Rendezvous Pluto

THEREwas something wonderfully childlike in the delight of scientists and the public at the rendezvous of the New Horizons spacecraft with that most distant and mysterious of the planets, Pluto, even if it was reclassified a few years ago as merely a “dwarf” planet.

But there was nothing childish in the extraordinary science and engineering required to send half a ton of highly sophisticated instruments hurtling through space at speeds of up to 75 000km/h for 4.8 billion kilometres.

The whoops at the operations centre at the Johns Hopkins Applied Physics Laboratory on Tuesday, at the moment when the probe shot past Pluto, and the cheers when the spacecraft broke silence many hours later to confirm it had survived the passage, spoke to an elemental curiosity in every human being.

That is ultimately what the mission was all about, as the celebrated British cosmologist Stephen Hawking declared in a message broadcast on Nasa TV: “We explore because we are human and we want to know.”

For the scientists who launched New Horizons nine and a half years ago, there was a distinctly parental anxiety in the hours after it went silent on Monday so it could dedicate all its energies – a mere 200 Watts – to taking pictures and measurements of the icy body.

There was a storybook quality to the entire mission. At the edge of the solar system, in a thicket of small frozen objects known as the Kuiper Belt, Pluto was discovered in 1930 by Clyde Tombaugh, a selftaught astronomer, a pinch of whose ashes were on board New Horizons.

What next? Scientists, of course, are full of ideas. But there need not be any commercial or ideological justification. The human impulse to know is more than enough.