Meteorite impacts leave behind time-capsules of ecosystems

Glass beads that form inside hot meteors as they fall to Earth capture particles from the atmosphere, creating a kind of permanent record of historic climates.

Meteorite impacts can be very destructive. One that fell in Mexico around 66m years ago created a 180km crater and caused the extinction of dinosaurs while spewing debris and molten rock into the air. Now, in what is a fascinating tale of serendipity, researchers have found that these events don’t entirely destroy all traces of life at the site of impact. Molten rocks can capture and preserve organic matter as they cool down to form glass beads.

When a meteor enters Earth’s atmosphere, the air around the meteor gets very quickly compressed causing it to heat up, scorching everything in its path. Most of the time that is where the story ends, as the meteor burns up in the sky as a “shooting star”. But sometimes it is big enough to reach all the way to the surface and transfer its remaining energy to the ground.

This energy is dissipated, as mild earthquakes, sound shockwaves – but mostly as heat. The heat energy can be so great that it melts rocks on the surface and hurls them up in the atmosphere. Anything that comes in contact with this molten rock would presumably get burnt, leaving nothing but rocky material that cools down in the atmosphere, forming glass beads and tektites (gravel-sized natural glass). This is what City University of New York researcher Kieren Howard assumed, but he was able to show that his assumptions were wrong.

For his PhD, Howard was studying the glass beads and tektites found near the Darwin crater in Tasmania. The 1.2km wide crater was created by a meteorite impact about 800,000 years ago.

The natural glass formed during cooling is (as implied by the term glass) not crystalline. Instead of a regular arrangement of atoms, the atoms inside it are randomly arranged. Howard’s analysis, however, kept showing the presence of crystals. At first, he dismissed this as a problem with the machine or with his method of analysis. But when it kept showing up, as a good scientist, he thought he should ask an expert to look at his data.

“This is unusual,” says Chris Jeynes, a physicist at the University of Surrey. “If there were indeed crystals, then it was the result of uneven cooling, which can occur when something gets trapped inside these glass beads.”

Jeynes used proton-beam analysis, a method to peer inside the glass to reveal its elemental make-up. Inside he found carbon. “Howard had no idea what his samples were, and he was very surprised when I told him,” Jeynes says.

The natural glass formed should contain only silicon, titanium, oxygen and other metallic elements in trace amounts. Detection of carbon meant that there was some organic matter inside. The only hypothesis was that, somehow during the formation of these glass beads, they captured organic matter that was floating in the atmosphere. That organic matter might have already been in the air, but it might also include material thrown up by the impact.

Howard then went to another expert to break open these glass beads and reveal what the carbon-rich matter was. It turned out that it included were cellulose, lignin and other biopolymers. This meant that somehow this matter, which originated from plants, had survived the temperature of more than 500°C, which is what the molten rock would have reached before cooling into a glass bead. Usually these temperatures will break down the organic matter, but clearly it didn’t in this case.

Mark Sephton, a geochemist at Imperial College London, was surprised and pleased: “What the results show is that these glass beads can capture an aliquot of the atmosphere of the planet at impact. It is like a time capsule of that ecosystem.” These results are published in Nature Geoscience.

The implications are enormous. It shows that other meteorite impacts, like the one that wiped out the dinosaurs, could have created such time capsules too. Sephton is now working on finding glass beads from other impact sites to reveal information about Earth’s ancient atmosphere.

This method of analysis means that we could also go looking for similar beads on other planets, like Mars, where meteorite impacts are common. They could also reveal vital information about the past atmosphere of those planets. Maybe they captured organic matter – if it ever existed there.

“We would not know any of this if it wasn’t for Howard,” Jeynes says, adding that Howard’s persistence to find out what “the wrong results” led the researchers to a phenomenon that nobody knew existed.

This article was originally published at The Conversation. Read the original article.

The Conversation

Meteor Crater in Arizona. (Photo: Angle Schatz/Flickr)
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The Tinder dating app isn't just about sex – it's about friendship, too. And sex

The lines between sex, love and friendship are blurrier than ever, as I found out quickly while using the app.

The first time I met someone using Tinder, the free dating app that requires users to swipe left for “no” and right for “yes” before enabling new “matches” to chat, it was an unqualified success. I should probably qualify that. I was newly single after five years in a committed relationship and wasn’t looking for anything more than fun, friendship and, well, who knows. A few weeks earlier I had tried to give my number to a girl in a cinema café in Brixton. I wrote it on a postcard I’d been using as a bookmark. She said she had a boyfriend, but wanted to keep the postcard. I had no date and I lost my page.

