Kids in the Hall of Planet Earth

Around Easter in 1993 I was lucky enough to be part of the EUROMET* meteorite collecting trip to the Nullarbor Plain in the southernmost part of western Australia. The name Nullarbor means "no trees," and it is an accurate description. Because of the low rainfall and the poor, thin soil cover on the limestone plateau, trees and other vegetation are nearly non-existent. Straggly grass grows in pathetic patches, unless there has been an unusually high rainfall. The low rainfall, lack of vegetation and soil makes this ideal terrain for collecting meteorites.

Every year, many hundreds of meteorites fall onto the Earth, but on average, only five to eight are actually seen falling and picked up right away.

For scientists, these meteorites are particularly valuable, as they have not been affected by rain, sun, bugs, and weeds--all of which alter meteorites, confusing scientists as to what is really cosmic and what is merely terrestrial contamination.

However if we waited only for these rarely found meteorites we would have very meager meteorite collections. Fortunately there are certain areas of the world where we have a good chance of finding meteorites. The best place is the Antarctic (the largest desert on Earth). Here, meteorites are deeply frozen and conveniently moved by the ice to certain areas where the ice is then eroded away by the wind, leaving the meteorites exposed for a passing scientist to pick up.

For the past 20 years American, Japanese, and European expeditions have been mounted with the purpose of retrieving meteorites from these areas. However, the Antarctic is difficult and expensive to get to so alternative sites have been explored--including the hot deserts of the world.

Hot deserts are not as ideal as the Antarctic because they experience rain and heat, which causes meteorites to rust and fall apart. Meteorites in deserts have considerably shorter lifetimes than those in the Antarctic. But the advantage of meteorites falling in deserts, rather than the Antarctic, is that deserts are easier to reach. Meteorites have been found in the Sahara, the semi-arid regions of the western U.S., the Atacama desert in South America, and the deserts of Australia. Of these, western Australia has many advantages: it is relatively easy to get to, and has a stable government, large areas of little explored land, and the city of Perth in western Australia is home to a group of scientists interested in meteorites.

The Nullarbor Plain is a particularly good place to look for meteorites because the bedrock in the area is limestone. So the black meteorites show up very nicely against the white limestone background. The only potential problem is confusing small black, fresh, shiny meteorites and small black, fresh, shiny Kangaroo-poo. This remained a real problem right up to the end of the expedition. Many a time you would hear mutters of disgust as team members picked up an apparent "meteorite," only to find that they had been fooled again.

And so it was that I found myself heading off, clutching the camp shovel for my daily visit to the local stand of trees, in this case, those known as Camel Donga.

It was the end of a long day of traveling from our previous camp where we had been relatively unsuccessful in finding meteorites. For the previous two days we had walked up and down, up and down, with our heads bowed looking for black meteorites against the white background of the limestone bedrock. We had found one small chip of something that, in a moment of wild optimism, someone thought might be interesting (it later turned out to be a piece of ordinary rock). The day's travel in one of the three bouncing expedition vehicles was enough to shake up anyone's insides; mine were no exception, so I hurried off into the trees.

Dongas are dense layers of rock with a high concentration of clay in which rain tends to sit a little longer than in the more rapidly draining limestone. Where the rain collects, vegetation takes advantage of it. The moisture also attracts other life. Kangaroos and other marsupials gather and add their dung to the soil, and introduced species like rabbits come to feed on the grasses. Feral cats and foxes turn up to feed on everything else. Along with these animals, there are also parasites, and insects, such as kangaroo ticks (like deer ticks, but up to 2 cm long), spiders, scorpions, and the interminable flies that inhabit dongas. Feeding on these, as well as on creatures that are already dead, are a large number of often big, beautiful lizards.

As I tottered toward the donga, I was looking at the ground, thinking I might find a meteorite. This was the area where the Camel Donga meteorite had fallen in a large meteorite shower, and pieces of it had been discovered.

Camel Donga, a type of meteorite (and the name for the place where these meteorites were found), was first noticed by the Campbells, who were driving home across the desert from a local party ("local" meaning a couple of hundred miles away). Mrs. Campbell suddenly shouted to her husband, "Stop the car! Stop the car!" Thinking it was some kind of emergency, he slammed the brakes on and asked what the problem was. "There's a rock!"

Mr. Campbell was understandably somewhat confused. "What the heck are you talking about? There are a hundred million . . . rocks out here!"

"No, no," insisted his wife. "This one is different."

Indeed it was. The shiny black crust of a freshly fallen meteorite had caught Mrs. Campbell's eye and this was the first recorded finding of a piece of Camel Donga.

