SCIENCE

How Did Mars Become the Red Planet?

A new NASA spacecraft, MAVEN, will explore the geologic history of our planetary neighbor

September 30, 2013

Around 3.7 billion years ago, Mars had the basic ingredients to support life. A thick, oxygen-rich atmosphere blanketed the planet, trapping enough heat to allow liquid water to flow freely on the surface. Then a catastrophic event rendered Mars cold and barren. Precisely what happened remains a mystery, but scientists will be searching for new clues with the November launch of NASA’s $671 million Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. Lockheed Martin

Scientists suspect that Mars’ molten core cooled, causing the planet’s magnetic field to collapse—which left it with no protection against the solar wind that slowly stripped gas particles and water vapor from the upper atmosphere. Also, huge craters suggest that a bombardment of meteors hastened the process, blasting large amounts of the atmosphere into space. Lockheed Martin

When MAVEN arrives at Mars in September 2014, it will go into orbit and gauge the rate at which gases are leaking into space, and whether that dissipation is affected by changes in solar activity. An instrument that detects hydrogen ions—chemical remnants of water molecules—will help estimate how much water has been lost over time. With such data in hand, scientists are optimistic that they can extrapolate backward billions of years to determine the total atmospheric loss that began back when the Red Planet was still blue. Lockheed Martin

Around 3.7 billion years ago, Mars had the basic ingredients to support life. Then a catastrophic event rendered Mars cold and barren. Precisely what happened remains a mystery, but scientists will be searching for new clues with the November launch of NASA’s $671 million Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft.With such data in hand, scientists are optimistic that they can extrapolate backward billions of years to determine the total atmospheric loss that began back when the Red Planet was still blue.