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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"Death to all Jews": Why Disney dropped YouTube's biggest star PewDiePie

The Minecraft vlogger turned internet celebrity's taste for shock comedy was too much for the family-focused corporation. 

Disney has cut ties with YouTube’s most-subscribed star after he paid two Sri Lankan men five dollars to hold up a sign that read “DEATH TO ALL JEWS”.

Feel free to read that sentence again, it’s not going anywhere.

A still from PewDiePie's video, via YouTube

PewDiePie, real name Felix Kjellberg, has over 53 million subscribers on YouTube, where his videos about gaming earned him over $15m last year. The 27-year-old, whose content is popular with children, came under fire this month after the Wall Street Journal investigated anti-Semitic comments in his videos. In one video, a man dressed as Jesus says “Hitler did absolutely nothing wrong”, while in another Kjellberg used freelance marketplace Fiverr to pay two men to hold up the offensive sign. The videos have since been deleted.

Jumpcut.

The Walt Disney Company became affiliated with PewDiePie after they bought Maker Studios, a network of YouTube stars, for nearly $1bn in 2014. Following the WSJ’s investigation, Maker dropped the star, stating: “Although Felix has created a following by being provocative and irreverent, he clearly went too far in this case and the resulting videos are inappropriate. Maker Studios has made the decision to end our affiliation with him going forward.”

When you sack a YouTube Star, makes no difference who they are.

Via Wall Street Journal

But why should the story stop there? Neo-nazi website The Daily Stormer are now defending PewDiePie, while the notoriously politically-incorrect 4Chan forum /pol/ have called him “our guy”.  

In his defence, Kjellberg wrote a blog post denying an affiliation with anti-Semitic groups and explained his actions, writing: “I was trying to show how crazy the modern world is, specifically some of the services available online.” In a video last December the star also said: "It's extremely annoying how I can't make jokes on my channel without anyone quoting it as actual facts, like something I actually said", before dressing as a soldier and listening to one of Hitler's speeches while smiling. 

Pause.

(If all of this sounds familiar, recall when disgraced YouTuber Sam Pepper claimed a video in which he groped unsuspecting females was a “social experiment”).

Play.

And yet the story still isn’t over. Disney have learned a hard lesson about assuming that YouTubers are the squeaky clean fairy-tale princes and princesses they often appear to be. Shay Butler, one of the original founders of Maker Studios, yesterday quit the internet after it was alleged he sent sexual messages to a cam girl via Twitter.

Butler is one of the original "family vloggers", and has spent nine years uploading daily videos of his five children to YouTube. A practicing Mormon, Butler has become emblematic of family values on the site. “My heart is sick,” he wrote on Twitter, neither confirming nor denying the allegations of his infidelity, “I have struggled with alcoholism for years… My purpose is to rehab.” 

The result is a very dark day for YouTube, which has now dropped Kjellberg from its premier advertising network, Google Preferred, and cancelled the second series of the star's reality show, Scare PewDiePie

Amelia Tait is a technology and digital culture writer at the New Statesman.