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Whether it feels or looks like spring or like winter outside your home today, spring is officially here. It slipped under my pillow while I was still asleep this morning at 6:28 am ET here in the Northern Hemisphere.
Our ancestors my not have understood what was happening to our planet from a celestial viewpoint, but they were more careful observers of the world around them and definitely marked today as something significant. Ancient observers built devices, buildings and places like Stonehenge to measure and mark changes in the Sun’s movements. Of course, that was what they thought was happening – that the Sun was moving closer or further from Earth. They may have been wrong on that part, but they were able to mark that today was midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.
Though we visualize an equinox as occurring on the imaginary dome of Earth’s sky, it is a very real point on Earth’s orbit that is halfway between the two extremes of the sun’s path in your sky. “Your sky” because though the equinox occurs at the same time for all of us. The seasons are based on whether you are in the Northern or Southern Hemisphere.
One thing you can observe easily at each equinox (no Stonehenge required) is that the sun rises due east and sets due west from where you live. An equinox happens when the ecliptic – or sun’s path – intersects the celestial equator, that imaginary line above Earth’s equator.
Go outside around sunset and sunrise and notice the location of the sun on the horizon with respect to local landmarks. You can then use those landmarks to find those cardinal directions in the months ahead and observe how the sunrise and sunset points move southward or northward. I showed my young sons this many years ago by crudely tracking the sunrise moving from window to window during the year from the vantage point of our East-facing family room. It was a pretty interesting lesson in science.
Today the sun is on the celestial equator. It may be springlike outside or it may still seem like winter, but the new season has arrived.
There is a system called Wu Xing by the Chinese, which translates to the Five Phases (sometimes as the Five Elements, Steps etc.). The “Five Phases” are Wood (木 mù), Fire (火 huǒ), Earth (土 tǔ), Metal (金 jīn), and Water (水 shuǐ).
Wu Xing also correlates to the seasons.
Wood is Spring, a phase of growth, which generates abundant wood and vitality.
Fire is Summer, full of swelling and flowering, and filled with fire and energy.
There is a shorter in-between transitional phase known as Late or Long Summer.
Metal is the element of Autumn when there is harvesting and collecting.
Water represents Winter, the period of retreat, stillness and storage.
Each season or “phase” also corresponds to other things. For example, the direction east and a green dragon correspond to springtime.
The Chinese also use Wu Xing to describe interactions and relationships between such diverse activities as music, military strategy, martial arts and how to heal the human body.
I view it as a way of thinking about nature and another way to encourage a closer observation of nature.
For a few weeks in February, it sure felt like spring was very near in Paradelle – or maybe it had arrived early – even if the calendar and Earth’s tilt said otherwise. I saw crocuses and daffodils up and blooming. Tree buds seemed to be starting their bud burst.
Then the thermometer reversed itself and we had our biggest snow of the winter.
The news reported that the cherry blossoms in the nation’s capital are threatened, and the ones in New Jersey, which generally peak in early April, might also be affected. [Not So Trivial Fact: New Jersey has more cherry trees than Washington D.C. – the largest cherry blossom collection in the United States. But the Branch Brook Park cherry blossom webcam in Newark just shows bare trees and snow as I write this.]
I have written before about the study of cyclic, seasonal natural phenomena which is called phenology. The National Phenology Network tracks “Nature’s Calendar” via phenological events. But can we actually predict the seasons with any accuracy?
These nature observations include the ones we all have been observing lately, such as trees and flowers, but also ones that you may not be able to observe or just don’t pay attention to. Those signs of seasonal change include male ungulates, such as elk or deer, growing antlers at the beginning of the rut and breeding season each year, mammals that hibernate seasonally to get through the winter, and bird migration during the year.
Other than the false Groundhog Day forced observations, phenological events can be incredibly sensitive to climate change. That change can be year-to-year, but the timing of many of these events is changing globally – and not always in the same direction and magnitude.
According to a Public Library of Science (PLOS) blog, “From 1982 to 2012, spring budburst (when the leaves first appear) has advanced by a bit over 10 days, while the onset of autumn in the northeast US has pushed back about 4.5 days. No trends were found for other regions. This lengthening of the growing season has profound implications for the ecology of these forests and potentially their ecological evolution. A longer growing season could translate to high carbon storage for increased growth, but higher rates of decomposition and changes in moisture availability. However, these changes in phenology are primarily driven by increasing temperatures. In a warmer world, some species may simply not be able to survive where they are now, creating a dramatic change in the species composition. And this is without considering changes in precipitation.”
