Twenty years ago astronomers discovered the first planet around a sun-like star, 51 Pegasi b. And in the last 20 years, astronomers have discovered thousands of new exotic worlds, begun to characterise atmospheres of faraway planets, and are developing cutting-edge technology to launch us on our search for alien life. Planets with two suns, rogue planets with no star, close cousins to planet Earth. This is the story of the pioneers in planet-hunting and how those who have followed are closer to answering one of humanity’s most ancient questions: Is there life elsewhere in the universe?
NASA has revealed the process that took Mars from a warm and wet environment that might have supported alien life – to the cold and arid planet Mars is today.
Researchers said that the red planets atmosphere was stripped away by solar winds which increased significantly during solar storms.
John Grunsfeld from the NASA Science Mission Directorate in Washington said “Mars appears to have had a thick atmosphere warm enough to support liquid water which is a key ingredient and medium for life as we currently know it”.
Bruce Jakosky of the Mars Atmosphere and Volatile Evolution at University of Colorado said “Like the theft of a few coins from a cash register every day, the loss becomes significant over time. We’ve seen that the atmospheric erosion increases significantly during solar storms, so we think the loss rate was much higher billions of years ago when the sun was young and more active.”
Learning what can cause changes to a planet’s environment from one that could host microbes at the surface to one that doesn’t is important to know, and is a key question that is being addressed in NASA’s journey to Mars.
Mars is a cold and barren desert today, but scientists think that in the ancient past it was warm and wet. The loss of the early Martian atmosphere may have led to this dramatic change, and one of the prime suspects is the solar wind. Unlike Earth, Mars lacks a global magnetic field to deflect the stream of charged particles continuously blowing off the Sun. Instead, the solar wind crashes into the Mars upper atmosphere and can accelerate ions into space. Now, for the first time, NASA’s MAVEN spacecraft has observed this process in action – by measuring the speed and direction of ions escaping from Mars. This data visualization compares simulations of the solar wind and Mars atmospheric escape with new measurements taken by MAVEN.