  We study astrophysical implications of the quark nugget model of dark matter
and propose observational techniques for detecting anti-Quark Nuggets
(anti-QNs) with modern telescopes. Anti-QNs are compact composite objects of
antiquark matter with a typical radius $R\sim 10^{-5}$ cm and density exceeding
that of nuclear matter. Atoms and molecules of interstellar medium collide with
anti-quark nuggets and annihilate. We estimate thermal radiation from anti-QNs
in cold molecular clouds in our galaxy and show that this radiation appears
sufficiently strong to be observed in infrared and visible spectra. Proton
annihilation on anti-QNs produces $\gamma$-photons with energies in the range
100-400 MeV which may be detected by telescopes such as Fermi-LAT. We have
found that anti-QN radiation inside the solar corona is too weak to produce a
significant plasma heating or any other observable effects, while the radiation
of $\gamma$-photons from the chromosphere may be observable. We also address
the problem of survival of anti-quark nuggets in the early universe.
