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In the standard Cold Dark Matter (CDM) theory of structure formation,virialized minihalos (with T_vir}<10^4 K) form in abundance at high redshift(z>6), during the cosmic ``dark ages.'' The hydrogen in these minihalos, thefirst nonlinear baryonic structures to form in the universe, is mostly neutraland sufficiently hot and dense to emit strongly at the 21-cm line. We calculatethe emission from individual minihalos and the radiation background contributedby their combined effect. Minihalos create a ``21-cm forest'' of emissionlines. We predict that the angular fluctuations in this 21-cm background shouldbe detectable with the planned LOFAR and SKA radio arrays, thus providing adirect probe of structure formation during the ``dark ages.'' Such a detectionwill serve to confirm the basic CDM paradigm while constraining the shape ofthe power-spectrum of primordial density fluctuations down to much smallerscales than have previously been constrained, the onset and duration of thereionization epoch, and the conditions which led to the first stars andquasars. We present results here for the currently-favored, flat $\Lambda$CDMmodel, for different tilts of the primordial power spectrum.Comment: Revised version. 10 pages, 4 figures, re-submitted to ApJ Letter

On the Direct Detectability of the Cosmic Dark Ages: 21 Centimeter Emission from Minihalos