That would give it an orbital period of 341 years the longest yet measured and far longer than, for example, comet Halley, which goes around the sun in a sprightly 76 years.

ECONOMIST: Comet Ikeya-Zhang is enlivening the skies

Annihilation aside, Halley's comet will damage the world economy and the environment.

ECONOMIST: Stop that comet

In 1910, after weeks of being viewed through telescopes, Halley's Comet was reported visible to the naked eye in Curacao.

CNN: Friday,

The heavens, he observed, remained agreeably unchanged: he saw Halley's comet when it passed over Pennsylvania in 1910 and again in 1986, when he was in New Zealand doing research.

ECONOMIST: William Sunderman

As for the specialness of the transit, well, it's rarer than passages of Mr. Halley's famous comet.

CNN: A transit of Venus, an age of wondrous science