When it comes to understanding the space environment of our solar system, our knowledge is divided between two extremes — we understand the influence of solar wind on the space around Earth, and on interstellar space, which the Voyager spacecraft is currently traversing. Now, data from NASA’s New Horizons spacecraft, which flew by Pluto last July, is helping scientists finally fill this enormous gap in information, helping them understand what has hitherto been an entirely unexplored part of the solar system’s space environment.
“Not only does the New Horizons data provide new glimpses of the space environment of the outer solar system, but this information helps round out our growing picture of the sun’s influence on space, from near-Earth effects to the boundary where the solar wind meets interstellar space. The new data shows particles in the solar wind that have picked up an initial burst of energy, an acceleration boost that kicks them up just past their original speed,” NASA said in a statement released Tuesday, describing the findings of a study published in the Astrophysical Journal Supplement.
During its decadelong voyage to Pluto, the New Horizons space probe had to not only wade through a constant stream of solar wind, but also occasionally brave much denser clouds of faster particles that make up the coronal mass ejections (CMEs). These particles produce aurorae when they hit Earth’s magnetosphere, and, in extreme cases, can interfere with aviation technology, GPS systems and power grids, and pose a radiation hazard to astronauts.
Scientists poring over the data beamed back by New Horizons found that the space environment in the outer solar system has less detailed structure than space closer to Earth.
“At this distance, the scale size of discernible structures increases, since smaller structures are worn down or merge together,” lead author Heather Elliott, a space scientist at the Southwest Research Institute in San Antonio, Texas, said in the statement. “It’s hard to predict if the interaction between smaller structures will create a bigger structure, or if they will flatten out completely.”
With this data in hand, scientists can now not only create better “maps” of the space environment, they can also test existing models of how the solar wind propagates throughout the solar system.
The CMEs, coupled with a constant stream of solar winds, influence the entire solar system — including space that astronauts would one day have to wade through during their journey to Mars. As a result, an accurate model of the space environment would be of immeasurable help to scientists planning future deep space missions.