NASA spacecraft finds atoms beyond solar system
A NASA spacecraft has captured the most complete glimpse yet of what lies beyond our solar system, which may help scientists map how our galaxy evolved and changed over time.
The Interstellar Boundary Explorer, known as IBEX for short, orbits Earth and has observed four separate types of atoms, including hydrogen, oxygen, neon and helium. They are byproducts of older stars that spread across the galaxy and fill the vast space between stars.
IBEX measured the distribution of these elements outside the solar system, which are flowing charged and neutral particles that blow through the galaxy — the so-called interstellar wind.
It found 74 oxygen atoms for every 20 neon atoms in the interstellar wind compared to 111 oxygen atoms for every 20 neon atoms in our own solar system. This means there is more oxygen in any part of the solar system than in nearby interstellar space.
The findings, described in a series of papers appearing in the Astrophysics Journal on Tuesday, provide clues about how and where our solar system formed, the forces that physically shape our solar system and the history of other stars in the Milky Way.
While the Big Bang initially created hydrogen and helium, only the supernovae explosions at the end of a star's life can spread the heavier elements of oxygen and neon through the galaxy.
"Our solar system is different than the space right outside it, suggesting two possibilities," said David McComas, IBEX principal investigator, at the Southwest Research Institute in San Antonio.
"Either the solar system evolved in a separate, more oxygen-rich part of the galaxy than where we currently reside or a great deal of critical, life-giving oxygen lies trapped in interstellar dust grains or ices, unable to move freely throughout space."
Scientists want to understand the composition of the local interstellar medium – the boundary region that separates the nearest reaches of our galaxy from our heliosphere.
The heliosphere is like a protective bubble that shields our solar system from dangerous galactic cosmic radiation that would otherwise enter the solar system from interstellar space.
IBEX scans the entire sky once a year, and every February, its instruments point in the correct direction to intercept incoming neutral atoms. IBEX previously counted those atoms in 2009 and 2010.