A mysterious encounter in space changed the Earth's orbit

A chance encounter between Earth and a star may be responsible for the climate anomalies. New research reveals surprising details.

Tucson/Arizona – Studying changes in the Earth's orbit in past eras is an important aspect of studying past climate anomalies. Because these changes seem to have had a direct impact on the Earth's climate. In this context, scientists simulated encounters between stars and our solar system.

56 million years ago, Earth's temperature rose dramatically

About 56 million years ago, at the threshold between the Paleocene and Eocene geological eras, Earth's temperature rose by as much as eight degrees Celsius. This dramatic rise in temperature, which occurred over a few thousand years, is known as the Paleocene/Eocene temperature maximum, and continues to puzzle scientists to this day.

Nathan Cape, a planetary scientist from the Planetary Science Institute, and Sean Raymond, an astrophysicist from the Purdue Astrophysical Laboratory, hypothesized that an accidental collision between Earth's orbit and a star could be responsible for this phenomenon. The results of their research were In the specialized magazine Astrophysical Journal Letters published.

Researchers investigate the encounter between the star and Earth's orbit

Scientists simulated how a passing star could disrupt planetary orbits so much that Earth briefly deviates from its path. Cabe explains in one notice: “One reason this is important is that the geological record shows that changes in the eccentricity of the Earth's orbit are linked to changes in the Earth's climate.” If we want to better investigate the causes of past climate anomalies, he adds, “it's important to have an idea of ​​what Earth's orbit looked like during these episodes.”

In fact, the dramatic climate changes may be related to the way the Earth orbits the Sun. However, modeling the orbital evolution of our solar system over time is a complex task, comparable to detective work. There are many variables to take into account, such as empty space, different orbits, trajectories, and velocities.

An example of a star that populates the solar system shows the change

“It has already been suggested that the eccentricity of Earth's orbit was particularly high during this event, but our results show that transiting stars make detailed predictions about Earth's past orbital evolution at this time that are highly uncertain and represent a broader range,” says Cape. To enable circular behavior.”

In their research, Cape and Raymond used the star HD 7977, which passed through the solar system 2.8 million years ago, as an example. They found that the distance of the planets from the sun affects their movement, especially when the planets are closer to the sun.

Star encounters and their impact on Earth's climate

Although HD 7977 is the only flyby that has been positively identified, scientists estimate that the star passes within about 50,000 astronomical units every million years and within 10,000 astronomical units about every 20 million years (an astronomical unit is the distance between Earth and the Sun, about 150 million km). This suggests that the transiting star may have influenced Earth's climate in the past, and even played a role in the Paleocene/Eocene temperature maximum.

“We have shown that stellar encounters play an important role in the long-term dynamical evolution of our solar system,” Knipp and Raymond emphasize in their study. (YH)

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