In just a few hours, we will officially transition into June 21st, but few are aware that this year, June 21st will be the most special day in 228 years.
Today is the most special day in 228 years.
According to the United States Naval Observatory, this year’s Summer Solstice will commence in the afternoon of June 20th (UTC time, which corresponds to midnight and early morning of June 21st in Vietnam).
The Summer Solstice is one of the two solstices each year (Summer Solstice and Winter Solstice), occurring around June 20th to 22nd annually. This is the time when the Sun reaches its highest point in the sky at noon in the Northern Hemisphere. For countries in the Northern Hemisphere, the Summer Solstice is the day with the longest daylight hours of the year. Conversely, for countries in the Southern Hemisphere, it is the day with the shortest daylight hours.
The Summer Solstice marks the beginning of summer in the Northern Hemisphere and winter in the Southern Hemisphere.
The Summer Solstice (left) and Winter Solstice (right) are the times when the Earth is farthest from the Sun (Photo: NASA).
On the day of the Summer Solstice, the North Pole of the Earth is tilted maximally towards the Sun. The Sun will appear directly overhead at the Tropic of Cancer. On this day, in the Northern Hemisphere, the Sun will follow the longest and highest path across the sky, which is why the Summer Solstice has the longest day and the shortest night of the year.
In most years, the Summer Solstice typically occurs on June 21st (June 22nd in Vietnam), but in 2024, it will begin from the afternoon of June 20th.
This means that 2024 will have the earliest Summer Solstice since 1796. Previously, the Summer Solstice in 1796 began at 5:45 PM on June 20th (UTC). Thus, June 21, 2024, will be a special day occurring in 228 years, marking the early arrival of the Summer Solstice and officially signaling the beginning of summer sooner.
Why is the Summer Solstice Early in 2024?
The early arrival of the Summer Solstice this year is not related to climate change or global warming… but simply because the human calendar we are using is not truly perfect.
While a normal year (a non-leap year) has 365 days, in reality, the Earth takes longer to complete one orbit around the Sun. On average, the Earth takes 365 days, 5 hours, and 49 minutes to revolve around the Sun. That is why every four years, we have a leap year with an additional day to compensate for that extra quarter-day.
The early Summer Solstice in 2024 is not due to climate change or global warming (Photo: Getty).
In leap years, such as 2024, the solstice (Summer Solstice, Winter Solstice) and equinox (Spring Equinox, Autumn Equinox) typically occur 18 hours and 11 minutes earlier than the previous year. Then, in consecutive non-leap years, these dates tend to start later by about 5 hours and 49 minutes compared to the previous years.
Over time, the solstices and equinoxes will occur approximately 45 minutes earlier every 4 years or earlier by ¾ of a day every century. This means that in this century, the Summer Solstice will not occur earlier than in 2024 until 2096.
Special Astronomical Events on June 21, 2024
June 21, 2024, not only marks the earliest Summer Solstice in 228 years, but it will also feature a special astronomical event, known as the maximum lunar standstill (or the phenomenon of the Moon moving horizontally across the sky).
The maximum lunar standstill allows the Moon to appear in the night sky longer (Photo: Getty).
This phenomenon occurs with an 18.6-year cycle when the Moon reaches its maximum height in the sky for an extended period. The term “standstill” here does not mean that the Moon stops moving but rather that it will cease its immediate variations in the sky. As a result, the Moon will appear in the night sky longer and move almost in a horizontal line.
The last occurrence of the maximum lunar standstill was on September 15, 2006.
Solstices are the points in the year when the Sun reaches its maximum or minimum height in the sky at noon, meaning when the Earth’s axis is tilted the most towards or away from the Sun. There are two solstices each year: Summer Solstice and Winter Solstice. Summer Solstice typically occurs around June 21st or 22nd. This is the longest day of the year in the Northern Hemisphere and the shortest in the Southern Hemisphere. The Summer Solstice marks the beginning of summer in the Northern Hemisphere and winter in the Southern Hemisphere. Winter Solstice usually occurs around December 21st or 22nd. In contrast to the Summer Solstice, the Winter Solstice is the shortest day of the year in the Northern Hemisphere and the longest in the Southern Hemisphere. The Winter Solstice marks the beginning of winter in the Northern Hemisphere and summer in the Southern Hemisphere.
Equinoxes are the points in the year when the Sun is aligned with the Earth’s equator, causing day and night to be almost equal in length globally. There are two equinoxes each year: Spring Equinox and Autumn Equinox. Spring Equinox typically occurs around March 20th or 21st, marking the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. Autumn Equinox usually occurs around September 22nd or 23rd, marking the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere. |
