Earthshine reflects Earth’s oceans and continents from the dark side of the Moon
Researchers from the University of Melbourne and Princeton University have shown for the first time that the difference in reflection of light from the Earth’s land masses and oceans can be seen on the dark side of the moon, a phenomenon known as earthshine.
The paper is published in this week’s edition of the international journal Astrobiology.
Sally Langford from the University of Melbourne’s School of Physics who conducted the study as part of her PhD, says that the brightness of the reflected earthshine varied as the Earth rotated, revealing the difference between the intense mirror-like reflections of the ocean compared to the dimmer land.
“In the future, astronomers hope to find planets like the Earth around other stars. However these planets will be too small to allow an image to be made of their surface,” she said.
“We can use earthshine, together with our knowledge of the Earth's surface to help interpret the physical make up of new planets.”
This is the first study in the world to use the reflection of the Earth to measure the effect of continents and oceans on the apparent brightness of a planet. Other studies have used a colour spectrum and infrared sensors to identify vegetation, or for climate monitoring.
The three year study involved taking images of the Moon to measure the earth’s brightness as it rotated, allowing Ms Langford to detect the difference in signal from land and water.
Observations of the Moon were made from Mount Macedon in Victoria, for around three days each month when the Moon was rising or setting. The study was conducted so that in the evening, when the Moon was a waxing crescent, the reflected earthshine originated from Indian Ocean and Africa’s east coast. In the morning, when the Moon was a waning crescent – it originated only from the Pacific Ocean.
“When we observe earthshine from the Moon in the early evening we see the bright reflection from the Indian Ocean, then as the Earth rotates the continent of Africa blocks this reflection, and the Moon becomes darker,” Ms Langford said.
“If we find Earth sized planets and watch their brightness as they rotate, we will be able to assess properties like the existence of land and oceans.”
More information about this article:
Ms Sally Langford
School of Physics
University of Melbourne
Ph (03) 8344 5442
Media Promotions Officer
Tel: +61 3 8344 8151
Nerissa Hannink | EurekAlert!
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...