SCIENCE LAB SCIENCE : GALACTIC RENEGADE.

 

In his spare time, Tom Bickle, an astronomy student in Southampton, England, likes to blast heavy metals while combing through time-lapses of the night sky, hunting for traces of hypothesized ninth planet and other hidden objects on the outskirts of our solar system.

While doing so, he stumbled across something strange ; a faint blob moving across his computer screen. '' I knew immediately that it was unusual,'' Mr. Bickle said.

Astronomers followed up on the observation. The object is either a low-mass star or an object known as a brown dwarf, and it is traveling at a million miles per hour - perhaps fast enough to break from the  Milky Way's gravitational clutches.

The discovery could shed light on the oldest stars in our galaxy, known as halo stars. Many stars in the vicinity of our sun orbit around the disk of the Milky Way - in a circle. But halo stars often have ovular trajectories, tilted away from the galactic plane.

That's because they most likely formed before the Milky Way settled into its current structure, said Adam Burgasser, a physicist at  University of California, San Diego, who led a study of the observation.

The illustration suggests a possible way the speedster got its kick : it many once have been in orbit around a white dwarf - the leftover core of an exploded star - and the forces unleashed by the explosion could have accelerated it to a high velocity. [ Katrina Miller ]