Was the New Horizons mission to Pluto worth the time and money?

A few weeks ago, a big group of my friends climbed Carrauntoohil. I wasn’t able to make it, unfortunately, but looked at the photographs of the trek with envy afterwards, as the fine day afforded them spectacular views of the Kingdom.That is, until they got to the summit,

when a blizzard descended, leaving them shivering and struggling back down through terrible visibility. I’m sure they felt very alive, though.

I had reason to think of that trek this week as a very different journey made headlines. The nine-year voyage of Nasa's New Horizons to the periphery of our solar system, sending back stunning images of that much-loved little planet Pluto, offered some much-needed perspective.

The high-resolution images instantly turned what had been a tiny speck into a whole new world, full of mysteries: they reveal a ruddy-brown planet with 3,300m-high ice mountains as well as an ice cap made of methane and nitrogen.

The success of New Horizons generated widespread enthusiasm and acclaim, but every such space mission is met with some carping by people who wonder what, exactly, is the point of such expensive expeditions. Surely, goes the criticism, the $700 million would have been better spent on more practical problems down here on Earth.

Dwarf planet

And in any case, wasn’t Pluto only discarded from the canonical list of planets in the solar system, when the

International Astronomical Union

reduced it to the status of “dwarf planet” back in 2006?

Not so much a planet, then, as a large piece of debris, just one of the orbiting globes that make up the Kuiper belt, with similar-sized siblings such as Eris, Quaoar, Haumea and Makemake also deserving dwarf planet status.

It's fair to say no one would have been as excited this week if Nasa released high-resolution images of something called Makemake.

Obviously, it is not unreasonable to ask if such a mission is worth the expense, but $700 million over 15 years really isn't that huge an outlay – just look at the sums being thrown at Greece this week alone and the $46.7 million a year seems like a steal.

But the larger question of why send New Horizons at all brings me back to Carrauntoohil. Nobody would ask my friends why they bothered climbing the highest peak in Ireland or suggest it was a waste of time, effort and money. The appeal, the purpose, is self-evident.

To say it’s not worth sending a vessel to the outer reaches of the solar system to get a good look at Pluto is, at its core, the same as saying there’s no point climbing Carrauntoohil, never mind Everest.

It is human nature to explore, to take in the view, to push ourselves to the limit, to feel alive at the discovery of new terrain.

The moment we decide to stop exploring, to stop that voyage of discovery, that’s when we need to start worrying about our priorities.