Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research sheds new light on how Earth and Mars were created

28.09.2017

Analysing a mixture of earth samples and meteorites, scientists from the University of Bristol have shed new light on the sequence of events that led to the creation of the planets Earth and Mars.

Planets grow by a process of accretion - a gradual accumulation of additional material - in which they collisionally combine with their neighbours.


This is a snapshot of a computer simulation of two (relatively small) planets colliding with each other. The colours show how the rock of the impacting body (dark grey, in centre of impact area) accretes to the target body (rock; light grey), while some of the rock in the impact area is molten (yellow to white) or vaporized (red).

Credit: Philip J. Carter

This is often a chaotic process and material gets lost as well as gained.

Massive planetary bodies impacting at several kilometres per second generate substantial heat which, in turn, produces magma oceans and temporary atmospheres of vaporised rock.

Before planets get to approximately the size of Mars, gravitational attraction is too weak to hold onto this inclement silicate atmosphere.

Repeated loss of this vapour envelope during continued collisional growth causes the planet's composition to change substantially.

Dr Remco Hin from the University of Bristol's School of Earth Sciences, led the research which is published today in Nature.

He said: "We have provided evidence that such a sequence of events occurred in the formation of the Earth and Mars, using high precision measurements of their magnesium isotope compositions.

"Magnesium isotope ratios change as a result of silicate vapour loss, which preferentially contains the lighter isotopes. In this way, we estimated that more than 40 per cent of the Earth's mass was lost during its construction.

"This cowboy building job, as one of my co-authors described it, was also responsible for creating the Earth's unique composition."

The research was carried out in an effort to resolve a decades long debate in Earth and planetary sciences about the origin of distinctive, volatile poor compositions of planets.

Did this result from processes that acted in the mixture of gas and dust in the nebula of the earliest solar system or is it consequence of their violent growth?

Researchers analysed samples of the Earth together with meteorites from Mars and the asteroid Vesta, using a new technique to get higher quality (more accurate and more precise) measurements of magnesium isotope ratios than previously obtained.

The main findings are three-fold:

  • Earth, Mars and asteroid Vesta have distinct magnesium isotope ratios from any plausible nebula starting materials
  • The isotopically heavy magnesium isotope compositions of planets identify substantial (~40 per cent) mass loss following repeated episodes of vaporisation during their accretion
  • This slipshod construction process results in other chemical changes during growth that generate the unique chemical characteristics of Earth.

Dr Hin added: "Our work changes our views on how planets attain their physical and chemical characteristics.

"While it was previously known that building planets is a violent process and that the compositions of planets such as Earth are distinct, it was not clear that these features were linked.

"We now show that vapour loss during the high energy collisions of planetary accretion has a profound effect on a planet's composition.

"This process seems common to planet building in general, not just for Earth and Mars, but for all planets in our Solar System and probably beyond, but differences in the collision histories of planets will create a diversity in their compositions."

###

Paper:

'Magnesium isotope evidence that accretional vapour loss shapes planetary compositions' by R. Hin, C. Coath, P. Carter, F. Nimmo et al in Nature.

Media Contact

Shona East
shona.east@bristol.ac.uk
44-117-928-8086

 @BristolUni

http://www.bristol.ac.uk 

Shona East | EurekAlert!

Further reports about: Earth Magnesium Mars isotope isotope ratios lighter isotopes nebula solar system

More articles from Physics and Astronomy:

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

nachricht Artificial agent designs quantum experiments
19.01.2018 | Universität Innsbruck

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>