The hugely successful Voyager spacecraft – fine products of American know-how – are still sending information back to Earth over thirty years after they were first launched. In this article can be found some preliminary details of Voyager 2’s latest achievement.

The beginning of the transition zone between the heliosphere (the solar wind bubble) and the rest of interstellar space is known as the 'termination shock'. Scientists report that Voyager 2 crossed this boundary closer to the sun than expected, suggesting that the heliosphere in this region is pushed inward, closer to the sun, by an interstellar magnetic field. These findings help build up a picture of how the sun interacts with the surrounding interstellar medium.

Voyager 1 is already well into the Heliosheath and has sent back much interesting data, but to have this data confirmed by Voyager 2 is invaluable. Some further background information on the Voyagers can be found in this older article.

Considering that the scientists, engineers and technologists reckoned that these craft when they were launched might only last five years, their continued existence and usefulness is all the more remarkable. If we’re lucky, very, very lucky, one or both will cross the heliopause into interstellar space and send back to us the first real data (as opposed to theory) about conditions in interstellar space.

For me, this is nail-biting stuff. I’m willing them on. They’ve got to make it! If mankind ever makes it into interstellar space our safety there on that first trip will, in no small measure, depend upon the data sets sent back to us by these tiny probes launched in 1977 by the USA to carry out an entirely different task from that now entrusted to them.

This really is science at the cutting edge. So, this fourth of July raise a glass to these two little American probes as they continue their voyages into the unknown, into the history books, and, as they massively extend human knowledge of the Universe in which we live, realise that this is tremendously exciting and wonderful – literally wonderful.