Northern Hemisphere solar spring is underway
You may have noticed the days getting longer recently. We are more than a month past the winter solstice. Now we will see the length of the day increase at its fastest clip. Welcome to solar spring!
You really have to think outside of the box to get the idea of why days are shorter and longer at different times of the year. In fact, a lot of astronomy requires outside-the-box thinking. However, that is what makes it so interesting!
The Earth orbits the sun on the orbital plane. We know the Earth rotates once per day, but this rotation is at an angle to the orbital plane. That tilt is at a 23-degree angle to the orbital plane, so just imagine the Earth tilted to the side as it goes around the Sun. Many people may think that the Earth actually tilts back and forth creating the season. Not so.
If you are like me, it is better to see this graphically as the above video shows.
As the Earth moves around the sun, you notice that the North Pole is tiled away from the sun on one side of its orbit. Meanwhile, the north pole then tilts right at the sun on the opposite side of its orbit. There is actually only one sunrise and one sunset per year at the North Pole! However, the day is six months long as is the night. Just imagine the sun moving 360 degrees around the horizon!
But, why doesn't spring start right when solar spring begins? It would make sense for the warmest days to be directly lined up with the longest days, etc. However, there is a lag. We have temperatures because the Earth absorbs solar radiation. The oceans absorb most of it. And it takes a while for water to be heated and cooled. (Think about boiling water). This is the source of the lag. The warmest time of year tends to be three to four weeks after the summer solstice and the coldest is after the winter solstice.
But, solar spring is a sure sign that things will turn around soon. If you are tired of shivering, you will at least have more daylight to make you feel better. In fact, most of the U.S. gains 15-20 minutes of daylight per week!
I want to thank AccuWeather.com Meteorologist Dave Dombek for his insight on this blog entry.
Report a Typo
