More than 20 years later, I can still remember the first time my mind was truly blown. While at elementary school in the mid 1980s, we were taught about the Voyager probes which had been launched in 1977 to take advantage of a rare event (“the planets in alignment”, in this situation, not being a cliche) that meant it would be possible for them to visit Jupiter, Saturn, Uranus and Neptune in a relatively straight-line journey.
By the time I was sat in the classroom, Voyager 1 had passed Saturn and was now headed out on a course far beyond any of our planets. What really grabbed my attention was the inclusion of the Golden Record, an audio record containing greetings in multiple languages, sounds of human life and a collection of music (including Johnny B Goode, which may explain its inclusion as the only music heard in nuclear apocalyptic drama Threads), designed to one day inform extraterrestrials about our planet.
Eventually, though, this information was filed away in the back of my mind until being reawakened this week by a television show, Wonders of the Solar System. I won’t go into too much detail about it as I am aware there’s a danger of my GeeksareSexy work turning into a promotional outlet for the British Broadcasting Corporation.
In short, though, it’s a truly compelling show hosted by Professor Brian Cox, perhaps the only physics professor to have a number one single (though Queen’s Brian May has a doctorate in astrophysics). The first show was based around our relationship with the Sun and included a wonderful scene where Cox went to a desert and used nothing more than an umbrella, a can of water, and a thermometer to calculate the energy given off by the sun across a square meter and then, with a little extrapolation, the entire energy value of the sun itself.
Later he demonstrated the scale of the sun’s gravitational power by setting up a demonstration using jelly beans on a restaurant table to show the solar system: on this scale the Earth was a centimeter from the Sun, the rest of the planets were laid out across the table, and then Cox got into his car to show the point representing the furthest reach of the solar system… 500 meters away.
And Voyager? Cox visited the station in the Mojave desert which still receives communications from Voyager 1 (albeit it on a 15 hour delay). It has now passed far beyond even the furthest dwarf planet and is now in the heliosphere, effectively the outer shield of material blown out by the sun’s solar winds.
Specifically Voyager 1 has passed a point known as the termination shock into the heliosheath. This means that it is now in the region where the solar winds are slowed because they are affected by the interstellar medium. And what’s that? Well, at the risk of oversimplifying, it’s pretty much the bits of space in between the various planetary systems.
It’s believed that as early as 2015, Voyager 1 will cross the heliosheath’s outer border, the heliopause. At this stage, it will be in the interstellar medium.
So, to recap, there is a very good chance that in the foreseeable future, a man-made object, with which we can communicate, will be outside our solar system… at which point it will be surrounded by material which does not ultimately derive from the formation of our sun.
And twenty-plus years later, that again blows my mind.