Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New NASA temperature maps provide 'whole new way of seeing the moon'

22.09.2009
UCLA professor leads first-ever effort to map moon's surface temperatures
NASA's Lunar Reconnaissance Orbiter (LRO), an unmanned mission to comprehensively map the entire moon, has returned its first data. One of the seven instruments aboard, the Diviner Lunar Radiometer Experiment, is making the first global survey of the temperature of the lunar surface while the spacecraft orbits some 31 miles above the moon.

Diviner has obtained enough data already to characterize many aspects of the moon's current thermal environment. The instrument has revealed richly detailed thermal behavior, throughout both the north and south polar regions, that extends to the limit of Diviner's spatial resolution of just a few hundred yards.

"Most notable are the measurements of extremely cold temperatures within the permanently shadowed regions of large polar impact craters in the south polar region," said David Paige, Diviner's principal investigator and a UCLA professor of planetary science. "Diviner has recorded minimum daytime brightness temperatures in portions of these craters of less than -397 degrees Fahrenheit. These super-cold brightness temperatures are, to our knowledge, among the lowest that have been measured anywhere in the solar system, including the surface of Pluto."

"After decades of speculation, Diviner has given us the first confirmation that these strange, permanently dark and extremely cold places actually exist on our moon," said science team member Ashwin Vasavada of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Their presence greatly increases the likelihood that water or other compounds are frozen there. Diviner has lived up to its name."

These observations, made during Diviner's "commissioning phase," provide a snapshot in time of current polar temperatures that will evolve with the lunar seasons.

"It is safe to conclude that the temperatures in these super-cold regions are definitely low enough to cold-trap water ice, as well as other more volatile compounds, for extended periods," Paige said. "The existence of such cold traps has been predicted theoretically for almost 50 years. Diviner is now providing detailed information regarding their spatial distribution and temperatures."

Diviner's thermal observations represent one component of the LRO's strategy for determining the nature and distribution of cold-trapped water ice in the lunar polar regions. Future comparisons between Diviner data, physical models and other polar data sets may provide important scientific conclusions regarding the nature and history of the moon's polar cold traps and any cold-trapped volatile materials they contain, Paige said.

The moon's surface temperatures are among the most extreme of any planetary body in the solar system. Noontime surface temperatures near the lunar equator are hotter than boiling water, while nighttime surface temperatures on the moon are almost as cold as liquid oxygen. It has been estimated that near the lunar poles, in areas that never receive direct sunlight, temperatures can dip to within a few tens of degrees of absolute zero.

Data accumulated by Diviner during August and the first half of September indicate that equatorial and mid-latitude daytime temperatures are 224 degrees Fahrenheit, and then decrease sharply poleward of 70 degrees north latitude. Equatorial and mid-latitude nighttime temperatures are -298 degrees Fahrenheit, and then decrease poleward of 80 degrees north latitude. At low and mid-latitudes, there are isolated warmer regions with nighttime temperatures of -208 degrees Fahrenheit.

"These correspond to the locations of larger, fresh impact craters that have excavated rocky material that remains significantly warmer than the surrounding lunar soil throughout the long lunar night," Paige said.

The thermal behavior at high latitudes contrasts sharply with that of the equatorial and mid-latitudes. Close to the poles, both daytime and nighttime temperatures are strongly influenced by local topography, and the thermal outlines of many partially illuminated impact craters are apparent.

"Getting a look at the first global thermal maps of the lunar surface is a whole new way of seeing the moon," Paige said.

NASA's LRO launched June 18. Diviner has been mapping the moon continuously during the LRO commissioning phase. Since the instrument was first activated on July 5, it has acquired more than 8 billion calibrated radiometric measurements and has mapped almost 50 percent of the surface area of the moon.

"The performance of the instrument has been excellent, and closely matches our predictions," said instrument engineer Marc Foote of JPL.

"We have already accumulated an enormous amount of high-quality data," Paige said.

