The Gravity Mystery By Fredrik Nygaard

From: Andrew Johnson

Date: 2016-10-01 18:47:09

Attachments :I’ve just posted a new article by Fredrik Nygaard – I think it’s a belter, myself!  The Gravity Mystery   By Fredrik NygaardSept 2016 A crescent moon hangs above a small lake a summer afternoon. Everybody is out and about, and nobody is paying much attention to the moon. It hangs above us as it always does every so many hours, and no one finds that mysterious in any way. Amazing Insect However, a large dragonfly with a wingspan of some 12 centimetres is moving swiftly across the lake [Dragonfly: Epiaeschna Heros]. And this spectacle draws our attention. It is quite incredible how it moves, one moment one way, the other moment another way.  For an insect, it is a giant, and it seems a small wonder that its wafer thin wings do not break under the strain of its aeronautic manoeuvrings. Surely, we think to ourselves, this must be as large as dragonflies get. And we are quite right in thinking so. The very largest dragonflies on our planet have a wing span of 19 centimetres [Dragonfly: Megaloprepus Caerulatus], and they have a peculiarly thin body relative to their wings, for the simple reason that they have reached the very upper limit to how large dragonflies can get. Any additional increase in their size would make them unable to do the manoeuvring required to feed themselves. Yet, when we research the matter, we learn that some 300 million years ago, there were dragonflies with wing spans of 65 centimetres [Dragonfly: Meganeura]. That is more than five times the wing span of the dragonfly at the lake. And the odd thing is that the shape of the prehistoric dragonflies was identical to that of current ones, so they must have had the exact same manoeuvring skills and function as their modern day descendants.  However, shapes do not scale well in the natural world. There is a limit to how large a given shape can become before it no longer manages to support itself. As animals become larger, their supporting structures must scale up.  Read More:        

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