Is it תשפ"ה 5785 or תתק"נ 5950 ?

 

 According to our calendar, we will be ushering in on Rosh Hashana the year 5785. 

Approximately 165 years are missing from our calendar. The correct year should be 5950. (only 50 years to the year 6,000)

My nephew R. Ari Dick שליט"א,explained the following חשבון

חורבן בית ראשון happened in 587 BCE - this much is indisputable, as it is corroborated by Babylonian, Egyptian, and Greek inscriptions which match very closely to the accounts in מלכים,ירמיהו & דבר הימים
 
חורבן בית שני is commonly taken to be 70 CE by secular historians, but it could be off by a year or two, so it may have been 68 or 69. There is a מחלוקת between רש"י and תוספות about whether the בית המקדש was destroyed in the 420th year, or after 420 years (ע"ז ט' ע"ב). This מחלוקת is based on the fact that it was a מוצאי שמיטה year. Based on this, the חורבן should have been 68 or 69. However, we are not so concerned with one year, compared to the bigger problem of 165 years described below.

This puts 656 between חורבן בית ראשון and חורבן בית שני. The chronologies of these years are very well known, and we know exactly who were the Persian and Greek Kings during these years and how many years each of them reigned, based on multiple corroborating sources. We know exactly when Alexander conquered Israel (329 BCE), and this means there were at least about 400 years from him to the destruction. And the Persian kings from Cyrus to Alexander take up about 200 years. So there are about 600 years - 587 to be precise, that the בית שני lasted.

But according to סדר עולם, there should have been 70 + 420 = 490 years between חורבן בית ראשון and שני. This means there are about 166 years missing from our current Jewish date of 5784. Of course, it could be off by a couple of years here or there due to kings starting their reign in the middle of a year, and the year being counted for both, and other such inaccuracies, but 5784 is definitely too low. In general, you need to add about 166-8.

This issue was addressed by many gedolim, from R Azariya min Ha'adumim  to Rav Shimon Schwab זצ"ל."
In a 1962 essay, Rabbi Shimon Schwab suggested that the 168 years were consciously removed from the Jewish calendar to obscure the date for the coming of Mashiach. However, in 1991, Rav Schwab felt that he had to pull back from his previous position and retract his suggestion.