SEMINAR – HYBRID EVENT: Impacts and Life – Extending the Habitable Zone in Time

Abstract

The discovery of Earth’s deep biosphere has extended the habitable zone of the solar system from Earth, to also include Mars and several icy moons around the outer planets. The geochemical conditions required to support deep life exist on most terrestrial planets, perhaps even on those beyond our own solar system. However, most terrestrial planets are geologically inactive and so the duration of habitable environments are limited. Without global processes like plate tectonics and volcanism, the planets need an external source of energy to generate heat to sustain life.

Meteorite impacts are universal phenomena that influence all planetary bodies. Besides being apocalyptic events, they generate enough heat to support hydrothermal systems, environments favourable for deep microbial life. Microbial communities persist if the impact-generated heat endures, which can be from thousands to millions of years. Yet, recent research on terrestrial craters shows that deep microbial life can linger hundreds of millions of years after the hydrothermal system has ceased. These microbial communities are heterotrophic and obtain necessary carbon and energy from hydrocarbons migrating in the impact-induced fracture system. Methane emissions from Martian craters also indicate hydrocarbon-cycling in extra-terrestrial craters, suggesting that this is an interplanetary phenomenon.

A new view of impact craters as long-lived biological systems and interplanetary habitats emerges, where they exist as isolated oases on otherwise barren planets that extend the habitable zones of planetary systems, not only through space, but also through time. This qualifies them as vital sites for future missions to Mars and beyond.

For more information and the webinar link, please see http://www.swedishcollegium.se/subfolders/Events.html.