Apollo Programme rock samples throw new light on the origins of the moon

 

Science Editor

Scientists studying samples of lunar rock from the Apollo space programme have discovered evidence to support the theory that the Moon was created from the debris of a massive cosmic collision between the Earth and an object as big as Mars.

Concentrations of oxygen isotopes in the lunar rock reveal a distinct chemical signature of the original planet-sized object that was supposed to have collided with the Earth about 4.5 billion years ago, a study has found.

Until now scientists have been unable to find substantial isotopic differences between lunar and terrestrial rock. This called into question whether the Moon was indeed created in a collision rather than being bits of the primordial Earth that had been flung out into orbit during its early formation.

However, the analysis of lunar rock samples from three Apollo missions half a century ago has revealed distinct isotopic differences with terrestrial rock. Scientists believe these differences are remnants of the original Mars-sized object, named Theia, the mythical Greek Titan who was the mother of the moon goddess Selene.

“The differences are small and difficult to detect, but they are there. This means two things: firstly, we can now be reasonably sure that the giant collision took place. Secondly, it gives us an idea of the geochemistry of Theia,” said Daniel Herwartz of George August University in Gottingen, Germany.

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.

Until now, the giant-impact hypothesis to account for the existence of the Moon has lacked the smoking gun of distinct isotopic differences between the rocks found on Earth and those found on the Moon.

However, the study, published in the journal Science and based on the analysis of three rock samples brought back on Apollos 11, 12 and 16, not only shows significant differences in the isotopes of oxygen, but indicates that Theia belonged to a class of rare meteorites known as enstatite chondrites.

“If this is true, we can now predict the geochemical and isotopic composition of the Moon, because the present Moon is a mixture of Theia and the early Earth,” Dr Herwartz said.

“The next goal is to find out how much material of Theia is in the Moon,” he said.

Mahesh Anand, a planetary scientist at the Open University in Milton Keynes, who was not involved with the study, said the findings highlight the unique nature of the Earth-Moon system – most of the other 150 moons in the Solar System are either captured planetesimals or were formed directly from the debris of the planet they orbit.

“It is an exciting story but is derived from just three lunar rock samples. We have to be cautious about representativeness of these rocks of the entire Moon and so further analysis of a variety of lunar rocks is required for further confirmation,” Dr Anand said.

“This research brings back into limelight some of the unanswered questions surrounding the giant impact hypothesis that will require additional analysis of lunar and terrestrial samples to gain further insights into the origin of the Moon,” he said.

Start your day with The Independent, sign up for daily news emails
ebooks
ebooksAn introduction to the ground rules of British democracy
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

Recruitment Genius: SAGE Bookkeeper & PA to Directors

£18000 - £24000 per annum: Recruitment Genius: An exciting opportunity has ari...

Recruitment Genius: Online Sales and Customer Services Executive

£15000 - £18000 per annum: Recruitment Genius: An On-line Sales & Customer Ser...

Recruitment Genius: Accounts Assistant - Fixed Term Contract - 6 Months

£15000 per annum: Recruitment Genius: One of the largest hospitality companies...

Recruitment Genius: Electricians - Fixed Wire Testing

£28000 - £32000 per annum: Recruitment Genius: As a result of significant cont...

Day In a Page

Seifeddine Rezgui: What motivated a shy student to kill 38 holidaymakers in Tunisia?

Making of a killer

What motivated a shy student to kill 38 holidaymakers in Tunisia?
UK Heatwave: Temperatures on the tube are going to exceed the legal limit for transporting cattle

Just when you thought your commute couldn't get any worse...

Heatwave will see temperatures on the Tube exceed legal limit for transporting cattle
Exclusive - The Real Stories of Migrant Britain: Swapping Bucharest for London

The Real Stories of Migrant Britain

Meet the man who swapped Romania for the UK in a bid to provide for his family, only to discover that the home he left behind wasn't quite what it seemed
Cheaper energy on the way, but it's not all sunshine and rainbows

Cheaper energy on the way, but it's not all sunshine and rainbows

Solar power will help bring down electricity prices over the next five years, according to a new report. But it’s cheap imports of ‘dirty power’ that will lower them the most
Katy Perry prevented from buying California convent for $14.5m after nuns sell to local businesswoman instead

No grace of God for Katy Perry as sisters act to stop her buying convent

Archdiocese sues nuns who turned down star’s $14.5m because they don’t approve of her
Ajmer: The ancient Indian metropolis chosen to be a 'smart city' where residents would just be happy to have power and running water

Residents just want water and power in a city chosen to be a ‘smart’ metropolis

The Indian Government has launched an ambitious plan to transform 100 of its crumbling cities
Michael Fassbender in 'Macbeth': The Scottish play on film, from Welles to Cheggers

Something wicked?

Films of Macbeth don’t always end well - just ask Orson Welles... and Keith Chegwin
10 best sun creams for body

10 best sun creams for body

Make sure you’re protected from head to toe in the heatwave
Wimbledon 2015: Nick Bollettieri - Milos Raonic has ability to get to the top but he must learn to handle pressure in big games

Nick Bollettieri's Wimbledon files

Milos Raonic has ability to get to the top but he must learn to handle pressure in big games
Women's World Cup 2015: How England's semi-final success could do wonders for both sexes

There is more than a shiny trophy to be won by England’s World Cup women

The success of the decidedly non-famous females wearing the Three Lions could do wonders for a ‘man’s game’ riddled with cynicism and greed
How to stop an asteroid hitting Earth: Would people co-operate to face down a global peril?

How to stop an asteroid hitting Earth

Would people cooperate to face a global peril?
Just one day to find €1.6bn: Greece edges nearer euro exit

One day to find €1.6bn

Greece is edging inexorably towards an exit from the euro
New 'Iron Man' augmented reality technology could help surgeons and firefighters, say scientists

'Iron Man' augmented reality technology could become reality

Holographic projections would provide extra information on objects in a person's visual field in real time
Sugary drinks 'are killing 184,000 adults around the world every year'

Sugary drinks are killing 184,000 adults around the world every year

The drinks that should be eliminated from people's diets
Pride of Place: Historians map out untold LGBT histories of locations throughout UK

Historians map out untold LGBT histories

Public are being asked to help improve the map