Scientists have observed an unexpected increase in the ratio of deuterium to hydrogen in the atmosphere of Venus, a stunning discovery that could rewrite the textbooks on our closest planetary neighbour. This apparently technical discovery has breathtaking implications that could overturn everything we thought we knew about this ‘amber world’.
Venus: Earth's Evil Twin?
For centuries, Venus has been regarded as a barren and inhospitable land, a hellish landscape of scorching temperatures and crushing atmospheric pressures. But new data suggests that this may not always have been the case.
“Venus is often called Earth's twin due to its similar size,” says Hiroki Karyu, a researcher at Tohoku University and one of the study's scientists. But unlike Earth, Venus has evolved into a world so hostile that it's almost unfathomable.
Surface temperatures can melt lead, and the pressure at ground level is 90 times that of Earth. Liquid water, the bedrock of life as we know it, is virtually non-existent. Or is it?
The Mysterious Deuterium Spike
In nature, deuterium, and hydrogen are isotopes of the same element, except that deuterium is heavier due to the presence of one neutron. In the atmosphere of Venus, researchers have found that the amount of HDO, in which one hydrogen atom of water is replaced with deuterium, is 120 times more prevalent than the normal H2O found on Earth. No, this is not some funny prank; it’s a possible revolutionary change in the near future.
This unusual depletion of HDO in the atmosphere of Venus is mainly due to the action of solar wind, which breaks the bonds of water vapour molecules present in high altitudes of the atmosphere. The light hydrogen atoms are more readily able to diffuse out into space, whereas deuterium, the heavier hydrogen isotope, remains trapped within. But we have only scratched the surface. Or rather, the crust of molten rock.
Could Venus Have Been Wet and Habitable?
Here is where it gets really crazy. If Earth and Venus had about the same amount of water and other volatile compounds in the beginning of their formation, like experts suggest. Why then is… the mystery of unwarrantable violence under awful pressure so evident in terrorists of today’s Venus so different? This spike in deuterium might just provide the critical answer to that puzzle.
New data from the Solar Occultation in the Infrared (SOIR) instrument on the Venus Express space probe reveals that water molecules, particularly those containing deuterium, increase with altitude in Venus' atmosphere. At higher altitudes, the concentration of deuterium-rich water skyrockets, becoming more than 1,500 times greater than what is found in Earth's oceans.
Venus’ atmosphere could mean that it can even support water bodies, and therefore water as a gas may have been abundant in the atmosphere. If this suggestion is proved right, it is suggested that Venus may have had an environment moderating enough to hold liquid water on the ground. Think about it: Venus, a possible source, and center for life, existing today in a dry roasting furnace.
But the plot thickens. The sulphuric acid aerosol sprays in the atmosphere of Venus, the study also suggests, can be responsible for such deuterium enrichment. Stratocumulus clouds are formed when such a point is reached, which is a layer where cooler temperatures make it possible for deuterium-rich water to condense.
When particles such as these get raised, they evaporate and accentuate more deuterium into the atmosphere, leading to a cycle that has changed Venus into the planet we are accustomed to.