tel: 256 961 7770
fax: 256 931 7524
Area of Expertise
Astrobiology, microbial extremophiles, diatoms; X-Ray/EUV Optics, microscopy
Richard B. Hoover is Astrobiology Group Leader at the NASA/MSFC/NSSTC in Huntsville, Alabama where he conducts research on microbial extremophiles, microfossils, and chemical biomarkers in Precambrian rocks and carbonaceous meteorites. He holds 11 U. S. Patents and was 1992 NASA Inventor of the Year. He served on Editorial Boards of several scientific Journals and the Boards of Directors of SPIE, the American Association of Engineering Societies, and the Council of Scientific Society Presidents. He is author/editor of 33 Volumes and 250 papers on Astrobiology, Extremophiles, Diatoms, Solar Physics, X-ray/EUV Optics and meteorites. He co-directed the NATO Advanced Study Institute on Astrobiology in Crete and his book "Perspectives in Astrobiology" appeared in June, 2005.
Richard Hoover has collected meteorites and microbial extremophiles from Antarctica; novel bacteria from glaciers and permafrost of Antarctica, Patagonia, Siberia, Alaska and from haloalkaline lakes, geysers and volcanoes of California, Alaska, Crete, and Hawaii. He has authored four new species of bacteria: (Spirochaeta americana, Desulfonatronum thiodismutans, Tindallia californiensis) from Mono Lake; and Carnobacterium plesitocenium that survived for 32,000 years in a frozen Alaskan pond.
Richard Hoover was Science Team Leader for the Antarctica 2000 Expedition (searching for meteorites and extremophiles in Antarctica's Thiel Mountains) and for the Russian/American Expedition Beringia (searching for microbes in permafrost of Northeastern Siberia). He was elected an Honorary Life Member of the Planetary Studies Foundation for his contributions to the study of carbonaceous meteorites. In 2001, Richard Hoover was elected a Fellow of the Explorers Club for his Scientific Expeditions to some of Earth's most hostile environments. He is an SPIE Fellow and in 2001 served as the President of SPIE.
Comets, Carbonaceous Meteorites, and the Origin of the Biosphere
Abstract: The biosphere is that portion of the Earth's atmosphere, waters, crust, and ice caps where living organisms can survive. The recent discoveries of barophilic chemolithotrophs living deep within the crust, hyperthermophilic archaea growing in vent fluids above 120 oC, and psychrophiles that survive in Pleistocene permafrost and deep Vostok cores have shown that the Earth's biosphere is far more extensive than previously envisioned. The evidence from molecular biomarkers and Bacterial Paleontology indicates that life appeared very early on the primitive Earth and it appears that the origin of the biosphere is closely linked with the emergence of life.
The role of comets, meteorites, and interstellar dust in the delivery of water, carbon, organics and prebiotic chemicals necessary for life is becoming better understood. Evidence continues to mount that comets played a crucial role not only in the origin of the early Earth's atmosphere and oceans, but also in the introduction of carbon and complex organic/prebiotic chemicals to the early Earth during the Hadean (4.5-3.8 Gyr) period of heavy bombardment. Images of the nucleus of Comet P/Wild 2 obtained during the closest (500 km) approach of the NASA Stardust spacecraft showed depressions, aligned escarpments, and tall pinnacles, indicating a thick crust and durable 100 meter cliffs possibly accreted from recondensing gases. The presence of a thick, black, kerogen-like crust, and elevated temperatures of the nucleus of comets indicates that some comets may contain liquid water and brines trapped within cavities between the crust and the interior ice and rock debris. Since life exists on Earth wherever there is liquid water - the types of microbial extremophiles that might be able to survive on comets are considered.
There exists a dramatic similarity exists between the chemical compositions of CI carbonaceous meteorites and comets and therefore these meteorites may well be the remains of cometary nuclei with volatiles removed. Field Emission Scanning Electron Microscope (FESEM) studies carried out during the past several years on freshly fractured interior surfaces of the Orgueil CI meteorite has revealed in-situ the existence of the well-preserved mineralized remains of a complex suite of trichomic prokaryotes. Many of the forms found embedded in the mineral matrix are morphotypes of cyanobacteria and sulphur bacteria. EDAX and 2-D X-ray analysis indicate the chemical composition of these remains are dramatically different from living cyanobacteria, although they bear elemental biosignatures that overlay that of the meteorite matrix.
This presentation reviews recent theories of the Origin of the Biosphere and presents new data on comets and microbial extremophiles. Recently obtained FESEM images and EDAX data on living cyanobacteria and microfossils in CI meteorites will be presented in support of the hypothesis that comets and meteorites may have contributed to the Origin and Evolution of the Biosphere by the delivery of not only water, carbon, and prebiotic chemicals to early Earth, but also via complex cryopreserved biomolecules and perhaps even viable intact microorganisms.
Searching for Life in All the Wrong Places
This is a talk for the general public with a description of the wonders of Microbial Extremophiles and a lot of photos of Travels to North Siberia, Volcanoes, and to Patagonia (with Magellanic Penguins) and the Thiel Mountains and the South Pole (with Owen Garriott and Jim Lovell) to search for meteorites and microbes. I can provide an Abstract if you wish.