Pennies in heaven?Why slam a copper impactor into Comet Tempel Comet Tempel may mean:
NASA in full National Aeronautics and Space Administration Independent U.S. probe burrows into a comet" SN: 7/9/05, p. 22)? Wouldn't copper vapor contaminate con·tam·i·nate v. 1. To make impure or unclean by contact or mixture. 2. To expose to or permeate with radioactivity. con·tam·i·nant n. the spray? Why not a high-temperature ceramic? P.M. DELAUBENFELS, CORVALLIS, ORE. According to Casey Lisse of the Deep Impact team, copper was chosen because its density put a lot of mass into a small package, its relative softness reduced bounce at impact, and its large atomic number atomic number, often represented by the symbol Z, the number of protons in the nucleus of an atom, as well as the number of electrons in the neutral atom. Atoms with the same atomic number make up a chemical element. and density contrast with those of elements that were expected to spew from the comet at impact (see p. 168).--R. COWEN |
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