Stars Can Alter Earth’s Orbit, Impact Climate: Scientists

Scientists have discovered that stars beyond our Sun could significantly influence the orbital paths of planets within our solar system, including Earth, potentially altering their climates. Research indicates that the gravitational forces exerted by passing stars could shift Earth’s orbit, leading to dramatic climate changes. Such orbital adjustments have occurred in the past, with one event millions of years ago causing Earth’s temperature to rise by 8 degrees Celsius. This phenomenon and its implications for Earth’s climate and orbital evolution are detailed in a study titled ‘Passing Stars as an Important Driver of Paleoclimate and the Solar System’s Orbital Evolution’, published in The Astrophysical Journal Letters, led by researchers Sean Raymond and Nathan A Kaib.

Kaib, a senior scientist at the Planetary Science Institute, explains that these perturbations—minor deviations in a planet’s course due to the gravitational pull of neighboring celestial bodies—can significantly impact the long-term orbital patterns of the solar system’s planets. This is critical since geological records link variations in Earth’s orbital eccentricity with significant climate changes. Understanding the orbital configurations during such climatic anomalies is essential for investigating their causes.

To explore how Earth’s orbit has evolved over its 4.5-billion-year history, the researchers conducted simulations. They focused on a specific event around 2.8 million years ago when a Sun-like star, HD 7977, passed through our solar system. While initially distant, coming within 31,000 astronomical units (an astronomical unit being the distance from the Earth to the Sun), the star’s proximity might have decreased to as close as 4,000 astronomical units, posing a potential influence. Despite previous assumptions about Earth’s orbital eccentricity being high during this period, the team’s findings suggest that passing stars introduce a significant degree of uncertainty into predictions of Earth’s past orbital behavior, allowing for a wider range of possible scenarios than previously considered.