It came up on Facebook that someone posted a photograph purporting to be from Voyager. The implausibility of it was hilarious but as with so many of these kinds of things, my mind started spinning in ways that would make theoretical physicists start to question their model of sub-atomic particles.
A little knowledge is dangerous and I knew that the visual systems on board both Voyager probes were shut down last century. They had already taken all of the useful photographs that they were ever going to, and were now hurtling through the very dark, cold, void of space with the view changing forever imperceptibly; with everything including the sun, being only points of light set against the darkness.
I sort of feel a wee bit sad for the Voyager probes. Having done their job and being more than five and a half light hours from us, they are among the fastest and furthest bits of rubbish that we as a species have ever made.
In 1977, which was before I was born, two spaceprobes named Voyager 1 and Voyager 2 were sent to do the grand tour of the planets because the wheels of coincidence had turned in our favour.
Voyager 1 took the closest photographs of the two big planets, Jupiter and Saturn, before shooting off at right angles to the plane of the ecliptic. Voyager 2 which although was launched weeks before, took longer to get there and took pictures of Jupiter and Saturn, as well as Uranus and Neptune. It visited Neptune in 1989 before the scientists decided to do one last burn of the cameras and out a selfie of the solar system. The earth was famously rendered as nothing more than 'a pale blue dot, suspended in a sunbeam'; before the cameras were shut off and the two spaceprobes continued to hurtle into space at about 60,000mph, seemingly forever. They have both subsequently become interstellar objects, subject to the definition therein.
The reason why a thing with essentially no rocket power and a grand total of 470W of instruments on board, was able to visit the planets is because of a slingshot effect where due to the conservation of momentum, the Voyager probes borrowed a little bit of the kinetic energy of the planets that they went into brief orbit around before repeating the same process at the next one. It is like a kid swinging off of a Hills Hoist clothesline and then letting go, only to catch the arm of the next clothesline.
Still, at 60,000mph, the Voyager probes might not even be the fastest thing that mankind has ever made. That story could very well be as much of a testament to the human condition as the Voyager probes are.
In the 1950s after the Americans got scared after letting a bunch of atomic bombs explode on Pacific islands, potentially poisoning the water and sky, instead of saying "Hey guys, this is stupid; we should stop", they thought "Hey guys, let's not poison the sky anymore; let's let off our stuff underground¹".
It was during one of those tests, in a project called Operation Plumbob, that a steel cap which had been put on top of the blast facility was blown clean off. The actual test called Pascal-B possibly blew the manhole cover off at about 125,000mph. I say possibly because the trail of clues here is so unreliable that I don't trust the scientists' calculations (and that's saying something).
The steel manhole cover was put on top of the shaft to the surface as a safety experiment. It failed. The manhole cover was 4 inches thick but I have no idea how large in diameter. The estimated velocity is supposed to have been as high as 41 miles per second; which is 147,600mph. The manhole cover is apparently photographed in one single frame of film but I honestly couldn't find it in the book I was looking at.
The scientist in question who conducted the test has tried to debunk the theory that this was the fastest man made object but the only original calculations on the subject, have the word 'irrelevant' written on them as the manhole cover was not the subject of the nuclear weapons test. The manhole cover was never recovered.
There is a theory that the steel manhole cover was vapourised on its way through the atmosphere and whilst I concede the fact that a thing doing more than six figures of speed through the atmosphere is going to encounter a metric elephant load of friction, it would pass through really quickly.
At 125,000mph, it is going at more than 34 miles per second. Space is only 62 miles in the direction of up. I don't think there would be enough heat to vapourise a steel plate of the size suggested in two seconds. The most obvious explanation for me is that the reason why it was never recovered was that it was and still is in space. Given that this happened in 1957, before the Russians had even threatened the free democracies of the world with their bleeping ball, Sputnik, the reason I think that the steel manhole cover was never recovered was because it had been ejected off into space in a random direction and there was nothing to track it.
I really like the idea that not only the fastest thing that we've ever made as a species was also the first thing shot into space because it should serve as a warning that messing around with nuclear weapons is really stupid. Hey kids, it's dangerous; don't do it; stay safe.
If the fastest thing we've ever made wasn't sent into space though, then by default that still serves as an object lesson that along with our more basic desires, we also posses a great deal of creativity and something amazing happens when we put that to work to learn about what's going on around us.
If it didn't go into space then there's bits of a leftover manhole cover, which was blasted off the top of a nuclear weapons test facility somewhere on Earth. Perhaps we should try to learn to be a little bit kinder to the spaceship that we live on?