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Meteorites search blog

Archive for the 'Desert' Category

Finding meteorites

Gretchen, Friday, October 20th, 2006

Each time we find a fresh meteorite, we record its position in latitude and longitude using a Global Positioning System (GPS). The biggest meteorite we’ve found is about the size of a small apple and the smallest about the size of the tip of my thumb.

We then make a preliminary guess about what kind of meteorite each one might be.

From left to right, cut example of an Iron, a Stony-Iron and a Stony meteorite © The Natural History Museum

From left to right, cut example of an Iron, a Stony-Iron and a Stony meteorite © The Natural History Museum

There are three main types of meteorite: Stony, Iron, and Stony-Iron. All the ones we’ve found have fallen into the Stony category. We can tell this by their weight - slightly heavier than an Earth rock of the same size - and also because they’re not very magnetic, unlike the many meteorites which contain some metal and so have some magnetism.

We’ve found two different kinds of Stony meteorite in our search. The first type, ordinary Chondrites, are quite common and come from asteroids that have been only slightly heated, and not melted.

The other type, which we found at Camel Donga, are called Eucrites (a type of Achondrite). These come from an asteroid that had melted and differentiated - like the Earth - into a core, mantle and crust. These Eucrites are thought to come from the crust of a specific asteroid - 4 Vesta. This type of meteorite is much more unusual, so we were happy to be able to find several pieces of this one.

There have also been some meteorites about which we’re not quite sure, so we’re going to have to wait until we get them in the lab to determine what kind they are.

After our preliminary assessment, we’ll put the meteorite into a bag, label the bag with a field number, the date it was found and the area.

We’ll take the meteorites to the Western Australia Museum, where Alex will give them numbers, then cut off a portion of each meteorite to send to the Natural History Museum where Caroline and I will classify them when we get back.

Meteorite strewnfield

Caroline, Thursday, October 19th, 2006

We were up bright and early today at our usual getting-up time of about 5.15am. After we had breakfast and got the camp ready we left for more filming and meteorite hunting around Camel Donga.

All of the meteorites here are related to each other and came from the same parent meteoroid, which broke up as it came through the atmosphere to form a shower of stones. These stones are scattered along a line about 7km long, which is known as a ’strewnfield’.

Strewnfield © Caroline Smith

Strewnfield © Caroline Smith

We started our usual searching method, where we go in a line spread over approximately 50m and walk along together, searching the ground in front of us and between us.
We were feeling confident and very soon after starting we found some lovely tektites. After about half an hour the BBC turned up to do more filming with Phil. I stopped to have some water and glanced down and I couldn’t believe it, I was standing just next to small piece of Camel Donga, the first one we found that day! Even with the breaks for filming we managed to find eight pieces of Camel Donga and quite a few tektites so we were really pleased.

Meteorite camp

Gretchen, Tuesday, October 17th, 2006

Setting up camp in the Nullarbor desert is a whole new experience. We sleep in ‘swags’ - single person tents which come with a three-inch thick mattress, so even sleeping on the ground is comfortable. Putting the swag on a camp bed is a whole new level of luxury! The swags also close up completely to prevent bugs from coming in to say hello.

Sunset in the Nullarbor Desert © Gretchen Benedix

Sunset in the Nullarbor Desert © Gretchen Benedix

our firepitPhil generally digs a fire pit while Caroline, Martin and I gather wood from the local trees (although Nullarbor technically means ‘no trees’, there are still a few hearty ones around that we can tap for fires). These are dead trees and they come apart easily by hand.

To make dinner we use an iron ‘plate’, half of which is a solid piece of metal and the other half of which is a grill. Frying is done on the solid side, while the grill side is used for boiling water and cooking in pots.

The BBC filmed us setting up, and also had Iain help us for the documentary. The picture shows the finished product with our swags unrolled.

