All confirmed copernicium isotopes are extremely unstable and radioactive; in general, heavier isotopes are more stable than the lighter. The most stable known isotope, Cn, has a half-life of 30 seconds; Cn has a half-life of 4 seconds, and the unconfirmed Cn and Cn have half-lives of about 15 and 8.45 seconds respectively. Other isotopes have half-lives shorter than one second. Cn and Cn both have half-lives on the order of 0.1 seconds, and the other two isotopes have half-lives slightly under one millisecond. It is predicted that the heavy isotopes Cn and Cn may have half-lives longer than a few decades, for they are predicted to lie near the center of the theoretical island of stability, and may have been produced in the r-process and be detectable in cosmic rays, though they would be about 10 times as abundant as lead.