The analysis of Apollo mission zircons (a mineral belonging to the group of nesosilicates) indicates that the moon is at least 4.51 billion years old, which means it was formed only 60 million years after the birth of the solar system. This puts our only natural satellite many millions of years older than scientists had previously thought.
The fragments of mineral from the moon date back to 1971, when astronauts collected the lunar material and transported back to Earth. Although the material was initially assessed, geological measuring technology has since become more sophisticated providing greater accuracy.
The method of analysis involved assessing the quantity of uranium in each of the fragments and how much of the element had decayed to form lead; and similarly the level of lutetium contained within the fragments that had decayed into the element hafnium. This was assessed by mass spectrometry. The zircon therefore acted as a type of historical clock.
The most widely accepted theory about the origins of the moon is that the satellite was formed following a collision between the Earth and a large item, most probably a “planetary embryo” which has been named Theia. This is called the ‘the giant impact hypothesis.’ The theory goes that Theia was an Earth trojan about the size of Mars and when it collided with Earth its semi-liquefied debris went onto form the moon (or perhaps two moons that eventually became one).
The new dating of the moon possibly gives further support to the Theia idea and it certainly assists astrophysicists with understanding the formation of the solar system. The dating also helps researchers to piece together how the solar system has developed since the possible giant impact.
In a forthright statement the lead researcher Dr. Mélanie Barboni, who is employed as a research geochemist in UCLA’s Department of Earth, Planetary and Space Sciences, said: “We have finally pinned down a minimum age for the moon; it’s time we knew its age and now we do.”
The research findings are reported to the journal Science Advances. The research paper is titled “Early formation of the Moon 4.51 billion years ago.”
