Warmth and flowing water on early Mars, were episodic

Although the surface is now cold and desiccated, in early Mars history water formed an open-basin lake, filling the crater, forming a delta, and breaching the lower rim as water flowed to lower elevations (blue). 

New research suggests that warmer temperatures and water flow on ancient Mars were likely related to periodic volcanism early in the planet's history 

Credit: NASA /Mars Reconnaissance Orbiter Rendering by James Dickson, Brown University

Ample evidence of ancient rivers, streams, and lakes make it clear that Mars was at some point warm enough for liquid water to flow on its surface.

While that may conjure up images of a tropical Martian paradise, new research published today in Nature Geoscience throws a bit of cold water on that notion.

The study, by scientists from Brown University and Israel's Weizmann Institute of Science, suggests that warmth and water flow on ancient Mars were probably episodic, related to brief periods of volcanic activity that spewed tons of greenhouse-inducing sulfur dioxide gas into the atmosphere.

The work, which combines the effect of volcanism with the latest climate models of early Mars, suggests that periods of temperatures warm enough for water to flow likely lasted for only tens or hundreds of years at a time.

With all that's been learned about Mars in recent years, the mystery of the planet's ancient water has deepened in some respects.

The latest generation of climate models for early Mars suggests an atmosphere too thin to heat the planet enough for water to flow.

The sun was also much dimmer billions of years ago than it is today, further complicating the picture of a warmer early Mars.

"These new climate models that predict a cold and ice-covered world have been difficult to reconcile with the abundant evidence that water flowed across the surface to form streams and lakes," said James W. Head, professor of earth, environmental and planetary sciences at Brown University and co-author of the new paper with Weizmann's Itay Halevy.

Itay Halevy

"This new analysis provides a mechanism for episodic periods of heating and melting of snow and ice that could have each lasted decades to centuries."

Halevy and Head explored the idea that heating may have been linked to periodic volcanism.

Many of the geological features that suggest water flow date to around 3.7 billion years ago, a time when massive volcanoes are thought to have been active and huge lava outpourings occurred.

On Earth, however, widespread volcanism often leads to cooling rather than warming. Sulphuric acid particles and thick ash reflect the sun's rays, and that can lower temperatures, but Head and Halevy thought the effects of sulphur in Mars' dusty atmosphere might have been different.

To find out, the researchers created a model of how sulfuric acid might react with the widespread dust in the Martian atmosphere.

The work suggests that those sulphuric acid particles would have glommed onto dust particles, which would reduce their ability to reflect the sun's rays.

Meanwhile sulphur dioxide gas would produce a modest greenhouse effect, just enough to warm the Martian equatorial region so that water could flow.

Head has been doing fieldwork for years in Antarctica and thinks the climate on early Mars may have been very similar to that of the cold, desert-like McMurdo Dry Valleys.

"The average yearly temperature in the Antarctic Dry Valleys is way below freezing, but peak summer daytime temperatures can exceed the melting point of water, forming transient streams, which then refreeze," Head said.

"In a similar manner, we find that volcanism can bring the temperature on early Mars above the melting point for decades to centuries, causing episodic periods of stream and lake formation."

But as that early active volcanism on Mars ceased, so did the possibility of warmer temperatures and flowing water.

Head said the research may offer new clues about where the fossilized remnants of life might be found on Mars, if it ever existed.

"Life in Antarctica, in the form of algal mats, is very resistant to extremely cold and dry conditions and simply waits for the episodic infusion of water to 'bloom' and develop," he said.

"Thus, the ancient and currently dry and barren river and lake floors on Mars may harbor the remnants of similar primitive life, if it ever occurred on Mars."

More information: Nature Geoscience, dx.doi.org/10.1038/ngeo2293

Saturn's Moon Enceladus: Cold, Bright Mosaic

The Cassini spacecraft has been studying Saturn and its moons since it entered orbit in 2004.

This image, taken on Oct. 5, 2008, is a stunning mosaic of the geologically active Enceladus after a Cassini flyby.

Declassified US Spy Satellites: Secret Cold War Space Program

The massive KH-9 Hexagon spy satellite on display at the Smithsonian National Air & Space Museum's Udvar-Hazy Center, after being declassified on Sept. 17, 2011. 

Longer than a school bus at 60 feet in length and weighing 30,000 pounds at launch, 20 KH-9 Hexagons were launched by the National Reconnaissance Office between 1971 and 1986.

CREDIT: Roger Guillemette/SPACE.com

Twenty-five years after their top-secret, Cold War-era missions ended, two clandestine American satellite programs were declassified Saturday (Sept. 17) with the unveiling of three of the United States' most closely guarded assets: the KH-7 GAMBIT, the KH-8 GAMBIT 3 and the KH-9 HEXAGON spy satellites.


The vintage National Reconnaissance Office satellites were displayed to the public Saturday in a one-day-only exhibit at the Smithsonian National Air and Space Museum's Udvar-Hazy Center at Dulles Airport, Va.

The three spacecraft were the centerpiece of the NRO's invitation-only, 50th Anniversary Gala celebration held at the center last evening.

Dark Matter may be hot stuff

"Cold, dark matter" has a certain ring to it, but new simulations of our corner of the cosmos suggest that dark matter – the stuff that is thought to underlie the universe – might be warm, with relatively fast-moving and lightweight particles.

In cosmology's standard model, dark matter is cold, made up of relatively heavy low-energy particles, and will happily settle into structures as small as planets.

Hot dark matter has already been ruled out because its particles would move too fast for galaxies to form. But warm dark matter has smaller, faster particles that still allow for our familiar starry sky.

Most computer models produce a generic universe that doesn't resemble ours in detail, but Gustavo Yepes at the Autonomous University of Madrid, Spain, and his collaborators on the Constrained Local Universe Simulations (CLUES) project have tuned theirs to resemble the galaxies and clusters nearest Earth.

The Cold Cold Heart of Darkness

The Heart of Darkness

Some of the coldest and darkest dust in space shines brightly in this infrared image from the Herschel Observatory, a European Space Agency mission with important participation from NASA.

The image is a composite of light captured simultaneously by two of Herschel's three instruments -- the photodetector array camera and spectrometer with its spectral and photometric imaging receiver.

The image reveals a cold and turbulent region where material is just beginning to condense into new stars. It is located in the plane of our Milky Way Galaxy, 60 degrees from the center.

Blue shows warmer material, red the coolest, while green represents intermediate temperatures. The red filaments are made up of the coldest material pictured here -- material that is slightly warmer than the coldest temperature theoretically attainable in the universe.

Moon is coldest known place in the solar system - New Scientist

Moon is coldest known place in the solar system - space - 18 September 2009 - New Scientist

Poor Pluto. First it gets kicked out of the planet club, now it's not even the coldest place in the solar system. Dark craters near the moon's south pole have snatched that title - which is good news for the prospects of finding water ice on Earth's companion.

The craters' towering rims block the sun from reaching their centres, like the long shadows cast by tall buildings at dusk. In this permanent darkness, they stay at a constant -240° Celsius - more than 30°C above absolute zero and 10°C cooler than Pluto, which was measured at -230°C in 2006.

"The lunar south pole is among the coldest parts of the solar system and may be in fact colder than what we expect from places like Pluto," NASA scientist Richard Vondrak said at a press conference on Thursday.

The cold temperature bodes well for the prospect of finding water ice deposits in the moon's shadowy pockets. Previous calculations had shown that water and other volatile gases would dissipate into space at temperatures above about -220°C.

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