Echoes of ancient Earth: Further proof that the Moon was created by massive collision

 

Science Editor

The idea that the Moon was created after a massive cosmic collision between a Mars-sized object and the primordial Earth some 4.5bn years ago has received its second boost in less than a week.

Scientists have detected the chemical signature of the ancient Earth, as it was before the collision took place, in material found deep within the planet’s mantle, which separates the Earth’s molten iron core from the surface crust.

Last week, a separate team of researchers found the chemical signature of the ancient object itself, known as Theia, within lunar rock samples brought back to earth by the Apollo missions 40 years ago.

The second piece of evidence comes from a study of unexplained ratios of chemical isotopes in deep mantle rock which scientists believe are the signature of the primordial Earth before it was hit by Theia.

The collision would have generated enough energy to melt the entire planet but the researchers believe that although material would have vaporised on the side of impact, some of the planet remained solid and intact on the opposite hemisphere.

“The energy released by the impact between the Earth and Theia would have been huge, certainly enough to melt the whole planet. But we believe that the impact energy was not evenly distributed throughout the ancient Earth,” said Professor Sujoy Mukhopadhyay of Harvard University.

“This means that a major part of the impacted hemisphere would probably have been completely vaporised, but the opposite hemisphere would have been partly shielded and would not have undergone complete melting,” Professor Mukhopadhyay.

The study found that isotope ratios of the gases neon and helium differed significantly depending on whether they came from the shallow mantle or the deeper mantle of the Earth – which indicates a different origin.

“This implies that the last giant impact did not completely mix the mantle and there was not a whole mantle-magma ocean,” Professor Mukhopadhyay said.

“If the theory is proven correct, then we may be seeing echoes of the ancient Earth, from a time before the collision,” he said.

Another piece of evidence comes from the analysis of xenon gas isotopes, which result from from the slow radioactive decay of iodine gas. This suggests that the formation of the more ancient part of the mantle came within the first 100m years of the Earth’s origins – thereby putting a possible date on the impact with Theia.

Most computer models of the collision suggest that between 70 and 90 per cent of the material making up the Moon comes from the original Theia, with the remaining 10 or 30 per cent coming from terrestrial debris flung out from Earth during the glancing blow of the impact.

Professor Richard Carlson of the Carnegie Institute in Washington, past president of the Geochemical Society, said: “This exciting result is adding to the observational evidence that important aspects of Earth’s composition were established during the violent birth of the planet and is providing a new look at the physical processes by which this can occur.”

The research was presented to the Goldschmidt conference in Sacramento, California.

PROMOTED VIDEO
News
peopleBenjamin Netanyahu trolled by group promoting two-state solution
Arts and Entertainment
Kylie performs during her Kiss Me Once tour
musicReview: 26 years on from her first single, the pop princess tries just a bit too hard at London's O2
Life and Style
fashionEveryone, apparently
Voices
The erotic novel Fifty Shades of Grey has already been blamed for a rise in the number of callouts to the fire brigade for people trapped in handcuffs
voicesJustine Elyot: Since Fifty Shades there's no need to be secretive about it — everyone's at it
Arts and Entertainment
A new Banksy entitled 'Art Buff' has appeared in Folkestone, Kent
art
Life and Style
Playing to win: for Tanith Carey, pictured with Lily, right, and Clio, even simple games had to have an educational purpose
lifeTanith Carey explains what made her take her foot off the gas
Arts and Entertainment
The White Sails Hospital and Spa is to be built in the new Tunisia Economic City.
architectureRussian billionaire designs boat-shaped hospital for new Dubai-style Tunisia Economic City
News
ebooksAn unforgettable anthology of contemporary reportage
Sport
Husain Abdullah returns an interception off Tom Brady for a touchdown
nflLeague has rules against 'sliding to ground on knees'
Arts and Entertainment
Critics say Kipling showed loathing for India's primitive villagers in The Jungle Book
filmChristopher Walken, Bill Murray, Scarlett Johanssen Idris Elba, Andy Serkis, Benedict Cumberbatch, Cate Blanchett and Christian Bale
Life and Style
tech
Extras
indybest
News
i100
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

Financial Controller

£60000 - £75000 per annum: Sauce Recruitment: This is a busy and varied role w...

Maths Teacher

£21000 - £35000 per annum: Randstad Education Cambridge: Maths teacher require...

KS1 Teacher

£21500 - £31500 per day: Randstad Education Chelmsford: Would you like to work...

Java Developer - web services, XML and API

£330 - £350 Per Day: Clearwater People Solutions Ltd: Our client based in Lond...

Day In a Page

Isis is an hour from Baghdad, the Iraq army has little chance against it, and air strikes won't help

Isis an hour away from Baghdad -

and with no sign of Iraq army being able to make a successful counter-attack
Turner Prize 2014 is frustratingly timid

Turner Prize 2014 is frustratingly timid

The exhibition nods to rich and potentially brilliant ideas, but steps back
Last chance to see: Half the world’s animals have disappeared over the last 40 years

Last chance to see...

The Earth’s animal wildlife population has halved in 40 years
So here's why teenagers are always grumpy - and it's not what you think

Truth behind teens' grumpiness

Early school hours mess with their biological clocks
Why can no one stop hackers putting celebrities' private photos online?

Hacked photos: the third wave

Why can no one stop hackers putting celebrities' private photos online?
Royal Ballet star dubbed 'Charlize Theron in pointe shoes' takes on Manon

Homegrown ballerina is on the rise

Royal Ballet star Melissa Hamilton is about to tackle the role of Manon
Education, eduction, education? Our growing fascination with what really goes on in school

Education, education, education

TV documentaries filmed in classrooms are now a genre in their own right
It’s reasonable to negotiate with the likes of Isis, so why don’t we do it and save lives?

It’s perfectly reasonable to negotiate with villains like Isis

So why don’t we do it and save some lives?
This man just ran a marathon in under 2 hours 3 minutes. Is a 2-hour race in sight?

Is a sub-2-hour race now within sight?

Dennis Kimetto breaks marathon record
We shall not be moved, say Stratford's single parents fighting eviction

Inside the E15 'occupation'

We shall not be moved, say Stratford single parents
Air strikes alone will fail to stop Isis

Air strikes alone will fail to stop Isis

Talks between all touched by the crisis in Syria and Iraq can achieve as much as the Tornadoes, says Patrick Cockburn
Nadhim Zahawi: From a refugee on welfare to the heart of No 10

Nadhim Zahawi: From a refugee on welfare to the heart of No 10

The Tory MP speaks for the first time about the devastating effect of his father's bankruptcy
Witches: A history of misogyny

Witches: A history of misogyny

The sexist abuse that haunts modern life is nothing new: women have been 'trolled' in art for 500 years
Shona Rhimes interview: Meet the most powerful woman in US television

Meet the most powerful woman in US television

Writer and producer of shows like Grey's Anatomy, Shonda Rhimes now has her own evening of primetime TV – but she’s taking it in her stride
'Before They Pass Away': Endangered communities photographed 'like Kate Moss'

Endangered communities photographed 'like Kate Moss'

Jimmy Nelson travelled the world to photograph 35 threatened tribes in an unashamedly glamorous style