Meteors hit the Moon constantly. About 1.4 tons of meteoroid material strikes the lunar surface every single day, a steady bombardment that never lets up because the Moon has no atmosphere to burn anything away. On Earth, the vast majority of incoming space debris disintegrates high in the atmosphere. On the Moon, every particle, from a speck of dust to a boulder, slams directly into the ground.
Why Every Meteoroid Reaches the Surface
Earth receives roughly 33 metric tons of meteoroid material per day, but almost all of it burns up during atmospheric entry. Only a tiny fraction survives to reach the ground. The Moon has essentially no atmosphere, so there is no friction, no heat shield, no breakup on the way down. A grain of sand traveling at 20 km/s hits the lunar surface at full speed. That lack of protection is the single biggest reason the Moon is so heavily cratered compared to Earth.
Impact speeds range from about 20 km/s (45,000 mph) on the slow end to over 72 km/s (160,000 mph) on the fast end. At those velocities, even a pebble-sized object releases enough energy to excavate a visible crater and produce a brief flash of light that telescopes on Earth can detect.
Daily, Monthly, and Yearly Rates
The 1.4 tons per day figure comes from modeling the meteoroid environment around the Earth-Moon system. That mass is spread across an enormous number of tiny particles and a much smaller number of larger ones. The relationship between size and frequency follows a steep curve: dust-grain impacts happen millions of times per day, marble-sized impacts happen many times per day, and impacts large enough to leave a crater visible from orbit happen a few hundred times per year.
The rate fluctuates by about 10% over the course of a year. These variations are tied to the Moon’s position relative to known streams of debris left behind by comets, the same streams that produce annual meteor showers like the Perseids and Geminids on Earth. During those shower periods, the Moon passes through denser bands of particles, and the impact rate ticks upward.
New Craters Spotted From Orbit
NASA’s Lunar Reconnaissance Orbiter (LRO) has provided the best direct evidence of how often sizable impacts occur. Since arriving at the Moon in 2009, the spacecraft has photographed the surface repeatedly at high resolution. By comparing older images with newer ones, the camera team has confirmed more than 25 brand-new craters, plus hundreds of smaller surface changes that are harder to classify definitively.
One of the most dramatic examples came on March 17, 2013, when observers on Earth spotted a bright flash on the Moon’s dark side. LRO later photographed the impact site and found a fresh crater 18 meters (about 59 feet) wide. The impactor that created it was probably only 30 to 40 centimeters across, roughly the size of a basketball, but it struck at tens of kilometers per second.
These confirmed craters represent only what LRO happened to photograph before and after an impact. The actual rate of new crater formation is far higher than 25 over a decade. Many impacts occur on parts of the surface that haven’t been re-imaged yet, or they create craters too small for the camera to resolve.
Impact Flashes Visible From Earth
You don’t need a spacecraft to watch the Moon get hit. Since 2005, NASA’s Lunar Impact Monitoring Program and a parallel European Space Agency effort have used ground-based telescopes to record flashes of light on the Moon’s unlit portion. Over 400 impact flashes have been confirmed so far. Each flash lasts a fraction of a second and represents a meteoroid (typically a few centimeters to tens of centimeters across) slamming into rock at hypervelocity.
These observations can only happen when conditions are right: the impact site must be on the Moon’s night side, the Moon must be in a crescent or gibbous phase so that enough dark surface is visible, and weather on Earth must cooperate. That means the confirmed 400-plus flashes represent a small sample of the total. The actual number of impacts in that size range is many times higher.
How the Moon Compares to Earth
Earth’s larger size and stronger gravity pull in more meteoroids overall. Roughly 20 asteroids strike Earth for every one that hits the Moon. But “strike Earth” is misleading for smaller objects, because the atmosphere destroys nearly all of them before they reach the ground. In practical terms, the Moon accumulates fresh craters far more quickly than Earth does, because every impact leaves a permanent mark.
The Moon receives about 30 times less mass per day than Earth (1.4 tons versus 33 tons), which reflects its smaller cross-section and weaker gravity. But that 1.4 tons hits bare rock at full cosmic speed, which is why even a modest impactor can leave a crater you could park a bus in.
What This Means for Lunar Exploration
For future astronauts and lunar bases, the constant bombardment is a real engineering concern. The vast majority of impacts involve particles too small to threaten a habitat, but the sheer volume means that over time, exposed surfaces accumulate tiny pits and damage. Spacesuits, solar panels, and optical equipment are all vulnerable.
Larger, rarer impacts pose a different kind of risk. A meteoroid the size of a golf ball could destroy equipment or breach a habitat wall. The probability of a direct hit on any given small structure is extremely low in a human lifetime, but mission planners factor it into habitat design, choosing locations and shielding strategies that reduce exposure. The same LRO data and impact flash observations that tell us how often the Moon gets hit are now feeding directly into those safety calculations.