“Lindberg notes that some observers have speculated that the objects may be Russian warships built around the end of the 1800’s. However, Lindberg points out that not only were those ships much smaller, they were not patrolling the Baltic during that era.”
THEREFORE it must be aliens. /sarc
If there is any suspiscion that it is an alien craft, the History Channel will do a special on it. They are convinced that Aliens have visited us and are responsible for everything they cannot otherwise explain.