Just as it's possible to squeeze out a fine mist of antimatter using particle colliders here on Earth, nature continues to shed antiprotons and antineutrons in cataclysmic high-energy events.

On a similar note, many dark-matter candidates are predicted to produce more cosmic-ray antiprotons than are observed if the annihilation rate is normalized to the electron and positron signals ...

KNOWLEDGE of the abundance of antiprotons in cosmic rays and in interstellar space could have important implications for cosmic ray theory, γ-ray astronomy and certain cosmological theories.