baryonic material was the 

 medium in which the big 

 bang occurred, and that it 

 is a part of the fabric of a 

 universe that preceded the 

 one we know? 

 David Shander 

 Denver, Colorado 



I wish that astronomical 

 articles in Natural His- 

 tory paid less attention to 

 exceptionally speculative 

 issues like dark matter. By 

 way of contrast to Donald 

 Goldsmith's article, see 

 "Modern Cosmology: 

 Science or Folktale?" in 

 the September/October 

 issue of American Scientist. 

 If anyone wonders why 

 the American public is 

 weary of funding these 

 games, that article would 



be a good place to begin 

 looking for an answer. 

 I suspect that there is a 

 growing contusion in 

 the scientific community 

 about the ontological 

 status of mathematics. 

 Nothing in mathematics 

 is real. There are often 

 interesting and useful 

 connections with the real 

 world, but extending 

 mathematical formalisms 

 too far beyond experi- 

 mental verification is sim- 

 ply abuse of a useful tool. 

 Dwight Brown 

 Kcrrville, Texas 



Donald Goldsmith 

 replies: I attempted to 

 explain the chain of rea- 

 soning that leads most 

 astrophysicists to conclude 



that dark matter predomi- 

 nates over visible matter in 

 the universe. Those astro- 

 physicists recognize that 

 their conclusion rests on 

 certain assumptions and 

 might be overturned, but 

 current data suggest that 

 dark matter is the most 

 reasonable way to explain 

 such matters as the ob- 

 served motions of galax- 

 ies in galaxy clusters and 

 the abundance of cosmic 

 nuclei. 



The question of what 

 existed before the big 

 bang remains largely un- 

 resolved, though the most 

 widely accepted answer 

 among cosmologists is 

 that nothing existed, not 

 even space or time. Dark 

 energy deserves an article 



by itself [see "Gravity in 

 Reverse, " by Neil deGrasse 

 Tyson, 12/03-1/04}. As 

 with dark matter, the 

 conclusion that dark en- 

 ergy provides most of the 

 energy in the universe 

 seems well established, 

 while remaining subject 

 to disproof by further 

 observations and better 

 interpretation of the 

 existing data. 



Natural History welcomes 

 correspondence from readers. 

 Letters should be sent via 

 e-mail to nhmag@natural 

 historymag.com or by fax to 

 646-356-6511. All letters 

 should include a daytime 

 telephone number, ami all 

 letters may be edited for length 

 and clarity. 



November 2007 natural history 



It is what makes people, places and things squeaky 

 clean and springtime fresh. It is chemistry. 



