Comets return to life after millions of years.
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A team of astronomers from the University of Anitoquia in Medellin, Columbia has discovered a graveyard of comets, some of which, they say, could become active again after remaining dormant for millions of years. The newly discovered comets are located in the main asteroid belt between Mars and Jupiter, which contains at least 85,000 dead and dormant comets. The study, by astronomer Prof. Ignacio Ferrin and his colleagues, will appear in the upcoming issue of Monthly Notices of the Royal Astronomical Society.
Comets fizzle out when most of their water content has evaporated. However, they may become active again with an increase of solar energy by only a few percent, according to Ferrin. This can occur fairly easily, he says, if they are pushed closer toward the sun by Jupiter’s gravity. When this happens, the shape of a comet’s orbit can change, drawing them nearer to the sun. When heated by the sun, the dormant comet’s water content begins to sublimate and causes it to become active again as long as its energy lasts, the authors write. They dubbed these comets ‘Lazarus comets’ after the biblical figure Lazarus who was resurrected several days after his death by Jesus Christ.