that a more distant "Jupiter" is unlikely, but terrestrial planets are possible. Lead researcher Ivan Ramirez explained the significance of finding solar siblings: "We want to know where we were born. If we can figure out in what part of the galaxy the Sun formed, we can constrain conditions on the early Solar System. That could help us understand why we are here." He suggested a "small, but not zero" chance that planets with life might orbit solar sibling stars, because during the frequent collisions during planetary formation material might have travelled from one system to another. He said the siblings might be "key candidates" in the search for extraterrestrial life. A scenario for transfer of life by this means might require life or a precursor molecule to be shielded from radiation for millions of years, dormant within an outgoing chunk of planetary debris a meter or more in diameter that is produced by a meteorite impact, until this new meteorite impacts on a different planet. Such an unlikely event might have transferred life from another planet to Earth or vice versa. See also Star cluster Solar analog HD 186302 References Hercules (constellation) 162826 087382 6669 BD+40 3225 F-type main-sequence stars