The eternal mystery of space

So the Huygens space probe, named after a 17th-century Dutch astronomer and costing £2bn, has finally managed to land on its target, Titan. It has taken more than seven years to travel the two billion miles to get there. It has demanded the combined resources of Nasa, the European Space Agency and the Italian space agency. And it has pursued its lonely way through years of setbacks on other space missions.

So the Huygens space probe, named after a 17th-century Dutch astronomer and costing £2bn, has finally managed to land on its target, Titan. It has taken more than seven years to travel the two billion miles to get there. It has demanded the combined resources of Nasa, the European Space Agency and the Italian space agency. And it has pursued its lonely way through years of setbacks on other space missions.

But finally it has made it. Twenty days after being detached from its mother craft, the Cassini, the probe, no bigger than a washing machine, has descended by a series of parachutes and a discarded shield through the thick atmosphere of Titan to land on this, the largest moon of Saturn and the second largest moon of the solar system.

Not only that, but Titan is the only moon in the solar system with an atmosphere. Which is what makes it so intriguing to astronomers. Its thick atmosphere has made it almost impossible to penetrate from Earth, however powerful the telescope. As the probe landed, its scientists had no idea whether it was falling on hard rock, liquid lake or primeval slime. As important, the organic chemical reactions believed to be taking place there could give us clues as to how the Earth developed billions of years ago.

Of life, there is probably none. The surface temperatures, at minus 180C, make it most unlikely. But its atmosphere is rich in nitrogen, like Earth's, and could be similar to the state of this planet before life began.

At this stage, we don't know precisely how much material has been transmitted from the probe to its mother ship. It will take days, weeks indeed, to process it, let alone interpret it properly. But for the moment, it is enough to celebrate. Over the past few years of failed European missions to Mars and tragic loss of life at Nasa, there has been a steady nag of voices arguing that space exploration is an expensive self-indulgence, a needless nod to popular romanticism that absorbs huge sums that could be better spent on dealing with the more pressing problems here on this planet.

That may be true in reason. But man's horizons have never been extended by managing only what is in his grasp. It is the reach for the unknown which best inspires his endeavours. The most wondrous aspects of this probe is not how much it will tell us, but how many more questions it will raise.