Since that January in 1984 many pieces have been found totaling many kilograms. So I was hopeful that, while wandering about, looking for a comfortable place to dig my hole, I might find a meteorite. But what I came across was something I had no desire to find at all.

I was walking up a gentle slope when I heard rustling and saw a quivering in the grass a few feet in front of me. I wondered idly what it might be and took a few more paces forward to get a better look. The next thing I knew I was staring at the head of a brown snake, poking out from the grass. This was rapidly followed by another 7 feet of snake, which slithered to a rather syrupy stop less than 5 feet in front of me.

At this point I was somewhat alarmed. The snake was looking at me in the same way I view a tray of donuts in a bakery. With its head slightly raised, the snake gently flicked out its tongue, scenting for food. I stood very, very still (apart from quaking knees).

The fact that there are more poisonous creatures per square mile in Australia than any other place on Earth kept running through my mind.

Although I had no idea what I was looking at, I was fairly certain that this was not a social visit. I stared at the snake; the snake stared at me. I was trying to show no fear and not to sweat like a potential victim.

The snake swayed toward me. I stood frozen. In a curiously calm and detached way, I wondered whether I was about to die. Then to my surprise and relief, the snake judged me unworthy and gracefully glided off into the bush.

When I returned to camp, I mentioned my brief encounter to the people in the expedition. Alex, the leader of our expedition, tensed visibly and asked for a description. "Very long, slithery, with a brown and light underbelly." Alex turned pale with fright. A strangled "Ooouuueerr" sound was followed by the encouraging statement, "You know, when people say, 'The snake is more afraid of you than you are afraid of the snake,' well in this case, it's not true." (I knew it wasn't true. The snake could not possibly have been more frightened than I was, or we'd still be standing there--both of us having heart failure).

"It's a Mulga snake (also known as a King Brown snake); they're really aggressive. And if they bite you, we don't even bother calling the Flying Doctor--as you'd be dead before he'd have taken off," said Alex. (The Flying Doctor is a doctor that is flown by plane out to remote areas.) Alex loaded up his shotgun and said "Don't like the sound of this fella round the camp; We'll see if we can find him." By this time, Jean, our fearless French co-expeditioner, was on top of the expedition vehicle saying "I am not coming down. No way. We should go 'ome now."

So while Jean sat atop the car, the rest of us huddled behind Alex to go snake hunting. After an hour or so of false alarms and taking pot shots at dangerous-looking sticks, we decided that the snake I met may not have been a local, and was just passing through. But Alex had his hunting head on and decided to search for rabbits for the stew pot that evening.

For the next hour, we heard the firing of Alex's gun and thought we would be getting a real feast. Ten minutes passed and a rather sheepish leader returned to camp: no rabbits! "Too darned quick," he said. At that point we realized how lucky we were that none of the rustling grasses or dead sticks were the famed 30-mile-an-hour Mulga snake. We could have been in a whole lot of trouble, but we never did see the snake again.

We spent a few days at the camp, which turned out to be our most successful stop. We found a dozen or so samples of different meteorites and numerous beautiful fusion-crusted stones of Camel Donga. Shortly after this, it looked like the rainy season was going to start early, and we had to start heading back before the dirt tracks became waterlogged and impassable.

We reached the Campbells' sheep station for kangaroo steaks and my first shower in a month. I watched my suntan wash down the drain, as the red dust of the field came off in clods revealing my usual pallid skin. I had never felt so clean. Three days later we were back in Perth for a seven-course meal and soft comfortable beds.

I later learned more about the Mulga snake. The Mulga snake Pseudechis australis, also known as the King Brown snake can reach up to 9 feet long. It is in the same family as the cobras, coral snakes (the most poisonous snakes in the world), the Mamba snake and the charmingly named Death Adder, the latter also a native of Australia. The Mulga is found throughout most of Australia. It kills its victims with a fast-acting neurotoxin. I have no idea how dangerous Mulgas are to people, but that snake certainly scared the willies out of me.

* EUROMET is a conglomerate of European universities with a mutual interest in meteorite research. Their purpose is to persuade the European Economic Community (EEC) to fund expeditions and some curatorial facilities for the collection and care of meteorites. The organization has funded expeditions to the Antarctic, the Sahara, Oman, Siberia and, most successfully, the Nullarbor Plain of western Australia.

Camel Donga is a type of meteorite called a eucrite. Eucrites are meteorites that look like some igneous rocks on earth. Meteoriticists (people who study meteorites) think that these came from a pretty large asteroid and that these meteorites are samples of the crust of an asteroid. By comparing the meteorites to large rocky bodies in the asteroid belt, meteoriticists think that the asteroid named Vesta, the fourth asteroid to have been discovered, may be where the eucrites come from.

Illustrations by Kelvin Chan

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