The atom-by-atom analysis made it possible for researchers to count how many atoms in the zircon crystals have undergone radioactive decay.” When the surface area was molten like that, zircon crystals couldnt endure and form,” Heck stated. “So, any crystals on the Moons surface must have formed after this lunar magma ocean cooled. Its essential to understand when the Moon formed, Heck stated, since “the Moon is an important partner in our planetary system. Without the Moon, life on Earth would look different.
A new research study using sophisticated atom-probe tomography has identified that the Earths Moon is 4.46 billion years old, 40 million years older than previous price quotes. This finding, stemmed from examining lunar crystals from Apollo 17, provides a deeper understanding of the Moons formation and its effect on Earths environment.
Scientists from Northwestern University added to the analysis of lunar samples that were collected by astronauts throughout the Apollo 17 objective.
By examining small crystals from the Moon, collected during the Apollo 17 objective in 1972, scientists have actually modified the approximated age of the Moon. Previously thought to be 4.425 billion years old, the new analysis suggests it is around 4.46 billion years old, making it 40 million years older than earlier quotes.
Led by scientists at the Field Museum and the University of Glasgow, the study was made possible by Northwestern Universitys atom-probe tomography center, which “pin down” the age of the oldest crystal in the sample. By exposing the age of these telltale zircon crystals– discovered concealed within dust gathered from the Moon– scientists had the ability to piece together the timeline of the Moons development.
The study was recently released in the journal Geochemical Perspectives Letters.
Technological Evolution in Space Studies
” This study is a testament to enormous technological progress we have made because 1972 when the last manned Moon mission went back to Earth,” said Northwesterns Dieter Isheim, who co-authored the study. “These samples were given Earth half-a-century back, but just today do we have the essential tools to perform microanalysis at the requisite level, consisting of atom-probe tomography.”
A lunar zircon grain under a microscopic lense. Credit: Jennika Greer
The atom-by-atom analysis enabled scientists to count the number of atoms in the zircon crystals have undergone radioactive decay. When an atom goes through decay, it sheds neutrons and protons to change into various aspects. Uranium, for example, rots into lead. Because researchers have developed how long it considers this process to unfold, they can assess the age of a sample by looking at the proportion of uranium and lead atoms.
” Radiometric dating works a little bit like an hourglass,” said the Field Museums Philipp Heck, the studys senior author. Radiometric dating works likewise by counting the number of moms and dad atoms and the number of daughter atoms they have changed to.
David Seidman, the Walter P. Murphy Professor Emeritus of Materials Science and Engineering at McCormick and founding director of NUCAPT, also co-authored the study. Jennika Greer, a research associate teacher at the University of Glasgow, is the studys lead author.
Lead author Jennika Greer working with the atom probe. Credit: Dieter Isheim, Northwestern
The Moons Formative Years
More than 4 billion years back, when the solar system was still young and the Earth was still growing, a huge Mars-sized things crashed into the Earth. An enormous hunk broke off Earth to form the Moon, and the energy of the impact melted the rock that ultimately became the Moons surface.
” When the surface was molten like that, zircon crystals could not form and endure,” Heck said. “So, any crystals on the Moons surface should have formed after this lunar magma ocean cooled. Otherwise, they would have been melted and their chemical signatures would be erased.”
Figuring out the age of the zircon crystals would reveal the minimum possible age of the Moon due to the fact that the crystals must have formed after the magma ocean cooled. To pinpoint the optimum possible age of the Moon, scientists turned to Northwesterns atom-probe tomography instruments.
” In atom-probe tomography, we start by sharpening a piece of the lunar sample into a very sharp pointer, using a concentrated ion beam microscopic lense, almost like an extremely elegant pencil sharpener,” Greer said. “Then, we use UV lasers to vaporize atoms from the surface of that pointer. The atoms travel through a mass spectrometer, and how quick they move tells us how heavy they are, which in turn informs us what theyre made of.”
After figuring out the materials in the sample and carrying out radiometric dating, the researchers concluded that the oldest crystals have to do with 4.46 billion years of ages. That suggests the Moon must be at least that old.
Its important to know when the Moon formed, Heck said, since “the Moon is a crucial partner in our planetary system. It stabilizes the Earths rotational axis. Its the reason there are 24 hours in a day. Its the reason we have tides. Without the Moon, life on Earth would look various. Its a part of our natural system that we desire to much better understand, and our research study provides a small puzzle piece in that entire picture.”
Referral: “4.46 Ga zircons anchor chronology of lunar magma ocean” by J. Greer, B. Zhang, D. Isheim, D.N. Seidman, A. Bouvier and P.R. Heck, 23 October 2023, Geochemical Perspectives Letters.DOI: 10.7185/ geochemlet.2334.
The study was supported by NASA and the Field Museums Womens Board Women in Science Graduate Fellowship. NUCAPT is supported by the National Science Foundation, the Office of Naval Research and the Paula M. Trienens Institute for Sustainability and Energy.