also see Exploration
Comsic Signatures, like their counterpart, Cosmic Anomalies, are a part of exploration in EVE. Generally speaking they are the harder of the two.
Cosmic signatures are found by Scanning & Probing.
The follow are scan results of Cosmic Signatures:
Gravimetric Sites
Ladar Sites
Radar Sites
Magnetometrics Sites
Unkown
--> Combat
--> Wormholes
see Exploration for further details