"These findings change the prediction for where we would expect to find water ice on the Moon, and it dramatically changes estimates for how much water ice there is on the Moon. Ancient water ice reservoirs are no longer expected," said Schorghofer, lead author of "Past Extent of Lunar Permanently Shadowed Areas" that appears in Science Advances.
Lunar water ice is a component integral to missions to the Moon, both to maintain human life and for producing fuel for spacecraft. Permanently shadowed regions (PSRs) are thought to have trapped ices and are a main focus of lunar exploration.
The Moon steadily migrates away from Earth, and it feels tidal forces from both the Earth and the Sun. It was known for decades that the Moon experienced a major spin axis reorientation at some point in the deep past, but there wasn't enough data to really know when. It was only last year that a group in France came up with a coherent history for the evolution of the Earth-Moon distance.
"When I heard about their result, I immediately realized it has profound implications for the search of water ice on the Moon. I dropped everything I was doing and began to work out the specifics, with the help of my co-author Raluca Rufu," Schorghofer said.
"We calculated the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-Moon distance," he said.
Early in its history, the Moon (which is 4.5 billion years old) was bombarded by comets and volcanism released water vapor from its interior, but continuously shadowed areas started to appear only 3.4 billion years ago. By that time these processes had started to die down, so most of the water that was delivered to the Moon or outgassed from its interior could not have been trapped in the polar regions. Any ice in the polar regions today must have a more recent origin.
"We have been able to quantify how young the lunar PSRs really are," Schorghofer said. "The average age of PSRs is 1.8 billion years, at most. There are no ancient reservoirs of water ice on the Moon."
The impact site of the Lunar Crater Observation and Sensing Satellite, a robotic spacecraft that detected water in 2009, lies within a PSR that is less than 1 billion years old, and therefore all the volatiles discovered there - which include water and carbon dioxide - must be young, he said. In a way this is very encouraging, because even the young PSRs contain ice. Older PSRs should contain even more ice.
This work might also explain why the polar regions of planet Mercury have much more ice than the Moon's. Mercury's PSRs are much older and could have captured water early on.
|Subscribe Free To Our Daily Newsletters|
Two Russians, American reach space station
Rockets and Porsches: rich Russians flock to Baikonur spaceport
Soyuz hatch opens, Expedition 69 expands to 10 crewmates
Kayhan Space Raises $7 million, Unveils First-Ever Autonomous Space Traffic Coordination Service
'Anomaly' ends Rocket Lab launch mid-flight
SpaceX deploys another 22 Starlink satellites
Mini space thruster that runs on water
Rocket Lab signs deal with Leidos to launch 4 HASTE missions
Curiosity reaches Mars ridge where water left debris pileup
Within the Margin
Dusty Skies in the Cloudy Season: Sols 3950-3952
Sols 3948-3949: A Rocky Road, or Two!
Tianzhou 5 spacecraft burns up on Earth reentry
Crew of Shenzhou XV mission honored for six-month space odyssey
China solicits names for manned lunar exploration vehicles
From rice to quantum gas: China's targets pioneering space research
Intelsat delivers new reliable broadcast connectivity service|
Successful entry into service of Eutelsat Hotbird 13F and 13G satellites
Sidus Space announces 180-Day extension on NASDAQ minimum pricing
Terran Orbital announces pricing of Public Offering
China builds new radio telescope to support lunar, deep-space missions
Every Gram Counts: SCHOTT Launches Lightweight Microelectronic Packages for Aerospace
AFRL'S newest supercomputer 'Raider' promises to compute years' worth of data in days
Skyloom and Satellogic sign agreement for Multipath Optical Comms Data Transmission
Exoplanet with a large iron core adds to puzzle of how planets form
New recipes for origin of life may point way to distant, inhabited planets
Tiny sea creatures reveal the ancient origins of neurons
On the road to spotting alien life
Juice: why's it taking sooo long
Possible existence of Earth-like planet predicted in Outskirts of Solar System
SwRI will lead Hubble, Webb observations of Io, Jupiter's volcanic moon
In the service of planetary science, astrophysics and heliophysics
|Subscribe Free To Our Daily Newsletters|