An article published in the journal “Earth and Planetary Science Letters” describes a research on the possible link between the primordial bombardment of meteorites on Earth and the emergence of life forms. According to a team of researchers directed by Simone Marchi of the Southwest Research Institute in Boulder, Colorado, USA, the meteorites that struck Earth during its first billion years of life created a greenhouse effect sufficient to maintain the water in its liquid state, allowing the emergence of life.
The problem of the so-called faint young Sun is given by the fact that the Sun became brighter with the passage of time and when it and the Earth were young the planet was receiving about 70% of the solar energy it receives today. When this characteristic of the young Sun was discovered it created a problem because in that condition the Earth was supposed to be a snowball while there are geological evidence that water was liquid.
According to this new research, the impacts caused following the primordial meteor bombardment were in such an amount as to produce a significant amount of carbon dioxide. That’s because a collision melts the rock in its impact area forming even lava lakes that release various gases including carbon dioxide.
The primordial Earth was the subject of a considerable amount of impacts. The consequence is that especially those caused by very large asteroids may have led to the release of such an amount of carbon dioxide to trigger a strong greenhouse effect in the primordial atmosphere. According to the researchers, the same impacts may have redistributed on the surface large amounts of sulfur, an essential element for life forms.
A few weeks ago an article published in the journal “Nature Geoscience” identified in the young Sun’s superflares the the possible origin of the energy needed to heat water enough to keep it in liquid form. Both studies bring interesting and plausible arguments and the two explanations are not mutually exclusive.
On the young Sun there were probably many super-flares and on the Earth there are traces of many impacts of large asteroids dating from the Hadean period, between 4.6 and 4 billion years ago, and from the early Archean period, just under 4 billion years ago. Sometimes the investigation of an event leads to discover that there were multiple causes. For this reason it’s necessary to keep on studying it by bringing together data from different research.