Weather on Earth might be shifting in part because of human activity, but larger context in which the Earth moves has some trends to deal with as well, according to new research published in Science and summarized by Science Now: "As Earth and the other planets orbit the sun, the solar system itself travels through space. Its slow journey is taking it though a wispy expanse of gas called the Local Interstellar Cloud. Now, astronomers have discovered signs of potential turbulence in the cloud, indicated by a shift in direction of helium atoms that flow into the solar system. If the shift is real and continues for hundreds to thousands of years—a dicey extrapolation—it could be a harbinger of more dramatic changes in our solar system, notes study co-author David McComas of the Southwest Research Institute in San Antonio. ... To detect the wind shift, researchers drew on measurements by 11 spacecraft and satellites that have recorded directly or indirectly the flow of helium atoms into the solar system. Many kinds of atoms infiltrate the heliosphere, but helium is a particularly good tracer for all of them because it is abundant and typically survives in its uncharged, atomic state all the way to Earth’s orbit, [study co-author Priscilla] Frisch says."