Watch the moment spring officially began: Incredible time-lapse video captured by satellite shows the sun shining directly over Earth’s equator

Spring has finally sprung, which means the days will continue to get longer from now until summer.

The season officially started when the sun shone directly over the equator and day and night were almost the same length all over the world.

An amazing timelapse video shows the moment this happened on Wednesday, at 3:06 a.m. GMT (Tuesday, March 19 at 11:06 p.m. EDT).

The fragment comes from GOES East, a space satellite operated by NASA and the National Oceanic and Atmospheric Administration (NOAA).

For a year, GOES East captured one still image per day at the exact same time – 11:50 UTC – from the same position before all the images were linked together.

The resulting animation shows the constant movement of the dividing line between day and night – known by some astronomers as the ‘terminator’.

“From their position 36,236 miles above the equator, the GOES satellites orbit the Earth at the same speed, allowing them to continuously monitor the same region,” NOAA said in a statement.

‘GOES East geostationary satellite, also known as GOES-16, keeps watch over most of North America, including the contiguous United States and Mexico, as well as Central and South America, the Caribbean and the Atlantic Ocean up to the west coast of Africa.’

Some people think that “spring” is an arbitrary name given to the time of year when the weather begins to warm and flowers begin to appear – but that is not the case.

In fact, the four seasons (and when exactly they start) all have to do with the Earth’s motion relative to the sun.

Remember that our planet rotates at an angle as it moves around the sun, so the amount of sunlight we get changes.

Because the Earth is tilted on its axis, the Sun illuminates the Northern or Southern Hemisphere more, depending on where the Earth is in its orbit.

There are two equinoxes every year – in September and March – when the sun shines directly on the equator and the lengths of day and night are almost equal. During equinoxes we experience quite average temperatures and equal lengths of day and night

However, at two points in the year the sun will illuminate the northern and southern hemispheres equally – known as the equinoxes.

In the Northern Hemisphere, spring begins when the first ‘equinox’ occurs, which is when the sun shines directly on the equator.

It means that the length of day and night is almost the same no matter where you are on the planet: 12 hours of sunlight and 12 hours of darkness.

The term ‘equinox’ is derived from Latin and means ‘equal night’.

The first equinox is officially called the ‘vernal equinox’ – and takes place on March 20 or 21 every year.

It marks the beginning of spring in the Northern Hemisphere and the beginning of autumn in the Southern Hemisphere.

The second equinox is officially called the ‘southward equinox’ – and occurs around September 22 every year.

It marks the beginning of autumn in the Northern Hemisphere and the beginning of spring in the Southern Hemisphere.

‘This week marks the vernal or vernal equinox, one of two points in the year when the hours of daylight and night are the same,’ Anna Ross, an astronomer at the Royal Observatory Greenwich, told MailOnline.

NASA chart explains the difference between the solstice and the equinox. The solstices occur in June and December; the equinoxes occur in March and September

The winter solstice is the day of the year when the Northern Hemisphere has the fewest hours of sunlight and the Southern Hemisphere has the most hours of sunlight.

‘It takes a year (or 365 and a quarter days) for the earth to revolve once around the sun and it is then slightly tilted on its axis.

‘So for half the year the Northern Hemisphere is tilted slightly towards the sun, which means we have longer daylight hours and higher temperatures.

‘The other half of the year we are a little further away from the sun, giving us longer nights and colder weather. It is this tilt that gives us our seasons.

‘There are two points in the year when the Earth’s tilt is most extreme relative to the sun.’

While the vernal equinox marks the point at which the Northern Hemisphere enters spring, the Southern Hemisphere enters autumn.

For the Northern Hemisphere, the spring equinox begins the countdown to the summer solstice – the longest day of the year and the start of summer – which will occur on June 20 this year.

Solstices – which are essentially the opposite of the equinoxes – occur when the planet’s geographic pole is tilted most strongly toward the Sun in the Northern or Southern Hemisphere.

“There are two points in the year when the Earth’s tilt is most extreme relative to the sun,” says Ross.

‘These days are known as the solstices.

‘On these dates, depending on which hemisphere you live in, you will experience midsummer with the longest day of the year or midwinter with the longest night.

‘Between these two extremes are our spring and autumn months, the exact centers being the equinoxes.’

Celebrated for centuries, the spring equinox is seen as the harbinger of new beginnings and the renewal of the natural world

However, if you ask a meteorologist when the seasons start, you may get a different answer.

Wednesday marked the start of “astronomical spring,” which is actually one of two definitions of when the seasons begin and end.

Astronomical spring differs from meteorological spring, which always starts on March 1 and ends on May 31.

Meteorological seasons are based on the annual temperature cycle and are more strictly defined by the months of the year.

The Met Office explains: ‘These seasons have been split to coincide with our Gregorian calendar, making it easier for meteorological observations and forecasts to compare seasonal and monthly statistics.’