What was the Christmas star? Some scientific explanations attempt to explain the Star of Bethlehem, including a planetary conjunction, comet or supernova.
The longest days accompany the winter solstice. In December, a day - a whole cycle of day and night - is about half a minute longer than the average 24 hours.
What are red giants? Most main-sequence stars, like our sun, will become one. Red giants swell to such a large size they can swallow their inner planets.