interstellar space

Renewed attention on the immense challenges of interstellar travel: the enormous distances involved, the limited speeds of current spacecraft, radiation, and the energy required to escape the Sun's gravity and reach another star. Commentators note that even probes like Voyager 1 would need tens of thousands of years to reach the nearest stars, making human travel beyond the solar system effectively out of reach with present technology.

NASA's Voyager 1 probe is now 25.78 billion kilometres (16.02 billion miles) from Earth and is set to reach a distance of one light-day — the distance light travels in a full day — in roughly 43 days and 18 hours. Its twin, Voyager 2, trails behind at 21.57 billion kilometres. Space watchers are marking the milestone as the farthest human-made object edges further into interstellar space.