Lunas populated by life forms, as in the recent Pandora "Avatar" are science fiction today, but may no longer be earlier than believed. The Kepler space telescope, in orbit since March 2009 has the ability to detect planets the size of Earth to about 500 light years away from us, and that includes large moons around giant planets. Furthermore, as Lisa Kaltenegger astronomer concludes a new study, the James Webb Space Telescope will be able to analyze any moons to be discovered, and to detect life-critical gases like oxygen, carbon dioxide and water vapor .
"If Pandora existed, we could potentially detect and study its atmosphere in the next decade, "said Lisa Kaltenegger, Center for Astrophysics (CfA), jointly run by Harvard University and the Smithsonian Institution.
Until recently, searches for planets in other solar systems have been limited to detecting giant planets Jupiter, of whom several hundred are known. The gas giants, although easy to detect, could not be used to sustain life, at least as we know it. However, a rocky moon orbiting a gas giant located the right distance from its star (which carries a temperature that allows the existence of liquid water) it could be suitable for life.
All giant planets of our solar system have rocky moons that are also rich in water ice in many cases. This suggests that the gas giants in other solar systems probably also possess moons that sort around. Some may have masses comparable to that of the Earth and be able to retain an atmosphere.
The Kepler mission is to find planets, from the direction of observation of the telescope, crossing in front of their stars. This creates a mini-eclipse and attenuates the brightness of the star in a tiny but detectable degree. Such transits last for a few hours and require very precise alignment of the star and the planet along the line of sight of land. The Kepler examined thousands of stars, so you end up finding a significant amount of soles with a transiting planet. Knowing
as a gas giant planet, astronomers can search for moons around it. The gravity of a satellite is able to alter, so subtle, but detectable, the movement of their planet, so it can speed up or slow transit in ways that betray the existence of the moon.
Having found the moon, the next question to be answered is: Do you have an atmosphere? If it has, these gases absorb a fraction of the starlight in transit, leaving a subtle but telltale traces of the atmospheric composition of the satellite.
Kaltenegger, after calculating what conditions are best for examining the atmospheres of moons in other solar systems, has concluded that the system of Alpha Centauri A, the scene in the movie "Avatar" would be an excellent target for search for satellites.
Alpha Centauri A is a nearby bright star, much like our Sun, so it provides a clear and easy to interpret. Kaltenegger few points would be sufficient to detect transits of water, oxygen, carbon dioxide and methane in an Earth-like moon, as it is in "Avatar" Pandora satellite. As stated Kaltenegger, if the moon's "Avatar" really existed, the astronomers could detect and study in the very near future by the James Webb Space Telescope.
While Alpha Centauri A is a promising target search of habitable planets or moons, red dwarfs, which are abundant, they are in equal or even greater degree. The orbital floor area (which, by the temperature prevailing in it, allows the existence of liquid water) is closer to the star in the case of a red dwarf, which increases the possibility of a transit.
Astronomers have long debated about the problems that could lead to a planet so close to its star, although the temperature at this distance is acceptable for life. The short distance of a planet to warm red dwarf star would influence their rotation so that it would conform to the translation and the planet always present the same face to the star, as does the moon with Earth. Although a good wind regime could perhaps spread the heat properly from the day side and night, it is obvious that a world with a hemisphere immersed in a perpetual day and the other in perpetual night, for life is more challenging than a world with a sufficient alternating days and nights.
This problem of the planets in orbital floor area of \u200b\u200ba red dwarf not suffer its moons. A moon in such a scenario will always present the same face to their planet, but not the star, and therefore would have a normal alternation of day and night. The existence of atmosphere would also help to moderate temperatures. Plant life may populate virtually all of the moon as it would have on solar energy source accessible from almost anywhere on the surface.
Due to these circumstances, in the orbital floor of a red dwarf moons orbiting gas giant planets are more likely to harbor life that rocky planets or super-Earths, two types of planets have been considered very promising for hosting life.
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