Moon Is Millions of Years Older Than Previously Thought, Scientists Say

Astronauts from Apollo 17 brought back some tiny crystals from the Moon in 1972. Scientists have now figured out that the Moon is older than we thought. Before this, we believed it was about 4.425 billion years old. However, the new study tells us it’s actually 4.46 billion years old. That’s forty million years older than previously thought.

The Field Museum and the University of Glasgow led this study. They used a special machine at Northwestern University to assist them. This machine is called an “atom-probe tomography facility.” It helped them find the age of the oldest crystal in the Moon sample.

These special crystals, called zircon crystals, were hidden in the Moon dust. By learning how old these crystals are, scientists could figure out when the Moon was formed.

The research findings were released on October 23rd in the journal Geochemical Perspectives Letters.

One of the study’s co-authors, Dieter Isheim from Northwestern University, mentioned that this study shows how far our technology has come since the last time people went to the Moon in 1972.

Moon samples were brought back to Earth fifty years ago, but we only now have the appropriate tools to closely examine the samples. This includes a special method called “atom-probe tomography.”

Radioactive decay analysis of zircon crystals

By looking at the zircon crystals atom by atom, scientists were able to see how many atoms had gone through a change due to radioactivity.

When an atom goes through such change, it loses some of its parts called protons and neutrons and turns into a different element entirely.

🌕👨‍🚀 Rock collected by Apollo 17 astronaut in 1972 reveals moon's age

The moon is about 40 million years older than previously thought – forming more than 4.46 billion years ago, within 110 million years after the solar system's birth, scientists said on Monday, based on… pic.twitter.com/HWPIOv9sSK

— PiQ (@PiQSuite) October 23, 2023

For instance, uranium changes into lead. Scientists know how much time it takes for this change to happen. By checking how many uranium and lead atoms are in a sample, they can figure out how old it is, according to Northwestern University.

Radiometric dating is somewhat like an hourglass, as explained by Philipp Heck, who is the senior author of the study from the Field Museum. In an hourglass, sand moves from one part to another, and as time passes, you can detect more sand in the lower part.

Radiometric dating works in a similar way. It determines how many original atoms, called parent atoms, there are and how many of these have morphed into different atoms, called daughter atoms. Since we know how fast this change happens, we can figure out how much time has elapsed.

Moon’s formation process around four billion years ago

Over four billion years ago, when our solar system was young and Earth was still developing, a huge object about the size of Mars smashed into Earth. This huge collision caused a piece of Earth to break away and form the Moon.

The intense energy from this impact melted the rocks that eventually became the Moon’s surface, reported Northwestern University.

“When the surface was molten like that, zircon crystals couldn’t form and survive,” Heck said. “So, any crystals on the Moon’s surface must have formed after this lunar magma ocean cooled. Otherwise, they would have been melted and their chemical signatures would be erased.”