Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate model for Earth also describes changes on Mars

26.09.2002


Orbit affects climate on Mars similar to the way it affects climate on Earth, say three scientists, who used a model of climate change on Earth to explain the layers of deposits in the polar regions of the Red Planet.


An image from the Hubble Space Telescope shows the full disk of Mars. Clouds and weather can be seen at the poles. [Image: NASA, Hubble Heritage Team (STScl/AURA) Hubble Space Telescope WFPC2 STScl-PRC01-24].


This image, from an exposure of layers in the North Pole of Mars, is the actual image used in the analysis. Mustard and his colleagues say the alternating bright and dark bands are due to changes in climate recorded in these layers. The image is of an area about a mile across. [Image: NASA/JPL/Malin Space Science Systems].



Their study appears in the Sept. 26 issue of Nature, and suggests that a climate change theory for Earth can also be applied to Mars and possibly to other Earth-like planets.

“The orbital theory of climate change has been successful in explaining changes in the Earth’s climate, and we have used cores of the Greenland and Antarctic ice caps to reconstruct past climates and atmospheres on Earth,” said author Jack Mustard, associate professor of geological sciences at Brown University. “This means that we can now use the Mars caps in a similar way.”


The study also produced “a much better constraint on the time required to form the layers on the polar cap of Mars,” he said. “This has importance in understanding the Martian climate, and also the water cycles and history. We have so little information on the rates of change on Mars, but this gives us a solid marker.”

Besides Mustard, the other two authors of the study are Jacques Laskar and Benjamin Levrard of the Astronomie et Systèmes Dynamiques in Paris.

The trio used orbital calculations and rotational parameters of Mars, new high-resolution images of its north pole terrain, and high-resolution topography data to correlate exposed layers of ice and dust with changes in climate, particularly the sum of solar radiation reaching the terrain. Their techniques mirrored those used for orbital-based climate studies on Earth.

Changes in the ratio of dust and ice over time are visible in the variations of brightness seen in the layers of polar deposits on Mars. First noticed in the earliest Mars missions, the layers were thought to be related to changes in climate possibly linked with the evolution of Mars’ orbit such as the tilt of the axis and deviations in circularity. But the image resolution of past data was insufficient to resolve such key details.

High-resolution images from the Mars Global Surveyor allowed Mustard to resolve the fine detail and analyze the patterns. “After correcting the observations for topography, we produced a measure of the brightness of the layers as a function of depth,” he said. “We assume that depth equals time and thus can peer into the past. We then compared this record with the predicted amount of sunlight received at the pole over the last 10 million years, which varies with orbital evolution involving tilt and circularity.”

The researchers’ goal was to determine whether the sunlight record at the north polar cap of Mars correlated with the brightness-depth profile, and over what time frame. If the record correlated, that would solidify their hypothesis that the layers are due to climate changes related to orbit and allow the researchers to determine the formation rate of the layers.

“Indeed we find an excellent correlation and show that the 350-meter thick package of layers formed within the last 1 million years or so,” Mustard said. For the most recent 250-meter thick deposit of the north ice polar cap, the researchers found an average deposition rate of 0.05 cm/yr. “For the first time, we showed that the orbital theory of climate change has a record in the polar deposits on Mars.”

In orbit, Earth tilts about 23-25 degrees. In contrast, Mars tilts as little as 15 degrees and as much as 40 degrees, which is enough to redistribute moisture from polar caps to equatorial regions, Mustard said. In the 1970s, research by geologists at Brown first showed an orbital effect on climate change for Earth.

“This study further ties Mars and Earth as similar planets and strengthens the foundations to compare their climates and orbital evolutions,” Mustard said. “Showing that a planet with as strange an orbit as Mars has climate changes recorded in its surface means we have a tool in this orbital driver to explore what happens on the surface of planets with differences and similarities to Earth. And as we learn more about deposits on Mars we can compare what we find with what we know about Earth.”

The Centre Nationale de la Recherche Scientifique Programme Nationale de Planétologie and NASA’s Solar System Exploration programs supported the research.

Scott Turner | EurekAlert!
Further information:
http://www.brown.edu/Administration/News_Bureau

More articles from Earth Sciences:

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

nachricht Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>