1,355,110 research outputs found
Martian impact fracturing pervasively influences habitability
No full textThis file is a Jupiter notebook file of the data used to calculate the fracturing volume and surface area as laid out by Cockell, CS and Collins (2024) Martian impact fracturing pervasively influences habitability. Journal of Geophysical Research. The equations used to calculate that data are shown in that paper.This file is a Jupiter notebook file of the data used to calculate the fracturing volume and surface area as laid out by Cockell, CS and Collins (2024) Martian impact fracturing pervasively influences habitability. Journal of Geophysical Research. The equations used to calculate that data are shown in that paper
The Microbial Habitability of Weathered Volcanic Glass Inferred from Continuous Sensing Techniques
No full textBasaltic glasses (hyaloclastite) are a widespread habitat for life in volcanic environments, yet their interior physical conditions are poorly characterized. We investigated the characteristics of exposed weathered basaltic glass from a surface outcrop in Iceland, using microprobes capable of continuous sensing, to determine whether the physical conditions in the rock interior are hospitable to microbial life. The material provided thermal protection from freeze-thaw and rapid temperature fluctuations, similar to data reported for other rock types. Water activity experiments showed that at moisture contents less than 13% wet weight, the glass and its weathering product, palagonite, had a water activity below levels suitable for bacterial growth. In pore spaces, however, these higher moisture conditions might be maintained for many days after a precipitation event. Gas exchange between the rock interior and exterior was rapid (<10?min) when the rocks were dry, but when saturated with water, equilibration took many hours. During this period, we demonstrated the potential for low oxygen conditions within the rock caused by respiratory stimulation of the heterotrophic community within. These conditions might exist within subglacial environments during the formation of the rocks or in micro-environments in the interior of exposed rocks. The experiments showed that microbial communities at the site studied here could potentially be active for 39% of the year, if the depth of the community within the outcrop maintains a balance between access to liquid water and adequate protection from freezing. In the absence of precipitation, the interior of weathered basaltic glass is an extreme and life-limiting environment for microorganisms on Earth and other planets
Limitations to a microbial iron cycle on Mars
No full textAnaerobic microbial metabolisms found on the Earth are the most plausible candidates for understanding potentially analogous energy gathering metabolisms on Mars. The iron-rich nature of Mars raises questions on whether the planet could support energy acquisition by iron-cycling microorganisms. This review paper addresses what is known about the redox couples that support microbial iron cycling on Earth, and evaluates evidence to date of the presence or absence of relevant redox constituents on Mars. We give particular focus to iron reduction. These constituents include the presence and prevalence of ferric iron-bearing minerals that may serve as terminal electron acceptors, and the likelihood of organic compounds (exogenous and endogenous) or hydrogen residing in the near- or sub-surface as a source of electron donors. Whilst it is feasible that redox couples for iron cycling may exist, or have existed in the past, current knowledge suggests that for chemolithotrophs (iron oxidation) Mars may be an electron acceptor limited world and that for chemoorganotrophs (iron reduction) Mars may be limited in widespread, readily available electron donors, particularly in its subsurface. There are several major limitations in this assessment due to lack of experimental data on Earth, and lack of measurements on Mars. We outline a series of high priority in-situ measurements that are necessary to fully evaluate the potential for a Martian biological iron cycle. Our conclusions also apply to the search for a Martian biological sulphur cycle.</p
Astrobiology on the Moon
No full textIan Crawford and Charles Cockell report on an RAS Specialist Discussion Meeting held on Friday 14 May 2010
A more direct way of connecting places and Parliament is needed in order for service delivery to move into the 21st century
No full textIn this age of austerity, there are many complex issues that face our society. In tackling them, communities need to be given more control over their local public services and budgets. Sir Merrick Cockell advocates giving neighbourhoods greater decision making powers as a way of progressing into the future
Finish Was Near For Cockell:
No full textPhotograph taken for a story in the Oklahoma Times newspaper. Caption: "Don Cockell, England's challenger for the heavyweight crown, is down on his haunches in the ninth and final round of his scheduled 15-round bout with heavyweight champion Rocky Marciano in San Francisco Monday night.
A laboratory for multi-century science
No full textCharles Cockell and colleagues consider what it takes to establish and maintain an experiment that lasts for decades – or even for centuries
Boxers Harry Matthews and Don Cockell in ring after fight, Seattle, July 30, 1954
No full textOn July 30, 1954, Seattle boxer Harry "Kid" Matthews (1922-2003) lost by technical knockout to English fighter Donald John "Don" Cockell (1928-1983) in a bout held at Sick's stadium. In this photo, Matthews congratulates Cockell, while his coach, renowned boxing manager John C. "Deacon Jack" Hurley (1897-1972), speaks to someone outside the ring.Caption information derived from captions written by PI staff.1 photographic print: b&w; 11 x 14 in
Effects of a simulated Martian UV flux on the cyanobacterium, Chroococcidiopsis sp. 029
No full textDried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars
- …
