Scientists discover fragment of 'missing link' asteroid that led to explosion of life on Earth

Sample from a Swedish quarry is thought to be from a 'bullet' asteroid that set off a massive meteor shower 470 million years ago

Scientists in Sweden have discovered a never-before seen class of meteorite that could be the ‘missing link’ between a gigantic collision in the asteroid belt 470 million years ago and the subsequent explosion of diverse life forms here on Earth.

Although it’s usually thought that meteorite impacts are disastrous for species on Earth (the classic example is the colossal impact thought to have killed off the dinosaurs 66 million years ago) there’s plenty of evidence to suggest that these events can also be beneficial to the overall diversity on the planet.

It's thought that just such an impact – or rather, a string of them – dramatically boosted biodiversity on the planet during the Ordovician Period some 470 million years ago. It's believed that a collision of two asteroids (or possibly an asteroid and a comet) out in space caused a shower of meteors to rain down on Earth.

Over time fragments of this meteor shower have been found around the planet and dated to 470 million years ago – but until now scientists had not found any evidence of the ‘killer’ asteroid that started this chain of events.

During the Ordovician Period most life on Earth was found in the ocean, with jawless fish, molluscs and insect-like arthropods making up the bulk of the species roll-call. However, a study from 2008 showed that the planet went through a “major phase of biodiversification” at this time shortly after “the largest documented asteroid breakup event during the past few billion years”.

The evidence for this breakup comes from the abundance of L-chondrite meteorites – the second most common meteorite type - fragments of which first started appearing on Earth around 470 million years ago.

"Something we didn't really know about before was flying around and crashed into the L-chondrites," said Gary Huss, co-author of the study that analysed the sample (published in Earth and Planetary Science Letters). This newly-discovered fragment is thought to be that very object – the mysterious ‘bullet’.

The composition of the fragment differs from known meteorite samples and its exposure age  – the length of time it sailed through space – places it at the 'scene of the crime’ when meteors rained down on the planet during the Ordovician Period.

“It's a very, very strange and unusual find," Birger Schmitz, the lead author of the study, told Live Science. "I think [it] adds to the understanding that the meteorites that come down on Earth today may not be entirely representative of what is out there.”

It’s not clear exactly why the Ordovician meteor shower led to a greater variety of life on the plane although some more far-fetched theories suggest that life itself was ‘seeded’ by organisms hitching a ride on asteroids.

A more likely explanation is that the impact craters caused by the collisions provided perfect test-beds for developing life. When meteorites hit the surface of the planet they scooped out bubbling pools of minerals and nutrients that served - in Carl Zimmer's words - as “natural beakers that synthesized new chemicals essential for life”. However, even this is still just a theory - and the impacts might have also fostered life by creating new habitats, like restructured shorelines.

If further geochemical tests on the newly discovered fragment confirm its suspected origins then scientists will have pinned down another piece of the solar system’s history – but figuring out what happened closer to home might be more difficult still.  

PROMOTED VIDEO
News
Happy in his hat: Pharrell Williams
people
Arts and Entertainment
Stella Gibson is getting closer to catching her killer
tvReview: It's gripping edge-of-the-seat drama, so a curveball can be forgiven at such a late stage
News
Brazilian football legend Pele pictured in 2011
peopleFans had feared the worst when it was announced the Brazil legand was in a 'special care' unit
News
i100(More than you think)
News
Phyllis Dorothy James on stage during a reading of her book 'Death Comes to Pemberley' last year
peopleJohn Walsh pays tribute to PD James, who died today
News
peopleExclusive: Maryum and Hana Ali share their stories of the family man behind the boxing gloves
News
ebooksNow available in paperback
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Austen Lloyd: Commercial / Residential Property - Surrey

Excellent Salary: Austen Lloyd: SURREY MARKET TOWN - SENIOR PROPERTY SOLICITOR...

Recruitment Genius: Graduate Programme - Online Location Services Business

Negotiable: Recruitment Genius: What do you want to do with your career? Do yo...

Recruitment Genius: Senior QC Scientist

Negotiable: Recruitment Genius: This company is a leading expert in immunoassa...

Recruitment Genius: Development Scientist

Negotiable: Recruitment Genius: A Development Scientist is required to join a ...

Day In a Page

Homeless Veterans Christmas Appeal: ‘We give them hope. They come to us when no one else can help’

Christmas Appeal

Meet the charity giving homeless veterans hope – and who they turn to when no one else can help
Should doctors and patients learn to plan humane, happier endings rather than trying to prolong life?

Is it always right to try to prolong life?

Most of us would prefer to die in our own beds, with our families beside us. But, as a GP, Margaret McCartney sees too many end their days in a medicalised battle
Thomas Cook's outgoing boss Harriet Green got by on four hours sleep a night - is that what it takes for women to get to the top?

What does it take for women to get to the top?

Thomas Cook's outgoing boss Harriet Green got by on four hours sleep a night and told women they had to do more if they wanted to get on
Christmas jumper craze: Inside the UK factory behind this year's multicultural must-have

Knitting pretty: British Christmas Jumpers

Simmy Richman visits Jack Masters, the company behind this year's multicultural must-have
French chefs have launched a campaign to end violence in kitchens - should British restaurants follow suit?

French chefs campaign against bullying

A group of top chefs signed a manifesto against violence in kitchens following the sacking of a chef at a Paris restaurant for scalding his kitchen assistant with a white-hot spoon
Radio 4 to broadcast 10-hour War and Peace on New Year's Day as Controller warns of cuts

Just what you need on a New Year hangover...

Radio 4 to broadcast 10-hour adaptation of War and Peace on first day of 2015
Cuba set to stage its first US musical in 50 years

Cuba to stage first US musical in 50 years

Claire Allfree finds out if the new production of Rent will hit the right note in Havana
Christmas 2014: 10 best educational toys

Learn and play: 10 best educational toys

Of course you want them to have fun, but even better if they can learn at the same time
Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

It's in all our interests to look after servicemen and women who fall on hard times, say party leaders
Millionaire Sol Campbell wades into wealthy backlash against Labour's mansion tax

Sol Campbell cries foul at Labour's mansion tax

The former England defender joins Myleene Klass, Griff Rhys Jones and Melvyn Bragg in criticising proposals
Nicolas Sarkozy returns: The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?

Sarkozy returns

The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?
Is the criticism of Ed Miliband a coded form of anti-Semitism?

Is the criticism of Miliband anti-Semitic?

Attacks on the Labour leader have coalesced around a sense that he is different, weird, a man apart. But is the criticism more sinister?
Ouija boards are the must-have gift this Christmas, fuelled by a schlock horror film

Ouija boards are the must-have festive gift

Simon Usborne explores the appeal - and mysteries - of a century-old parlour game
There's a Good Girl exhibition: How female creatives are changing the way women are portrayed in advertising

In pictures: There's a Good Girl exhibition

The new exhibition reveals how female creatives are changing the way women are portrayed in advertising
UK firm Biscuiteers is giving cookies a makeover - from advent calendars to doll's houses

UK firm Biscuiteers is giving cookies a makeover

It worked with cupcakes, doughnuts and macarons so no wonder someone decided to revamp the humble biscuit