Our camp © Gretchen Benedix

Our camp © Gretchen Benedix

We tend to get to bed around 8pm, in part because we’ve worked a hard days work, but partly because we also get up with the sun, which rises around 5am. It’s fantastic to see the stars in the southern hemisphere. We’ve now seen the Milky Way, as well as the small and large Magellanic clouds, which are not visible from the northern hemisphere. We’ve also seen Mercury and Jupiter.

Filming the meteorite search

Caroline, Sunday, October 15th, 2006

We left Forrest and set off with the BBC team to a place called Camel Donga, our next meteorite collecting location. Camel Donga’s only a couple of hundred kilometres from Forrest, but it took us a while because the BBC were doing quite a bit of filming along the way. It was VERY hot, over 40°C, with strong, hot and dry winds coming from the north.

BBC crew © Caroline Smith

BBC crew © Caroline Smith

The BBC took lots of footage of us driving the 4-wheel drives, as well as filming us actually hunting for meteorites. Camel Donga is a great place to look for meteorites. In the mid-1980s there was a large fall of eucrite meteorites here - about 25 kg have been found so far. These are called Camel Donga meteorites after the place where they fell. Iain Stewart, the BBC presenter, actually found a meteorite while we were filming! They can be quite hard to spot, even when you’ve been looking for a while and have got used to the terrain.

Camel Donga meteorite © Caroline Smith

Camel Donga meteorite © Caroline Smith

We were all very tired by the end of the day, and tried to get as much sleep as possible although it was difficult as it was still very warm.

Wildlife - and the BBC

Caroline, Friday, October 13th, 2006

We’ve been travelling quite a bit through the desert. The roads aren’t that bad (relatively speaking)! There are patches where we can get up to 30mph, but most of the time it’s quite rocky and we try to keep it under 20mph. We’ve seen a whole variety of wildlife, including camels and dingos.

Camel in the Nullarbor Desert © Caroline Smith

Camel in the Nullarbor Desert © Caroline Smith

There are also lots of kangaroos, but it’s difficult to get a reasonable picture because they always start to run away any time they see the cars within a couple of miles of them! They are weird and interesting to watch as they jump along. They’re very speedy, but it does look like a tiring way to get about.

We’ve now arrived at Forrest, where we’re meeting up with some BBC people who are filming a documentary. Forrest is an amazing place, with an airstrip and six bungalows where people can stay. Darryl and Lynn, who run the place, also provide meals and sundries. Forrest even has postal services – a rare find in the middle of a desert.

Tonight we’ll sleep in real beds and we’ve all had a shower - just the most amazing thing after you’ve not had one for a few days. Tomorrow we head out again, with the BBC people who’ll be filming along the way.

The search begins

Gretchen, Wednesday, October 11th, 2006

Heading into the Nullabor from Kalgoorlie, we ran out of paved road within about a half hour, but the road had a pretty good surface and surprisingly we could move at a pretty fast clip - until we popped a tyre.

Intrepid explorers, Caroline, Gretchen and Phil © Gretchen Benedix

Intrepid explorers, Phil, Martin, Caroline and Gretchen © Gretchen Benedix

No one other than Phil had experienced this while driving. When the tyre popped there was a slight pull, followed by a noise that sounded exactly like a 747 landing. We stopped and saw the very flat tyre. The hardest part was getting the spare off the roof, and the sandy ground didn’t help. But in a bit we were on our way again – until a tyre popped on the other car. In all it took about six hours to get to our first stop.

The next day, we headed off to camp further into the desert to begin our meteorite hunt, checking one of the cameras in the Desert Fireball Network on the way. The hardest thing when looking for meteorites is to get your eye acclimatised to the local rock types, so you can spot the meteorites – rocks that don’t fit in with the local rocks.

Our first meteorite, can you spot it? © Gretchen Benedix

Our first meteorite, can you spot it? © Gretchen Benedix

Caroline was the first to find a meteorite, within about 30m of the camp. We walked about another 2km before turning around, but didn’t find any more meteorites, only kektites (pieces of glass from impactors that hit the Earth and launch molten earth rock into space, where it can’t escape gravity and falls back down). We did find lots of ‘meteowrongs’ though, meaning we are recognising things that look a bit out of place but are the local rock!

