- Research claims Venus never had oceans, despite hopes that it once sheltered them
- Model shows that its temperature never decreased for water to condense
- Clouds at night on the planet also created a greenhouse effect to prevent rain from falling
- If this is true, it would raise doubts whether there could ever be life on the planet.
Venus has long been regarded as a ‘dead’ planet, but new missions to Earth’s ‘evil twin’ may soon reveal whether it is much more alive and still geologically active .
Not only that, but one of the key questions scientists hope to answer is whether Venus sheltered oceans shortly after its birth 4.5 billion years ago.
Earth has had oceans for about four billion years and Mars had lakes and rivers 3.5-3.8 billion years ago.
But it’s still a mystery whether water ever condensed on Venus’s surface because the planet – which is now completely dry – went through global resurfacing events that obscured much of its history.
According to new research, however, that appears unlikely – which will also cast doubt on whether Earth’s nearest neighbor may have ever hosted life.
A team of astrophysicists led by the University of Geneva and the National Center of Competition in Research (NCCR) Planets, Switzerland created a climate model to replicate the condition of a young Venus.
This suggests that the temperature of Venus’s atmosphere never dropped enough to allow water to condense and then rain and form oceans.
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A model suggests that Venus, seen here in an image taken by NASA’s Mariner 10 spacecraft, was never covered in oceans because clouds created the greenhouse effect that blocked rain, a model suggests
Venus: The Basics
Venus, the second planet from the Sun, is a rocky world about the same size and mass as Earth.
However, its atmosphere is radically different to ours—96 percent carbon dioxide and a surface temperature of 867°F (464°C) and 92 times the pressure on Earth.
The inaccessible planet is enveloped in clouds of sulfuric acid that makes the surface impossible to see.
In the past, it has been suggested that Venus likely had oceans similar to those of Earth – but these may have evaporated as it went through a runaway greenhouse effect.
The surface of Venus is a dry desert, which is periodically changed by volcanic activity.
Facts & Figures
orbital time: 225 days
surface area: 460.2 million km²
distance from the sun: 108.2 million km
day length: 116d 18h 0m
RADIUS: 6,051.8 km
Mass: 4.867 × 10^24 kg (0.815 sq. m)
“We simulated the climates of Earth and Venus at the very beginning of their evolution, more than four billion years ago, when planetary surfaces were still molten,” said Martin Turbett, one of the researchers who worked on the model. .
‘The associated high temperature meant that any water would exist as steam, as in a giant pressure cooker.’
For oceans to form, the researchers said, atmospheric temperatures would have dropped enough for the water to condense and fall as rain over a period of several thousand years, as happened on Earth.
But his model showed that the temperature never decreased enough for this to happen, and instead the water remained as a gas in the atmosphere.
The astrophysicists said that although the Sun was 30 percent weaker at the time than it is now, this would not be enough to reduce the temperature of Venus to the point where oceans could form.
Such a drop in temperature would be possible only if the surface of Venus was shielded from solar radiation by clouds, but the model suggests clouds formed on the night side of the planet, where they could not cover the Sun.
Instead, these clouds help maintain high temperatures by creating a greenhouse effect, which traps heat in the planet’s dense atmosphere, the researchers said.
“Thanks to our simulations, we were able to show that climatic conditions did not allow water vapor to condense in the atmosphere of Venus,” Turbet said.
This means that the temperature has never dropped enough that the water in its atmosphere can form raindrops that can fall on its surface. Instead, water remained as a gas in the atmosphere and oceans never formed.
‘One of the main reasons for this is clouds that form preferentially on the night side of the planet. These clouds cause a very powerful greenhouse effect that prevented Venus from cooling as quickly as previously thought.’
If the authors are right, Venus has always been the center of hell. However, the data collected by Future space missions to the planet should make it possible to test these results.
In June, NASA announced that it was sending two new spacecraft to Venus to probe the planet’s atmosphere and geological features.
Image of Venus showing its acidic clouds as taken by the Ultraviolet Imager of the Venus Climate Orbiter Akatsuki on November 27, 2018
New Missions to Venus
NASA and the European Space Agency recently announced three missions to Venus in the coming years.
NASA announced in early June its two new $500 million missions, which will launch over the next 10 years, to understand how Venus ‘became a hell-like world’.
Just a week later, ESA said it would send a probe known as EnVision to study ‘Earth’s evil twin’, targeting a launch in the early 2030s.
The missions, each of which have been awarded $500m (£352m) in funding, are due to launch between 2028 and 2030, nearly 40 years after the last. The American probe – the Magellan orbiter – visited the planet in 1990.
Just a week after NASA’s announcement, the European Space Agency said it would send a probe known as EnVision to study Venus, targeting a launch in the early 2030s.
The University of Geneva not only witnessed the birth of Venus, but it also simulated the early Earth,…