Have you truly understood the future of Earth? Our neighboring planet offers us a glimpse of what could happen to Earth if climate change remains unchecked.
Scientists from the University of Colorado Boulder have recently discovered that Earth’s neighboring planet, Venus, is devoid of water. Venus lost its water due to a combination of processes that occurred billions of years ago. Initially, during its formation, Venus may have received a similar amount of water as Earth from comets and asteroids from the outer Solar System. However, over time, catastrophic events led to Venus losing all of its water, turning it into a hellish environment devoid of life.
The surface of Venus is the most hostile among rocky planets in the Solar System.
The Story of Water on Venus
Planetary scientists have utilized computer simulations to trace the “story of water on Venus.” A key factor contributing to Venus’s water loss is the development of a severe greenhouse effect caused by a thick layer of carbon dioxide in the planet’s atmosphere. This layer traps heat, raising surface temperatures significantly.
The greenhouse effect on Venus is the strongest in the Solar System, causing surface temperatures to soar to about 500 degrees Celsius. As a result, water on Venus evaporated, escaping into space never to return. This has rendered the environment on Venus scorching and uninhabitable due to its lack of water.
Eryn Cangi, a research scientist at the Laboratory for Atmospheric and Space Physics (LASP) and co-author of the new study, stated: “Water is really important for life. We need to understand the conditions that support liquid water in the universe, and that may explain the extremely dry state of Venus today.”
Double the Water Loss Rate
Despite the initial water loss due to the greenhouse effect, Venus continued to lose water to space at nearly twice the rate previously thought. The study indicates that hydrogen atoms in Venus’s atmosphere escape into space through a process called “dissociative recombination,” which is facilitated by molecules like HCO+. This ongoing water loss contributes to the current arid state of Venus.
(Dissociative recombination is a chemical process in which positively charged polyatomic ions combine with a free electron, resulting in the formation of a neutral dissociated molecule). This reaction is crucial for chemical processes in interstellar or interplanetary space. On Earth, dissociative recombination rarely occurs naturally, as free electrons react with any molecules they encounter (including neutral molecules). Even under the best laboratory conditions, dissociative recombination is difficult to observe. However, it is a key reaction in environments with large numbers of ionized molecules, such as plasma at atmospheric pressure.
In astrophysics, dissociative recombination is one of the main mechanisms through which broken molecules reform and new molecules are formed. The existence of dissociative recombination can occur due to the vacuum of the interstellar medium.
Cangi asserts that Venus is undoubtedly arid, comparing: “If you took all the water on Earth and spread it across the planet like jam on toast, you would have a liquid layer about 3 kilometers deep. If Venus underwent a similar process with the amount of water retained in the atmosphere, this planet would only have 3 centimeters of water left, not even enough to wet a person’s toes.”
Michael Chaffin, the lead co-author of the study and a scientist at LASP, remarked: “Venus has 100,000 times less water than Earth, even though it is essentially the same size and mass.”
This scientist also noted that the new findings suggest reasons why Venus looks so different today, even though it may have resembled Earth in the distant past.
Cangi added: “We are trying to understand what small changes occurred on each planet that led them to such different states.”
The Sun and Orbit are Key Issues
During the early formation period, both Earth and Venus likely received similar amounts of water from comets. Venus might have had oceans like Earth and was ready to be a nursery for life. However, over time, the Sun became more active while Venus’s orbit is closer to the Sun than Earth’s by nearly 50 million kilometers. This made Venus hotter, caused more water to evaporate, and led to the hellish conditions we see today.
In the distant future, the Sun is predicted to become even more active, and Earth risks following in Venus’s footsteps. This forces humanity to find ways to leave Earth before our planet becomes a second Venus or to find ways to push Earth’s orbit further out to avoid the heat.
The issue is that the day the Sun becomes more active is still far off, while human-induced greenhouse gas emissions are already at our doorstep and have a much more immediate and dangerous impact.
