Millions of years ago, our solar system sailed through the Orion star-forming complex, which was part of the giant Radcliffe Wave structure. This cosmic journey may have affected Earth's climate by compressing the heliosphere and adding interstellar dust, possibly leaving traces in the geological record. Using data from ESA's Gaia mission, scientists pinpointed this channel and linked it to the Miocene climate transition, a major shift in Earth's climate history.
An international team of researchers led by scientists at the University of Vienna has found that our solar system passed through the Orion star-forming complex, which was part of the larger Radcliffe wave, about 14 million years ago.
The journey through dense regions of space may have compressed the heliosphere, the protective layer surrounding the solar system, and increased the flow of interstellar dust. Scientists believe this may have affected Earth's climate and left traces in the geological record.
Their findings, recently published in Astronomy and Astrophysics, highlight interesting connections between astrophysics, paleoclimatology and geology.
As the solar system orbits the center of the Milky Way, it passes through different galactic environments. "Imagine it like a ship at sea, sailing in different conditions," explains lead author and PhD student Ephraim Marconi at the University of Vienna. "Our sun encounters a region of denser gas as it passes through the Radcliffe wave in the constellation Orion."
The research team used data and spectroscopic observations from the European Space Agency's (ESA) Gaia mission to identify Radcliffe waves that passed through the Orion region of the solar system approximately 14 million years ago. "This discovery builds on our previous identification of Radcliffe waves," said João Alves, professor of astrophysics at the University of Vienna and co-author of the study. Radcliffe waves are large, thin structures made up of interconnected star-forming regions, including the famous Orion complex, which the Sun passes through, as this study identified.
"As we pass through the Orion region, famous star clusters such as NGC 1977, NGC 1980 and NGC 1981 are forming," Alves noted. "This region is clearly visible in northern hemisphere winter skies and southern hemisphere summer skies. Look for the constellation Orion and the Orion Nebula (Messier 42) - that direction our solar system comes from!"
The increased dust produced by this galaxy collision could have a variety of effects. It may have penetrated Earth's atmosphere, possibly leaving a trace of supernova radioactive elements in the geological record. "While current technology may not be sensitive enough to detect these traces, future detectors could do so," Alves said.
The research team's research shows that the solar system passed through the Orion region about 18.2 million to 11.5 million years ago, with the most likely time being 14.8 million to 12.4 million years ago. This time frame coincides with the Miocene climate transition, a major shift from a warm and variable climate to a cooler climate that gave rise to the continental-scale prototype structure of the Antarctic ice sheet.
While the study raises the possibility of a connection between the Solar System's past transits through its neighboring galaxies and Earth's climate through interstellar dust, the authors stress that the cause-and-effect relationship requires further investigation.
"While the underlying processes responsible for the Miocene climate transition are not yet fully identified, existing reconstructions suggest that a long-term decline in concentrations of the atmospheric greenhouse gas carbon dioxide is the most likely explanation, although there are large uncertainties. However, our study highlights that interstellar dust associated with Radcliffe wave crossings may have affected Earth's climate and may have played a role in this climate transition. To alter Earth's climate, the amount of extraterrestrial dust on Earth would have to be much greater than current data suggest," Marconi said.
"Future studies will explore the significance of this contribution. It is important to note that past climate transitions are not comparable to current climate changes, as the Miocene climate transition spans timescales of hundreds of thousands of years. In contrast, the current evolution of global warming due to human activities is occurring at an unprecedented rate, lasting decades or even centuries."
This study is important because it adds a small piece of the puzzle to the solar system's recent history, helping to place it within the context of the Milky Way.
"We are inhabitants of the Milky Way," said Alves, "and the European Space Agency's Gaia mission gives us the means to track our recent path through the Milky Way's interstellar ocean, allowing astronomers to communicate with geologists and paleoclimatologists. This is very exciting."
In the future, the team led by João Alves plans to study in more detail the galactic environment the Sun encounters as it travels across the Milky Way.
Compiled from /ScitechDaily