Huge Sharks ‘Fly’ Like Fighter Pilots Underwater
Monster sharks can execute underwater “flight” moves that would have put some fighter pilots to shame, two researchers announced last week.
Normally seen cruising slowly at the surface, the whale shark, which does not harm humans, can transform in the deep, hurling itself into a swift, steep dive like a pilot, soaring up and then down again in a series of great bounds, said researcher Rory Wilson of Swansea University in Wales.
To be fair, I’ve seen fighter pilots ashore that acted like sharks, so…
On to more substantive matter, turns out that glass is not a solid, as so many of us may have assumed, but only a liquid that wants to be a solid, and can’t quite manage it. On account of the icosahedrons. Which you only care about because maybe scientists will maybe find a way to make wings. Out of glass.
Knowing the structure formed by atoms as a glass cools represents a major breakthrough in the understanding of meta-stable materials and will allow further development of new strong yet light materials called metallic glasses, Royall said, which is already used to make some golf clubs.
This stuff is generally shiny black in color, not transparent, due to having a lot of free electrons (think of mercury in an old thermometer).
Metals normally crystallize when they cool, but stress builds up along the boundaries between crystals, which can lead to metal failure.
For example, the world’s first jetliner, the British built De Havilland Comet, fell out of the sky due to metal failure.
When metals are be made to cool with the same internal structure as a glass and without crystal grain boundaries, they are less likely to fail, Royall said.
Metallic glasses could be suitable for a whole range of products beyond golf clubs that need to be flexible such as aircraft wings and engine parts, he said.
And you thought that flying couldn’t get any more stressful…
The article asserts that glass is a liquid, but this is a bogus claim/old urban legend. The facts are that old plate-glassmaking techniques sometimes led to uneven panes, not that the panes had drooped in their frames over the years. The existence of perfectly-proportioned ancient glass vases also serves as a disproof of this notion: if glass were liquid they’d be puddles by now, and no longer vases.
And what’s this about shiny black mercury? I’ve only ever seen the silvery type.
Dave,
Glass is indeed a liquid that moves very, very slowly. Those ancient glass vases retain their shape because chemical impurities impart some stability — they give the molecules something to hang on to, rather than flow.
The stained glass windows for the great cathedrals were poured and cooled on *flat* surfaces (polished slate) — and a thousand years later, they’re all thicker at the bottom than they are at the top. Not much, but measurably so, nonetheless. Take a close look in about another thousand years and you’ll notice a distinct difference in the color — it’ll be lighter towards the top.
BTW, the mercury *appears* black due to the age of the glass — the structure has miniscule hairline fractures that reflect the light internally rather than allowing it to pass freely in-and-out. No reflected light = looks black.
I thought it enlightening that our host took 2 unrelated news items about Sharks and Glass and tied them together with wings and pilots.
I am nowhere near imaginative enough to do that, yet am suitably awed when it is there in Black and White.
It’s back? Well I suppose it’s about due. I have often noted how R&D seems to cycle, usually around a 20 year cycle. Metglass was a hot topic back in the mid to late 80’s.
High-temp superconductors should be due for a resurgence.
There was interest at one time, and may still be, about using glass to create deep-sea vessels, capable of reaching depths that the best steel frames would crush at. The idea has some merit. Perfectly-formed glass, without chips, has a compression strength approaching 1 million psi before fracturing. That’s a lot of water above the bridge, so to speak.
The difficulty is, since glass is a chrystalline material, that one minor chip or flaw will reduce its compression strength dramatically.
Still, the thought of riding in a psuedo-liquid shell to great depths in a very-liquid environment has a certain ironic appeal.
– Max
Max,
I think Waldo Lyon tried to sell Rickover on a glass hulled submarine back in the ’60s. My memory is hazy but I seem to recall reading that in Bill Leary’s book about Waldo.
craig
How often to sharks go into the shop to get a center-barrel-replacement?
Hmmm. Transparent aluminum, anyone?
Heh.
BillT,
Glass only flows if “very, very slowly” means “over more time than the age of the Universe.” Please refer to Cornell research at this link: http://www.cmog.org/dynamic.aspx?id=294 . Note that lead flows billions of times faster.
Yes, my late followup reminds me of this: http://xkcd.com/386/ but it took me a while to remember on what forum I’d found this thread.
Dave