Too bad, we do not have a precise reference point to answer this question!
We thought that the C14 radiocarbon method will give us the independent irrefutable dating of objects, but it doesn’t because the historians have smuggled therein their erroneous chronology. To make matters worse we have made thousands of nuclear explosions that have distorted the picture.
We have the remnants of a Supernova explosion called the Crab Nebula that shone for a couple of month above our heads about 1000 years ago. Alas, the date of this Bang is approximate, AKA +/- 100 years calculated on the basis of changes in photographs for the last 150 years.
The date of such an event may serve as the origin of coordinates to fix historical events to their more probable positions on the time axis. The sky provides us with such a visible phenomenon.
The astronomers found the exact date of the explosion of the Crab Nebula Supernova in XII century A.D. in the Taurus constellation by calculating its expansion speed by comparing its photographs taken from 1844 to 2018.
Dozens of ‘ancient’ learned chroniclers and astronomers report about the appearance of very a bright star approximately 1000 years ago. These reports are often conflicting as they used real or an imaginary phenomenon in the sky to stress their local events.
Corollary A: an irrefutable astronomical phenomenon itself serves as the reference point for the dating of historical events and not the dates of astronomical events found in chronicles of refutable dates and/or origin.
Corollary B: taking into account the irrefutable events only, confirmed by exact sciences the true timeframe of human history does not exceed 1000 years. All ‘ancient’ histories are ‘on agenda’ produce of XVI-XXVIII centuries.
Corollary C: the explosion of the Crab Nebula Supernova is a reference point for datings events on the time axis. Today we are in 965, not in 2019 AD.
History of discovery
The Crab Nebula was identified as the supernova remnant of SN 1054 between 1921 and 1942, at first speculatively (the 1920s), with some plausibility by 1939, and beyond a reasonable doubt by Jan Oort in 1942.
In 1921, Carl Otto Lampland was the first to announce that he had seen changes in the structure of the Crab Nebula. This announcement occurred at a time when the nature of the nebulas in the sky was completely unknown. Their nature, size and distance were subject to debate.
Observing changes in such objects allows astronomers to determine whether their spatial extension is “small” or “large”, in the sense that notable fluctuations to an object as vast as our Milky Way cannot be seen over a small time period, such as a few years, whereas such substantial changes are possible if the size of the object does not exceed a diameter of a few light-years.
Lampland’s comments were confirmed some weeks later by John Charles Duncan, an astronomer at the Mount Wilson Observatory. He benefited from photographic material obtained with equipment and emulsions that had not changed since 1909; as a result, the comparison with older snapshots was easy and emphasized a general expansion of the cloud. The points were moving away from the centre and did so faster as they got further from it.
In 1928, Edwin Hubble was the first to note that the changing aspect of the Crab Nebula, which was growing bigger in size, suggests that it is the remains of a stellar explosion. He realised that the apparent speed of change in its size signifies that the explosion which it comes from occurred barely nine centuries ago.
1844 b/w photo 2018 X-ray photo