Featured Research

from universities, journals, and other organizations

First microwave image of the complete Moon

Date:
September 21, 2010
Source:
Europlanet Media Centre
Summary:
The first microwave image of the complete Moon was obtained thanks to the Chinese lunar satellite Chang’E-1. Global brightness temperature maps reveal radiation from the surface and deeper layers of the Moon and its diurnal variation. This will help astronomers to determine the detailed heat flow and, thus, the inner energy of the Moon.

Day time brightness temperature map of the Moon from China’s first first lunar probe Chang’E-1 at 37 GHz. False-colour image.
Credit: Image courtesy of Europlanet Media Centre

The first microwave image of the complete Moon was obtained thanks to the Chinese lunar satellite Chang'E-1. Global brightness temperature maps reveal radiation from the surface and deeper layers of the Moon and its diurnal variation. This will help astronomers to determine the detailed heat flow and, thus, the inner energy of the Moon.

These exciting new results are being presented by Dr. Yong-Chun Zheng and Dr. Kwing L. Chan at the European Planetary Science Congress in Rome.

Chang'E-1 (CE-1) is China's first scientific mission to explore planetary bodies beyond Earth. The stereo camera, one of the eight science instruments on board the spacecraft, has produced a state-of the-art global image of the Moon with unprecedented image quality and positioning precision. The Solar Wind Ion Detector (SWID) has discovered the acceleration of scattered solar wind protons close to the lunar polar terminator. And now, the Lunar Microwave Radiometer (MRM) made it possible, for the first time, to globally map the Moon in microwave frequencies.

Astronomers know that active radar observations of the Moon cannot provide thermal information, only passive observations in the infra-red and microwave regimes can achieve that. Furthermore, only microwave detectors can sense emission from below the lunar surface (down to tens of meters). Ground-based microwave observations are not the best choice in order to do this, because they cannot "see" the far side of the moon neither can obtain accurate brightness temperature near the limb.

Before CE-1, there was no passive, multi-channel, microwave remote sensing of the Moon from a satellite. CE-1 had a polar orbit and, thus, was able to observe essentially every location of the moon with a nadir view. Thanks to the long lifespan of CE-1 (494-days), the MRM obtained brightness temperature data that cover the Moon globally eight times, during both lunar daytime and nighttime periods. This global, diurnal coverage provides extremely valuable data for studying the lunar regolith ('dust' and impact debris covering almost the entire Moon surface).

CE-1 was observing from an altitude of 200 km from the lunar surface, providing spatial resolution orders of magnitude better than any ground-based microwave observation can ever achieve on Earth. Indeed, the sensitivity (0.5K) and dynamical range (20-500K) of the observable brightness temperature obtained by CE-1 is unsurpassed. "No future mission, from any country, has been planned with a comparable program in microwave measurement," says Dr. Zheng of the Chinese Academy of Sciences.

The CE-1 microwave observations have made several important breakthroughs. MRM passively measured microwave emission in four frequency channels: 3, 7.8, 19.35, and 37 GHz. The higher frequency emission comes from a layer just a little below the surface (a few centimeters), whereas the lower frequency emission can probe depths beyond a few meters. "With such penetrative ability, the microwave data can be used to infer thermo-physical properties of the lunar regolith, as well as, to find out about the variation of regolith thickness across the lunar surface," says Dr. Chang from Hong Kong University Sci&Tech. Such information is useful for estimating the distribution and amount of helium 3, a promising nuclear fuel for in situ fusion energy production in the future human settlements on the Moon. (Helium 3 originated from the sun and is believed to have been implanted in the lunar regolith by the solar wind).

Using the MRM data, Dr. Zheng and his team have constructed global brightness temperature maps of the Moon for different frequencies, and separately for day and night times. The results are particularly revealing. On the 37 GHz daytime map, the maria, which appear dark in visible light, become bright in microwave wavelengths to reflect the higher temperatures (due to stronger absorption in the solar visible spectrum). Geological features like craters and mountains are clearly visible, but the prominent bright areas correlate mainly with the surface abundance of titanium. The correspondent nighttime microwave image is even more striking: The nighttime moon appears dotted by dark (cool) areas that turn out to be associated with hot areas during lunar eclipses. "This enigma will keep the theorists busy for a while!" says, Dr. Zheng.

A sister orbital probe to CE-1, Chang'E-2, is scheduled to be launched in October 2010.


Story Source:

The above story is based on materials provided by Europlanet Media Centre. Note: Materials may be edited for content and length.


Cite This Page:

Europlanet Media Centre. "First microwave image of the complete Moon." ScienceDaily. ScienceDaily, 21 September 2010. <www.sciencedaily.com/releases/2010/09/100920110942.htm>.
Europlanet Media Centre. (2010, September 21). First microwave image of the complete Moon. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2010/09/100920110942.htm
Europlanet Media Centre. "First microwave image of the complete Moon." ScienceDaily. www.sciencedaily.com/releases/2010/09/100920110942.htm (accessed April 23, 2014).

Share This



More Space & Time News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins