A study published in The Astrophysical Journal Supplements reports findings from NASA’s Interstellar Boundary Explorer (IBEX) mission, which has been observing the heliosphere for over eleven years. The heliosphere describes the “cosmic bubble” that the Sun’s magnetic field produces that engulfs the planets in our solar system. The heliosphere’s boundaries are not constant; they shift as the Sun cycles through its 11-year cycle of high and low activity.
Given the longevity of the mission, IBEX has been able to capture never-before-seen images documenting the shifting boundaries of the heliosphere, showing its morphing shape and ultimately providing a map of our solar system’s edges.
IBEX itself is small, only as big as a bus tire, says the principal investigator for the mission at Princeton University in New Jersey, David McComas. "It's this very small mission. It's been hugely successful, lasting much longer than anybody anticipated. We're lucky now to have a whole solar cycle of observations."
IBEX measures energetic neutral atoms (ENAs) within the heliosheath of the interstellar medium and records their direction and energy, detecting about one every two seconds. From this information, IBEX outlines the boundaries of the heliosphere. As Eurkea Alert explains, the process itself is analogous to the way a bat uses echolocation to sense an incoming signal to learn about its surroundings.
"We're so lucky to observe this from inside the heliosphere," said Justyna Sokol, a visiting scientist on the Princeton team. "These are processes that happen at very small distances. When you observe other stars that are very far away, you observe distances of light years, from outside their astrospheres."
Jamey Szalay, another Princeton researcher on the team, added: "It takes so many years for these effects to reach the edge of the heliosphere. For us to have this much data from IBEX, finally allows us to make these long-term correlations."
The data gathered from IBEX also helped clear up some questions that scientists have had about the heliosphere’s IBEX ribbon. Watch the video below to learn more about the IBEX ribbon. Also of note is that NASA will be launching another mission by the end of 2024 called the Interstellar Mapping and Acceleration Probe (IMAP), which will collect information that will complement that gathered by IBEX.
Sources: The Astrophysical Journal Supplements, NASA, Eureka Alert