At the ragged frontier where the Sun’s influence gives way to the galaxy, a decades‑old spacecraft has stumbled into a furnace that theory did not predict. As Voyager pushes through the heliopause, ...

Our Sun’s outer atmosphere, the corona, is millions of degrees hotter than it should be, and no one knows why.

At the farthest reach of the Sun’s influence, NASA’s Voyager 1 spacecraft has stumbled into a region that behaves less like empty space and more like a furnace, where charged particles heat to tens of ...