Abstract: What are the gravitational proprieties of antimatter is still not known. One
possibility is the gravitational repulsion between matter and antimatter (in
short we call it antigravity). We point out two possible signatures of the
assumed existence of antigravity. First, the supermassive black hole in the
center of our Galaxy (Southern Sky)and in the center of the Andromeda Galaxy
(Northern Sky)may produce a flux of antineutrinos measurable with the new
generation of the neutrino telescopes; like the IceCube Neutrino Detector under
construction at the South Pole, and the future one cubic kilometer telescope in
Mediterranean Sea. Second, if microscopic black holes are successfully produced
at the Large Hadron Collider (LHC) at CERN, their thermal (Hawking's) radiation
should be dominated by a non-thermal radiation caused by antigravity.