The Earth would have passed through a glacial cloud, capable of completely modifying the evolution and climate of our planet: here’s what we know about this theory.
Today the Earth is a habitable planet, albeit increasingly hotter – as demonstrated by the latest temperatures recorded. But it hasn’t always been like this: about two million years ago a very long period began during which glaciations followed one another which have literally transformed the Earth’s climate and evolution. The surface of our planet was covered in ice and only very few creatures were able to survive in this hostile environment. At least until, around 12 thousand years ago, the situation completely changed. But what were the causes that led to the alternation of ice ages on Earth? Scientists have developed a new theory.
The ice cloud hypothesis
The paleoclimatology experts they have been wondering for years about the possible causes that triggered the series of ice ages that completely disrupted the climate on Earth. From the greenhouse effect to volcanic eruptions, there are many factors that could have contributed to this phenomenon. But now a new and interesting theory has emerged, thanks to the work of a research team from Boston University, published in Nature Astronomy. The study speaks of the existence of one icy interstellar cloud which, about two million years ago, would have met our planet.
Using some computer-generated modelsscholars have tried to analyze how the position of the Sun and the heliosphere (i.e. the protective shield of plasma emanating from the Sun itself) two million years ago may have influenced the Earth’s atmospheric chemistry. The hypothesis is that an ice cloud, precisely in that period of time, would have interfered with the solar wind temporarily reducing the heliosphereleaving our planet “uncovered” by its protection against cosmic rays.
The consequences of the encounter between the Earth and the ice cloud
“Our study is the first to quantitatively demonstrate that there has been a meeting between the Sun and something outside the Solar System that may have affected Earth’s climate. Stars move and this work shows not only that they move, but also that they undergo drastic changes” – he said Merav Opher, space physicist at Boston University and lead author of the study. If this theory were to prove correct, our planet would have experienced a particularly difficult period that made it inhospitable.
Without the protection of the heliosphere, would have been exposed to radioactive particles and gas, dust and atomic elements from the exploded stars. A demonstration of this phenomenon can be found in the sampling carried out on the oceans, on Antarctic snow and on ice cores (as well as on the Moon): isotopes of elements such as iron and plutonium have been identified which must have arrived from deep space. In that period, the temperature on Earth it collapsed rapidly and the ice ages began.
“Only rarely do our cosmic neighbors beyond the Solar system influence life on Earth. It’s exciting to discover that our passage through dense clouds a few million years ago may have exposed our planet to a much larger stream of cosmic rays and hydrogen atoms. Our results open a new window on the relationship between the evolution of life on Earth and our cosmic neighborhood,” he said. Avi Loebdirector of the Institute for Theory and Computation at Harvard University and co-author of the study.
