First Mars Express gravity results plot volcanic history
Five years of Mars Express gravity mapping data are providing unique insights into what lies beneath the Red Planets largest volcanoes. The results show that the lava grew denser over time and that the thickness of the planet's rigid outer layers varies across the Tharsis region. The measurements were made while Mars Express was at altitudes of between 275330 km above the Tharsis volcanic bulge during the closest points of its eccentric orbit, and were combined with data from NASAs Mars Reconnaissance Orbiter. Read more
US researchers have determined the surface temperature of early Mars for the first time, providing evidence consistent with a warmer and wetter Martian past. By analysing carbonate minerals in a four-billion-year-old meteorite that originated near the surface of Mars, scientists at the California Institute of Technology determined that the minerals formed at about 18 degrees Celsius (64 degrees Fahrenheit). Read more
Jupiter's Early Migration Could Explain Mars's Small Size
The migration of giant planets has been invoked to explain a number of features of planetary systems, such as the uneven spacing among the objects of the Asteroid Belt in our solar system. Migration would also explain the huge planets in other planetary systems known as "hot Jupiters" that orbit extremely close to their host stars, far closer than where they could have plausibly formed. Now a new study, published online June 5 in Nature, demonstrates that a peculiar migration of Jupiter - first inward, then outward - could account for Mars's relatively small size. Read more
Mars developed in as little as two to four million years after the birth of the solar system, far more quickly than Earth, according to a new study published in the May 26 issue of the journal Nature. The red planets rapid formation helps explain why it is so small, say the studys co-authors, Nicolas Dauphas at the University of Chicago and Ali Pourmand at the University of Miami (Fla). Mars probably is not a terrestrial planet like Earth, which grew to its full size over 50 to 100 million years via collisions with other small bodies in the solar system, said Dauphas, an associate professor in geophysical sciences. Mars instead is a planetary embryo that never developed into a full-fledged planet. Read more
Mars: Red Planet's Rapid Formation Explains Its Small Size Relative to Earth
Mars developed in as little as two to four million years after the birth of the solar system, far more quickly than Earth, according to results of a new study published in this week's issue of the journal Nature. The red planet's rapid formation helps explain why it is so small, say the study's co-authors, Nicolas Dauphas at the University of Chicago and Ali Pourmand at the University of Miami. Their research was funded by the National Science Foundation (NSF). Read more
NASA Orbiter Reveals Big Changes in Mars' Atmosphere
NASA's Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms. Researchers using the orbiter's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. The findings are published in this week's issue of the journal Science.
Les volcans de Mars, témoins de son refroidissement
Le manteau de Mars se refroidirait de 30 à 40°C par milliard d'années. C'est la conclusion des chercheurs du CNRS et de l'Université Paul Sabatier à Toulouse, qui ont reconstitué l'évolution thermique de cette planète depuis 4 milliards d'années, pour la première fois, à partir de la composition des roches volcaniques observées par satellite. Ces valeurs impliquent un refroidissement plus lent que pour la Terre (70 à 100°C par milliard d'années). Elles soulignent la particularité de notre planète, dont l'évolution thermique est influencée par la tectonique des plaques. Les résultats sont publiés dans la revue Nature (advanced online publication du 6 avril 2011). Read more
There is no place on Earth that is a perfect copycat of Mars as it is now, or as it was at any specific point in the past. But scientists suggest Earth has little versions of Mars as it might have been over decades. These places could help scientists develop a timeline of the Red Planet's history. By providing insights on how Mars has changed over time, these terrestrial mimics could help us better understand the results of past and current missions to Mars. They also could help researchers plan future expeditions to look for signs of life on Mars. In addition, investigating these extreme sites on Earth could shed light on the limits of life. Read more