Our spring almanac 19.03.2010 – 25.03.2010
The Spring Equinox
Astronomical Spring begins on Saturday with the arrival of the spring equinox. The spring equinox for this year 2010 is on March 20 at 17.32h GMT. The astronomical season of spring begins and carries on until the summer solstice. Equinox is a Latin word that means equal nights, a term that refers to the fact there are 12 hours of daylight followed by 12 hours of night on the spring and and autumn equinoxes.
The Earth spins on its axis every 24 hours, giving us our 24 hours and night and day, but this axis has got a tilt of 23.4 degrees. It is this tilt that causes the seasonal changes we see over the 12 months of the year. For instance, on the date of the winter solstice the northern half of our planet is tilted away from the Sun at the full angle of 23.4 degrees, so that sunlight reaching us is not so strong as it is on the summer solstice when our part of the planet is tilted fully towards the Sun. Every living thing on our planet has evolved to adapt to these four seasons.
The equinoxes happen when during the Earth’s orbit round the Sun the Earth’s tilt ends up sideways to the Sun. If you were able to stand on the equator at noon on either of the equinoxes, the Sun would be directly overhead, casting the smallest shadow possible.
For us, in the northern hemisphere of our planet, the arc of the sun as it travels across the sky for 12 hours looks like this.
Night and Day
Why is the night sky never completely dark? The answer is airglow (also called nightglow). This is the very weak emission of light by a planetary atmosphere. In the case of Earth’s atmosphere, this phenomenon causes the night sky to never be completely dark (even after the effects of starlight and diffused sunlight from the far side are removed).
Airglow is caused by various processes in the upper atmosphere, such as the recombination of ions which were photoionized by the sun during the day, luminescence caused by cosmic rays striking the upper atmosphere, and chemiluminescence caused mainly by oxygen and nitrogen reacting with hydroxyl ions at heights of a few hundred kilometers. It is not noticeable during the daytime because of the scattered light from the Sun.
The stars that form the constellation Lyra against the night sky. Lyra is a constellation that appears in Spring.
Lyra (from Greek λύρα) is a constellation. Its name derived from the lyre, a stringed musical instrument well known for its use in classical antiquity and later. Lyra was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations recognized by the International Astronomical Union today.
Lyra is a small constellation, but its principal star, Vega, is one of the brightest in the sky. Beginning at the north, Lyra is bordered by the Dragon Draco, the Greek hero Hercules, the little fox Vulpecula and Cygnus the swan.
Lyra is the Constellation Logo for Marnel School in Basingstoke.
One of Marnel’s students came up with a new identity for the pattern of stars that forms the Lyra constellation, Elvis Presley! He was the King!
The lyre of Classical Antiquity was ordinarily played by being strummed with a plectrum, like a guitar or a zither, rather than being plucked, like a harp.
Dark skies and light pollution
Light pollution is excessive or obtrusive artificial light. The International Dark-Sky Association (IDA) defines light pollution as: “Any adverse effect of artificial light including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste. It obscures the stars in the night sky for city dwellers, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects.
Blue skies research and global dimming
We are all seeing rather less of the Sun. Scientists looking at five decades of sunlight measurements have reached the disturbing conclusion that the amount of solar energy reaching the Earth’s surface has been gradually falling. Paradoxically, the decline in sunlight may mean that global warming is a far greater threat to society than previously thought.
The effect was first spotted by Gerry Stanhill who was astonished to find that his research pointed to a large fall in solar radiation. “There was a staggering 22% drop in the sunlight, and that really amazed me,” he says.
Intrigued, he searched out records from all around the world, and found the same story almost everywhere he looked, with sunlight falling by 10% over the USA, nearly 30% in parts of the former Soviet Union, and even by 16% in parts of the British Isles. Although the effect varied greatly from place to place, overall the decline amounted to 1-2% globally per decade between the 1950s and the 1990s.
Gerry called the phenomenon global dimming, but his research, published in 2001, met with a sceptical response from other scientists. It was only recently, when his conclusions were confirmed by Australian scientists using a completely different method to estimate solar radiation, that climate scientists at last woke up to the reality of global dimming.
