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In the very long term, how could humans colonise the Galaxy? Colonisation cannot be centrally controlled; deeper drives must be tapped. It may take centuries to colonise the nearest stars: it may be a 'programme' like the Industrial Revolution, fuelled by entrepreneurship. To build a respectable interstellar empire may take millennia. Religions are similar multigenerational projects. Perhaps colonists will be motivated by appropriate creeds. To win the Galaxy, starship technology must persist for tens or hundreds of millennia. Homo erectus made the same hand-axe for a million years. The driver was biological, not conscious. Perhaps to our descendants starships will be like peacock tails.  相似文献   
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In this study, we utilized transmission electron microscopy to examine the contents of fluid inclusions in halite (NaCl) and solid halite crystals collected 650 m below the surface from the Late Permian Salado Formation in southeastern New Mexico (USA). The halite has been isolated from contaminating groundwater since deposition approximately 250 Ma ago. We show that abundant cellulose microfibers are present in the halite and appear remarkably intact. The cellulose is in the form of 5 nm microfibers as well as composite ropes and mats, and was identified by resistance to 0.5 N NaOH treatment and susceptibility to cellulase enzyme treatment. These cellulose microfibers represent the oldest native biological macromolecules to have been directly isolated, examined biochemically, and visualized (without growth or replication) to date. This discovery points to cellulose as an ideal macromolecular target in the search for life on other planets in our Solar System.  相似文献   
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