equinox

Happy Autumn Equinox! With all this lovely weather we have been having it was easy to forget it. I thought it was apt that the weather became more chilly today as it is the official Autumn Equinox, marking, for many, the start of Autumn.

I have written before of how we Irish like to define the seasons in our own bizarre ways. The same post also describes what an equinox is, if you want the nitty, gritty detail. Personally, I judge the seasons more by the cues in Nature and I certainly have noticed the birds starting to gather for their migration, the days beginning to shorten and the leaves on the trees beginning to change colour. I always thing the colour display of Autumn is worth the colder nights and darker days.

Did you ever wonder why and how the leaves change colour? Well it turns out I wrote about that too, in my first ever blog post. Today I get to share it with you again while joining in a blog linky by lovely fellow Galway blogger, Aedin, over at Minis and Mum, as she invites people to share their first ever post in celebration of her lovely blog’s three year anniversary.

So here is a repost of mine…

CARROTS, CABBAGES AND CUPS OF TEA…

It’s funny how Autumn comes around every year and I realise how much I love this time of year…. it’s as though I seem to forget I like it all throughout the other seasons. Of course we have had a particularly nice Autumn this year in the West of Ireland and maybe that has re-enforced my happy memories of the season. The days have been bright and crisp showing off all the beautiful colours in all their glory and splendour.

photo credit: Stellas mom via photopin cc

I grew up in Co. Wicklow surrounded by some beautiful deciduous woods and forests and this Autumn has really brought my childhood memories flooding back. My mother brought us often to the woods as children and we would hunt around for hidden treasures and delights to bring home and turn into some “masterful” collage in homage to the season. There was also the foraging, a distinctive primordial instinct in us all, there is nothing as pleasing as returning home with your bounty… be it blackberries or sweet horse chestnuts- to be turned into jams and tarts or painstakingly peeled off all nasty layers to reveal the divinely sweet, fruity, nutty delight beneath. In fact the joy that came with eating the nut always made it suddenly worth your while to start the arduous task of peeling all over again!

…and I hope that I will never outgrow the delight of running, kicking, shuffling through a crisp new crop of fallen leaves!

As many people know, the lovely green of most leaves is caused by the pigment chlorophyll… green in colour (obviously) and capable of using sunlight to convert water and carbon dioxide into energy (sugar) for the plant. However, when the sunlight hours fade coming into winter so too does the chlorophyll in the leaves of trees, or, to be more precise, the pigment begins to degrade and is not replaced. Once the green colour is gone other pigments that are often present in the leaf come into view… carotenoids are pigments responsible for the yellow/orange colour of leaves, anthocyanins are responsible for the redder colour of leaves and tannins are responsible for the brown colour of leaves. There is, within this pigmented system, a sense of hierarchy, at least in part. But did you ever wonder about the science behind those wonderful colours? I did… why the green suddenly disappears, where does it go and how do the other colours get there in its place? So, if like me, you ever wondered about these things… here is some insight into the why and what of Autumn!

Carotenoids are the pigments responsible for the orange colour of carrots. If carotenoids are present their colour tends to dominate leaving the leaves yellowy and orange.

In the absence of carotenoid, anthocyanin is the dominant pigment. Anthocyanin (the same pigment found in red onions, red grapes, red apples and red cabbage) is a natural pH indicator, meaning that it can change colour depending on the levels of acids or bases/alkali in its environment. In fact one of my favourite experiments that I often do with children is to demonstrate this colour changing using anthocyanin extracted from red cabbage (but that’s a whole other blog in itself). At the beginning of Autumn the levels of sugar in the leaves tends to be quite high, increasing the acid levels in the leaves, this strengthens the red colour of Anthocyanin if it is present in the leaves.

At the end of Autumn the leaves die off and the levels of carotenoids and anthocynins die off too, leaving another pigment to dominate… and this is the brown pigment of tannin, the same pigment that give a cup of tea it’s colour!

So there you have it… next time you are crunching through those leaves you may wonder why you are suddenly thinking of carrots and cabbages and cups of tea!!!

There are lots of lovely “first steps” posts to read in this linky, just click on the image below to find some more.

Minis and Mon - First Steps Liny — Minis and Mum – First Steps Linky

Spring does not officially arrive in the Northern Hemisphere this year until March 20 at 16.47 GMT, the Spring Equinox – but when does Spring start for you?

The Sun FINALLY came out this week. It was a long, long winter and we all needed to feel a little of its warmth. To most of us in Ireland it has been spring since the 1^st of February but this new boost has sent the conversations about spring into overdrive at the school gate. We are all more than ready to embrace it but no one wants to hear that, to some, it is not even spring yet! Here in Ireland we seem to live in a bubble when it comes to the seasons as much of the rest of the Northern Hemisphere will tell you it is not Spring until the Equinox, which this year will occur at 16.57 (GMT) on March 20th.

