Goodbye Voyager, soon

Apologies if this post sounds a somewhat portentous note, but I've always found contemplation of deep space rather consoling. Amid the blanket Budget coverage yesterday I was glad to spot a little story speculating that the Voyager 1 probe, launched in 1977, is on the verge of leaving the Solar System, the first object issued from Earth to do so.

Voyager is now more than 18 million kilometres away. A sudden change in the signals it has been sending back in the past few days indicate that it is moving from the region of the Sun's influence, the 'heliosphere', to the 'heliopause' on the Solar System's border. Scientists are divided on precisely how the data should be interpreted: the probe may not yet have exited the System completely. But it is clear that it has reached the threshold.

I've been interested in Voyager since reading about it as a child, and remember news reports every few years broadcasting the pictures of planets it sent back. I remember the images of Neptune as being particularly spectacular.

Things are now going to get very lonely for Voyager, for a long, long time. The probe's electricity generators will die in ten years or so, then it will drift towards a star called AC +793888, taking tens of thousands of years to get within two light-years of it. After that, onwards into the inconceivable abyss. For me, a soothing reminder of the infinitude encompassing our busy little planet.