Message #135522

[Bianca]

More seasonal facts



As we orbit the sun, the part of the night sky that's in our view changes. A given star sets about 4 minutes earlier each night. Over a month, this amounts to two hours. In winter, this means that we're looking at stars that during the summer were in our daytime sky, overwhelmed of course by the glare of the sun. Since we complete a circle around the sun every year, the stars of summer, such as those in the Big Dipper, are always the stars of summer.


During summer on the top half of Earth, our planet is actually farther from the sun than during winter, a fact owing to our non-circular orbit around the sun. The difference is about 3 million miles (5 million kilometers), and it makes a difference in radiant heat received by the entire Earth of nearly 7 percent. But the difference is more than made up for by the longer days in the Northern Hemisphere summer with the sun higher in the sky.


Which brings up a common question: If the summer solstice is the longest day of the year, why are the dog days of August typically hotter? It takes a while for the oceans to warm up, and a lot of weather on land is driven by the heat of the oceans.