Last week, a handful of telescopes recorded two distinct flashes of light emanating from the moon’s surface, evidence of asteroids impacting the lunar landscape. These events serve as a reminder that the moon, often perceived as a tranquil orb, is actually a dynamic environment constantly bombarded by space debris.
A Noisy Neighbor: Lunar Impacts and Their Significance
Astronomers have long known that the moon is not immune to the relentless rain of asteroids, but these recent flashes highlight the ongoing nature of this activity. Daichi Fujii, a curator at the Hiratsuka City Museum in Japan, who monitors the moon’s surface with his telescopes, first detected a brief luminous outburst on Thursday at 8:33 p.m. local time. Then, just two days later, on Saturday at 8:49 p.m., he observed another bright flash, making for a rare back-to-back event.
These impacts aren’t spooky—they are the natural result of space rocks colliding with the moon’s surface.
High-Speed Collisions: What Happens When Asteroids Hit?
Without an atmosphere to slow them down, these asteroids impact the moon’s volcanic soil at staggering speeds—up to 60,000 miles per hour, a velocity roughly 30 times faster than a fighter jet. Even relatively small asteroids, just a few feet in length, can release powerful explosions upon impact, equivalent to a modest stockpile of dynamite. These explosions create fleeting flashes visible across vast distances from Earth.
Understanding how often the moon is struck by these smaller asteroids allows astronomers to refine their estimates of the number of larger, potentially hazardous asteroids in our solar system.
Tracking the Impacts: A Dedicated Observer
Fujii’s ongoing project to monitor the lunar surface has documented approximately 60 impacts since 2011. He utilizes a network of telescopes in Fuji and Hiratsuka, with software automatically detecting motion and explosions. While individual impacts are common, observing two within such a short timeframe is less frequent.
The first flash occurred just east of the 70-mile-wide Gassendi Crater. The second appeared west of Oceanus Procellarum, a vast 1,600-mile-long plain composed of crystallized magma.
Ruling Out Illusions: Confirming the Asteroid Strikes
While cosmic rays can sometimes produce false positives—strange sparks appearing on telescopes—multiple observatories in Japan independently captured the same glimmers from different angles, strongly suggesting genuine asteroid strikes.
“Those impact flashes seem real,” said Juan Luis Cano, an aerospace engineer with the European Space Agency’s Near-Earth Object Coordination Centre. “What caught my eye is that they both seem to be somewhat above the average in terms of flash size” — indicating that the impacts were more energetic than usual.
Possible Origins: Linking the Events to a Meteor Shower
Fujii suspects that these asteroids may be linked to the Taurid meteor shower, which streams off Comet Encke and peaks this month. The Taurids are known for producing larger-than-average meteors traveling at high speeds, increasing the likelihood that some will strike the moon instead of burning up in Earth’s atmosphere.
Future Implications: Protecting Our Lunar Future
Fujii’s dedication to monitoring the moon is driven by a desire to improve lunar security. As both space agencies and private companies pursue lunar habitation, understanding the frequency and energy of these impact flashes becomes increasingly vital for designing and operating safe lunar bases.
The ongoing research serves as a crucial step towards protecting our future in space.
