Of all the animals of prey, man is the only sociable one.
Every one of us preys upon his neighbour, and yet we herd together.
The Beggar's Opera: John Gay

Friday, 31 January 2014

Asteroid round-up

As regulars are well aware, an asteroid fly-by always calls for a drink. 

That being so, we have been in something of a celebratory mood for the past few days, what with 2014 BA3 and 20134 BP8 on Sunday - at 2.3 million and 1.4 million km respectively - followed by Wednesday's 2014 BK25 at 1.2 million km and 2014 BM25 at a bit over a million.

And it goes on: next Monday gives us 2014 BW32, at a mere 730,000km and, to make matters even more exciting, while those others are somewhere around 10-15m wide, this one could be up to 37m across, getting on for the size of the one that caused the Tunguska airburst in 1908. 

If it were to hit us, the results could be catastrophic. The devastation seen at the Siberian site when the first expedition arrived there (in 1927, which suggests a certain lack of urgency) shows the force of the explosion on the ground. If a tree falls in a forest and no one is around to hear it, does it make a sound? You bet!

It's all a lot of numbers, I know - don't you long for the old days, when you knew your asteroid by name? - but it's worth pointing out that the 2014 prefix means these have all been identified this year; it just shows what can be done once the need is recognized. Eagle-eyed asteroid spotters, both human and machine, are clocking up sightings at an unprecedented rate.

Apart from having a noticeable effect on the Tavern's drinks bill, this painstaking labelling of everything hurtling around our neighbourhood clearly shows just how busy it is out there. Every week this year has brought us at least one within 10 Lunar Distances, most of them discovered only a few days or even hours before their closest approach.

The majority, of course, are mere tiddlers by asteroid standards, with  no room to swing a space slug, and there are probably thousands more of them out there. In fact, given the way the Chelyabinsk meteor came out of the blue, it's hardly surprising that a large number of fireballs are recorded annually as rocks up to 2m in diameter burn up in the atmosphere - and that's just the ones that appear over inhabited areas.

In the face of the cosmic pinball going on around us and the certainty that, one day, the big one will arrive , the only sensible attitude is a degree of fatalism. At least we know it's random -   if fire from heaven were truly a manifestation of divine displeasure, Celebrity Big Brother would surely have elicited a bolt from the blue by now.

Meanwhile, though this weekend - as far as NASA are aware, at least - will not bring a close flyby, I invite you to raise a glass to this week's crop of space rocks and to those currently whistling past us but as yet unknown.

6 comments:

  1. Phew, nearly missed this, been a bit busy. Phew!

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  2. "If it were to hit us, the results could be catastrophic."

    Might wake us up to genuine risks though.

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  3. I have something of a concern. Given detection of all these relatively small asteroids, do we have the capability to recognise them if and when they return.

    As I understand it, asteroids making such repeat passes can really only be labelled as 'seen before' if we have accurate information on both mass and orbit.

    There is some doubt in my mind that we have this information with sufficient accuracy. This is especially on mass, for which we only have the intensity of reflected solar illumination as a proxy.

    If anyone has information on this, it would be good to know what are the current limits. I might get round to a more thorough look myself, in due course.

    Best regards

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  4. Don't worry, JH, there'll be another one along in a minute.

    AKH, I doubt it; so many people have been crying 'wolf' recently that the easiest thing to do is ignore all the warnings.

    NS, an interesting thought, especially given that recent research suggests perturbation is much more common than previously believed.

    The risk of inaccuracy must be increased by the fact that the observations come from a number of different sources; certainly there are plenty of warnings about margin for error attached to the published ephemerides and orbital predictions.

    It's out of my league - I just count 'em as they go by - but the Minor Planet Center might have the information.

    Are you writing on this elsewhere? If so, please feel free to link.

    (In an utterly charming accidental metaphor, spellcheck wants to change 'ephemerides' to 'shepherdesses'.)

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  5. Just double checking any updates.

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  6. JH, it was worth a check; 2014CE got within 570,000 km of us without being seen on February 1st.

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