The National Phenology Network’s project called Nature’s Notebook collects data from more than 15,000 naturalists across the nation who, using standardized methods, provide information about plant and animal phenology.
Project BudBurst is another citizen science focused project using observations of phenological events and phases through crowd-sourcing. Project like this give you the opportunity to make your observations of nature more conscious, and to contribute to the knowledge base.
This post first appeared, in slightly different form, on my Endangered New Jersey blog
The first full moon of this spring season came early enough after the March 2016 equinox to allow for a fourth full moon to take place just prior to the summer solstice.
We had the equinox on March 20 and full moons on March 23, April 22, May 21 and now on June 20 at 11:02 Universal Time. The summer solstice will follow at 23:34 Universal Time. (That is 7:30 pm EDT – use the worldtimeserver.com to convert time zones.)
Last year, we had a father’s day solstice that got me thinking about childhood summer and father memories. Thinking about summer and full moons, sends my thoughts to nights on the beach when the full moon over the ocean looks bigger and more dramatic and gives a soft light to the beach.
As we slide into summer in the Northern Hemisphere, the solstice (from the Latin solstitium, from sol-sun) and stitium- to stop), it’s a good day to stop ourselves and consider the season past and one ahead.
We now know that the Sun does not stop on the two solstices but simply crosses a path and “shifts” position at a moment in time. Do you observe the position of the Sun during the year? You probably don’t in as careful a way as I do or astronomers, but perhaps you notice that the Sun is higher in the sky throughout the day now. Have you ever noticed in the morning that the sun rises in relation to your home and your windows from different places in winter and summer? From my usual morning coffee spot in the family room, the Sun is shining right on me in winter, but come summer it’s streaming in a window on the other side of the room.
On the summer solstice tomorrow, the Sun is directly overhead at its most northern point at “high-noon.” There will be more sunlight in the Northern Hemisphere on this day than any other – even if it is cloudy or raining in your little corner of the world.
Why isn’t this also the hottest time of year? The atmosphere, land, and oceans are still cool from winter and spring and absorbing part of the incoming heat and energy from the Sun. But as the land and, especially, the oceans release that stored heat later in the summer, that will bring us our hottest days and nights.
Back in early June, I wrote about looking westward in evening twilight and easily spotting the planet Venus as the brightest “star.” That third-brightest object in all the heavens (after the sun and moon) was accompanied then by an also bright Jupiter.
From then on, Venus slowly began to sink toward the sunset. Like the arrival of the Perseid meteor shower, this movement is surer than the seasons in nature. Sometimes summer stays longer than the calendar tells it to stay and winter comes earlier or later. But today, 10 weeks later, Venus will set with the sun and make its transition out of the evening sky and into the morning sky.
The celestial clock clicks forward, unconcerned with us and our little lives.
I have always had a sundial in my garden. It keeps you in touch with the movement of the Sun during the day and during the seasons.
My basic horizontal sundial shows a shadow from its style onto a surface marked with lines indicating the hours of the day. The style is the time-telling edge of the gnomon, the straight edge. As the sun moves across the sky, the shadow-edge aligns with hour-lines.
Sundials that directly measure the sun’s hour/angle must have that edge parallel to the axis of the Earth’s rotation to tell the correct time throughout the year. The style’s angle from the horizontal should equal the sundial’s geographical latitude, but in most inexpensive sundials the hour angles are off and cannot be adjusted. There are many other types of sundials.
Isaac Newton developed a convenient and inexpensive reflection sundial using a small mirror placed on the sill of a south-facing window. The mirror casts a single spot of light on the ceiling and, depending on the geographical latitude and time of year, the light-spot on the ceiling was drawn large enough to be accurate.
Most mass-produced sundials are not the most accurate timekeepers, but in mid-April time by the sun and time by my clocks agrees. Noon is noon in both places.
I adjust my sundial as the months move past me, but I suppose that is a bit of a cheat. This weekend the length of the day as measured by the midday sun is slightly less than 24 hours long. This discrepancy between my watch and the Sun accumulates until mid-May when noon on my sundial will be a few minutes earlier than the clock. After that the sundial middays will become slightly more than 24 hours long and by mid-June, they will match up again.
Cycles. Very much a part of our lives, whether we pass attention to them or not.