Scientists believe streaming particles called "interstellar" winds have switched directions over the past 40 years.
The winds move past Earth as the interstellar cloud that surrounds our solar system moves past the sun at a breakneck speed of 50,000 miles per second.
The finding helped researchers analyze the scope of our solar system's heliosphere (the "bubble" that protects us from intergalactic radiation), a University of New Hampshire press release reported.
The winds also helped "map our location within the Milky Way galaxy and [are] crucial for understanding our place in the cosmos through the vast sweep of time-where we've come from, where we're currently located, and where we're going in our journey through the galaxy," the press release stated.
"It was very surprising to find that changes in the interstellar flow show up on such short time scales because interstellar clouds are astronomically large," Eberhard Möbius, UNH principal scientist for the IBEX mission and paper co-author, said. "However, this finding may teach us about the dynamics at the edges of these clouds-while clouds in the sky may drift along slowly, the edges often are quite fuzzy and dynamic. What we see could be the expression of such behavior."
Data from NASA's Interstellar Boundary Explorer (IBEX) mission showed interstellar particles are flying into the solar system from a different direction than has previously been observed.
A research team compared IBEX data (which directly measures the neutral helium atoms) with information from 11 other spacecrafts that flew between the years of 1972 and 2011. The team wasn't sure if the sudden direction change was real, or was a figment of more accurate data from IBEX.
"Prior to this study, we were struggling to understand why our current measurements from IBEX differed from those of the past," co-author Nathan Schwadron, lead scientist for the IBEX Science Operations Center at UNH, said. "We are finally able to resolve why these fundamental measurements have been changing with time: we are moving through a changing interstellar medium."
