New high-res map suggests little water inside moon

February 12, 2009

COLUMBUS, Ohio -- The most detailed map of the Moon ever created has revealed never-before-seen craters at the lunar poles.

The map is also revealing secrets about the Moon's interior -- and hinting about Mars's interior as well.

C.K. Shum, professor of earth sciences at Ohio State University, is part of the international research team that published the map in the February 13 issue of the journal Science.

"The surface can tell us a lot about what's happening inside the Moon, but until now mapping has been very limited," Shum said. "For instance, with this new high-resolution map, we can confirm that there is very little water on the Moon today, even deep in the interior. And we can use that information to think about water on other planets, including Mars."

Using the laser altimeter (LALT) instrument on board the Japanese Selenological and Engineering Explorer (SELENE) satellite, the researchers mapped the Moon at an unprecedented 15-kilometer (9-mile) resolution.

The principal investigator of the LALT instrument is Hiroshi Araki of the National Astronomical Observatory of Japan, and he is the lead author of the study. Shum is a member of the LALT science team.

The map is the first to cover the Moon from pole to pole, with detailed measures of surface topography, on the dark side of the moon as well as the near side. The highest point -- on the rim of the Dririchlet-Jackson basin near the equator -- rises 11 kilometers (more than 6.5 miles) high, while the lowest point -- the bottom of Antoniadi crater near the south pole -- rests 9 kilometers (more than 5.5 miles) deep.

In part, the new map will serve as a guide for future lunar rovers, which will scour the surface for geological resources.

But Araki and his colleagues did something more with the map: they measured the roughness of the lunar surface, and used that information to calculate the stiffness of the crust.

If water flowed beneath the lunar surface, the crust would be somewhat flexible, but it wasn't. The surface was too rigid to allow for any liquid water, even deep within the Moon.

Earth's surface is more flexible, by contrast, with the surface rising or falling as water flows above or below ground. Even our planet's plate tectonics is due in part to water lubricating the crust.

And Mars? On a scale of surface roughness, it falls somewhere between the Earth and the Moon, which indicates that there may have once been liquid water, but that the surface is now very dry.

No surprise there.

But Mars' roughness coupled with the complete absence of plate tectonics suggests that if there is water in the red planet's interior, it is not located near the surface, where it could lubricate the crust, Shum explained.

The LALT map is the most detailed lunar map ever created. The last three Apollo missions mapped part of the surface in the early 1970s, and the 1994 Clementine mission in offered a resolution between 20-60 kilometers in certain locations, but not the entire surface.

The SELENE mission offers 15-kilometer resolution consistently over the entire surface, because it features two smaller sub-satellites which closely track the main satellite.

"This design significantly improved our ability to model gravity fields on the moon, and let us compute the main satellite's orbit more accurately than was possible before, especially over the far side the Moon. That led to more accurate measurement of the lunar topography using LALT," Shum said.

The map revealed several small craters at the north and south poles that hadn't been seen before. For example, a 15-kilometer-wide crater can be seen inside the much larger de Gerlache crater at the south pole.
-end-
Araki and Shum's coauthors on the paper hail from the National Astronomical Observatory of Japan, the Geographical Survey Institute of Japan, the Japan Aerospace Exploration Agency (JAXA), and the German Aerospace Center. At Ohio State, research scientist Yuchan Yi and doctoral student Hoksum Fok worked on lunar data processing.

The American component of this research was partially funded by Ohio State and JAXA.

Ohio State University

Related Plate Tectonics Articles from Brightsurf:

Lost and found: UH geologists 'resurrect' missing tectonic plate
A team of geologists at the University of Houston College of Natural Sciences and Mathematics believes they have found the lost plate known as Resurrection in northern Canada by using existing mantle tomography images.

Plate tectonics goes global
A research team led by Dr. WAN Bo from the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences has revealed that plate tectonics went global 2 billion years ago.

Remixed mantle suggests early start of plate tectonics
New Curtin University research on the remixing of Earth's stratified deep interior suggests that global plate tectonic processes, which played a pivotal role in the existence of life on Earth, started to operate at least 3.2 billion years ago.

Why the Victoria Plate in Africa rotates
The East African Rift System is a newly forming plate tectonic boundary at which the African continent is being separated into several plates.

Evidence for plate tectonics on earth prior to 3.2 billion years ago
New research indicates that plate tectonics may have been well underway on Earth more than 3.2 billion years ago, adding a new dimension to an ongoing debate about exactly when plate tectonics began influencing the early evolution of the planet.

Upper-plate earthquakes caused uplift along New Zealand's Northern Hikurangi Margin
Earthquakes along a complex series of faults in the upper plate of New Zealand's northern Hikurangi Subduction Margin were responsible for coastal uplift in the region, according to a new evaluation of local marine terraces.

Breathing? Thank volcanoes, tectonics and bacteria
A Rice University study in Nature Geoscience suggests Earth's first burst of oxygen was added by a spate of volcanic eruptions brought about by tectonics.

What drives plate tectonics?
Scientists found ''switches'' between continental rupture, continental collision, and oceanic subduction initiation in the Tethyan evolution after a reappraisal of geological records from the surface and new global-scale geophysical images at depth.

Plate tectonics may have driven 'Cambrian Explosion, study shows
The quest to discover what drove one of the most important evolutionary events in the history of life on Earth has taken a new, fascinating twist.

Zipingpu Reservoir reveals climate-tectonics interplay around 2008 Wenchuan earthquake
A new study led by Prof. JIN Zhangdong from the Institute of Earth Environment (IEE) of the Chinese Academy of Sciences provided a new insight on the interplay between climate and tectonics from a sediment record in the Zipingpu Reservoir around the 2008 Wenchuan earthquake.

Read More: Plate Tectonics News and Plate Tectonics Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.