Seldom Bucket
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An object the size of Mars crashed into the Earth over 4 billion years ago, creating a cloud of debris that formed the Moon. When the Apollo astronauts landed on the lunar surface, they found and brought back Moon rocks that helped pinpoint when this event happened. Now, a new study of crystals in the lunar samples pushed that event back even further –about 40 million years earlier than previous estimates — setting the Moon’s formation to about 4.46 billion years old – not long after the Earth formed.
Researchers at Northwestern University and the Field Museum in Chicago, along with the University of Glasgow in Scotland used an atom-probe tomography facility to study Moon rocks and dust collected during the Apollo 17 mission in 1972. This facility allowed them to perform an improved form of radiometric dating. Radiometric dating calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element, such as carbon-14, or a long-life radioactive element plus its decay.
A lunar zircon grain under a microscope. Credit: Photo courtesy of Jennika Greer.
The Moon is 40 Million Years Older Than We Thought
An object the size of Mars crashed into the Earth over 4 billion years ago, creating a cloud of debris that formed the Moon. When the Apollo astronauts landed on the lunar surface, they found and brought back Moon rocks that helped pinpoint when this event happened. Now, a new study of crystals...
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