Just in time for Halloween, scientists have discovered something spooky and strange happening at the edge of the solar system: the heliopause, the boundary between the heliosphere (the bubble of solar wind that surrounds the solar system) and the interstellar medium (the material between the stars) seems to be undulating and creating oblique angles in an unexpected way.
The general concept that the heliopause changes shape is not new; over the last decade, researchers have determined that it is not static. They made this discovery using data from traveler 1 Y traveler 2the only two spacecraft to have left the heliosphere so far, as well as NASA’s Interstellar Boundary Explorer (IBEX), which studies the emissions of energetic neutral atoms (ENA) that are created when the solar winds and the interstellar medium interact.
“The Voyager spacecraft provides the only direct in situ measurement of the locations of these boundaries. But only at one point in space and time,” Eric Zirnstein, a space physicist at Princeton University, wrote in an email to Vice (opens in a new tab). IBEX helps round up that data.
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Scientists have used the data to create models that predict how the heliopause changes. In one word solar winds and the interstellar medium push and pull on each other to create a constantly moving boundary.
But recent research on the heliopause has yielded data that contradicts previous findings. Over a period of several months in 2014, IBEX captured ENA brightnesses that indicated asymmetries in the heliopause, and the team later realized that those asymmetries were inconsistent with the models, Vice noted.
Also, by reviewing data from the voyages of Voyager 1 and Voyager 2, scientists found that the heliopause changed dramatically in a very short period of time. That helps explain why there was such a large gap between the two probes’ entries into interstellar space, which happened in 2012 Y 2018, respectively. But that kind of movement of the heliopause also clashes with the models.
In an article published in Oct. 10 on the daily nature astronomy (opens in a new tab), the researchers called these discrepancies “intriguing and potentially controversial.” They plan to continue studying the heliopause, hoping to get more information from NASA. Interstellar mapping and acceleration probea new and improved satellite that can detect ENA and is scheduled to launch in 2025, Zirnstein told Vice.
Until then, we can only ponder this terrifying phenomenon occurring in the unsettling depths of the Solar system.
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