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- Are astronomers always looking for their keys under the lamppost? Are we looking for life in environments where is it is easy to see and familiar to our own situation? Maybe if we get outside the lighted circle we will find other habitable zones where life could exist? “Habitable” in this context means a temperate zone orbit where liquid water can exist on the surface of the planet. For our solar system this includes the orbits between 0.8 astronomical units and 2 A.U. This zone contains the planets Venus, Earth, and Mars.
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-. So, if we look beyond earthlike planets we might find life on planets around stars much smaller than our sun. Smaller stars are Red Dwarfs Stars. The smaller stars are 200 times more abundant than the bright yellow stars like our Sun. However, smaller stars are dimmer and red in color. To get enough warming radiation the planets would need to orbit much closer to the star, equivalent to inside the orbit of Mercury.
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-. Then, another outside the circle likelihood for life exists on moons, not just planets. This review explores the moon Titan orbiting the planet Saturn.
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-. Titan is Saturn’s largest moon. We have landed a space probe on Titan’s surface, January 15, 2005. (Cassini mission, Huygens Space Probe ). The space probe saw dark drainage channels. Are these channels created by methane rivers that flow like water?
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-. On later fly-bys the Cassini spacecraft discovered rainstorms in the atmosphere and lakes on the surface, all liquid methane. Titan has a diameter of 3,200 miles and is larger than the planet Mercury. If it were orbiting the Sun instead of Saturn it would be a planet.
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-. Another moon of Saturn is Ganymede that is even larger, having a diameter of 3,270 miles.
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- Titans crust is made of water ice with temperatures of -290 degrees Fahrenheit ,and, with 150 % atmosphere pressure, the ice is as solid as granite. Methane does not mix with water. It flows over the ice surface slowly eroding the rock hard ice.
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-. Titan flybys have occurred over 100 times. Measurements of thunderstorms have calculated that 100 inches of methane rainfall can occur in only two hours. An earthly record might be 12 inches in one hour. Such a deluge would create horrendous flash floods on Titan's surface.
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-. Most of Titan’s mysteries remain hidden , or fuzzy at best. Radar is the only measurements that have been made over time. Until we can launch another mission with better instruments Titan’s true nature will remain fuzzy.
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-. Finding life on a moon now seems just as likely as finding life on the planet. Most of the naked eye stars we see our giants and supergiants because of their intensive brightness. Increase a stars mass by 10 and its brightness increases by 3,000. At the same time the supergiants that we can see are fewer than 0.2 % of all the stars. 99.8 % of the stars are too dim to see with the naked eye.
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-. If a stars 10 % the mass of the Sun its brightness is only 0.08 percent as bright as our Sun. It is a Red Dwarf Star and hard to see. Bernard Starr, only six light-years away has a Magnitude of 9.5 and is a Red Dwarf star. The larger the brightness magnitude number the dimmer the star. A brightness magnitude of 6.0 is considered a brightness able to be seen by the naked eye. Proxima Centuri, another Red Dwarf Star, is closer at 4.23 light-years but only a magnitude 11.0.
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-. Of all the stars in our neighborhood of the galaxy 74 % are Red Dwarf Stars. These are dim stars, with low power outputs,. If their planets and moons are to have a chance for life there orbits must be very close to the stars. For planets to have a liquid water on the surface they would have to have orbits inside Mercury’s orbit, and they would have to be tightly locked like our Moon, always one side facing the star.
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- Without enough solar power photosynthesis can not occur. With one side of the planet always facing the sun, one side would be hot and the other side would be cold. This temperature difference would create wild winds and ocean currents between the two hemispheres. What astronomers envision is a strip of land with mild temperatures straddling these two hemispheres.
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-. This oasis would be in perpetual daylight. Plants could point their leaves in one direction and get all day sunshine.
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-. When astronomers crank the numbers, after studying 3,897 Red Dwarf Stars, 16 % have habitable zones, orbits where liquid water can exist. For our Solar System that is 0.8 to 2 astronomical units, orbits of Venus, Earth, and Mars. Extrapolating this out to the 200,000,000,000 Red Dwarf Stars in our galaxy, 24,000,000,000 have habitable earthlike planets.
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-. When stars like our Sun, larger than Red Dwarfs Stars, add another 9,000,000,000 habitable planets.
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-. Most plants are green because they absorbed red light at 670 nanometers and reflect green light. However , some bacteria absorbed 900 nanometer wavelength light for their energy. That near infrared light may be a perfect match for Red Dwarf Stars to support life.
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-. Our Sun and all the sun -size stars have a lifetime of 10 billion years. Red Dwarf Stars have a lifetime of 10 times larger 100,000,000,000 years, and , they hardly age over their entire lifetime.
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-. The Earth took 3,000,000,000 years of aging to go from microscopic life to intelligent life. The total time life could exist is only twice this length of time for our Sun. Red Dwarf Stars would allow tens of billions of years longer for a chance for life to evolve. An announcement will be made shortly, stay tuned.
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RSVP, with comments, suggestions, corrections. Index of reviews available ---
--- Some reviews are at: -------------------- http://jdetrick.blogspot.com -----
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---- www.twitter.com , --- 707-536-3272 ---- Saturday, April 19, 2014 ---
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