A team of U.S. scientists has shown that about 5% of the gas giants orbiting their stars at a distance, like Earth, are satellites that can support life.
Discovered dozens of planets located in appropriate orbits, and many of them are too hot or gas for life. Simon Porter of Lowell Observatory and his colleagues still call these distant worlds chance 12 thousand simulated hypothetical planets the size of Earth, which had been captured by the gravitational fields of gas giants like Jupiter, located on favorable for life orbits.
All simulated satellites have embarked on an extremely elongated orbits. For several hundred thousand years, half fell to the planet or take back into space, while the other half appeared stationary orbit, and with it — a stable climate that can survive for billions of years. This stability is one of the conditions necessary for the evolution of complex life forms. "We were shocked to see how much free initial configurations become stationary orbits, and how quickly it happened," — said co-author Will Grundy.
Ekzosputniki not yet been discovered, so the estimate of the number of speculative, said Alan Boss of the Carnegie Institution (USA), referring to the model, which showed that the possibility of such a discovery is very small.
Mr. Porter retorted: even with such a low chance of habitable moons will be found set. If we assume that 10% of the giant planets in habitable zones become Earth-satellites, which were formed in the interior of a young star system, and 50% of these moons will go into stationary orbit, it turns out that one in twenty giant, located in the habitable zone of a star similar to Sun will have a satellite. It is expected that a space telescope "Kepler" to the end of his mission (and it will last 3.5 years) found about three hundred of the giant planets that satisfy these conditions.
Could life survive on such moons — is another question. Jupiter and gas ekzogiganty have strong radiation belts, which blocks any attempts life began in the immediate vicinity. Mr. Grundy nevertheless notes that water and solid ground stand in the way of almost any energy. Therefore, life is possible under water or underground. Jack Lissauer of NASA Research Center. Ames, however, believes that the heat is generated soon after the capture of the satellite, it will force all the water to evaporate. "The body must have a truly huge quantities of water, so it does not boil dry completely and unable to support the emergence of life," — explains the researcher.
One way or another, but the real problem, says Lisa Kaltenegger of the Harvard-Smithsonian Center for Astrophysics, will be the identification of potentially habitable moons after their discovery. Have to observe the atmosphere, and this is not easy.
The results will be published in the edition of Astrophysical Journal Letters.
Prepared according to ScienceNOW.