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ROSH HASHANAH 21-25 - Dedicated in memory of Max (Meir Menachem ben Shlomo ha'Levi) Turkel, by his children Eddie and Lawrence and his wife Jean Turkel/Rafalowicz. Max was a warm and loving husband and father and is missed dearly by his family and friends. His Yahrzeit is 5 Teves.

1) OPPOSITION OF THE MOON, OBSERVED FROM LAND AND FROM SEA
QUESTIONS: The Gemara relates that Rav Nachman gave advice to people who would be traveling at sea at Pesach time and would have no way of knowing when the new month was declared. Rav Nachman taught them a way to know when the time had arrived to get rid of their Chametz: when they see that the full moon sets at the same time that the sun rises, that is the day to get rid of their Chametz.
The Gemara asks that we observe the moon to set at the same time the sun rises on the fifteenth of the month. Chametz, however, must be destroyed on the fourteenth of the month! The Gemara answers that at sea the horizons are clearer and thus the moon can be seen setting at sunrise on the fourteenth of the month, one day earlier than people on land see the moon set at sunrise.
(a) Why do people on land see the moon set at sunrise one day later than people at sea?
(b) What day is considered the halfway point of the month? The average length of a month is slightly more than 29 1/2 days, and thus half of that amount is about 14 3/4 days. After 14 3/4 days have passed since the beginning of the month, the moon should be seen setting at the time the sun rises. However, Rav Nachman says that the moon can be seen setting at sunrise on the fourteenth day. At sunrise on the fourteenth day of the month, however, only 13 1/2 days have passed since the appearance of the new moon. Why does Rav Nachman give that day as the day on which Chametz must be destroyed?