Far more Earth-like planets?
According to sophisticated simulations, there are far more Earth-like planets in distant planetary systems than previously thought. With their calculations, Sean Raymond of the University of Colorado at Boulder and his colleagues mimicked the development of systems with so-called "hot Jupiters".
"Hot Jupiters" refer to giant planets that orbit their star unusually closely - closer than Mercury is to the Sun. Astronomers suspect that during the formation of the planetary system these objects approached the center on spiral paths and, according to the opinion so far, destroyed all other planets and clumps of material on their way or ejected them from the system. However, in Raymond and his collaborators' scenario, scattered chunks accumulate in a habitable zone where a planet could have permanent water in liquid form.
Water, according to the researchers' simulation, came from ice chunks from the outer regions of the gas and dust disks around the stars, which were slowed down on their orbit by the dense gas and thus deflected inwards. Ultimately, this would result in planets that harbor oceans several kilometers deep and thus possibly life, Raymond and his colleagues explain.
The simulations also yielded Earth-like planets still within the giant planetary orbit. Such a "hot earth", with twice the radius of our planet, was even discovered in 2005. In contrast to the relatives in the outer regions, which take several million years to develop, the candidates close to the sun are said to develop in as little as 100,000 years.