near-zone magnetic field
51Astronomy — (from the Greek words astron (ἄστρον), star , and nomos (νόμος), law ) is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth s atmosphere (such as the cosmic… …
52Atmosphere of Venus — Atmosphere of Venus …
53X-ray astronomy — X rays start at 0.008 nm and extend across the electromagnetic spectrum to 8 nm, over which the Earth s atmosphere is opaque. X ray astronomy is an observational branch of astronomy which deals with the study of X ray observation and detection… …
54Brown dwarf — Brown dwarfs are sub stellar objects which are too low in mass to sustain hydrogen 1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no… …
55Mid-ocean ridge — Oceanic ridge, including a black smoker A mid ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges (chains), typically having a valley known as a rift running along its spine, formed by plate… …
56Silurian Period — Interval of geologic time, 443–417 million years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes. The continents were… …
57Tertiary Period — Interval of geologic time, 65–1. 8 million years ago. It constitutes the first of the two periods of the Cenozoic Era, the second being the Quaternary. The Tertiary has five subdivisions: (from oldest to youngest) the Paleocene, Eocene, Oligocene …
58Transmission electron microscopy — A TEM image of the polio virus. The polio virus is 30 nm in size.[1] Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it… …
59Polar wind — is the permanent outflow of ionization from the polar regions of the magnetosphere. [http://amsglossary.allenpress.com/glossary/browse?s=p p=43 AMS Glossary] ] Ionospheric Plasma SourceThe ‘ground state’ of the ionosphere consists of the baseline …
60paleogeography — paleogeographer, n. paleogeographic /pay lee oh jee euh graf ik/ or, esp. Brit., /pal ee /, paleogeographical, adj. paleogeographically, adv. /pay lee oh jee og reuh fee/ or, esp. Brit., /pal ee /, n. the science of representing the earth s… …
