Bursting the sun's bubble
The sun's environment in interstellar space — the heliosphere — is essentially a bubble that encompasses the entire solar system and has a diameter about 100 times the distance from the Earth to the sun. This region, in which the solar wind dominates before it smashes into the surrounding galactic gas and dust, was supposed to look something like the shape of a comet: a region pushed inward on one side and streaming outward on the other. But a new NASA orbiting observatory designed to study this vast zone found something completely different. Our sun's sphere of influence, according to a series of papers published in Science on Oct. 16 detailing the initial results from the Interstellar Boundary Explorer (IBEX) satellite, seems instead to be a bubble that is cinched at the waist by a vast ribbon as seen by energetic neutral atoms — atoms that are not electrically...