All you need to know: June 2019 solstice | The essential of astronomy

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The June solstice – your signal to celebrate summer in the northern hemisphere and winter in the southern hemisphere – will take place on June 21, 2019 at 15:54 UTC. June 21, at 10:54 pm CDT, North America. Convert UTC into your time. For us, in the northern hemisphere, this solstice marks the longest day of the year. The first dawns. Long days. Late sunsets. Short nights. The sun at its peak every day, as it crosses the sky. Meanwhile, south of the equator, the winter begins.

What's a solstice? Ancient cultures knew that the path of the sun in the sky, the length of daylight, and the position of sunrise and sunset changed regularly throughout the year.

They built monuments, such as Stonehenge, to track the annual progress of the sun.

Today, we know that the solstice is an astronomical event, caused by the inclination of the Earth on its axis and its movement in orbit around the sun.

This is because the Earth is not in vertical orbit. Instead, our world is tilted on its axis of 23 1/2 degrees. The northern and southern hemispheres of the Earth have the privilege of directly receiving the light and heat of the sun.

At the June solstice, the Earth is positioned in its orbit so that the North Pole of our world is leaning the most towards the sun. Seen from the Earth, the sun is directly above midday, 23 1/2 degrees north of the equator, on an imaginary line surrounding the globe, known as the Tropic of Cancer, named after the Crab Cancer constellation. It's as far as the sun is to the north.

All locations north of the equator have days of more than 12 hours at the June solstice. Meanwhile, all places south of the equator have less than 12 hours days.

When is the solstice where I live? The solstice takes place on June 21, 2019 at 15:54 UTC. It's 10:54 AMC in North America on June 21st.

A solstice occurs at the same time for all of us, all over the world. To find the time of the solstice near you, you must convert your time zone.

Here is an example of how to do this. In the center of the United States, for those of us who use Daylight Savings Time, we subtract five hours from universal time. This is how we get 10 h 54 min TAC as the June 2019 solstice time (15:54 UTC 21 June minus 5 equals 10:54 min on 21 June).

Want to know the time in your area? Check out EarthSky's article How to translate UTC into your time. And remember: you translate June 21st from 15:54 UTC.

Where should I look to see the signs of solstice in nature? All over. For all the creatures of the Earth, nothing is as fundamental as the duration of the day. After all, the sun is the ultimate source of almost all the light and warmth of the Earth's surface.

If you live in the northern hemisphere, you may notice sunrise and late-night sunsets, as well as the great arc of sun across the sky each day. You could see how high the sun appears in the sky at noon. And be sure to watch your midday shade. At the time of the solstice, it is your shortest shadow of the year.

If you are an outsider, you know the feeling of peace and comfort that accompanies these signs of the longest day of the year.

Is the solstice the first day of summer? No global organization has designated an official day to start each new season and different schools of thought or traditions define the seasons in different ways.

In meteorology, for example, summer begins on June 1 st. All schoolchildren know that summer starts when the last ring of school rings.

However, June 21 is perhaps the best-known day for early summer in the northern hemisphere and winter for the southern half of the globe. This is not official, but it is so old a tradition that we all recognize that it is so.

It was universal in humans to cherish this period of heat and light.

For us, in the modern world, the solstice is an opportunity to recall the reverence and understanding that the first peoples had for heaven. Some 5,000 years ago, people placed enormous stones in a circle in a vast plain of present-day England and aligned them on the solstice of June.

We will never understand the full meaning of Stonehenge. But we know that this type of knowledge is not limited to one part of the world. At about the same time that Stonehenge was under construction in England, two large pyramids and then the Sphinx were built on Egyptian sands. If you were standing at the Sphinx at the summer solstice and looking at the two pyramids, you would see the sun go down exactly between them.

How come it gets warmer later in the summer, if June has the longest day? People often ask:

If the June solstice marks the longest day, why do we have the hottest weather in late July and August?

This effect is called the shift of seasons. This is the same reason why it is warmer in the middle of the afternoon than at noon. The Earth just takes a little time to warm up after a long winter. Even in June, ice and snow still cover the ground in some places. The sun must melt the ice – and warm the oceans – and we then feel the stifling summer heat.

Ice and snow have been melting since the beginning of spring. The meltwater and rainwater filtered through the snow at the top of the glaciers.

But glacial runoff is not as important as it will be in a month, even if the sun hits the northern hemisphere directly.

Wait a month longer for the hottest time. This will happen when the days are already starting to shorten, as the Earth continues to orbit the sun, bringing us closer to another winter.

And so the cycle continues.

Conclusion: the solstice of June 2019 will take place on June 21st at 15:54 UTC. It's 10:54 AMC in North America. This solstice – which marks the beginning of summer in the northern hemisphere – marks the northernmost point of the sun in the earthly sky. It is an event celebrated by people throughout the ages.

Visit EarthSky Tonight for easy-to-use night sky graphics and information. Updated daily.

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