<p>Researchers at the California Institute of Technology have found that our solar system may have once harboured super-earths - planets larger than the Earth but smaller than Neptune.<br /><br /></p>.<p>It means that the Earth belongs to a second generation of planets.<br /><br />Those early super-earths are long gone - broken up and fallen into the Sun billions of years ago largely due to a great inward-and-then-outward journey that Jupiter made early in the solar system's history, said the paper published in the journal Proceedings of the National Academy of Sciences (PNAS).<br /><br />"Our work suggests that Jupiter's inward-outward migration could have destroyed a first generation of planets and set the stage for the formation of the mass-depleted terrestrial planets that our solar system has today,"said Konstantin Batygin, planetary scientist at California Institute of Technology.<br /><br />The results suggest the possibility of a new picture of the early solar system that would help to answer a number of outstanding questions about the current makeup of the solar system and of the Earth itself.<br /><br />Thanks to recent surveys of exoplanets - planets in solar systems other than our own - we know that about half of Sun-like stars in our galactic neighbourhood have orbiting planets.<br /><br />"Indeed, it appears that the solar system today is not the common representative of the galactic planetary census. Instead we are something of an outlier," Batygin said.<br /><br />But there is no reason to think that the dominant mode of planet formation throughout the galaxy should not have occurred here.<br /><br />It is more likely that subsequent changes have altered its original makeup.<br /><br />The paper also suggests that the formation of gas giant planets such as Jupiter and Saturn - a process that planetary scientists believe is relatively rare - plays a major role in determining whether a planetary system winds up looking something like our own or like the more typical systems with close-in super-earths.<br /><br />As planet hunters identify additional systems that harbour gas giants, the researchers will have more data against which they can check their hypothesis<br /></p>
<p>Researchers at the California Institute of Technology have found that our solar system may have once harboured super-earths - planets larger than the Earth but smaller than Neptune.<br /><br /></p>.<p>It means that the Earth belongs to a second generation of planets.<br /><br />Those early super-earths are long gone - broken up and fallen into the Sun billions of years ago largely due to a great inward-and-then-outward journey that Jupiter made early in the solar system's history, said the paper published in the journal Proceedings of the National Academy of Sciences (PNAS).<br /><br />"Our work suggests that Jupiter's inward-outward migration could have destroyed a first generation of planets and set the stage for the formation of the mass-depleted terrestrial planets that our solar system has today,"said Konstantin Batygin, planetary scientist at California Institute of Technology.<br /><br />The results suggest the possibility of a new picture of the early solar system that would help to answer a number of outstanding questions about the current makeup of the solar system and of the Earth itself.<br /><br />Thanks to recent surveys of exoplanets - planets in solar systems other than our own - we know that about half of Sun-like stars in our galactic neighbourhood have orbiting planets.<br /><br />"Indeed, it appears that the solar system today is not the common representative of the galactic planetary census. Instead we are something of an outlier," Batygin said.<br /><br />But there is no reason to think that the dominant mode of planet formation throughout the galaxy should not have occurred here.<br /><br />It is more likely that subsequent changes have altered its original makeup.<br /><br />The paper also suggests that the formation of gas giant planets such as Jupiter and Saturn - a process that planetary scientists believe is relatively rare - plays a major role in determining whether a planetary system winds up looking something like our own or like the more typical systems with close-in super-earths.<br /><br />As planet hunters identify additional systems that harbour gas giants, the researchers will have more data against which they can check their hypothesis<br /></p>