Welcome to the Summer Solstice
Peak sunshine has arrived in the Northern Hemisphere — the summer solstice. Friday is the longest day of the year north of the equator, where the solstice marks the start of astronomical summer. It’s the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start.
This year in the Chicago area, the longest day of the year comes with extreme heat warnings, watches and advisories, with three straight days of “feels-like” temperatures over 100 degrees. In Chicago, summer officially beginning at 9:42 p.m.
“It’s the longest day of the year,” NBC 5 Storm Team Meteorologist Kevin Jeanes said, with 15 hours and 14 minutes of sunlight.
The word “solstice” comes from the Latin words “sol” for sun and “stitium” which can mean “pause” or “stop.” The solstice is the end of the sun’s annual march higher in the sky, when it makes its longest, highest arc. The bad news for sun lovers: It then starts retreating and days will get a little shorter every day until late December.
People have marked solstices for eons with celebrations and monuments, including Stonehenge, which was designed to align with the sun’s paths at the solstices. But what is happening in the heavens? Here’s what to know about the Earth’s orbit.
Solstices are when days and nights are at their most extreme
As the Earth travels around the sun, it does so at an angle relative to the sun. For most of the year, the Earth’s axis is tilted either toward or away from the sun. That means the sun’s warmth and light fall unequally on the northern and southern halves of the planet.
The solstices mark the times during the year when this tilt is at its most extreme, and days and nights are at their most unequal.
During the Northern Hemisphere’s summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22.
Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun — leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23.
The Equinox: Equal Day and Night
During the equinox, the Earth’s axis and its orbit line up so that both hemispheres get an equal amount of sunlight.
The word equinox comes from two Latin words meaning equal and night. That’s because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet.
The Northern Hemisphere’s spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall – or autumnal — equinox can land between Sept. 21 and 24.
On the equator, the sun will be directly overhead at noon. Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time.
Meteorological vs. Astronomical Seasons
These are just two different ways to carve up the year.
While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1.
Understanding the Earth’s Orbit
The Earth’s orbit is the path it takes around the sun. It takes 365.25 days to complete one orbit, which is why we have a leap year every four years to account for the extra quarter of a day.
The Earth’s axis is tilted at an angle of about 23.5 degrees, which means that the amount of sunlight that reaches the Earth’s surface varies throughout the year. This tilt is responsible for the changing seasons.
The Earth’s orbit is not a perfect circle, which means that the distance between the Earth and the sun varies throughout the year. This variation in distance also affects the amount of sunlight that reaches the Earth’s surface.
Conclusion
In conclusion, the summer solstice is a significant event that marks the beginning of astronomical summer in the Northern Hemisphere. It is the longest day of the year and the start of the sun’s retreat from its highest point in the sky. Understanding the Earth’s orbit and the solstices can help us appreciate the changing seasons and the beauty of our planet.
Frequently Asked Questions
Q: What is the summer solstice?
A: The summer solstice is the longest day of the year and the beginning of astronomical summer in the Northern Hemisphere.
Q: What is the difference between astronomical and meteorological seasons?
A: Astronomical seasons are based on the Earth’s orbit around the sun, while meteorological seasons are based on annual temperature cycles.
Q: What is the equinox?
A: The equinox is the time of year when the Earth’s axis and orbit line up, resulting in equal amounts of sunlight on both hemispheres.
Q: How long does the Earth take to complete one orbit around the sun?
A: The Earth takes 365.25 days to complete one orbit around the sun.
Q: Why do we have leap years?
A: We have leap years to account for the extra quarter of a day it takes the Earth to complete one orbit around the sun.
