[1]) From an astronomical point of view, there is nothing special to these dates; e.g. the Sun, Moon, planets and stars will not be aligned in any specific pattern.

[3]The primary source for the institution of Birkat Hachama is a Beraita mentioned in the Talmud:[4] תנו רבנן הרואה חמה בתקופתה...אומר ברוך עושה מעשה בראשית Our rabbis taught: "One who sees the sun at its turning point...recites the blessing of the maker of works of creation.

The Gemara clarifies when the 'turning point' (תקופה) mentioned in the beraita occurs: ואימת הוי אמר אביי כל כ״ח שנין And when does this happen?

Abaye answers: every 28 years...Next, the gemara explains the basis of the 28 years: והדר מחזור ונפלה תקופת ניסן בשבתאי באורתא דתלת נגהי ארבע ...when the cycle renews and the "season of Nisan" (i.e. vernal equinox) falls in Saturn, on the evening of Tuesday going into Wednesday.This explanation provided by Abaye is based on a ruling of Shmuel also mentioned in the Talmud:[5] Shmuel stated: The vernal equinox occurs only at the beginning of one of the four quarters of the day, either at the beginning of the day or at the beginning of the night, or midday or midnight.

The duration of a season of the year is no longer than 91 days and 7.5 hours.Shmuel's calculations, however, are imprecise because the Earth does not travel around the Sun with a constant speed.

[6] His imprecision, according to Abraham ibn Ezra, was a function of the desire of the time to avoid the necessity of manipulating fractions.

[7][8] The Shulchan Aruch states that this blessing, generally said upon experiencing natural phenomena, should also be recited upon witnessing the chammah bi-tkufatah (חמה בתקופתה = sun at its turning point).

This term, quoted from the above-mentioned Beraita, is explained by the Chofetz Chaim as referring to the point in time at which the Sun returns to the start of its cycle, similar to when it was created.

[12] The Mishnah Brurah, however, states on behalf of numerous Achronim that it is permitted the blessing to be recited until halachic noon.

According to Jewish tradition, the Sun was created[16] on the fourth day (יום רביעי, yom revi'i) of the week of Creation.

As explained in the Talmud, there is a tradition that the Sun was created in its vernal equinox position at the beginning of the springtime Jewish lunar month of Nissan.

[19] The sages of the Talmud settled disputes over the halachic definition of the vernal equinox by establishing it on March 25 of the Julian calendar.

The calendar was adjusted to allow for Easter to be celebrated in the appropriate time according to an agreement reached at the First Council of Nicaea in 325 CE.

The Hebrew calendar itself uses a solar year of 365.2468222 days, but utilizes the less precise approximation of 365.25 for Birkat Hachama so that the blessing might occur with some frequency.

Then we follow with all the six other "planets" (Jupiter, Mars, Sun, Venus, Mercury, and Moon) and repeat the order until all the hours of the week have a "star" assigned to them.

Because the astronomical year is slightly shorter than 365.25 days, the date of Birkat Hachama shifts away from the spring equinox as history proceeds.

They were left with a number of options, 532 years apart from each other, and Lerman suggests that they chose the dating closest to what seemed to be the truth according to a literal interpretation of biblical accounts.