Earth, of all known planets, is as life-friendly as any planet could possibly be, or is it? A new study suggests that if Jupiter's orbit shifts, Earth may become more habitable than it is now. When a planet orbits its star in a completely circular orbit, the distance between the star and the planet remains constant. Most planets, on the other hand, have "eccentric" orbits around their stars, which means the orbit is oval-shaped. As the planet comes closer to its star, it absorbs more heat, which affects the environment. UC Riverside researchers developed an alternate solar system using comprehensive models based on data from the solar system as it is understood today. They discovered that if the massive Jupiter's orbit became more eccentric, it would cause significant changes in the geometry of Earth's orbit.
According to Pam Vervoort, primary research author and UCR Earth and planetary scientist, if Jupiter's position stayed constant but the geometry of its orbit altered, it may actually boost the planet's habitability.
The Earth's surface is livable for a variety of known life forms between zero and 100 degrees Celsius. If Jupiter caused Earth's orbit to grow more eccentric, sections of the Earth would sometimes approach the sun. Parts of the Earth's surface that are currently sub-freezing would warm up, raising temperatures into the habitable zone. This finding, which has been published in the Astronomical Journal, challenges two long-held scientific beliefs about our solar system.
According to Vervoort, many people believe that Earth is the pinnacle of a livable planet and that any alteration in Jupiter's orbit, being the giant planet that it is, can only be harmful for Earth. We demonstrate that both assumptions are incorrect.
The researchers want to use this discovery in the hunt for habitable worlds surrounding other stars, known as exoplanets.
According to Stephen Kane, a UCR astronomer and research co-author, the habitable zone is the distance between a star and a planet that determines whether there is enough energy for liquid water on the planet's surface.
Different areas of a planet get more or less direct rays during its orbit, resulting in seasons. Parts of the world may be nice one season but excessively hot or frigid the next.
According to Kane, having water on a planet's surface is a very simplistic initial metric that does not account for the geometry of a planet's orbit or seasonal fluctuations.
Existing telescopes can calculate a planet's orbit. However, there are other elements that might influence habitability, such as how far a planet is oriented toward or away from a star. The area of the planet that is inclined away from the star will get less energy, making it cooler. The same study discovered that if Jupiter were significantly closer to the sun, it would cause considerable tilting on Earth, causing vast parts of the Earth's surface to freeze. Because measuring tilt or a planet's mass is more challenging, the researchers would want to work on approaches that will allow them to estimate those characteristics as well.
Finally, the movement of a big planet is crucial in both predicting the habitability of planets in distant systems and understanding its effect on our solar system.
According to Kane, it is critical to understand the influence Jupiter has had on Earth's climate across time, how its effect on our orbit has changed us in the past, and how it may affect us again in the future.
Journal Information: Pam Vervoort et al, System Architecture and Planetary Obliquity: Implications for Long-term Habitability, The Astronomical Journal (2022). DOI: 10.3847/1538-3881/ac87fd