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Earth lost 40% mass during formation

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Earth lost 40% mass during formation
Earth lost 40% mass during formation. IANS
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London, Sep 28: The violent and chaotic process that led to the formation of Earth resulted in the loss of more than 40 per cent of its mass, says a study.

Analysing a mixture of earth samples and meteorites, the scientists shed new light on the sequence of events that led to the creation of our home planet.

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

This is often a chaotic process and material gets lost as well as gained, said the study published in the journal Nature.

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

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

“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,” said lead researcher Remco Hin from University of Bristol in Britain.

“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,” he said.

For the study, the researchers analysed samples of the Earth together with meteorites from Mars and the asteroid Vesta, using a new technique to get higher quality measurements of magnesium isotope ratios than previously obtained.

“We now show that vapour loss during the high energy collisions of planetary accretion has a profound effect on a planet’s composition,” Hin said.

“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,” he added. (IANS)

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NASA’s Kepler Discovers Nearly 100 New Exoplanets

NASA researchers found that some of the signals were caused by multiple star systems or noise from the spacecraft

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Countless galaxies exist in the universe, each hiding secrets that humankind is yet to unearth. Pixabay
  • NASA’s Kepler has discovered nearly 100 new exoplanets
  • Some of the planets discovered are as large as Jupiter
  • NASA has also found planet which orbits very bright stars

An international team of scientists have confirmed the discovery of nearly 100 new exoplanets — planets located outside our solar system.

The discovery was based on data from the second mission of NASA’s Kepler Space Telescope or K2 released in 2014.

NASA has discovered nearly 100 exoplanets. Wikimedia Commons
NASA has discovered nearly 100 exoplanets. Wikimedia Commons

K2 searches for exoplanet transits by registering dips in light caused by the shadow of an exoplanet as it crosses in front of its host star.

NASA researchers found that some of the signals were caused by multiple star systems or noise from the spacecraft.

But they also detected planets that range from sub-Earth-sized to the size of Jupiter and larger.

Also Read: Milky Way’s neighbouring galaxy is of the same size, not bigger

One of the planets detected was orbiting a very bright star.

“We validated a planet on a 10-day orbit around a star called HD 212657, which is now the brightest star found by K2 missions to host a validated planet,” said lead author Andrew Mayo, a doctoral student at the National Space Institute (DTU Space) at the Technical University of Denmark.

Some of the planets found are as big as Jupiter. VOA
Some of the planets found are as big as Jupiter. VOA

For the study, appearing in the Astronomical Journal, the team started out analyzing 275 candidates of which 149 were validated as real exoplanets.

In turn 95 of these planets have proved to be new discoveries, Mayo said.

The Kepler spacecraft was first launched in 2009 to hunt for exoplanets in a single patch of sky, but in 2013 a mechanical failure crippled the telescope.

NASA has found many planets before as well. Wikimedia Commons
NASA has found many planets before as well. Wikimedia Commons

However, astronomers and engineers devised a way to repurpose and save the space telescope by changing its field of view periodically. This solution paved the way for the follow up K2 mission.

Adding the newly discovered exoplanets brings the total number of exoplanets by K2 mission to almost 300, the study said.

Also Read: NASA sounding rocket probing dark regions of space falter

The first planet orbiting a star similar to our own Sun was detected only in 1995. Today some 3,600 exoplanets have been found, ranging from rocky Earth-sized planets to large gas giants like Jupiter. IANS