the isotopic composition of all elements
71mass spectrometry — or mass spectroscopy Analytic technique by which chemical substances are identified by sorting gaseous ions by mass using electric and magnetic fields. A mass spectrometer uses electrical means to detect the sorted ions, while a mass spectrograph …
72Sun — This article is about the star. For other uses, see Sun (disambiguation). The Sun …
73spectroscopy — 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… …
74Chondrite — Not to be confused with Chondrodite. A specimen of the NWA 869 chondrite (type L4 6), showing chondrules and metal flakes Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They… …
75Superior craton — in the west. The western margin extends from northern Minnesota through eastern Manitoba to northwestern Ontario.The formation of the Superior craton is best explained within the context of 2.72 2.68 Ga accretion of small continental plates and… …
76earth — /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… …
77dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …
78Helium — otherusesHelium (He) is a colorless, odorless, tasteless, non toxic, inert monatomic chemical element that heads the noble gas group in the periodic table and whose atomic number is 2. Its boiling and melting points are the lowest among the… …
79Cosmic dust — Space dust redirects here. For other uses, see Space dust (disambiguation). Porous chondrite interplanetary dust particle. Cosmic dust is a type of dust composed of particles in space which are a few molecules to 0.1 µm in size. Cosmic dust… …
80Moon — This article is about Earth s Moon. For moons in general, see Natural satellite. For other uses, see Moon (disambiguation) …
