For many years now, it has been believed that our planet Earth is about 4.567 billion years old - Now, a new study conducted by scientists at the University of Cambridge's Trinity College has revealed that we may have overestimated the date - by about 70 million years!
Earth and the rest of the planets in the Solar System were formed as a result of a series of collisions between small dwarf planets that were orbiting a newly formed sun. When they bumped into each other the resulting heat melted the cores and they fused together to form larger planets.
Scientists had previously calculated that Earth, an amalgamation of many small planets, had taken approximately 30 million years to get to its current size. It finally stopped forming when a planet the size of Mars, hit it and instead of fusing with it, broke off a chunk from the Earth's surface - resulting in what is now our moon! However, the time frame of 30 million years was based on the assumption that it all happened continuously - with no break in between.
A new study based on the pace of decay of atoms or isotopes of radioactive chemicals in the Earth's crust, suggests that while 60% of the Earth was formed within the first 10-40 million years, the remaining 40% took much longer - about 70 million years longer. Since the moon was formed at the very end, it too was declared 70 million years younger, than originally thought!
sources: tgdaily.com, thehindu.com,csmonitor.com