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Rather worryingly, US space agency NASA has out of the blue issued a strident denial that an approaching comet poses any threat to planet Earth.
"COMET ELENIN POSES NO THREAT TO EARTH," begins the NASA statement emailed to the Register.
"Often, comets are portrayed as harbingers of gloom and doom in movies and on television, but most pose no threat to Earth," it continues, adding, "Comet Elenin, the latest comet to visit our inner solar system, is no exception" (presumably is no exception to the rule that most comets are harmless, rather than the rule that some of them, apparently, do pose a threat).
The space agency goes on to say that Comet Elenin will make its closest approach to Earth on 16 October, at which point it will be 22 million miles away – more than 90 times as far off as the Moon.
A handy Q&A is also included, which rather labours the central point that Comet Elenin will definitely not crash into the Earth and wipe out all life on its surface. Nor will it cause any other apocalyptic disasters:
Q: Can this celestial object cause shifting of the tides or even tectonic plates here on Earth?
A: [Paraphrasing NASA] No. Idiot.
Q: I've heard about three days of darkness because of Comet Elenin. Will Elenin block out the sun for three days?
A: [Again paraphrasing a rather waffley answer] WTF? No!
And best of all:
Q: Why aren't you talking more about Comet Elenin? If these things are small and nothing to worry about, why has there been no public info on Comet Elenin?
A: [Again, distilled] Because it is small and nothing to worry about! Moron.
Nonetheless we feel sure that all right-thinking internet denizens will react to this unconvincing, overly wordy denial with the disbelief it deserves, and will wonder just what NASA has to hide here – if not indulge in a full-fledged and hopefully mildly hilarious panic.
As ever, feel free to share your thoughts in the comments or by mail. ®
"Comet Elenin will not encounter any dark bodies that could perturb its orbit, nor will it influence us in any way here on Earth," said Yeomans. "It will get no closer to Earth than 35 million kilometers [about 22 million miles]. "
"Comet Elenin will not only be far away, it is also on the small side for comets," said Yeomans. "And comets are not the most densely-packed objects out there. They usually have the density of something akin to loosely packed icy dirt.
"So you've got a modest-sized icy dirtball that is getting no closer than 35 million kilometers," said Yeomans. "It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean's tides than comet Elenin ever will."
Yeomans did have one final thought on comet Elenin.
"This comet may not put on a great show. Just as certainly, it will not cause any disruptions here on Earth. But there is a cause to marvel," said Yeomans. "This intrepid little traveler will offer astronomers a chance to study a relatively young comet that came here from well beyond our solar system's planetary region. After a short while, it will be headed back out again, and we will not see or hear from Elenin for thousands of years. That's pretty cool."
In solar system terms, 35 million km is a very close call.
We travel 2.6 million km per day around the Sun, so if the comet orbit intersects the Earth's orbit and the comet had arrived at that point 13.8 days before or after the actual arrival date, it would have been on a course to slam into Earth.
