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‘Rise above yourself and grasp the world’ Archimedes – attribution

Posts Tagged ‘Tunguska

reasons to be cheerless, part one…

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Tunguska – caused by an alien

Will anthropogenetic global warming be an unmitigated disaster or will it be a boon to some species, possibly even our own? Will artificial intelligence make slaves of us all or enable us to become masters of the multiverse? Will social media developments turn us all into obese opinionated ignoramuses or will it help to unite the powerless against destructive autocrats? Will virtual reality sex liberate the unattractive or simply diminish real relations? And so on. When considering the future we often make the error of imagining the past as having been more predictable than it was. In particular, we think we know ‘human nature’, and we generally consider it unchanging, so we can predict our response to events, even if we can’t predict the events themselves. IMHO, we’re mistaken even on that count.

But let’s consider an event we definitely can’t control. Maybe there’s an object out there in space, a very big one, that’s on track to smash into our planet, with such speed, power and accuracy, that all concerns about human development and response become superfluous.

Few things can be more chilling than inevitability. I experienced this once in my early twenties, in casual conversation with a friend. Something in our talk struck me, and I realised, in a heart-freezing moment, that I was destined to die. Of course, I’ve had a long time since then to come to terms with it! But in reading of fatal events, what often torments the mind is the gap between the knowing and the happening. As they say, falling off a cliff never hurt anyone, it’s the landing that does it – but that’s probably wrong, you can suffer a lot of hurt in anticipating the end.

So this morning I was reading about Shoemaker-Levy 9, a comet named after those who discovered it, more or less by accident (though it was the ninth comet discovered by the team, hence the name), in 1993, by which time it had been captured by the gravitational field of Jupiter. In fact, studies of its orbital motion showed that it had been orbiting Jupiter for at least twenty years, and had begun to fragment a year or so before its discovery, when it passed close to Jupiter in an eccentric orbit. It was the first comet ever discovered to be orbiting a planet rather than the sun. Its discovery caused a sensation in the astronomical community, especially as further calculations of its behaviour confirmed that it was certain to collide with the planet. Which, in one week in July 1994, it spectacularly did, in bits and pieces, the largest of which had an impact described at the time as ‘500 times more powerful than the detonation of the whole world’s nuclear weaponry’.

Jupiter is, of course, the largest planet in our solar system, and has been described as a ‘cosmic vacuum cleaner’, sucking asteroids and small comets into its orbit at a rate many thousands of times more than Earth does. The assumption being that it’s protecting us little planets from a lot of nasty stuff. And yet…

great pic of Comet Hyakutake, in 1996

That protection isn’t guaranteed, as what is now called the Cretaceous-Palaeogene impact even shows. That was pretty massive, and the Tunguska event of 1908 was relatively tiny, as was the Chelyabinsk event of 2013, and then there are much larger bodies passing by, such as Comet Hyakutake, and so on. But as to the size and placement of these events, we seem not to reliably forewarned. The second largest impact in over 100 years (since Tunguska) occurred in December 2018, but few lay people even know about it. It occurred over the Bering Sea, between Russia and Alaska. The meteor had a diameter of 10 metres – nothing compared to Shoemaker-Levey 9’s five kilometre nucleus – and of course it impacted in a region uninhabited by humans, but the fact that these impacts aren’t picked up until the last minute is a worry. Of course technology is being developed to improve the situation, but it’s not there yet. And then there’s that mighty, faraway object that might be hurtling towards us, beyond our ken…

Written by stewart henderson

November 24, 2019 at 12:00 pm