Science & technology
Scientists date Moon at 4.470 billion years
Publish Date: Apr 03, 2014
Scientists date Moon at 4.470 billion years
Scientists say the Moon was formed in a collision that also settled the structure of Earth as we know it
  • mail
  • img
newvision

PARIS - The Moon was formed about 95 million years after the birth of our Solar System, in a collision that also settled the structure of Earth as we know it, according to the latest attempt at dating that impact.

A study in the journal Nature said the crash between an early, proto-Earth and a Mars-sized object that dislodged what would become the Moon, happened some 4.470 billion years ago -- give or take 32 million years.

Apart from creating our satellite, the event is also believed to have marked the final phase of Earth's core formation from molten metals sinking to the centre from a superhot surface.

Previous estimates had ranged from an "early" impact about 30 million years after the start of the Solar System, to a later one as much as 200 million years after.

The Solar System itself is known to be 4.567 billion years old thanks to accurate dating of some components of meteorites -- the oldest materials to be found on our planet.

Earth is believed to have formed at some time during the first 150 million years.

Many earlier age estimates had been based on measuring the rate of radioactive decay of atomic nuclei found in rocks.

For the new study published in the journal Nature, a team of planetary scientists from France, Germany and the United States created a computer model of how dust and rock accumulated in the early Solar System to form tiny planets called planetesimals.

These grew into "planetary embryos" that ended up as the rocky planets we know today -- Mercury, Venus, Earth and Mars -- through a succession of giant impacts, according to the new model.

Each massive collision allowed the planets to "accrete" or accumulate matter. In Earth's case, the lunar impact would have marked its final major growth event.

The team also looked at the chemical composition of the Earth's mantle to trace the amount of material the planet accumulated after the impact -- only about 0.5 percent of its total mass.

If the impact had happened early in the Solar System's history, there would still have been many free-floating planetesimals for the Earth to sweep up, and if it was later, fewer.

The evidence suggested Earth took 95 million years to form, "which confirms it as the planet in our Solar System that took the longest to form," study co-author Alessandro Morbidelli told AFP by email.

The statements, comments, or opinions expressed through the use of New Vision Online are those of their respective authors, who are solely responsible for them, and do not necessarily represent the views held by the staff and management of New Vision Online.

New Vision Online reserves the right to moderate, publish or delete a post without warning or consultation with the author.Find out why we moderate comments. For any questions please contact digital@newvision.co.ug

  • mail
  • img
blog comments powered by Disqus
Also In This Section
Microsoft launches Biz4Afrika in Kenya for SMEs
Microsoft 4Afrika has launched Biz4Afrika, an online portal for Kenyan small and medium enterprises (SMEs) to access locally relevant information and resources to promote SMEs and improve trade....
Microsoft unveils low-cost Surface 3 tablet
Microsoft unveils a low-cost version of its Surface tablet computer, cutting the screen size of the device which starts at $499....
Government working on laws governing drones
A government effort is underway to put guidelines and restrictions on how private citizens can use unmanned aerial vehicles...
Japan company makes tear-free onions
The sobbing of a chef as he chops onions in the kitchen could be a thing of the past thanks to one Japanese company....
Samsung, LG agree to end legal feuds
Samsung and LG agreed Tuesday to end all pending legal disputes that had seen the South Korean electronics rivals accuse each other of stealing technology and vandalising products....
Solar Impulse departs Myanmar for China
Solar Impulse 2 took off from Myanmar''s second biggest city of Mandalay in a landmark journey to circumnavigate the globe powered solely by the sun....
Should police arrest parents who do not take their children to school?
Yes
No
Can't Say
follow us
subscribe to our news letter