Our planet’s orbit around the Sun has not been exactly the same since the inception of the Solar System – and isn’t actually stable after all – but 2.8 million years ago a passing star surely perturbated Earth’s orbital dynamics.

A new study published in the Astrophysical Journal Letters suggests that the stellar encounter also created ancient climate anomalies, which were investigated by Planetary Science Institute researchers when they sensed a possible connection with the visitor, called HD-7977. 

This star passed by the Sun at a distance between 4,000 and 32,000 astronomic units (AU – the distance from Earth to Sun, or 93 million miles / 150 million kilometers).

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Lead author Nathan Kaib, a senior scientist at the Planetary Science Institute, emphasized in a press release the relevance of understanding Earth's orbital characteristics during past climate shifts, citing the correlation between orbital eccentricity variations and climate fluctuations evident in the geological record. 

"If we want to best search for the causes of ancient climate anomalies, it is important to have an idea of what Earth's orbit looked like during those episodes," he noted.