Human beings are in for a double treat in January with the appearance of two supermoons. The first one rises on the night of New Year’s Day. The second comes on the last night of the month, ending up with a lunar eclipse (月食). That is the end of a trilogy (三部曲) of big moon treats that began in Dec. 3 with a full cold moon. The Jan. 1 supermoon will be the biggest of the year. The moon will appear to be oversized for a few nights after that, though it will no longer be a full moon.A supermoon is a full moon that appears at the closest point in the moon’s orbit to earth, about 14 p