Did Earth lose its protective bubble 2 million years ago?
https://earthsky.org/space/earth-protective-bubble-heliosphere-interstellar-medium/
Around 2 million years ago, Earth may have lost its protective bubble, the heliosphere, due to a dense cold cloud of hydrogen atoms. This event could have exposed Earth to stronger interstellar radiation, leaving traces of heavier metals and potentially cooling our climate. The heliosphere usually shields us from harsh cosmic conditions, but this ancient encounter shrunk the bubble, impacting our planet significantly. The discovery, published in Nature Astronomy, was led by Merav Opher from Boston University. Using computer models, the researchers traced our solar system’s path through the Milky Way, highlighting how these cosmic events could have contributed to Earth’s ice ages and climate changes.