Dadka kale ma jiraan?
Inkastoo aysan jirin cadeymo cad oo muujinaya jiritaanka nolosha dibada, haddana tirada badan ee meerayaasha laga yaabo inay ku jiraan caalamka waxay soo jeedinayaan in, in kasta oo horumarka nolosha ay adag tahay in la bilaabo, ay jiraan noocyo kale oo nolosha ah oo caalamka ka jira.  Khilaafka u dhexeeya rajada jiritaanka nolosha ee caalamka iyo caddeymo la'aanta waxaa lagu magacaabaa is khilaafka Fermi.