New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Arctic Circle

The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. This is the parallel of latitude that (in 2000) runs 66.56083 degrees north of the Equator. Everything north of this circle is known as the Arctic, and the zone just to the south of this circle is the Northern Temperate Zone.

The Arctic Circle marks the southern extremity of the polar day (24 hour sunlit day) of the summer solstice in June and the polar night (24 hour sunless night) of the winter solstice in December. Within the Arctic Circle, the Sun is above the horizon for 24 continuous hours at least once per year, in conjunction with the Arctic's Summer Solstice. Likewise, in conjunction with the Arctic’s Winter Solstice, the Arctic sun will be below the horizon for at least 24 continuous hours.

Related Stories
 


Earth & Climate News

April 28, 2026

A new study suggests Neanderthals didn’t go extinct simply because of climate change or competition with Homo sapiens. Instead, the key difference may have been social connectivity—Homo sapiens formed stronger, more flexible networks that helped ...
The mysterious collapse of the Maya civilization may not have been driven solely by drought after all. New evidence from lake sediments in Guatemala reveals that one key city, Itzan, enjoyed a stable climate even as its population abruptly vanished. ...
A mysterious “golden orb” found more than two miles deep in the Gulf of Alaska left scientists baffled for over two years, sparking wild speculation about its origins. After an intensive ...
A major new study finds that living in pesticide-heavy environments could raise cancer risk by up to 150%, even when the chemicals are considered “safe” on their own. The research suggests these mixtures may silently damage cells years before ...
For decades, the Gulf of Panama has relied on strong seasonal winds to trigger upwelling, bringing cool, nutrient-packed water to the surface. But in 2025, this dependable event didn’t happen. Researchers point to unusually weak winds as the ...
As Alaska’s rivers warm, invasive northern pike are becoming noticeably more voracious. Scientists discovered that pike of all ages are eating more fish, with young pike increasing consumption by over 60%. Warmer water speeds up their metabolism, ...
For ages, wall lizards coexisted in three distinct color types, each with its own strategy for survival. Now, a powerful green variant is taking over. These dominant “Hulk” lizards are outcompeting the others, causing yellow and orange morphs to ...
Beneath East Africa’s Turkana Rift, scientists have found the crust is thinning to a critical point, suggesting the continent is gradually breaking apart. This “necking” process marks an ...
The golden oyster mushroom may be a culinary hit, but it’s becoming an ecological problem. Scientists warn it’s spreading quickly through U.S. forests, where it outcompetes native fungi and reduces biodiversity. In just a decade, it has appeared ...
Microplastics are floating through the atmosphere and spreading across the globe, but their true origins have been misunderstood. New research shows land sources emit over 20 times more microplastic particles into the air than the ocean, challenging ...
Ancient Antarctic ice is revealing a surprising new chapter in Earth’s climate story, stretching back 3 million years. By analyzing tiny pockets of trapped air and rare gases, scientists have discovered that while the planet cooled ...
Beneath the dry farmland of New South Wales lies a hidden window into a lost rainforest teeming with life from 11-16 million years ago. At McGraths Flat, scientists have uncovered fossils preserved in astonishing detail—not in typical rock like ...

Latest Headlines

updated 12:56 pm ET