Lasers fired from ESO's Very Large Telescope create artificial stars that correct for the blur of Earth's air
the gist
At first glance this ESO image looks like a weapon, with bright orange beams fanning into the sky, but it shows a telescope doing something clever. The Adaptive Optics Facility on one of the 8.2-metre Unit Telescopes of the Very Large Telescope is firing lasers into the atmosphere. The beams excite sodium atoms high in the upper air, making them glow and creating artificial stars called laser guide stars. Astronomers measure how the atmosphere distorts these points of light and use that information to correct the blurring in real time, using deformable mirrors. The result is far sharper images of real stars and galaxies. The technique lets ground-based telescopes approach the clarity that was once possible only from space.
so what
Adaptive optics lets large ground telescopes match or beat space telescopes for sharpness at a fraction of the cost, and the technology is central to next-generation observatories.
fun fact
The sodium layer that the lasers excite sits roughly 90 kilometres up, in the mesosphere.
In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.
how it works
To corner a market, a trader buys up most of the available supply and the futures contracts that promise more. Anyone who has to deliver the commodity must then buy from the cornerer at whatever price is demanded. The trader profits until the stock is released or the scheme collapses.
so what
A century on, it still shows how markets can be rigged by someone who controls supply, and how the people at either end, farmers and eaters, pay for it. It also helped establish editing as a way to argue a point, not just tell a story.
the bigger pattern
Corners have recurred whenever supply could be locked up, from the Hunt brothers' attempt on silver in 1979 to 1980 to the 'Black Friday' gold panic of 1869. Many such schemes end by collapsing, and the response is often new rules on speculation.
fun fact
In the film the Wheat King dies by falling into a grain elevator and being buried in the wheat he hoarded, an ending borrowed from Norris's novel The Octopus.
more on this
background
A Corner in Wheat is a 1909 American short silent film which tells of a greedy tycoon who tries to corner the market in wheat, destroying the lives of the people who can no longer afford to buy bread. It was directed by D. W. Griffith and adapted by Griffith and Frank E. Woods from a novel and a short story by Frank Norris, titled The Pit and "A Deal in Wheat". Griffith may have had a real-life inspiration: six months earlier, James A. Patten had actually cornered the market in wheat, and in some cities, the price of bread doubled from five cents to ten, just as in the movie.
In 1994, A Corner in Wheat was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".
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