At the ragged frontier where the Sun’s influence gives way to the galaxy, a decades‑old spacecraft has stumbled into a ...

The Milky Way and Andromeda galaxies are predicted to collide and merge between 3.9 and 5.6 billion years from now, based on observed relative motion. The merger process will involve multiple ...

More than 200 extrasolar planets have been found so far, but our knowledge about those distant worlds is very limited. In most cases we haven’t seen the planets; we only know they exist because of the ...