Scientists suggest that Earth might have experienced ice ages due to dramatic changes in interstellar space that affected the planet‘s atmosphere’s chemistry.
According to researchers from Boston University, Harvard University, and Johns Hopkins University, a massive interstellar storm around two million years ago could have altered Earth’s climate by exposing it to radiation.
While factors like the planet’s tilt, carbon dioxide levels, and tectonic plate movements contribute to ice ages, this study is the first to explore the impact of interstellar clouds on Earth’s climate.
Merav Ocher, a professor of astronomy at Boston University, along with a fellow at the Harvard Radcliffe Institute, highlighted the significance of the Sun’s interaction with objects outside the Solar System in influencing Earth’s climate.
Our planet is shielded from harmful cosmic rays by the Heliosphere, a protective bubble formed by the solar wind of charged particles.
Researchers propose that an interstellar storm may have disrupted the Heliosphere, exposing Earth to galactic radiation and particles that could have cooled the climate.
Using computer models, the team studied the Sun’s position two million years ago and tracked the motion of the Local Ribbon of Cold Clouds, a system of massive cold hydrogen clouds.
One of these clouds, the Local Lynx of Cold Cloud, could have interacted with the Heliosphere, potentially causing its collapse and exposing Earth to radiation.
The planet’s atmosphere might have undergone changes due to remnants of star explosions like iron and plutonium, found in higher concentrations in geological evidence from that period.
The presence of isotopes like iron-60 and plutonium-244 in the Moon, Antarctic Snow, oceans, and ice cores from that era supports the theory of interstellar cloud interaction.
Earth may have been outside the protective Heliosphere up to 10,000 years ago, exposing it to interstellar space.
Opher mentioned, “This cloud is indeed from our past. If we had crossed something so massive, then we would have been exposed to interstellar space.”
The complete findings of the study were published in Nature Astronomy.