If the orbit of Jupiter, the largest planet in the Solar System, were hypothetically changed, a new study shows that the Earth could be even more habitable than it is today.

 

Astronomers have confirmed the existence of over 5,000 exoplanets in the Galaxy, and thousands more are awaiting confirmation. Hundreds of billions of planets are estimated to exist in our Galaxy alone. Of all these worlds –and those yet to be found– as far as we know, Earth is the most favorable for life. But just how much so? A new study shows Earth could become more hospitable if Jupiter’s orbit changes. Planets that orbit their stars in perfectly circular orbits never change their distance from them. An oval-shaped orbit is common for most planets around their stars, meaning they have “eccentric orbits.” Getting closer to a star increases the amount of heat received by the planet, which affects its climate.

A model of an alternative solar system was created by UC Riverside researchers using data from the solar system today. The researchers found that a more eccentric Jupiter orbit would result in significant changes to Earth. According to UCR Earth and planetary scientist Pam Vervoort, the change in Jupiter’s orbit may actually increase this planet’s habitability. There are multiple known life forms that can live on the Earth’s surface between 0 and 100 degrees Celsius. Occasionally, parts of Earth would get closer to the sun if Jupiter pushed Earth’s orbit more eccentric. Currently, subfreezing parts of the Earth’s surface would warm, increasing the habitable temperature range. Two long-held assumptions about our solar system have been overturned by this study, published in Astronomical Journal.

“Many believe that Earth is the epitome of a habitable planet and that any change to Jupiter’s orbit, being such a massive planet, could only be detrimental to us,” Vervoort said. “We show that both assumptions are wrong.” It is hoped that this discovery will assist in the search for exoplanets orbiting other stars. Astrophysicist and study co-author Stephen Kane said that in searching for exoplanets, the first thing to look for is the habitable zone, the distance between a star and a planet where liquid water could exist.

Planets have seasons because they receive different amounts of direct sunlight during their orbits. At one time of the year, parts of the planet may be pleasant, but at another time, they might be extremely hot or cold. Kane says that having water on a planet’s surface is a very simple first metric that doesn’t take into account the shape of a planet’s orbit or seasonal changes. A planet’s orbit can be measured using existing telescopes. There are, however, additional factors that may affect habitability, such as a planet’s tilt toward or away from a star. In the tilted region of the planet, less energy would reach the surface, resulting in a colder climate.

According to the same study, Jupiter’s closer position to the sun would cause extreme tilting on Earth, causing large sections of the Earth’s surface to freeze. Researchers would like to develop methods for estimating a planet’s mass and tilt, which are harder to measure. To understand the impact of giant planets in our solar system, as well as to make predictions about planets in other systems, we need to understand their movements. Jupiter’s impact on Earth’s climate throughout time, its effect on our orbit in the past, and its impact on us in the future are important to understand, Kane said.