Lovers in the Sky

Sex sells, or so the saying goes, so here is my shameless attempt to jump on that bandwagon. In East Asian cultures the 七夕 ("Tanabata" in Japanese, "Qi Xi" in Chinese ... by the way, I hereby disprove, in one fell swoop, the widespread but misplaced notion that the Japanese and Chinese languages are related) festival takes place on the seventh day of the seventh month.

Originally, this refers to the seventh lunar month, but as Japan has abandoned the lunisolar in favour of the Gregorian calendar, there, the festival was moved to July 7, i.e., today!

So, what about the sex? You'll be no doubt wondering. Legend has it that a beautiful (what else) princess, 織姫  ("orihime", the weaving princess, in Japanese), daughter of the king of the skies, fell in love with the cow herd 彦星("hikoboshi"). So they got married and lived happily ever after. 

Err ... not quite, because if they had, there would have been no story, no festival, and ultimately, no blog posting in the SciLogs. In fact, things turned out quite badly for the two lovers, because they were condemned to the fate of living on different sides of the amanokawa, the river in the sky. They are however allowed to meet once per year, on the seventh day of the seventh month - provided that it doesn't rain. 

You will have guessed by now, aided by the subtle placement of the image to the left, that the river in the sky is nothing else but the Milky Way. Modern day city dwellers may never have consciously observed this, but for anyone lucky enough to see the night sky - the real night sky, I mean, unpolluted by the myriad light sources that apparently we can no longer do without - it is an amazing spectacle. Truly a river that meanders its majestic way across the celestial vault, and a formidable river at that. 

What about the two lovers' place in the skies? They represent the bright stars Vega and Altair, which in fact are on different sides of the Milky Way as seen from the Earth: Vega is in the constellation Lyra, Altair in the Eagle. As an aside, these two, together with Deneb in the Swan, form the so-called summer triangle ... but that is not part of the tanabata legend. 

If either of them did manage to leave their home constellation to join the other, we'd have a lot to worry about. If stars could scoot around the skies at such speeds, then everything we think we know about physics would be wrong.

So let's hope it rains!

Aside: I never understood the part about the rain. It would make more sense to me if legend had it that the lovers could meet only when the skies are shrouded in clouds. After all, if the skies are clear, anyone can see that neither star is budging. Conversely, if you can't see the stars, then you are free to imagine that they are engaged in that kind of activity that (though it would certainly not have been illicit - remember, these two were married!) does require a modicum of privacy. Ah well, logic probably just doesn't enter the picture ...