What is it - antiHe? (Patreon)

Antihelium is like helium, only in reverse. Just like there is a proton and an antiproton. An antihelium atom is a particle with antiprotons and antineutrons. There are quite a lot of antiprotons in space, they are easy to generate, but antihelium is not easy to obtain. To do this, you need to collect 2 antiprotons and 2 antineutrons together and force them to form a particle :) at high cosmic speeds this is almost unrealistic.  

probability 1:10¹⁶