The following is a study on whether the weekly cycle has been altered:
So what actual documentation do you have which proves that the seventh day cycle has been interrupted?
-Astronomy observance
"The human race never lost the septenary [seven day] sequence of week days and
that the Sabbath of these latter times comes down to us from Adam, though the ages,
without a single lapse."—Dr. Totten, professor of astronomy at Yale University.
"Seven has been the ancient and honored number among the nations of the earth.
They have measured their time by weeks from the beginning. The origin of this was
the Sabbath of God, as Moses has given the reasons for it in his writings."
—Dr. Lyman Coleman.
"By calculating the eclipses, it can be proven that no time has been lost and the
creation days were seven, divided into 24 hours each."—Dr. Hinkley,
The Watchman, July 1926 [Hinkley was a well-known astronomer].
"There has been no change in our calendar in past centuries that has affected in
any way the cycle of the week."—James Robertson, Director American Ephemeris,
Navy Department, U.S. Naval Observatory, Washington, D.C., March 12, 1932.
"It can be said with assurance that not a day has been lost since Creation, and all
the calendar changes notwithstanding, there has been no break in the weekly cycle."
—Dr. Frank Jeffries, Fellow of the Royal Astronomical Society and Research
Director of the Royal Observatory, Greenwich, England.
There is no question about which day the seventh day of the week is.
The weekly cycle? The break between the shift from the Julian
to the Gregorian calendar? There was a well known break of 10 days.
In 1582, that Thursday the 4th was followed by Friday the 15th.
The weekly cycle was not interrupted. Now take a look at 1752, Wednesday
the 2nd was followed by Thursday the 14th. Again, the calendar had to be
adjusted to correct it to the seasons but the weekly cycle remained unchanged.
\ End of study.
We do have historical records back to the time of Christ. He had no problem accepting out weekly cycle.