Produced by: Tarun Mishra
Scientists suggest Earth may have briefly lost protection from the sun around two million years ago as the solar system passed through a dense cloud of gas and dust between stars. The findings were published in Nature Astronomy journal on June 10.
This period coincided with the presence of early human ancestors and prehistoric animals like mastodons and sabretooth tigers, amidst an ice age that lasted until about 12,000 years ago.
The research proposes that radical climate changes, including ice age onset and end, could be influenced by the position of our solar system in the Milky Way galaxy.
Earth's protective shield, the heliosphere, created by solar winds, shields it from radiation and galactic rays, crucial for life's emergence and evolution.
A cold cloud of interstellar material might have compressed the heliosphere temporarily, exposing Earth to the interstellar medium and removing its protection.
Credit: NASA
Sophisticated computer models traced the solar system's position and tracked the progress of a dense cold gas cloud, revealing a potential clash with the heliosphere.
Credit: NASA
The clash may have exposed Earth to heavy and radioactive elements, contributing to an increase in isotopes like iron 60 and plutonium 244 found in Antarctic snow and ice cores.
The pressure from the interstellar cloud could have sparked a cooling period on Earth, akin to an ice age, lasting from a few hundred to a million years.
Further investigation aims to explore the impact of interstellar material on Earth's atmosphere and determine if similar encounters align with past ice ages, providing insight into Earth's climatic history.