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If it weren’t for Jupiter, Venus could be habitable today



Venus Akatsuki

Composite of images taken by the Japanese Akatsuki spacecraft of Venus. Credit: JAXA / ISAS / DARTS / Damia Bouic

The study shows the destabilizing effect of the giant gas planet.

Venus it might not be a sweltering, waterless hell today, though Jupiter it hadn̵

7;t altered its orbit around the sun, according to new research from UC Riverside.

Jupiter has a mass that is two and a half times that of all the other planets in our solar system – combined. Because it is relatively gigantic, it has the ability to disrupt the orbits of other planets.

Early in the formation of Jupiter as a planet, it moved closer to and away from the sun due to interactions with the disk from which planets and other giant planets are formed. This movement in turn affected Venus.

Observations of other planetary systems have shown that migrations of similar giant planets soon after formation can be a relatively common occurrence. These are among the findings of a new study published in Planetary Science Journal.

Scientists believe that planets without liquid water are unable to host life as we know it. Although Venus may have lost some water at first for other reasons, and may have continued to do so anyway, UCR astrobiologist Stephen Kane said that Jupiter’s motion likely triggered Venus on a path to the its current and inhospitable state.

“One of the interesting things about Venus today is that its orbit is almost perfectly circular,” said Kane, who led the study. “With this project, I wanted to explore whether orbit has always been circular and if not, what are the implications of that?”

To answer these questions, Kane created a model that simulated the solar system, calculating the position of all the planets at any given time and how they drag each other in different directions.

Scientists measure how non-circular a planet’s orbit is between 0, which is completely circular, and 1, which isn’t circular at all. The number between 0 and 1 is called the eccentricity of the orbit. An orbit with an eccentricity of 1 would not even complete an orbit around a star; it would simply launch into space, Kane said.

Currently, the orbit of Venus is measured at 0.006, which is the most circular of any planet in our solar system. However, Kane’s model shows that when Jupiter was probably closer to the Sun about a billion years ago, Venus probably had an eccentricity of 0.3, and there is a much higher probability that it was habitable then.

“With the migration of Jupiter, Venus would undergo dramatic climate changes, warming and then cooling and losing more and more of its water to the atmosphere,” Kane said.

Recently, scientists have generated a lot of excitement by discovering a gas in the clouds above Venus that could indicate the presence of life. The gas, phosphine, is typically produced by microbes, and Kane says it is possible that the gas represents “the last surviving species on a planet that has undergone a dramatic change in its environment.”

For this to be the case, however, Kane notes that the microbes would have had to support their presence in the sulfuric acid clouds above Venus for about a billion years since Venus last had surface liquid water – a scenario that is difficult to imagine but not impossible.

“There are probably many other processes that could produce the gas that hasn’t been explored yet,” Kane said.

Ultimately, Kane says it’s important to understand what happened to Venus, a planet that was once likely habitable and now has surface temperatures of up to 800 degrees. Fahrenheit.

“I focus on the differences between Venus and Earth, and what went wrong with Venus, so that we can get insights into how the Earth is habitable and what we can do to guide this planet in the best possible way,” Kane said.

Reference: “Could the migration of Jupiter have accelerated the atmospheric evolution of Venus?” by Stephen R. Kane, Pam Vervoort, Jonathan Horner and Francisco J. Pozuelos, 4 September 2020, The Planetary Science Journal.
DOI: 10.3847 / PSJ / abae63




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