If Aries is a sheep then why is a goat also acceptable for the Passover offering? Rabbi Moshe Sofer explained that what makes a zodiac sign, is the constellation that rises in the eastern sky with the sun in the morning. In early Spring,around the time of Passover, Aries rises together with the sun. However, the goat is another constellation, namely, Capricorn. Capricorn is a six hours behind Aries in the sky. The Jews left Egypt at sunrise, when Aries was shining. However, about six hours earlier, when Capricorn shined, the Creator slayed the Egyptian first born while the Jews ate their very first Passover meal. Therefore, the sign of Capricorn also played a role in the redemption story. That's why a goat can also be used for the Pesach offering.