For the first time, a NASA spacecraft has directly observed alien particles that came from beyond our solar system, astronomers announced today. The discovery not only gives us a glimpse of what exists in the so-called interstellar medium—the matter between stars—but also offers clues to the anatomy of our local galactic neighborhood. Orbiting Earth some 200,000 miles 322,000 kilometers away, the Interstellar Boundary Explorer IBEX spacecraft was able to snag samples of hydrogen, oxygen, and neon that came from interstellar space.
It s exciting to be able to have these first observations of alien matter—stuff that didn t come from our sun or the planets, but came from the outside of our solar system, from other parts of the galaxy, David McComas, team leader for the IBEX program, said during a NASA news conference Tuesday. We think these are really important measurements, because these elements are the fundamental building blocks of stars, planets, and people.
Related: Solar System s Nose Found; Aimed at Constellation Scorpius. IBEX Find a 15-Billion-Mile Hole-in-One Since its launch in October 2008, the IBEX probe has been mapping the boundary of the solar system, called the heliosphere. This bubble in the Milky Way galaxy is created by solar wind, which is the stream of charged particles that s constantly blowing out from the sun in all directions. The edge of the heliosphere lies about a hundred times farther from us than Earth does from the sun, and it shields the inner solar system from deadly cosmic radiation. That s because the heliosphere and its associated magnetic field push away damaging charged particles. These particles—remnants from supernovae that are dispersed through interstellar space—flow toward us at 50,000 miles 80,000 kilometers an hour. Also see Frothy Magnetic-Bubble Sea Found at Solar System s Edge.
But half of the particles in the interstellar wind are neutral, and these uncharged atoms can make it into our solar system. A few of these neutral hydrogen, oxygen, and neon particles then made it all the way to Earth, where IBEX was able to detect them, McComas said during the conference. I like to call it the 15-billion-mile 24-billion-kilometer hole-in-one, he said. …