About this Research Topic
In this Frontiers Topic, we will investigate the feasibility of finding evidence of past or present life elsewhere in our Solar System and beyond. Bringing together field and laboratory-based studies, in-situ space experiments, and theoretical modelling, we aim to present a unique picture of how life survives at the boundaries of habitability and the implication that this has on biosignatures, and finding evidence of life elsewhere in the Solar System and on exoplanets.
The presence of water is central to when, where, and under what conditions life may exist. Geochemical data suggests that habitable environments may exist, or existed, elsewhere in the Solar System with promising targets include Mars and the icy bodies, such as Enceladus and Europa, where liquid water is believed to exist. Furthermore, potential habitable exoplanets have been discovered where there is thought to be sufficient atmospheric pressure to maintain liquid water. Yet, for life to exist it is not solely dependent on liquid water it also needs certain chemical elements and the environmental conditions, such as temperature, pressure and pH values, must be conducive to life.
Our understanding of potential life in extraterrestrial environments and their biosignatures has mainly focused on studying extreme environments on Earth. A large number of analogue sites have been identified that are similar to the environmental conditions we would expect elsewhere in our Solar System. For example, the glaciers of the McMurdo dry valleys in Antarctica are an analogue site for the polar regions of Mars and even the icy moons around Jupiter and Saturn. At the surface microorganisms are exposed to cold temperatures, UV radiation and periods of desiccation. The ocean below the Antarctica icy shelf is also a potential analogue for the sub-surface oceans of Europa and Enceladus.
Survivability in potential habitable environments beyond the Earth has been studied using ground based simulation experiments and in-situ space experiments on-board the International Space Station (ISS). Certain microorganisms are known to survive the environmental conditions associated with low Earth orbit when protected from the detrimental effect of solar extraterrestrial UV radiation.
In this Frontiers Research Topic, we will present up-to-date information regarding the following areas:
1) Life in analogue environments on Earth
2) Ground- based simulation experiments
3) Exposure experiments on-board the ISS
4) Biosignatures and future life detection missions
We will use this opportunity to reciprocal exchange ideas and analytical approaches across disciplines.
Keywords: Extremophiles, survivability, space, habitability, biosignatures
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.