The following morning was spent searching for meteorites systematically in a line. We went out about 1.5km before turning around and heading back to the cars. The whole thing took over two hours because we have to walk fairly slowly, but we did find several meteorites. Then, in the afternoon, we found more by going out in pairs and searching in a much more random pattern.

That night we had a fabulous dinner to celebrate Martin’s birthday. The fridges we’ve brought give us some opportunity to have fresh fruit and vegetables, and we had roast lamb, potatoes and onions. Delicious! The wind was blowing a gale and the clouds were gathering, which made eating the dinner interesting - we had five minutes to eat it while it was hot!

Fireballs and lightning

Caroline, Friday, September 29th, 2006

This dramatic image was taken by one of the cameras in the Desert Fireball Network that we’ll be visiting in the Nullabar. The white streak across the bottom of the picture is a meteorite fireball, shooting across the sky in the middle of an electrical storm. Less than ten of the 32,000 or so known meteorites have their falls recorded by camera or video.

Electrical storm and fireball captured on camera © Phil Bland

Electrical storm and fireball captured on camera © Phil Bland

As well as looking for meteorites, one of our most important tasks will be to check that the cameras are working correctly, and fix any problems that we find.

Australia here I come

Gretchen, Thursday, September 21st, 2006

I’m very excited to be going to the Nullarbor desert. My previous meteorite hunting experience has been in the Antarctic (a frozen desert), but to prepare for this trip, I’ve had to rethink everything I know about desert camping. Conditions in the Antarctic are very different to those we’ll experience in Australia. The biggest difference, of course, is the temperature. For this trip, I won’t need to take along all my woolly winter clothes; just a good sleeping bag and regular hiking boots.

Gretchen on a meteorite trip to the Antarctic

Gretchen on a meteorite trip to the Antarctic.

Most of the gear we need is already in a storage locker in Perth. We’ll gather it all together when we get there, and make sure that nothing needs to be replaced or repaired. After that, we’ll get a day or two of rest before we head out into the desert.

While we’re in Australia, we’re also going to be shooting a video for a Nature Live presentation on meteorite hunting, which will be presented at the Museum in December. I’ve acquired a video camera and have had some preliminary training and advice. Stay tuned for this Nature Live program, which will also be webcast.

Caroline has summed up how busy we’ve both been getting ready for this trip to search for meteorites. As well as all the paperwork we’ve had to fill out, we’ve also had to have medicals to make sure we’re in tip-top shape for working in such a harsh environment. We both passed with flying colours!

Since returning from travels to conferences I’ve also spent much of my time getting a variety of research projects to a point where I can leave them for a few weeks. This included writing an abstract for a meeting in San Francisco in December.

I just can’t wait to get out there and start looking for meteorites.

Getting ready to search for meteorites

Caroline, Wednesday, September 20th, 2006

The Nullarbor Plain in south western, Australia © Phil Bland

The Nullarbor Plain in south western, Australia © Phil Bland

Organising everything for our meteorite search trip to Australia has kept me really busy over the last couple of weeks. We have to make sure that we have everything that we need for our fieldwork in the desert. At some points we’re going to be tens of miles from the nearest other people and there certainly won’t be any local shops to buy anything that we’ve forgotten! I’ve never been anywhere so isolated before, so I think I’m going to find it very strange. I’m a bit nervous - and excited as well. One important job has been sorting out all the paperwork, so that we can collect the samples. Australia classes meteorites as cultural and historical artefacts, and we can’t just go out to collect them and bring them back to the Museum. We have to make sure that we have all the necessary paperwork ready and signed – otherwise we’d be breaking Australian law and Museum rules!

We’re flying out to Australia on Thursday and, after a couple of days in Singapore we will be arriving in Perth on Sunday. When we get to Perth we have to buy more equipment and supplies for our field work and we’ll co-ordinate with our colleagues from the Western Australian Museum in Perth. Then, a week later, we’re off to the desert.