isotopic mass
81Presolar grains — are isotopically distinct clusters of material found in the fine grained matrix of primitive meteorites, whose differences from the surrounding meteorite suggest that they are older than the solar system [Maria Lugaro (2005) Stardust from… …
82Evolution of water on Mars and Earth — The evolution of H2O on either planet needs be understood in the context of the other terrestrial planetary bodies and their current H2O inventories.H2O Inventory of MarsA significant amount of surficial H has been observed globally by the Mars… …
83John H. Hoffman — articleissues cleanup=June 2008 original research=June 2008 sections=June 2008 likeresume=June 2008 unreferenced=June 2008 wikify=June 2008 orphan=June 2008 do attempt=June 2008John Hoffman is a space scientist who developed instruments for… …
84glacier — glaciered, adj. /glay sheuhr/, n. an extended mass of ice formed from snow falling and accumulating over the years and moving very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of… …
85Sun — This article is about the star. For other uses, see Sun (disambiguation). The Sun …
86spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
87chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
88meteorite — meteoritic /mee tee euh rit ik/, meteoritical, meteorital /mee tee euh ruyt l/, adj. /mee tee euh ruyt /, n. 1. a mass of stone or metal that has reached the earth from outer space; a fallen meteoroid. 2. a meteoroid. [1815 25; METEOR + ITE1] * * …
89Isotopes of uranium — Uranium (U) is a naturally occurring element with no stable isotopes. In other words, all uranium is radioactive and hence vanishing by radioactive decay, yet it is also found in great quantity in the earth s crust. The natural isotopes are… …
90earth — /errth/, n. 1. (often cap.) the planet third in order from the sun, having an equatorial diameter of 7926 mi. (12,755 km) and a polar diameter of 7900 mi. (12,714 km), a mean distance from the sun of 92.9 million mi. (149.6 million km), and a… …
