Oct 15, 2021 06:00:00

Research results that 'the sea did not exist on Venus in ancient times'

Venus , which is the second closest to the Sun in the solar system after Mercury , is now a harsh planet with high temperature and pressure, but there is a theory that ' Venus once had an ocean and a warm climate.' However, a new study simulating the environment of 'Venus and the Earth more than 4 billion years ago' showed that 'Venus has never had an ocean in its history since its birth.' ..

Day–night cloud asymmetry prevents early oceans on Venus but not on Earth | Nature
https://www.nature.com/articles/s41586-021-03873-w

Did Venus ever have oceans? | EurekAlert!
https://www.eurekalert.org/news-releases/931214

There's No Way Venus Could Ever Have Had Oceans, Astronomers Say
https://www.sciencealert.com/there-s-no-way-venus-could-ever-have-had-oceans-new-research-finds

Venus has a strong greenhouse effect due to the fact that the main component of the atmosphere is carbon dioxide, and the surface temperature reaches nearly 460 degrees, the atmospheric pressure near the surface of the earth is about 90 atmospheres, and the sky is a thick cloud of concentrated sulfuric acid. It is a harsh planet covered with. On the other hand, Venus is also called 'Earth's sister planet' because it has the closest orbit to the Earth and is a terrestrial planet with similar size and average density.

In recent years, space agencies in various countries have been paying attention to Venus, and it has been pointed out that the Venus exploration vessel rush may arrive. One of the reasons for this is that when the Sun was younger and darker than it is now, Venus was not so hot, and it was a planet warm enough for the ocean to exist. It is expected that important hints will be given to the conditions of birth.

According to the standard solar model , 3.5 billion years ago, the brightness of the sun was only about 75% of the current brightness, and past studies suggest that Venus may have had an ocean under these conditions. .. However, if the Sun were 25 to 30% darker than it is now and emitted less heat, the Earth away from Venus would have been an ice sphere, but at this time the Earth had liquid water. There is evidence that it existed.

So, a research team led by Martin Turbet , a postdoctoral fellow in astronomy at the University of Geneva, Switzerland, decided to simulate 'the climate of the early Earth and Venus over 4 billion years ago' to find the answer to this question. Did.

The research team simulated the ancient Venus and Earth's environment using sophisticated three-dimensional atmospheric models similar to those used by meteorologists to simulate Earth's climate and future changes. ..

As a result of the simulation, it was found that water existed in the form of steam on Venus at that time due to the high temperature, and the entire planet became like a huge pressure cooker. Venus needed to be cooled for thousands of years before the vapors in the atmosphere condensed into clouds and rained on the surface. Cooling occurs only when clouds that block the sun's rays are formed, but it seems that the clouds were formed only on the cooler night side on Venus, which does not prevent the sunlight from reaching. In addition, it created a powerful greenhouse effect on the night side and warmed the entire Venus.

As a result, the researchers conclude that on Venus, steam did not rain and fall on the surface, creating no ocean. On the other hand, instead of turning the earth into a sphere of ice, it seems that the planet has cooled properly and the water has become liquid and the sea has been created thanks to the darker sun than in modern times. If the earth were a little closer to the sun or the sun was stronger, the earth wouldn't cool, so the dark sun was fortunate for the earth.

Emeline Bolmont , a professor of astrophysics at the University of Geneva, who co-authored the paper, said that the darkness of the sun billions of years ago was called the 'weak and young sun paradox' and life was born on Earth. He pointed out that it has been considered an obstacle to doing things. 'But I realized that this weak sun might have been an unfortunate opportunity for life to be born on a very hot planet,' he said. Insist.

'Our results are based on theoretical models and are an important factor in answering the history of Venus, but we can't settle the problem on our computer. Our work,' said Bolmont. To confirm or deny, we need observations by three future Venus space missions (under consideration by NASA and ESA). '