Dimming appears to be caused by air pollution. Burning coal, oil and wood, whether in cars, power stations or cooking fires, produces not only invisible carbon dioxide (the principal greenhouse gas responsible for global warming) but also tiny airborne particles of soot, ash, sulphur compounds and other pollutants.
Spring and the New Year
Beginning the new year in the spring makes sense. The signs of new growth in spring suggests new beginnings, especially in olden times when most people made their living from the land.
In England, Lady Day was New Year’s Day up to 1752 when, following the move from the Julian Calendar to the Gregorian Calendar, 1 January became the start of the year. In the Christian calendar, Lady Day is the traditional name of the Feast of the Annunciation of the Blessed Virgin which takes place on 25 March, nine months before Christmas celebrations of the birth of Jesus, and the first of the four traditional Irish and English quarter days.
The “Lady” was the Virgin Mary.
New year celebrations that take place on the spring equinox
Noruz (also known as Jamshedi or Jamshidi Noruz) is the seventh obligatory feast and it is dedicated to fire. It is the Zoroastrian New Year celebration, and occurs on the spring equinox. Zoroastrianism is a religion and philosophy based on the teachings of prophet Zoroaster (aka Zarathustra) founded in the early part of the 5th century BCE.
Bas-relief in Persepolis, Iran, showing a symbol of the Zoroastrian Noruz, where the day of a spring equinox shows how the power of the eternally fighting bull (personifying the Earth), and a lion (personifying the Sun), are equal.
Noruz is so deeply embedded in Iranian culture that it is still celebrated as the Iranian New Year in Islamic Iran, although without the religious connotations. Many fires are lit and there is feasting and celebrations. In modern times fireworks have also become part of the festivities.
Haft Sīn (هفت سین) or the seven ‘S’s is a major tradition of Noruz. The haft sin table includes seven specific items starting with the letter ‘S’ or Sīn (س) in the Persian alphabet. The items symbolically correspond to seven creations and holy immortals called Amesha Sepanta protecting them. The seven elements of Life, namely Fire, Earth, Water, Air, Plants, Animals, and Human, are represented. They also have Astrological correlations to five planets Mercury, Venus, Mars, Jupiter, Saturn, and Sun and Moon. With the advent of Islam the word Amesha Sepanta shortened to and eventually was remembered by just the letter S and the number 7. The Haft Sin has evolved over time, but has kept its symbolism. Traditionally, families attempt to set as beautiful a Haft Sīn table as they can, as it is not only of traditional and spiritual value, but also noticed by visitors during Noruzi visitations and is a reflection of their good taste.
The Haft Sīn items are:
sabzeh – wheat, barley or lentil sprouts growing in a dish – symbolizing rebirth
samanu – a sweet pudding made from wheat germ – symbolizing affluence
senjed – the dried fruit of the oleaster tree – symbolizing love
sīr – garlic – symbolizing medicine
sīb – apples – symbolizing beauty and health
somaq – sumac berries – symbolizing (the color of) sunrise
serkeh – vinegar – symbolizing age and patience
Other items on the table may include:
Sonbol – Hyacinth (plant)
Sekkeh – Coins – representative of wealth
traditional Iranian pastries such as baghlava, toot, naan-nokhodchi
Aajeel – dried nuts, berries and raisins
lit candles (enlightenment and happiness)
a mirror (symbolizing cleanness and honesty)
decorated eggs, sometimes one for each member of the family (fertility)
a bowl of water with goldfish (life within life, and the sign of Pisces which the sun is leaving). As an essential object of the Nowruz table, this goldfish is also “very ancient and meaningful” and with Zoroastrian connection.
rosewater, believed to have magical cleansing powers
the national colours, for a patriotic touch
a holy book (e.g., the Avesta, Qur’an, Bible, Torah, or Kitáb-i-Aqdas) and/or a poetry book (almost always either the Shahnama or the Divan of Hafez)
Connected to this festival historically is Naw-Rúz (literally new day) which is the Bahá’í new year festival and falls at the spring equinox, although it has been fixed at 21st March for countries outside the Middle East. Naw-Rúz symbolises the new life of spring. The Bahá’í Faith is a monotheistic religion founded by Bahá’u'lláh in nineteenth-century Persia (modern Iran), emphasizing the spiritual unity of all humankind.