Halakhah su Genesi 6:18

In addition, a number of sources, including the Palestinian Talmud, Berakhot 8:6; Bereishit Rabbah 11:2, 12:6 and 82:17; Midrash Tehillim 92:4; and Pesikta Rabbati 23:6, record that there was no period of darkness during the very first Sabbath which came after the six days of creation; rather, there was a period of thirty-six hours of daylight followed by nightfall marking the conclusion of the Sabbath day. Yet that thirty-six hour period included a "day" deemed to be the Sabbath and was followed by a day deemed to be the first day of the following week.³³R. David Spira, Teshuvot Bnei Ẓion, III, Kuntres Midot ha-Yom, sec. 21, cites these aggadic sources as evidence that the length of a day is determined on the basis of twenty-four clock hours. Again, it may be postulated that terrestrial time was temporarily transcended rather than suspended³⁴Cf., however, Bein ha-Shemashot, p. 54. Rabbi Tucatzinsky suggests that even on the first Shabbat the sun set at its normal time and that the illumination that was perceived was provided by the primordial light that was created before the sun. That explanation is supported by a comment found in Bereshit Rabbah 11:1. and that, when normal time patterns based upon alternating periods of light and darkness marked by sunrise and sunset resumed, time continued as if it had not been interrupted.³⁵For a discussion of calculation of time during the period of the Deluge when, according to one opinion recorded in the Palestinian Talmud, Pesaḥim 1:1, as well as in Bereshit Rabbah 25:2 and 34:15, the constellations did not move in their orbits, see Siftei Ḥakhamim, Genesis 8:22, Teshuvot Minḥat Elazar, IV, no. 42; R. Jonathan Eibeschutz, Tiferet Yonatan, Genesis 6:18; and Divrei Yaẓiv, no. 108, sec. 6, and no. 109. See also Rav Pe‘alim, II, Sod Yesharim, no. 4, who cites that source in support of the position that days are calculated in terms of twenty-four hour periods.