DAY EIGHTY FIVE The Rods of God
It is possible to make mistakes: at lunch we ordered the deluxe chocolate tapas selection at the Willy Wonka Cafe in Nördlingen. Willy Wonka was here because this very pretty place was the setting for his film – as Wonka's glass elevator rises up and away, a vista opens of the medieval wall (one of only three in Germany to survive intact) encircling the town.
Nördlingen has a lot that is special. Since 1438, the Scharlachrennen ('Scarlet Race' - horse races) have been contested here. These days the action is from smart showjumpers, but in early times there was a special race jockeyed by the town's prostitutes – a profession well-documented in the archives. One manuscript describes the trial of the married couple who owned the local brothel. They apparently forced an abortion on one of their girls: the court banished the husband and had the wife's forehead branded.
But Nördlingen had a tender side too. In 1604 a précised Romeo and Juliet was performed here. Very likely the actors declaimed in German: even during Shakespeare's lifetime English actors were touring the courts of Germany.
There is an extract from Romeo and Juliet in a time capsule on the Moon:
And, when he shall die
Take him and cut him out in little stars
And he will make the face of heaven so fine
That all the world will be in love with night
And pay no worship to the garish sun.
The lines are an elegy for Eugene Merle Shoemaker whose ashes are interred in the capsule – the only human remains to rest on another planetary body.
Eugene Merle Shoemaker (c)wikicommons
You will know of him from the Shoemaker-Levy comet that crashed into Jupiter a few years ago. One of the founders of planetary science, he made his name by establishing how meteor craters are really formed. It seems extraordinary now, but as late as the 1960s, common wisdom said craters were formed by volcanoes.
Barringer Crater, near Flagstaff Arizona (c)USGS
On a field trip for the US Geological Survey, Shoemaker inspected the Barringer Crater – the huge dent near Flagstaff in Arizona, a mile in diameter and some 600 feet deep. To Shoemaker's mind, the crater looked remarkably like those he had examined at the Nevada Atomic Test Site. When he found in the spoil of Barringer the same odd material – coesite - that he had unearthed at the Nevada site, he deduced that Barringer had been gouged out by a massive explosion at some point in geological time.
His reasoning was based on the chemistry of coesite which is formed only by intense pressure and temperature. The reckoning is that the Barringer meteor generated a force equal to 1,400,000 tons of TNT (1,385,000 tons more than the Hiroshima atomic bomb).
These explosions happen through compression. Once a diesel engine is running, for example, the gas in the cylinders explodes spontaneously through simple compression by the pistons. Likewise, when a meteor travelling at upwards of 50,000 mph crashes into us, the ground and the meteor are compressed so much that they explode.
This phenomenon has not gone unnoticed by the world's military. During the Cold War, the Americans proposed putting Rods of God into orbit – telegraph poles made of titanium to be dropped on targets on earth. The mass of the rods pulled down by gravity would have given an impact speed of 8,000 mph and explosive energy sufficient to destroy even the deepest of Soviet silos.
A less dramatic proposal involved dropping thousands of small chunks of metal from space onto invading fleets of Soviet tanks, if needed. In Vietnam, high-flying aircraft dropped thousands of Lazy Dog bombs, one-inch long projectiles with stabilising fins that fell at the speed of a rifle bullet. Even these days, strategists appreciate the kinetic value of high-speed projectiles. The Chinese and Russians have hypersonic cruise missiles that fly at over 3,000 mph - carrying no explosives, but with sufficient mass to devastate their target. The Americans are a bit behind on this but they do have rail guns – electromagnetic blowpipes that accelerate projectiles to speeds of 3 km per second.
Of course, what we all want to know is when the kinetic energy of an asteroid will destroy life on earth. I don't know if Shoemaker was paranoid but he did set up an asteroid watch when he was at the Lowell Observatory in Arizona. (Percival Lowell had postulated the existence of Pluto, and to find the planet he built the observatory on a mesa outside Flagstaff to find it. Incidentally, Pluto was named such at the suggestion of an 11 year old English girl, Venetia Burney, daughter of the Oriel Professor of the Interpretation of Holy Scripture at Oxford. The Burney Crater on Pluto is named after her).
When Carolyn Shoemaker was obviously suffering from empty nest syndrome after their children left home, Eugene suggested she train as an astronomer and join the asteroid watch at Lowell. She did and they worked together for the rest of their lives (ending, in Eugene's case, when the two of them were on the look out for meteor craters in the Australian desert. On perhaps the most remote road in the world, their car hit a truck head-on).
Once he had established his theory in Arizona, Shoemaker prospected at other large craters. Famously, even then, Nördlingen was known to be in the centre of a huge 15 mile-wide crater, believed to be volcanic. I like to think that on his first evening in the town, he would have strolled past St. George's church and chuckled, his theory proven there and then.
suevite from the Nördlinger Ries (c)wikicommons - Johannes Baier
The church is built of suevite, a local stone which, like coesite, is indicative of a vast explosion - in the case of the Nördlinger Ries, the work of a meteorite striking Bavaria with the force of 1.8 million Hiroshimas. The heat of the explosion also changed the molecular bonds of the graphite in the ground: as you walk round Nördlingen, stone buildings enchant with the sparkle of millions of tiny, tiny diamonds.
Today, of course, is the anniversary of Neil Armstrong's small step. While the Race Marshal went off on her own Apollo mission to find more chocolate, I went to the Nördlinger Ries Museum to see their Moon rock. This precious artefact is here because Shoemaker, who was in charge of investigating lunar geology for three Apollo missions, had brought some of the astronauts to Nördlingen. His hope was that on the Moon, they could find proof that the craters were not ancient eruptions but, as he postulated, the product of meteor strikes. The Apollo crews needed to practice their geological skills, so Shoemaker brought them here - and also to the crater at Flagstaff.
Ironically, as we know now, the Nördlingen Crater is different from those on the Moon. It is a so-called 'rampart crater', a type found exclusively on Mars; Nördlingen is the only one here on earth. Ordinary craters are formed by the explosion throwing spoil up into the air so it falls in reverse order, topsoil landing before the deeper rocks (which is why the edges of craters show a reverse geological history). But this does not happen with Martian (and Nördlingen) rampart craters: the way they are formed is more like the bleuch of a speeding bullet hitting mud – or, perhaps, the molten chocolate in Willy Wonka's cauldron.
Wonka's flying machine over Nördlingen - https://youtu.be/VYrMjkW8BgY
Rods from God - https://youtu.be/KjcNICe4Sqs
A tour of Nördlingen - https://youtu.be/XOb9UE0QqWI
The remarkable podcast 13 Minutes to the Moon from BBC World Service - https://www.bbc.co.uk/programmes/w13xttx2/episodes/downloads
Leontyne Price singing Song To The Moon (with some publicity photos) - https://youtu.be/fdgKA_gfz7Y
This post is dedicated to Phylis who, on their 40th wedding anniversary, gave Aarfy a ring made from a meteor.