In January 2012, the IBEX science team released new observations of neutral atoms drifting in from outside our heliosphere toward Earth’s region of the Solar system. Thanks to IBEX’s amazing sensitivity and resolution, we can use these observations to probe the local region outside our heliosphere. Previous IBEX neutral atom results included observations of neutral hydrogen, oxygen, neon, and helium. Prior to IBEX, the Ulysses spacecraft also detected neutral helium atoms, and others had used the spectral signature to infer the neutral helium. For the first time, we have now combined these results to look for change over time. A new paper published in the journal Science by IBEX Co–Investigator Dr. Priscilla Frisch and others on the IBEX Science team (and other missions), shows the amazing result that the direction the local interstellar wind flowing into the solar system has varied over only a few decades. We look forward to continuing to use IBEX to unlock the secrets within, at the edge of, and outside our heliosphere. Congratulations to the talented IBEX science team for these exciting results! Go IBEX!

To detect interstellar neutral atoms, we get a lot of help from our Sun. Our Sun emits a "wind" of material outward, at an average of one million miles (1.6 million kilometers) per hour. As the solar wind streams away from the Sun, it races out toward the space between the stars. We think of this space as "empty" but it contains traces of gas, dust, and charged, or "ionized," gas — together called the "interstellar medium." The solar wind blows against this material and clears out a cavity–like region in the ionized gas. This cavity is called our "heliosphere."

Our entire heliosphere, which contains our Sun, the planets, and everything else in our Solar System, is moving through the interstellar medium. Because of this motion, a "breeze" of interstellar material moves toward our heliosphere’s boundary. The interstellar neutral atoms are just that — "neutral" — meaning they do not interact with magnetic fields. Interstellar neutral atoms, or ISNs, move through the boundary of our heliosphere without the boundary itself affecting them.

As the atoms approach the region containing the Sun and the planets, the breeze of ISNs is deflected by the Sun’s gravity into a curved path. Different atoms are deflected in different amounts based on their masses, and these deflections can be calculated. Based on these calculations, the IBEX team knows when to look for them as the IBEX spacecraft passes through these deflection regions in Earth’s orbit.

The IBEX science team used a variety of data to develop their conclusions. Measurements of ultraviolet radiation emitted from interstellar helium were made by such spacecraft as STP 72–1 (1972–1973), Mariner 10 (1973–1975), SOLRAD 11B (1976), Prognoz 6 (U.S.S.R., 1977–1978), Extreme Ultraviolet Explorer (1992–2001), Nozomi (Japan, 1998–2003) and others. The team also used interstellar helium measurements from the long–lived joint NASA and European Space Agency Ulysses satellite (1990–2002) and, of course, IBEX (2009 to present). In all, the data came from eleven different spacecraft that operated at various times from 1972 to 2012.