Is the Sabbath 12 or 24 hours Long?

Is the Sabbath 12 or 24 hours Long?

News Letter 5851-052 18th day of the 12th month 5851 years after the creation of Adam The 12th Month in the Sixth year of the Third Sabbatical Cycle The Third Sabbatical Cycle after the 119th Jubilee Cycle The Sabbatical Cycle of Earthquakes, Famines and Pestilence...