Out of This Solar System
By DENNIS OVERBYESTRANGERS among us?
People who still haven't gotten over the idea that Antarctica is littered with meteorites from Mars now have an even more fantastical example of cosmic intermingling to contemplate. Thousands or even millions of planetoids from another star are probably lurking in the outer regions of our solar system, courtesy of a near collision between our Sun and the other star with their nascent planetary systems more than 4 billion years ago.
In a Nature paper this week a pair of astronomers, Scott Kenyon of the Harvard-Smithsonian Center for Astrophysics and Brian [BENJAMIN!] Bromley of the University of Utah, invoked such a world-swapping encounter as the best way to explain a strange world known as Sedna. Named for the Inuit goddess of the seas, Sedna travels in elongated orbit far beyond Pluto and the rest of the known solar system, never venturing closer than about seven billion miles from the Sun. It is the coldest, most distant object known to orbit the sun ....
The interest in these aliens goes beyond Sedna itself, however, to what they might tell scientists about the formation of our own solar system and others ....
Meant to ping you on this, if the others haven't already.