My Tinder date was a master’s student from Valencia called Anna (her name wasn’t really Anna, of course, I’m not a sociopath). When I arrived at the appointed meeting place, she told me I was far more handsome IRL (“in real life”) than my pictures suggested. I was flattered and full of praise for the directness of continental Europeans but also thought sadly to myself: “If only the same could be said about you.”

Anna and I became friends, at least for a while. The date wasn’t a success in the traditional sense of leading us into a contract based on exclusivity, an accumulating cache of resentments and a mortgage, but it had put me back in the game (an appropriate metaphor – people speak regularly of “playing” with the app).

According to Sean Rad, the co-founder who launched Tinder in late 2012, the service was invented for people like me. “It was really a way to overcome my own problems,” he told the editor of Cosmopolitan at an event in London last month. “It was weird to me, to start a conversation [with a stranger]. Once I had an introduction I was fine, but it’s that first step. It’s difficult for a lot of people.” After just one outing, I’d learned two fundamental lessons about the world of online dating: pretty much everyone has at least one decent picture of themselves, and meeting women using a so-called hook-up app is seldom straightforwardly about sex.

Although sometimes it is. My second Tinder date took place in Vienna. I met Louisa (ditto, name) outside some notable church or other one evening while visiting on holiday (Tinder tourism being, in my view, a far more compelling way to get to know a place than a cumbersome Lonely Planet guide). We drank cocktails by the Danube and rambled across the city before making the romantic decision to stay awake all night, as she had to leave early the next day to go hiking with friends. It was just like the Richard Linklater movie Before Sunrise – something I said out loud more than a few times as the Aperol Spritzes took their toll.

When we met up in London a few months later, Louisa and I decided to skip the second part of Linklater’s beautiful triptych and fast-track our relationship straight to the third, Before Midnight, which takes place 18 years after the protagonists’ first meet in Vienna, and have begun to discover that they hate each others’ guts.

Which is one of the many hazards of the swiping life: unlike with older, web-based platforms such as Match.com or OkCupid, which require a substantial written profile, Tinder users know relatively little about their prospective mates. All that’s necessary is a Facebook account and a single photograph. University, occupation, a short bio and mutual Facebook “likes” are optional (my bio is made up entirely of emojis: the pizza slice, the dancing lady, the stack of books).

Worse still, you will see people you know on Tinder – that includes colleagues, neighbours and exes – and they will see you. Far more people swipe out of boredom or curiosity than are ever likely to want to meet up, in part because swiping is so brain-corrosively addictive.

While the company is cagey about its user data, we know that Tinder has been downloaded over 100 million times and has produced upwards of 11 billion matches – though the number of people who have made contact will be far lower. It may sound like a lot but the Tinder user-base remains stuck at around the 50 million mark: a self-selecting coterie of mainly urban, reasonably affluent, generally white men and women, mostly aged between 18 and 34.

A new generation of apps – such as Hey! Vina and Skout – is seeking to capitalise on Tinder’s reputation as a portal for sleaze, a charge Sean Rad was keen to deny at the London event. Tinder is working on a new iteration, Tinder Social, for groups of friends who want to hang out with other groups on a night out, rather than dating. This makes sense for a relatively fresh business determined to keep on growing: more people are in relationships than out of them, after all.

After two years of using Tinder, off and on, last weekend I deleted the app. I had been visiting a friend in Sweden, and took it pretty badly when a Tinder date invited me to a terrible nightclub, only to take a few looks at me and bolt without even bothering to fabricate an excuse. But on the plane back to London the next day, a strange thing happened. Before takeoff, the woman sitting beside me started crying. I assumed something bad had happened but she explained that she was terrified of flying. Almost as terrified, it turned out, as I am. We wound up holding hands through a horrific patch of mid-air turbulence, exchanged anecdotes to distract ourselves and even, when we were safely in sight of the ground, a kiss.

She’s in my phone, but as a contact on Facebook rather than an avatar on a dating app. I’ll probably never see her again but who knows. People connect in strange new ways all the time. The lines between sex, love and friendship are blurrier than ever, but you can be sure that if you look closely at the lines, you’ll almost certainly notice the pixels.

Philip Maughan is Assistant Editor at the New Statesman.

This article first appeared in the 26 May 2016 issue of the New Statesman, The Brexit odd squad