A busy afternoon but I couldn't let this one pass unremarked. Opik may have strayed from his erstwhile preoccupation but some of us are still watching the skies:
An asteroid will pass by the Earth on Friday in something of a cosmic near-miss, making its closest approach at about 1600 GMT.
At its closest, the space rock - named 2012 BX34 - will pass within about 60,000km of Earth - less than a fifth of the distance to the Moon.
A near thing, in cosmic terms, but a long way from sending us the way of the dinosaurs; in any case, the asteroid in question, first detected on Wednesday, is a mere 11m in diameter.
There seems to have been some uncertainty about its exact path:
Earlier estimates put the asteroid's closest distance at as little as 20,000km, near the distance at which geostationary satellites reside, but observations overnight showed it will pass at a more comfortable distance.
That's quite a difference; the predictability of Newtonian mechanics is all very well but you can only calculate with the observational data you have available - in this case, that has evidently been subject to a certain amount of revision.
"It's one of the top 20 closest approaches recorded," said Gareth Williams, associate director of the US-based Minor Planet Center.
So quite a rare occurrence, then? Er, no; according to a NASA statement last year, an object of this size can be expected to come this close to Earth about every 6 years or so, on average. They may want to rethink that calculation, though...
The asteroid's path makes it the closest space-rock to pass by the Earth since object 2011 MD in June 2011.
That one, you may recall, passed us by at 12,000km, while in September 2010, one whizzed by a more generous 80,000km away. Certainly these are vast distances when you're talking about a rock a few metres in diameter, but it does suggest there are quite a few of the things up there.
So for all the apocaholics out there, don't worry; there'll be another one along soon! Meanwhile, we in the Tavern always regard a passing asteroid as the perfect excuse for a party; feel free to join us in spirit (or spirits).
Natural and constructed truths
1 hour ago