14 DAY TRIAL // What happened to the lost oceans of Mars and Venus? What have scientists been discovering about the thick atmosphere on Saturn's moon Titan? How has the climate changed on each of these worlds, and could what happened to them happen to our Earth?
Earth sits between two worlds that have been devastated by climate catastrophes. In the effort to combat global warming, our neighbors can provide valuable insights into the way climate catastrophes affect planets.
Modeling Earth's climate to predict its future has assumed tremendous importance in the light of mankind's influence on the atmosphere. The climate of our two neighbors is in stark contrast to that of our home planet, making data from ESA's Venus Express and Mars Express invaluable to climate scientists.
Venus has the densest atmosphere of all the terrestrial planets, consisting mostly of carbon dioxide. It is a cloudy inferno with extensive volcanism, possessing some 167 giant volcanoes that are over 100 km across.
On the other hand, Mars is a frigid desert and has a thin atmosphere and surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of Earth. The red-orange appearance of the Martian surface is caused by iron oxide, more commonly known as rust.
As current concerns about global warming have now achieved widespread acceptance, pressure has increased on scientists to propose solutions to prevent Earth for becoming as inhospitable as the two sisters. Now planetary scientists want to turn the clock back to understand why and how Venus and Mars changed from their former Earth-like conditions into the infernos of today.
Astronomers believe that Venus experienced a runaway greenhouse effect as the Sun gradually heated up. They think the young Sun was dimmer than the present-day Sun by 30 percent. Over the last 4 thousand million years, it has gradually brightened. During this increase, Venus' surface water evaporated and entered the atmosphere. As Earth warms in response to manmade pollution, it risks the same fate. Reconstructing the climate of the past on Venus can give scientists a better understanding of how close our planet is to such a catastrophe. However, determining when Venus passed the point of no return is not easy. That's where ESA's Venus Express comes in.
While in orbit around Venus, it will be collecting data that will help unlock the planet's past. Understanding all of this will help scientists pin down when Venus lost its water.
Understanding Mars' past is equally important. ESA's Mars Express is currently investigating the fate of the Red Planet. Smaller than the Earth, Mars is thought to have lost its atmosphere to space. When Martian volcanoes became extinct, so did the planet's means of replenishing its atmosphere, turning it into an almost-airless desert.
What happened to these two worlds is very different but either would be equally disastrous for Earth. They are banking on their ability to accurately predict Earth's future climate. Anything that can shed light on our own future is valuable. That is why the study of our neighboring worlds is vital.