research needs to uncover the true formation of life. Other important elements include carbon, nitrogen, phosphorous, and sulfur. Europa’s orbit is only 400,000 miles from Jupiter, about twice the Earth-Moon distance. Spacecraft require heavy radiation shielding from the high-energy electrons streaming off Jupiter. A planned mission to visit Europa again in 2020 hopes to get a probe there under the ice to learn if the biological processes there are friendly to bring life into these oceans.
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- Europa is 90% the size of our Moon, 1,944 miles diameter. Our Moon is 2,160 miles diameter. Europa’s ice shell is 12 miles thick with liquid water below that is 60 miles thick.
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- The Cassini Mission to Saturn had some of the same issues. With its last remaining life, the last 20% of its fuel, the last 155 orbits, Cassini’s flybys discovered hydro-thermal vents on Enceladus and rainfall on Titan.
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- Request these Reviews to learn more about Europa:
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- #1788 - Europa - moon of Jupiter.
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- #1725 - Europa at surface temperature of -300 F, how can it have liquid water?
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- #1702 - Europa gets 25 less sunlight than our Moon.
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- #1361 - Europa has no atmosphere to carry water vapor.
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- #1152 - Europa has had Pioneer, Voyager ( 1979), Galileo (1995), and Cassini ( 2004) spacecraft made flybys.
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- Request these Reviews to learn more about Enceladus, Saturn‘s moon:
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- #1786 - Enceladus is 311 miles diameter. Cryo-volcanoes on the surface are spewing jets of water vapor and ice into space.
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- #1714 - There is an ocean about the size of Lake Superior under a 25 mile thick sheet of ice.
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- $957 - Enceladus reflects 100% of its sunlight. Our Moon reflects 7% of its sunlight.
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- Request these Reviews to learn more about Titan, Saturn‘s moon:
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- #1787 - The dense atmosphere is mostly methane.
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- #1363 - Titan is 3,100 miles in diameter, larger than the planet Mercury. It orbits Saturn in 16 days.
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- #1144 - Titans average density is 1.88 grams / cubic centimeter.
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- #818 - Huygens space probe landed on January 14, 2005.
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- #555 - Biography of Christiaan Huygens who discovered Titan in 1655.
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