In Ireland spring usually means people abandon their clothing in a rapid and frenzied manner.Or, to be more accurate, it means the sighting of a lot of tee shirts and shorts and the accumulated exposure of acres of alabaster skin. It’s a wonder the glow cannot be seen from space.

A SHORT GEOGRAPHICAL LOOK AT HOW WE DEFINE SPRING

To be honest I was a little surprised to learn that most of the World is celebrating the start of a season while we Irish are smack bang in the middle of it! I took to twitter and Facebook to find out what people really thought and was delighted with the variety of responses we got.

In Ireland we learn at school that spring starts 1^st February. Many people said the biggest problem they had with this was that it pushes August into autumn so most Irish seem to either amend the seasons to a four month summer or they mentally move the seasons on a month. We Irish are not afraid to bend the rules to suit ourselves!
Many Irish people follow the Celtic calendar which also says spring starts on the 1st of February. This coincides with the arrival of certain seasonal plants and the spring lamb.

Once we move outside of Ireland it would seem that the rest of the Northern Hemisphere shift the seasons on a little. Our nearest neighbours in the UK start spring on 1^st March.

If we move further West into France and the rest of Europe it seems the Spring Equinox is generally held as the beginning of the season.

In the USA the Spring Equinox is the official start of spring although many will hold the 1^st March as an acceptable alternative.

My favourite response to the question of “When does spring start for you?” was this one…

My husband says it’s Spring when we stop making stew once a week!

SOME OFFICIAL DEFINITIONS OF SPRING

The national meteorological body in Ireland defines March 1^st as the first day of spring.

The Old Farmer’s Almanac defines the spring equinox as the start of the season.

WHAT IS AN EQUINOX?

An equinox is an astronomical phenomenon – a time on Earth when we experience almost equal day and night. There are two equinoxes in our calendar year, one in March (between 19th and 21st) and one in September (between 20th and 23rd). The March one is referred to as the Spring (vernal) equinox in the Northern hemisphere and the September one is the Autumn equinox.

These are reversed in the Southern hemisphere.

The word Equinox literally means equal night derived from the Latin words “equi” (equal) and “nox” (night).

HOW DOES IT WORK EXACTLY?

The equinox refers to a time when there is almost equal day and night in most parts of the World. On the Equinox the centre of the Sun will be directly above the Earth’s equator at noon.

The Northern and Southern hemispheres will be equally illuminates at this moment. http://en.wikipedia.org/wiki/Equinox

A LITTLE MORE DETAIL…

To better understand the seasons we need to look at the movement of the Earth within its celestial space.

Firstly, the Earth rotates on its own (Polar) axis every 24 hours. Thus different parts of the Earth are facing towards the Sun at different stages of the day – this is what makes day and night.

The Earth also travels around the Sun once every 365.25 days (or 365.24219 days to be more exact) – that explains a complete year on Earth.

I hope all this isn’t making you dizzy as there is a third factor to take into account and this is the factor that accounts for the seasons; The Earth is actually tilted on its own axis by 23.5 degrees. This tilt remains constant as the Earth orbits the Sun. Therefore at different times during this orbit the Northern or Southern hemispheres will gain more Sunlight as they are tilted more towards the Sun.

The Equinoxes (Spring and Autumnal) are the only times during the year when the Earth’s 23.5 degree axis is not tilted towards or away from the Sun. At these times in the year the Sun sits exactly over the equator.

WHY DOES THE EXACT TIME OF THE EQUINOX DIFFER EACH YEAR?

Our year is governed by how long it takes the Earth to orbit the Sun. By the Gregorian calendar there are 365 days in a year. However this is not quite true as mentioned above, a year is actually 365.25 days in length (the actual duration of a full orbit of the Sun by the Earth). We fix the error by adding a Leap Year in every four years.

This does not completely fix the timing for the equinoxes however which will occur six hours later every year. The Gregorian calendar does manage to confine the timing of the equinox to within the same few days. By this calendar the equinox will occur at the exact same time every 400 years.

SOME COOL PLACES TO BE ON THE EQUINOX…

If you are standing at the North Pole on the Spring Equinox you will see the Sun start to peep over the horizon, signalling the end of six months or darkness and marking the start of six months of daylight.

If you are standing at the South Pole on the Spring Equinox the opposite is true.

If you are standing on the Equator at noon on the Equinox you will observe the Sun exactly overhead.

SpringDaffs — photo credit: Βethan via photopin cc

WHAT DOES MOTHER NATURE HAVE TO SAY ABOUT ALL THIS?

If, like me you find this scientific definition of spring hard to take in, don’t worry, Nature seems to have its own definition of spring. I do not think the emerging buds or the territorial birds are too bothered about when the Sun might sit exactly over the Equator.

To them spring is in full throttle and to me it is too!

So what is your definition of spring?

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