I wait for it all year long! The first day of summer known as the summer solstice. It’s the start of my favorite season: Summer!!! I especially love summers in New York City. It’s so easy to get out and about, enjoying Happy Hours with good friends, good bar food, and good wine. Outside dinners under a canopy or sitting under the fountain at Lincoln Center before the ballet, or open air concerts and theater.
How wondrous is the above image showing us the position of the Earth when the Western Hemisphere enters the summer solstice.
According to NASA the 2025 summer solstice falls on Friday, June 20th, at 10:42 p.m. ET. It marks the longest day of the year in the northern hemisphere when the Earth’s tilt is closest to the Sun. Imagine if you were spacewalking gazing at the tilted Earth and the Sun from space yet at a safe distance!
Did you know the Earth’s axis is always tilted -- 23.5 degrees relative to its orbital plane around the sun? The tilt causes different hemispheres to get varying hits of direct sunlight throughout the year. The tilt is called obliquity and without it, there would be no seasons as we know them. When a hemisphere is tilted towards the Sun it experiences summer, while the opposite hemisphere experiences winter.
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Have you heard of Pangaea? About 300 million years ago the Earth assembled into one supercontinent, Pangaea (from the Greek word pan meaning all, whole, or entire and gaea (meaning land, Earth, or Mother Earth). As Pangaea formed it became surrounded by a single gigantic ocean called Panthalassa, which means all the sea in Greek. While Panthalassa was the only ocean there was a smaller sea called the Tethys Ocean, an embayment within the coastline of Pangaea.
Tectonic plate movement caused Pangaea to form, break up and is the reason continents continue to shift positions today. As the plates move, they cause landmasses to inch together, break apart, and transform. The plates are massive slabs of solid rock that are always moving and glide over the Earth’s mantle (the rocky middle layer above the Earth’s core). Fault lines are fractures or cracks within those plates or at their boundaries. Fault lines can exist on one plate or over two plates.
Some 200 million years ago Pangaea the supercontinent comprising all the continental crust of the earth broke into pieces named Laurasia and Gondwana.
There were 3 major phases in the breakup of Pangaea: 1) The opening of the Central Atlantic Ocean caused by the rifting (a major fault separating blocks of the earth's surface) between North America and northwestern Africa. 2) The breakup of Gondwana into Africa, South America, India, Antarctica, and Australia. 3) The opening of the Norwegian Sea. Australia and Antarctica broke up. Laurasia split into North America and Eurasia.
Evidence for the existence of Pangaea remains with us today: The eastern coast of South America closely fits the western coast of Africa. One of Australia’s coastlines fits a coastline of Antarctica, and certain coastlines of North and South America match up with certain coastlines of Europe and Africa. The Appalachian Mountain chain extends from the southeastern United States to the Scandinavian Caledonides of Europe. They are believed to have formed a single chain, the Central Pangaea Mountains. Moreover, fossils of identical species are present on continents that are now very far apart.
Today we have 7 continents. Isn’t it fascinating? What if when humans came along, geology had not separated us?
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