Mars and venus dating 5 stages
For this reason, 'Follow the Water' was the science theme of NASA's Mars Exploration Program (MEP) in the first decade of the 21st century.
Discoveries by the 2001 Mars Odyssey, Mars Exploration Rovers (MERs), Mars Reconnaissance Orbiter (MRO), and Mars Phoenix lander have been instrumental in answering key questions about water's abundance and distribution on Mars.
These were regarded by many early cultures as divine, or as emissaries of deities.
As scientific knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects.
Although the surface of Mars was periodically wet and could have been hospitable to microbial life billions of years ago, the current environment at the surface is dry and subfreezing, probably presenting an insurmountable obstacle for living organisms.
In addition, Mars lacks a thick atmosphere, ozone layer, and magnetic field, allowing solar and cosmic radiation to strike the surface unimpeded.
In 2006, the International Astronomical Union (IAU) officially adopted a resolution defining planets within the Solar System.