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Cave environments on Earth have long provided shelter to a variety of organisms, from microbes to humans. Though their scales of interest differ vastly, these two examples have sought the same comfort from caves: a stable and sheltered environment, protected from the woes of the surface world. Since the discovery of lava caves on Mars (see Sauro et al., 2020 for a review), they have become of renewed interest as targets for human shelter in future missions, as well as areas of astrobiological interest, with the potential of harboring traces of extant or extinct extraterrestrial life.

Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference or workshop dedicated to early-career researchers, providing a friendly environment where early-career minds would be able to present their research without being intimidated by the possibility of facing a more traditional audience, composed mainly of senior scientists. Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European, early-career astrobiologists. This article aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.

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<p>Polycyclic aromatic hydrocarbons (PAHs) represent ~20% of cosmically available carbon [1, 2]. The further photochemical evolution of PAHs on planetary surfaces is of interest to early Earth origin-of-life studies and Mars origin-of-life speculations. Much of the literature has focused on small molecules contained in meteorites, such as amino acids and nucleic acid bases, and their potential as a carbon source for prebiotic chemistry on early Earth. However, 75% of extraterrestrial organic matter in meteorites is in aromatic form [3], and is more likely to survive the journey to a planetary surface, during which much of the small molecules can be destroyed. These stable carbon compounds could later be broken down into smaller, more biologically relevant molecules by photocatalysis on clay mineral surfaces in the ultraviolet radiation regime of early Earth and Mars.</p> <p>Here we experimentally test whether PAHs degrade when adsorbed to nontronite clay and exposed to ultraviolet radiation. Experiments were performed at the INAF Observatory of Arcetri and in the PALLAS chamber at Utrecht University and were monitored with <em>in-situ</em> diffuse reflectance infrared spectrometry (DRIFTS) measurements. PAHs and any degradation products were extracted post-irradiation and analyzed with nuclear magnetic resonance (NMR).</p> <p>[1] Allamandola, L. J., Tielens, A. G. G. M., & Barker, J. R. (1989). <em>The Astrophysical Journal Supplement Series</em>, <em>71</em>, 733-775.</p> <p>[2] Puget, J. L., & Léger, A. (1989). <em>Annual review of astronomy and astrophysics</em>, <em>27</em>(1), 161-198.</p> <p>[3] Sephton, M. A. (2002). <em>Natural product reports</em>, <em>19</em>(3), 292-311.</p>