Astronomer/"Killer of Pluto" Mike Brown has posted two pieces on finding Sedna and – seven years on – how he's still trying to figure out why Sedna is where it is.
A lucid explanation, in layman's terms, of a fascinating mystery.
[Via James Nicoll]
Emily Lakdawalla brings news from Neptune:
Congratulations to Scott Sheppard and Chad Trujillo for identifying the first known L5 Trojan asteroid of Neptune! This story is not just interesting because it is a first-of-its-kind discovery, but because of the tricky way that the astronomers went about searching for it, and because of the collateral benefits that their search will have for the New Horizons mission. [...]