NPR Story
12:00 pm
Fri February 3, 2012

IBEX Spacecraft Intercepts 'Alien' Particles

As it circles Earth, NASA's Interstellar Boundary Explorer hunts for particles streaming in from beyond the solar system. It has intercepted hydrogen, helium, neon and oxygen atoms. IBEX principal investigator Dave McComas discusses how the abundance of those atoms hints at the Milky Way's composition.

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