First Day of Spring 2018: How the vernal equinox marks the changing seasons
The March equinox has long been celebrated as a time of rebirth in the Northern Hemisphere. Spring-time festivals and holidays such as Easter and Passover are the main celebrations across many cultures as the path of the Sun aligns with Earth's equator.
The start of Spring in the Northern Hemisphere begins on Tuesday, March 20 and will end on Thursday, June 21.
Recognised as the season of early flower blossoms reaffirming the ascendancy of global warming, and the first occasion after Christmas for unmonitored chocolate consumption.
The spring (vernal) equinox in the Northern Hemisphere is also known as the March equinox. Whilst in the Southern Hemisphere it's called the "autumnal (fall) equinox".
The March equinox marks the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s equator – from south to north. This happens on March 19, 20 or 21 every year.
Why is it called the spring 'equinox'?
Since night and day are nearly exactly the same length – 12 hours – all over the world the event is called the equinox, which literally means 'equal night' in Latin (equi – equal, and nox – night).
In reality though, equinoxes do not have exactly 12 hours of daylight. Solstices and equinoxes mark key stages in the astronomical cycle of the earth. In a year there are two equinoxes (spring and autumn) and two solstices (summer and winter).
The dates of the equinoxes and solstices aren't fixed due to the Earth's elliptical orbit of the sun. They are closest in January, and most distant in July (aphelion).
The equinox marks the change of seasons, as the balance of light shifts to make for longer days or nights. Whether that means snow storms or heat waves depends on the hemisphere.
It is also possible to see the Sun rising and setting directly in the East and West, whereas it appears off-centre at other times of year.
What happens on an equinox?
The Earth's axis always tilts at an angle of about 23.5° in relation to the ecliptic, i.e the imaginary plane created by the Earth's orbit around the Sun. On any other day of the year, either the Northern Hemisphere or the Southern Hemisphere tilts a little towards the Sun but on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays.
The equinox occurs at the exact moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s Equator – from south to north. At this moment, the Earth's axis is neither tilted away from nor towards the Sun. In 2018, this happens at 16.15am UTC (GMT).
Spring festivals around the world
Japan's cherry blossom
As spring approaches in Japan, the arrival of cherry blossom (Sakura) is hotly anticipated as the nation turns a shade of pink. Months before the blossom arrives, retailers switch into sakura mode, Danielle Demetriou writes.
The countdown excitement is heightened further by the televised Cherry Blossom Forecast which offers a petal-by-petal analysis of the advance of the blooms – known as the cherry blossom front – as they sweep from the south to the north of the archipelago.
Nowruz is the name of the Iranian New Year, also known as the Persian New Year, which is celebrated worldwide, along with some other ethno-linguistic groups, as the beginning of the New Year.
In Farsi, Nowruz means "New Day". It is a festival that has roots in Zoroastrianism and has been celebrated for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin and the Balkans.
Before the collapse of the Soviet Union, Iran was the only country that officially observed the ceremonies of Nowruz.
When the Caucasian and Central Asian countries gained independence from the Soviets however, they also declared Nowruz as a national holiday.
Nowruz marks the first day of the first month (Farvardin) in the Iranian calendar and is often celebrated at the exact moment of the vernal equinox, when the days start getting longer, and the celebrations can continue for up to two weeks.
Perhaps the most enduring image of Nowruz is gathering together with friends and family around a bonfire.
The colourful Hindu festival of Holi is celebrated as the vernal equinox approaches. In 2018, this was the first two days of March.
The ancient religious festival is mainly observed in India and Nepal, although celebrations have spread around the world and the UK.
The celebrations begin with a bonfire the previous evening where revellers sing and dance. Holi celebrations then become colourful as participants throw coloured powder over each other.
The festival signifies the victory of good over evil with the onset of spring and the end of winter.
The Easter Bunny
Rabbits and hares have been associated with spring since ancient times.
It is thought that the Ango-Saxon Goddess of Spring, Eostre, had a hare as her companion, which symbolised fertility and rebirth.
It’s hardly surprising that rabbits and hares have become associated with fertility as they are both prolific breeders and give birth to large litters in early spring.
The legend of the Easter Bunny is thought to have originated among German Lutherans, where the ‘Easter Hare’ judged whether children had been good or bad in the run-up to Easter.
Over time it has become incorporated into Christian celebrations and became popular in Britain during the 19th century.
Many children believe that the Easter Bunny lays and hides baskets of coloured eggs, sweets and sometimes toys in their homes or around the garden the night before Easter Sunday – much like Father Christmas delivering gifts on Christmas Eve.
This has given rise to the tradition of the Easter egg hunt which is still popular among children today.
Spring Lamb recipes
Jose Pizarro's roast rack of lamb with braised peas and lemon-thyme salsa.
A Spanish roast with a spring-like twist of lemony herb relish and warmed peas
Angela Hartnett's lamb sweetbreads with crispy lamb breast and ricotta
Caramelised sweetbreads contrast with fresh ricotta and a minty, citrus salad.
Scott Hallsworth's tea-smoked BBQ lamb chops
Plump lamb chops cured in garlic, ginger and chilli are smoked over green tea and wood chips before grilling. Delicious with a spicy Korean miso.
Rose Prince's lamb steak with broad beans, shallots and mint
A simple and quick dish of pan-fried lamb teamed with warm broad beans and fresh mint.
Martin Morales' Peruvian lamb braised in beer
A rich and vibrant stew of chunky lamb with red peppers and coriander.
Michel Roux Jr's roast saddle of lamb stuffed with spinach and garlic
A beautiful stuffed roast saddle, served with a saffron jus.