Equinox
Vs Solistice.
Four times a
year, the season officially changes. And each change is marked by a specific
point known as an equinox or
a solstice.
One term is
used for the transition from winter to spring and summer to fall, and one is
used for the switch from spring to summer and fall to winter.
Join us on a
journey through the seasons as we differentiate between equinoxes and solstices
to tell you when they occur, and explain why this is different depending on
what hemisphere you’re in.
Quick
Summary.
An equinox is
one of the two times of the year when the amount of daylight and night time
hours are just about of equal length.
The vernal equinox marks
the start of spring, and the autumnal equinox marks the start of
fall.
A solstice is
one of the two times of the year resulting in the most amount of daylight time
or the least amount of daylight time in a single day. Solstices mark
the start of summer and winter.
What is
an equinox?
An equinox is
one of the two times of the year when the amount of daylight and night time
hours are just about of equal length.
The
two equinoxes occur around March 20–21 and September 22–23, marking
the onset of both spring and autumn.
During the
equinox, the sun crosses the plane of Earth’s equator, making night time
and day time (roughly) equal length all over the world.
In the Northern
Hemisphere, the spring equinox, or vernal
equinox, occurs around March 21, when the sun moves northward across the
celestial equator.
The autumnal equinox occurs around September 22 or 23,
when the sun crosses the celestial equator going
south.
In the Southern
Hemisphere,
it’s the
reverse.
For this
reason, the terms March equinox and September equinox are
sometimes used to avoid a Northern Hemisphere bias.
Contrary to
popular usage, an equinox doesn’t last for a full 24 hours.
Technically speaking, an equinox is one of the two specific
moments in time when the sun is exactly above the celestial equator.
The
word equinox can also refer to the position of the sun at this
moment.
Where
does the word equinox come from?
The
word equinox comes from the Latin aequinoctium, meaning “the
time of equal days and nights,” from equi-, meaning “equal,”
and nocti-, meaning “night.”
What is
a solstice?
A solstice is
one of the two times of the year when the positioning and tilt of Earth
relative to the sun results in the most amount of daylight time or the least
amount of daylight time in a single day.
Technically
speaking, a solstice is one of the two the exact moments in the
year when the sun reaches its northern most point (around June 21, when the
North Pole tilts closest to the sun) or southern most point (around December
22, during the winter solstice) from Earth’s equator.
The solstices are
traditionally considered to mark the start of summer and winter.
But which
season begins with each solstice depends on which hemisphere you’re
in.
In the Northern
Hemisphere, the summer solstice occurs in June and the winter
solstice
occurs in
December.
In the Southern
Hemisphere,
it’s the
opposite.
The summer
solstice results in the longest day of the year (sometimes
called mid summer),
meaning it has the most time of daylight, and the winter
solstice results in the shortest day of the year, meaning it has the
longest period of darkness.
Where does
the word
solstice come
from?
The
word solstice ultimately derives from the Latin sōlstitium,
which comes from the parts sōl, “sun,” and sistere, “to stand still.”
This means
that sōlstitium
literally translates
to something like “the standing still of the sun.”
What is
the difference between an equinox and a solstice?
When
the equinox occurs, as the equi- prefix might
suggest, day and night are of equal length, and it marks the onset of spring
(vernal equinox) and autumn (autumnal equinox).
The solstice,
meanwhile, marks the beginnings of summer and winter, and it’s either the
longest day of the year (summer solstice) or the shortest (winter solstice).
Remember, sol means
sun, and solstices are the days with the most or the least amount of
daylight.
Courtesy
Dictionary.com
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