Moon’s Ice Took More Than 1.5 Billion Years to Form, New Research Suggests

Ridges connected the aboveground of the moon. Credit: NASA

Ice astatine the moon’s poles apt formed implicit a agelong period, gathering up for astatine slightest 1.5 cardinal years alternatively than arriving successful a azygous event, according to a caller survey published successful Nature Astronomy.

The probe was led by an planetary squad of scientists, including planetary idiosyncratic Paul Hayne from the Laboratory for Atmospheric and Space Physics astatine the University of Colorado Boulder.

A long-standing lunar mystery

For decades, information from NASA missions person suggested that h2o exists connected the moon. Much of it appears arsenic crystal trapped successful heavy craters adjacent the lunar South Pole.

These craters stay successful imperishable shadow. Sunlight ne'er reaches them. Temperatures tin driblet to astir minus 160 degrees Celsius (−256°F) , acold capable to sphere crystal for billions of years.

Scientists person struggled to explicate however this h2o formed and wherefore it appears unevenly crossed antithetic craters.

Evidence points to gradual accumulation

The caller survey supports a dilatory and dependable process. Water apt arrived successful tiny amounts implicit time. Possible sources see comet and asteroid impacts, past volcanic activity, and reactions driven by the star wind.

Hydrogen from the star upwind perpetually hits the lunar surface. Some of it reacts with oxygen successful the ungraded to signifier water. The findings suggest that this process continued for astatine slightest 1.5 cardinal years and perchance arsenic agelong arsenic 3 to 3.5 cardinal years.

The survey besides rules retired the thought that a azygous ample comet delivered astir of the moon’s water.

Older craters clasp much ice

The researchers recovered that older craters thin to incorporate much crystal than younger ones. This signifier points to semipermanent accumulation. Much of the crystal is stored successful “cold traps.” These are craters that person remained successful acheronian for highly agelong periods.

Ice connected the satellite didn’t get successful 1 large lawsuit — it built up dilatory implicit astatine slightest 1.5 cardinal years, a caller survey finds.Scientists accidental past craters adjacent the South Pole clasp the astir ice, making them cardinal targets for aboriginal missions.#Moon #Space #NASA #Science pic.twitter.com/ePJebEQdAA

— Tom Marvolo Riddle (@tom_riddle2025) April 7, 2026

Observations from NASA’s Lunar Reconnaissance Orbiter, launched successful 2009, enactment this. Its instruments detected signals accordant with crystal successful respective shadowed regions. However, the crystal is not evenly distributed. Some craters incorporate overmuch much crystal than others.

Moon’s changing tilt explains uneven distribution

To recognize this pattern, the squad examined the moon’s history. Oded Aharonson of the Weizmann Institute of Science led portion of the enactment during a probe sojourn successful 2025.

Using somesthesia information and machine simulations, the squad recovered that the moon’s tilt has shifted implicit time. Craters that are permanently shadowed contiguous were not ever successful darkness.

The researchers identified which craters stayed acheronian the longest. These oldest and coldest regions lucifer areas wherever the strongest signs of crystal person been observed.

Key sites for aboriginal exploration

The findings could assistance usher aboriginal missions. Scientists tin present absorption connected craters that are astir apt to clasp ice.

One starring campaigner is Haworth Crater adjacent the South Pole. It whitethorn person remained successful shadiness for much than 3 cardinal years, making it a beardown determination for ample crystal deposits.

NASA plans to research these regions further nether its Artemis program, which aims to instrumentality humans to the moon.

Water could enactment quality missions

Lunar crystal could go a invaluable assets for astronauts. It tin beryllium utilized for drinking h2o oregon divided into hydrogen and oxygen to nutrient fuel.

Hayne said much elaborate observations are inactive needed. He is processing a caller instrument, the Lunar Compact Infrared Imaging System (L-CIRiS), which NASA plans to deploy adjacent the South Pole successful 2027.

He added that the root of the moon’s h2o volition lone beryllium confirmed done nonstop illustration analysis. Scientists volition request to survey worldly connected the satellite oregon bring it backmost to Earth.

Aharonson said finding usable h2o beyond Earth remains 1 of the astir important challenges successful astronomy.