PITTSBURGH (KDKA) -- Today is one of our two 'Equal Days'. Obviously, we all know about the fall and spring equinox.
The Latin word for equinox is 'aequinoctium'. You can break that down to two Latin words, aequus & nox. Aequus means equal. Nox means night. When you think about the dynamics of what is occurring with the earth, the two yearly equinoxes that we have is a time when the earth's poles are parallel to the sun regarding our path around the sun.
Sunrise and sunset occur 12 hours apart at the equator on both of the 'equinox days. Every other day of the year we see one of the poles either closer to or farther from the sun.
Going more in-depth with this, the earth's poles always point in the same direction. During the winter solstice, the earth's north pole points away from the sun. If looking above the earth you could draw a line from the north pole to the sun and the south pole would be along that line. During the summer solstice, the south pole is pointing directly away from the sun. Again if you had a top-down view you could draw a line from the south pole to the sun and the north pole would be along that line. That now gets us to the spring and fall equinox. If you were to draw a line from the center of the Earth to the sun it would be perpendicular to a second line drawn from both poles, making a perfect 'T'. The place of the poles would flip-flop on each equinox.
This finally gets us to what is happening today where Pittsburgh will see sunrise occurring at 7:12 and sunset also occurring at 7:12. Since we are moving towards the winter solstice, the earth's north pole is now pointing 'away' from the earth. How much farther away than last Saturday?
Well if you were to draw a line between us and the sun (not the equator) it would make a 'T' with the poles today, giving us equal amounts of daylight and nighttime.
Let's quickly talk about today's weather, with highs expected to hit the upper 60s.
Morning conditions will be cloudy with some pockets of drizzle in spots.
Most will be dry throughout the day. Lows dipped to the upper 50s this morning and will be in the mid-50s on Wednesday morning. Noon temperatures today should hit the mid-60s.
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