CAPE CANAVERAL, Fla. — Final steps are underway here to prepare the next sun-observing spacecraft, a $1.5 billion joint project between NASA and the European Space Agency (ESA), for launch. Dubbed ...

At the ragged frontier where the Sun’s influence gives way to interstellar space, Voyager 1 has stumbled into something that ...

This story appears in the July 2013 issue of National Geographic magazine. The dust speck had been plucked from the tail of a comet more than 200 million miles away. Now, under an electron microscope ...

There’s a bit of a paradox about our galaxy: it’s both jam-packed with stars and cavernously empty. The Milky Way is crowded in the sense that it holds hundreds of billions of stars, as well as ...