Esplorazione spaziale: gli elementi per capire - Apogeo Editore
Il sistema Solare e lo spazio interstellare sono pieni di campi magnetici. Alcuni processi fisici permettono al nucleo di ferro liquido, posto ...
utilizzerebbe degli aerogel
Un’idea, ben descritta nella rivista Nature Astronomy, <anchor>utilizzerebbe degli aerogel</anchor>, molto simili a quelli usati per mantenere in temperatura i veicoli spaziali, per trattenere il calore in alcune regioni della superficie marziana, con lo scopo di rilasciare i composti volatili intrappolati. Per esempio, gli aerogel a base silicea sono trasparenti alla luce visibile, per cui permettono alla luce del Sole di attraversarli. Ma possono essere resi opachi agli infrarossi, così che risultino in grado di intrappolare il calore generato quando la luce visibile viene assorbita dal suolo ghiacciato presente sotto l’aerogel.
Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect | Nature Astronomy
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- Letter
- Published: 15 July 2019

# Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect

### Subjects

## Abstract

The low temperatures1, 2 and high ultraviolet radiation levels3 at the surface of Mars today currently preclude the survival of life anywhere except perhaps in limited subsurface niches4. Several ideas for making the Martian surface more habitable have been put forward5, 6, 7, 8, but they all involve massive environmental modification that will be well beyond human capability for the foreseeable future9. Here, we present a new approach to this problem. We show that widespread regions of the surface of Mars could be made habitable to photosynthetic life in the future via a solid-state analogue to Earth’s atmospheric greenhouse effect. Specifically, we demonstrate via experiments and modelling that under Martian environmental conditions, a 2–3 cm-thick layer of silica aerogel will simultaneously transmit sufficient visible light for photosynthesis, block hazardous ultraviolet radiation and raise temperatures underneath it permanently to above the melting point of water, without the need for any internal heat source. Placing silica aerogel shields over sufficiently ice-rich regions of the Martian surface could therefore allow photosynthetic life to survive there with minimal subsequent intervention. This regional approach to making Mars habitable is much more achievable than global atmospheric modification. In addition, it can be developed systematically, starting from minimal resources, and can be further tested in extreme environments on Earth today.

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Fig. 1: Schematic of the solid-state greenhouse habitability concept for Mars.



Fig. 2: Image of silica aerogel used in the experiment.



Fig. 3: Results of the silica aerogel solid-state greenhouse warming experiments.



Fig. 4: Attenuation of UV radiation by silica aerogel.



Fig. 5: Simulated warming underneath a silica-aerogel solid-state greenhouse habitat on Mars.



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## Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

## Code availability

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## Author information

### Authors and Affiliations

1. Harvard Paulson School of Engineering and Applied Sciences, Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA

R. Wordsworth

2. Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA

R. Wordsworth

3. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA

L. Kerber

4. UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK

C. Cockell

Authors

1. R. Wordsworth

2. L. Kerber

3. C. Cockell

### Contributions

All authors discussed the experimental and numerical results and contributed to a draft version of the manuscript. R.W. proposed the solid-state greenhouse habitability idea, performed the experiments and wrote much of the manuscript. L.K. helped to write the sections on site selection on Mars and silica aerogel properties, and compiled data on the evidence for subsurface water sources. C.C. provided input on the nutrient, UV and pressure constraints on Martian habitability and on the ethical considerations.

### Corresponding author

## Ethics declarations

### Competing interests

The authors declare no competing interests.

## Additional information

Peer review information: Nature Astronomy thanks Joshua Bandfield, Dirk Schulze-Makuch and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

## Supplementary information

### Supplementary Information

Supplementary Tables 1–2, Supplementary Figs. 1–5.

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## About this article

### Cite this article

Wordsworth, R., Kerber, L. & Cockell, C. Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect.
Nat Astron 3, 898–903 (2019). https://doi.org/10.1038/s41550-019-0813-0

- Received: 27 November 2018

- Accepted: 14 May 2019

- Published: 15 July 2019

- Issue Date: October 2019

- DOI: https://doi.org/10.1038/s41550-019-0813-0

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