Nasa goes the distance to explore Pluto

Nasa’s New Horizons spacecraft is closing fast on an unexpectedly spotted Pluto, the most distant planetary body ever explored.

From New Horizon’s position, 4.8bn kilometres from Earth, radio signals, travelling at the speed of light, take four and a half hours to reach the ground.

Not that the probe, which has been travelling toward Pluto for nine years, is spending much time relaying back pictures and data from its seven science instruments.