"Just Friends" Say Coupled Trojans
Jupiter shares its orbit with two swarms of small bodies, called the Trojans, suspended at the gas giant's Lagrange points. These are the points leading and trailing the planet where Jupiter's and the Sun's attractive forces balance each other.
In the rear Trojan swarm are two ex-cons, umm, ex-comets, that orbit each other: a binary Trojan system. According to research published in Nature for 2 February, 617 Patroclus and Menoetius measure only about 122 and 112 kilometres in diameter, and their density is only a third of that of rock. This indicates a cometary origin in the Oort Cloud or the Kuiper Belt. Wild!
And while I wax astronomical: did you hear that Xena is actually quite a bit larger than Pluto?
[More blog entries about astronomy, comet, Jupiter; astronomi, komet, Jupiter.]