Cosmological lithium problem

<p>In <a href="/facts/Astronomy/0ArJVM1p">astronomy</a>, the lithium problem or lithium discrepancy refers to the discrepancy between the primordial <a href="/facts/Abundance_of_the_chemical_elements/CE9WehBl">abundance</a> of <a href="/facts/Lithium/7vXX6BWA">lithium</a> as inferred from observations of metal-poor (<a href="/facts/Stellar_population/8ur1qDRK">Population II</a>) <a href="/facts/Stellar_halo/tBr2th1p">halo stars</a> in our galaxy and the amount that should theoretically exist due to <a href="/facts/Big_Bang_nucleosynthesis/IvM4gbKH">Big Bang nucleosynthesis</a>+<a href="/facts/Wilkinson_Microwave_Anisotropy_Probe/UUJWfy0U">WMAP</a> cosmic baryon density predictions of the <a href="/facts/Cosmic_microwave_background/ThB2HkLS">cosmic microwave background</a> (CMB). Namely, the most widely accepted models of the Big Bang suggest that three times as much primordial lithium, in particular <a href="/facts/Lithium-7/XC311sQu">lithium-7</a>, should exist. This contrasts with the observed abundance of isotopes of <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> (1H and <a href="/facts/Deuterium/Bv4wfCkw">2H</a>) and <a href="/facts/Helium/yRul93TG">helium</a> (<a href="/facts/Helium-3/SmPC5oT3">3He</a> and <a href="/facts/Helium-4/vNsL5qhC">4He</a>) that are consistent with predictions. The discrepancy is highlighted in a so-called "Schramm plot", named in honor of astrophysicist <a href="/facts/David_Schramm_(astrophysicist)/eo4yIMrP">David Schramm</a>, which depicts these primordial abundances as a function of cosmic baryon content from standard <a href="/facts/Big_Bang_nucleosynthesis/IvM4gbKH">BBN</a> predictions.
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Cosmological lithium problem open-in-new

Cosmological lithium problem