Climate Change and Human Evolution from the Passage of the Solar System through a Cold Cloud 2-3Myrs ago
Abstract
There is overwhelming geological evidence from 60Fe and 244Pu isotopes that Earth was in direct contact with the interstellar medium (ISM) 2-3 Myr ago. The local interstellar medium is home to several nearby cold clouds. Here we show that if the solar system passed through a cloud such as Local Leo Cold Cloud, then the heliosphere which protects the solar system from interstellar particles, had shrunk to a scale smaller than the Earth's orbit around the Sun (0.22AU). Using a magnetohydrodynamic simulation that includes charge exchange between neutral atoms and ions, we show that during the heliosphere shrinkage, Earth was exposed to a neutral hydrogen density of up to 3000cm-3. This could have had drastic effects on Earth's climate and potentially of human evolution at that time, as suggested by previous data.
- Publication:
-
44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.3203O