  In supersymmetric unified theories the dark matter particle can decay, just
like the proton, through grand unified interactions with a lifetime of order of
10^{26} sec. Its decay products can be detected by several experiments --
including Fermi, HESS, PAMELA, ATIC, and IceCube -- opening our first direct
window to physics at the TeV scale and simultaneously at the unification scale
10^{16} GeV. We consider possibilities for explaining the electron/positron
spectra observed by HESS, PAMELA, and ATIC, and the resulting predictions for
the gamma-ray, electron/positron, and neutrino spectra as will be measured, for
example, by Fermi and IceCube. The discovery of an isotropic, hard gamma ray
spectral feature at Fermi would be strong evidence for dark matter and would
disfavor astrophysical sources such as pulsars. Substructure in the cosmic ray
spectra probes the spectroscopy of new TeV-mass particles. For example, a
preponderance of electrons in the final state can result from the lightness of
selectrons relative to squarks. Decaying dark matter acts as a sparticle
injector with an energy reach potentially higher than the LHC. The resulting
cosmic ray flux depends only on the values of the weak and unification scales.
