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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

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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Koch to Set Record for Longest Spaceflight by Woman, Will Spend 328 Days in Space

"One month down. Ten to go," Koch wrote Wednesday on Twitter. "Privileged to contribute my best every single day of it"

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astronaut, longest spaceflight, record
FILE - In this April 8, 2019, photo made available by NASA, astronaut and Expedition 59 Flight Engineer Christina Koch works on U.S. spacesuits inside the Quest airlock of the International Space Station. VOA

A female astronaut is due to set a record for the longest spaceflight by a woman, the U.S. space agency said Wednesday, the same astronaut who was to have been in the first all-female spacewalk scrapped over lack of a right-sized spacesuit.

Astronaut Christina Koch, who completed the space walk with a man instead of a female colleague last month, will remain in orbit on board the International Space Station until February, the National Aeronautics and Space Administration (NASA) said.

Part of NASA’s study of the effects of long spaceflights on the human body, Koch will spend 328 days in space.

The 40-year-old astronaut has been in orbit since last month.

“One month down. Ten to go,” Koch wrote Wednesday on Twitter. “Privileged to contribute my best every single day of it.”

astronaut, longest flight
FILE – U.S. astronaut Christina Koch, member of the main crew of the expedition to the International Space Station (ISS), looks on prior the launch of Soyuz MS-12 space ship at the Russian leased Baikonur cosmodrome, Kazakhstan, March 14, 2019. VOA

In late March, NASA canceled what would have been the first all-female spacewalk with Koch and astronaut Anne McClain due to a lack of a spacesuit in the right size for McClain.

The walk was would have occurred during the final week of Women’s History Month.

On board the orbiting space station, astronauts work on a range of experiments in biology, biotechnology, health, earth, space and other sciences.

The typical stay for astronauts is six months, NASA said.

“NASA is looking to build on what we have learned with additional astronauts in space for more than 250 days,” Jennifer Fogarty, a chief scientist for NASA’s Human Research Program, said in a statement.

longest spacecraft, women
Part of NASA’s study of the effects of long spaceflights on the human body, Koch will spend 328 days in space. Pixabay

Record holders

Astronaut Peggy Whitson holds the record for the longest single spaceflight by a woman, staying in orbit 288 days in 2016 and 2017, NASA said.

“It’s my honor to follow in Peggy’s footsteps,” Koch said in a video from the International Space Station, orbiting over 200 miles (322 km) above Earth.

ALSO READ: SpaceX Launches Second Supersized ‘Falcon’ Heavy Rocket, For the First Time Lands all Three Boosters

Of the more than 500 people who have traveled to space, fewer than 11 percent have been women. But Koch graduated from NASA’s 2013 class of astronauts that was 50 percent women.

The overall NASA record of 340 days, set in 2016, is held by astronaut Scott Kelly in an experiment to compare his physical and mental health to his identical twin Mark Kelly, who remained on Earth. (VOA)