Could there be more life on the surface of the Earth? The shape of Jupiter’s orbit plays a key and overlooked role on Earth

Of all the known planets, Earth is as supportive of life as any planet could be – or is it? If Jupiter’s orbit changes, a new study shows Earth could be more hospitable than it is today.

When a planet has a perfectly circular orbit around its star, the distance between the star and the planet never changes. Most planets, however, have “eccentric” orbits around their stars, meaning the orbit is oval in shape. As the planet moves closer to its star, it receives more heat, affecting the climate.

Using detailed models based on data from the solar system as it is known today, UC Riverside researchers have created an alternate solar system. In this theoretical system, they discovered that if the gigantic orbit of Jupiter became more eccentric, this would in turn induce great changes in the shape of the Earth’s orbit.

“If Jupiter’s position remained the same, but the shape of its orbit changed, it could actually increase the habitability of this planet,” said Pam Vervoort, UCR Earth and planetary scientist and lead author of the study.

Between zero and 100 degrees Celsius, the Earth’s surface is habitable for several known life forms. If Jupiter pushed Earth’s orbit to become more eccentric, parts of the Earth would sometimes move closer to the sun. Parts of the Earth’s surface that are currently below freezing would warm up, raising temperatures into the habitable range.

This result, now published in the Astronomical Diaryupends two long-held scientific assumptions about our solar system.

“Many are convinced that Earth is the epitome of a habitable planet and that any change in Jupiter’s orbit, being the massive planet that it is, could only be bad for Earth,” Vervoort said. “We show that both assumptions are wrong.”

The researchers want to apply this finding to finding habitable planets around other stars, called exoplanets.

“The first thing people look for in a search for exoplanets is the habitable zone, the distance between a star and a planet to see if there is enough energy for liquid water on the surface of the planet” , said Stephen Kane, UCR astrophysicist and co-author of the study. .

During its orbit, different parts of a planet receive more or less direct rays, causing the planet to have seasons. Some parts of the planet can be pleasant in one season and extremely hot or cold in another.

“Having water on its surface is a very simple first metric, and it doesn’t take into account the shape of a planet’s orbit, or any seasonal variations a planet might experience,” Kane said.

Existing telescopes are capable of measuring a planet’s orbit. However, there are other factors that could affect habitability, such as how much a planet tilts toward or away from a star. The part of the planet tilted away from the star would receive less energy, making it cooler.

This same study found that if Jupiter were positioned much closer to the sun, it would induce extreme tilt on Earth, which would render large sections of the Earth’s surface under-frozen.

It’s harder to measure a planet’s tilt or mass, so researchers would like to work on methods that help them estimate those factors as well.

Ultimately, the motion of a giant planet is important in the quest to make predictions about the habitability of planets in other systems as well as in the quest to understand its influence in this solar system.

“It’s important to understand the impact Jupiter has had on Earth’s climate over time, how its effect on our orbit has changed us in the past, and how it might change us again in the future,” Kane said.