There are large gaps between Diviner's individual ground tracks at the equator, but in the polar regions, the ground tracks overlap to create continuous high-resolution maps. During the commissioning phase, the plane of the LRO orbit moved from 5:40 to 1:10 a.m. and p.m., on the night side and day side, respectively. It will take about six months for LRO’s orbit to sample the full range of lunar local times.

In addition to mapping the moon, Diviner executed a series of specialized calibration sequences during the commissioning phase. These included scans of the "limb," or visible edge of the moon to better define the instruments' fields of view and an infrared panorama of a portion of the LRO spacecraft, as well as infrared scans of the Earth from lunar orbit, which are presently being analyzed.

"Diviner has been put through her paces and has executed our commands brilliantly," said JPL scientist and lead observational sequence designer Benjamin Greenhagen. "Diviner's operations have run very smoothly."

During the course of LRO's mapping mission, Diviner will map the entire surface of the moon at high resolution to create the first global picture of the current thermal state of the moon and its daily and seasonal variability.

The moon's extreme temperature environment is of interest to future human and robotic explorers, especially if they plan to visit the moon for extended periods. Detailed thermal maps of the moon can also yield information regarding the locations of rocky areas that may be hazardous to landing vehicles and details for mapping compositional variations in lunar rocks and soils. In the moon's polar regions, temperature maps also point to the locations of cold traps where water ice and other volatile materials may have accumulated. Mapping the locations of these lunar cold traps and searching for the presence of frozen water are among the main goals of the LRO mission.

Diviner is operated by the California Institute of Technology Jet Propulsion Laboratory (JPL), which designed and built the instrument.

Diviner determines the temperature of the moon by measuring the intensity of infrared radiation emitted by the lunar surface. The hotter the surface, the greater the intensity of emitted infrared radiation. Diviner measures infrared radiation in seven infrared channels that cover an enormous wavelength range, from 7.6 to 400 microns. Diviner is the first instrument designed to measure the full range of lunar surface temperatures, from the hottest to the coldest. Diviner also includes two solar channels (channels 1 and 2) that measure the intensity of reflected solar radiation.

The following Diviner images can be found in the right-hand column of this page:

Figures 3a-b, 4a-b and 5 show Diviner's high-resolution daytime thermal maps of the north and south polar regions acquired between July 17 and Aug. 14.

Figures 3a and 4a show Diviner Channel 3, the instrument's shortest-wavelength infrared channel, which is sensitive only to warmer surfaces, making it useful for mapping the extent of shadowed regions.

Figures 3b and 4b show Diviner Channel 8, which is one of Diviner's longest-wavelength infrared channels; it has excellent capability to measure extremely low temperatures in unilluminated areas.

Figure 5 shows a close-up view of Diviner Channel 8 high-resolution thermal maps of a portion of the south polar region.

Figures 2a-b show the first global daytime and nighttime thermal maps of the moon, created using Diviner data accumulated during August and the first half of September. The maps show Channel 8 brightness temperatures, which approximate actual surface physical temperatures.

Figures 1a-c show scans of the limb of the moon and an infrared panorama of a portion of the LRO spacecraft.

As the LRO orbits the moon every two hours, Diviner maps a nearly continuous swath on the lunar surface. Diviner's swath samples the full range of lunar longitudes once per month to create thermal maps. Diviner will acquire 24 thermal maps of the moon over the course of a year — 12 daytime maps and 12 nighttime maps — each covering a different range of lunar local times.

For more information, visit the Diviner's web site at http://diviner.ucla.edu and the LRO website: http://lunar.gsfc.nasa.gov.

UCLA is California's largest university, with an enrollment of nearly 38,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 323 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Four alumni and five faculty have been awarded the Nobel Prize.

Stuart Wolpert | EurekAlert!
Further information:
http://www.ucla.edu

More articles from Physics and Astronomy:

nachricht New thruster design increases efficiency for future spaceflight
16.08.2017 | American Institute of Physics

nachricht Tracking a solar eruption through the solar system
16.08.2017 | American Geophysical Union

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>