Uncovering Apollo's Archive: Tripling the Known Moonquake Count

Rummaging through the dusty annals of space exploration, scientists have unearthed a forgotten treasure that shines new light on our lunar companion's dynamic character. Half a century ago, the Apollo astronauts, in a feat that marks one of humanity's boldest ventures, left behind on the Moon's desolate surface a set of tools destined to peel back layers of lunar mystery. Among these were seismometers, designed to capture the Moon's faint whispers, its quakes—a testament to the celestial ballet it performs with the Earth and the cosmos at large. Fast forward to the present, and a meticulous analysis has sent shockwaves through the scientific community: the number of known moonquakes has soared to new heights, nearly tripling with the addition of over 22,000 newly identified tremors.

This revelation, delivered with palpable excitement at the Lunar and Planetary Science Conference in The Woodlands, Texas, propels the Moon from a seemingly static relic of the past to a dynamic entity, more alive and active than ever imagined. Jeffrey Andrews-Hanna, a distinguished geophysicist, couldn't hide his amazement, marveling at the Moon's capacity to still surprise us, half a century after humans first set foot upon its ghostly terrain.

The Apollo missions, a series of epic journeys undertaken between 1969 and 1977, had equipped the Moon with two varieties of seismometers. The first kind diligently recorded the slow, undulating dances of long-period seismic waves, while the second was tasked with capturing the rapid, jolting movements of shorter-period quakes. For decades, it was from the long-period instruments that all the previously recognized moonquakes emanated, the data from their short-period counterparts muddled by the harsh realities of lunar temperature swings and radio transmission errors, beyond the deciphering capabilities of the technology of the time.

Enter Keisuke Onodera, a seismologist from the University of Tokyo, who, with a mix of curiosity and determination, plunged into the neglected archives of short-period data. Onodera's approach was methodical yet innovative, leveraging time-tested denoising techniques over flashy artificial intelligence algorithms to sift through the cacophony. His laborious three-month endeavor unearthed a trove of 30,000 moonquake candidates, each meticulously vetted for the quintessential seismic signature.

Among the newfound seismic events, 46 enigmatic quakes stood out, originating from the enshrouded depths of 10 kilometers or more below the lunar surface, painting a picture of a Moon more complex and geologically active than our previous sketches had allowed. Alice Turner, a seismologist from the University of Texas, further corroborated these findings through independent methods, reinforcing the notion that the Moon's interior is a landscape still ripe for exploration.

The discovery also invites a reevaluation of the Moon's b-value, an esoteric measure comparing the frequency of small tremors to larger ones. Contrary to expectations based on terrestrial analogs, the newfound quakes suggest a lunar interior that defies easy categorization, possibly hinting at ancient magmatic intrusions lying dormant in the Moon's crust.

As NASA gears up to place a seismometer on the Moon's far side in the coming year, the scientific community waits with bated breath, hopeful that this will unlock further secrets of our nearest celestial neighbor. Meanwhile, Yosio Nakamura, whose unwavering dedication preserved the invaluable Apollo data, watches on, perhaps pondering what other revelations lie hidden within those reels, waiting for the light of discovery.

In an age where the cosmos remains vast and largely uncharted, our Moon—a familiar face in the night sky—reminds us that mystery and wonder can be found in our own celestial backyard, urging us ever onward in our quest for knowledge.

Source: [https://www.science.org/content/article/number-known-moonquakes-tripled-discovery-apollo-archive](https://www.science.org/content/article/number-known-moonquakes-tripled-discovery-apollo-archive)