Crystals from the Moon 50 Years Ago Prove We Were So Wrong

In 1972, humans set foot on the Moon for the last time (for now) after the Moon landing. Apollo 17. On board were the command module pilot, Ronald Evanscommander Eugene Cernan and lunar module pilot, Harrison Schmitt. The last two were the ones who, during their last walk, collected 66 kilograms of lunar samples for their analysis on Earth. And it was a small portion of these samples that, half a century later, was used to demonstrate that the age of the Moon is much older than we previously thought.

These samples of lunar material are exactly the same as those collected by others Apollo missions, were stored at NASA facilities for research. Only a small portion went towards memorial gifts to governments around the world. And also several samples taken from a sterile chamber by two students who wanted to find out what it would be like to have sex “on the moon.”

Leaving aside this curious extravagance, it is true that analysis Moon samples Over the years, it has been used by dozens of scientists to better understand our satellite. And the latest to do one of these analyzes are the authors of a study that was just published in the journal Letters on Geochemical Perspectives. It uses highly innovative methods to calculate the age of the Moon. It’s interesting because what they found is the minimum age. It may be much more, but nevertheless it is so. 40 million years higher than what was believed until now.

What did we know about the age of the Moon?

Does more than 4 billionPlanet Earth, still in its infancy, was abruptly hit by an object the size of Mars.

Millions of debris of all sizes were violently ejected, and one of them, under the gravitational pull of its damaged origin, managed to enter orbit around it, forming what remains today. your only companion. Thus the Moon was born.

How and when this birth might have occurred has been studied for many years. How, as we see, is quite clear. But when this will happen remains the question. There were rough estimates, although it was not known exactly. Now, thanks to this new study, we have new information about the age of the Moon that allows it to be considered a satellite. much longer than we thought at first.

Very new technology

To carry out this calculation, the study authors used a completely new technique called atom probe tomography.

This requires initial sample processing, which aggravates, for example, when you sharpen a pencil. Thus, the crystals are ready for expose them to ultraviolet lasers, which evaporate atoms from the surface of this tip. The atoms are then passed through a mass spectrometer, which can analyze the evaporated samples and determine the speed at which its atoms move. This speed provides information about their mass, which in turn can provide information about the radioactive decay they have undergone. The authors of the study say this.

“When an atom has an unstable configuration of protons and neutrons in its nucleus, it undergoes decay, releases some of those protons and neutrons, and turns into various elements.” This is very useful because we know how long it takes for this phenomenon to occur, so the proportions of the various atoms already transformed can tell us sample age. If there are a lot of them untransformed, it is still very new, but if enough have already been transformed, then they are much older.

Now there is something important to remember. And after this Mars-sized object hit Earth, material on the surface melted, resulting in the formation of magma ocean. Not a single crystal could survive in this ocean. The new elements that were able to form evaporated and disappeared. Therefore, the analyzed crystals will appear after the molten material has cooled. This indicates that the age of the Moon calculated in this study is the minimum age. That is, the years that have passed since the magma ocean crystallized. But the impact happened earlier, and we cannot know that. At least not at the moment.

Anyway, now we know that at least 4.7 billion years that the Earth has a faithful satellite orbiting around it. Who knows? Perhaps in the future there will be methods that will allow us to further refine the age of the Moon.