OUR best theories of the early universe also tell us which atoms should have been forged in the first 5 minutes after the big bang. The existing amounts of hydrogen and helium match theory perfectly 鈥� so well, in fact, that cosmologists claim this is the best evidence we have for the big bang. Things aren鈥檛 so good for the third element, lithium, however (New 杏吧原创, 5 July 2008, p 28).
When we count up the lithium atoms held in stars, there is only one-third as much of the lithium-7 isotope as there should be. Another isotope, lithium-6, is overabundant: there may be as much as 1000 times too much of it.
So something in the big bang is not adding up. Is it a serious problem? Yes, says Gary Steigman of Ohio State University in Columbus, but it is not fatal. 鈥淭here are too many successes for big-bang cosmology to be troubled by these lithium problems,鈥� he says.
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Others disagree. 鈥淭he lithium problem is one of the very few hints that there may be a problem with the big bang,鈥� says Jonathan Feng at the University of California, Irvine.
One thing that everyone does agree on is that things are getting worse. 鈥淭he lithium-7 problem is more serious than ever,鈥� says Joseph Silk at the University of Oxford. Improved observations of stars suggest they contain even less lithium-7 than previously thought. 鈥淭he gap between prediction and observation has widened,鈥� Steigman says.
So what is going on? The lithium-6 problem might just be an accounting issue: it is hard to discern lithium-6 abundances by looking at the light from stars. The lithium-7 shortfall might be due to destructive processes within stars, but there is no consensus as to what these processes might be. Others suggest the lithium-7 discrepancy is somehow linked to dark matter. 鈥淚t will be extremely interesting to see what we learn about that when the Large Hadron Collider turns on,鈥� Feng says.
Read more: 13 more things that don鈥檛 make sense