Australian IT JOBS : Sydney IT jobs, UNIX jobs, Linux jobs, Java jobs, ASP jobs Linux.conf.au Linux.conf.au
Technology news and Jobs arrow Science arrow Swiss give best estimate of Moon age at 62M years after solar system formed
Swiss give best estimate of Moon age at 62M years after solar system formed PDF Print E-mail
Written by William Atkins   
Saturday, 05 January 2008

They state in their Nature article: “The Moon is thought to have formed from debris ejected by a giant impact with the early 'proto'-Earth and, as a result of the high energies involved, the Moon would have melted to form a magma ocean. The timescales for formation and solidification of the Moon can be quantified by using 182Hf–182W and 146Sm–142Nd chronometry, but these methods have yielded contradicting results. In earlier studies, 182W anomalies in lunar rocks were attributed to decay of 182Hf within the lunar mantle and were used to infer that the Moon solidified within the first ~60 million years of the Solar System. However, the dominant 182W component in most lunar rocks reflects cosmogenic production mainly by neutron capture of 181Ta during cosmic-ray exposure of the lunar surface, compromising a reliable interpretation in terms of 182Hf–182W chronometry.”

Further, they state, “Here we present tungsten isotope data for lunar metals that do not contain any measurable Ta-derived 182W. All metals have identical 182W/184W ratios, indicating that the lunar magma ocean did not crystallize within the first ~60 Myr of the Solar System, which is no longer inconsistent with Sm–Nd chronometry. Our new data reveal that the lunar and terrestrial mantles have identical 182W/184W. This, in conjunction with 147Sm–143Nd ages for the oldest lunar rocks, constrains the age of the Moon and Earth to 62 (+90/-10) Myr after formation of the Solar System. The identical 182W/184W ratios of the lunar and terrestrial mantles require either that the Moon is derived mainly from terrestrial material or that tungsten isotopes in the Moon and Earth's mantle equilibrated in the aftermath of the giant impact, as has been proposed to account for identical oxygen isotope compositions of the Earth and Moon."

{moscomment}



Get stories like this delivered daily - FREE - subscribe now
When you subscribe get a 12 months license for LiveProject
Valued at $99 USD


LiveWire - Desktop alerts Download the FREE iTWire desktop alert widget LiveWire - Desktop alerts


Del.icio.us!


 
< Prev   Next >

Latest jobs

Contact , Register , Advertise with iTWire , Links , Register , About iTWire , Feedback , Post your jobs , Events , iTWire site map , Start Blogging
Industry Releases , Submit your release now , Start submitting to iTWire , How to post video