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
1
2
Earth & Climate News
April 24, 2026
Apr. 24, 2026 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 ...
Apr. 24, 2026 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 ...
Apr. 24, 2026 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 ...
Apr. 24, 2026 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 ...
Apr. 22, 2026 A new AI-driven method called GOFLOW is turning weather satellite images into highly detailed maps of ocean currents. By tracking how temperature patterns shift over time, it can reveal fast-moving, small-scale currents that were previously ...
Apr. 20, 2026 Scientists have discovered that moringa seeds can help pull microplastics out of water, rivaling standard chemical treatments. The plant-based extract causes plastic particles to clump together, making them easier to filter away. In some conditions, ...
Apr. 20, 2026 Many of the world’s largest river deltas—home to hundreds of millions of people—are sinking faster than rising seas, according to a sweeping global study. Using high-resolution satellite radar maps, researchers found that human activities like ...
Apr. 20, 2026 After two centuries of failed attempts, scientists have finally grown dolomite in the lab, cracking a long-standing geological puzzle. They discovered that the mineral’s growth stalls because of tiny defects—but in nature, those flaws get washed ...
Apr. 19, 2026 Human societies didn’t just adapt to the planet—they learned to reshape it. From early fire use to today’s global supply chains, our cultural and social innovations have unlocked extraordinary power to transform Earth and improve human life. ...
Apr. 19, 2026 Scientists have developed a fuel cell that uses microbes in soil to produce electricity. The device can power underground sensors for tasks like monitoring moisture or detecting touch, without needing batteries or solar panels. It works in both dry ...
Apr. 18, 2026 That “magic” sponge under your sink may be hiding an environmental downside. While melamine sponges are famous for effortlessly scrubbing away stubborn stains, they slowly break down as you use them—shedding tiny plastic fibers that wash into ...
Apr. 18, 2026 Scientists drilling deep beneath Greenland’s ice have uncovered a startling clue about its past—and future. Evidence shows that the Prudhoe Dome, a major high point of the ice sheet, completely melted around 7,000 years ago during a relatively ...
Latest Headlines
updated 12:56 pm ET
Apr. 23, 2026 Scientists have mapped how Earth’s deepest mantle is being deformed—and the results point to long-lost tectonic plates buried thousands of ...
Apr. 18, 2026 As the Moon swallowed the Sun during the April 8, 2024, total solar eclipse, something remarkable happened on the ground—cities went eerily quiet. Scientists analyzing seismic data found that ...
Apr. 17, 2026 Long before rising seas swallowed Doggerland beneath the North Sea, this lost landscape may have been a surprisingly lush and life-friendly haven. New DNA evidence reveals that forests of oak, elm, ...
Apr. 17, 2026 A hidden threat is emerging in the world’s glaciers: while most are shrinking, a rare group known as “surging glaciers” can suddenly ...
Apr. 16, 2026 The ozone layer has been on track to recover thanks to the Montreal Protocol—but a loophole may be holding it back. Chemicals still permitted for industrial use are leaking into the atmosphere at ...
Apr. 16, 2026 Researchers have discovered lithium hidden in pyrite within ancient shale rocks—an unexpected find that could reshape how we source this critical battery material. It raises the possibility of ...
Apr. 16, 2026 Scientists have discovered that methane in the open ocean is produced by microbes under nutrient-poor conditions, solving a long-standing mystery. As ...
Apr. 14, 2026 For years, water managers have been puzzled as the Colorado River kept delivering less water than expected—even when snowpack levels looked promising. New research reveals the missing piece: spring ...
Apr. 13, 2026 Africa’s forests have undergone a shocking reversal, switching from carbon absorbers to carbon emitters after 2010. Researchers found that heavy deforestation in tropical regions has led to massive ...
Apr. 13, 2026 Gray whales are beginning to break their long-established migration patterns, venturing into risky new territory like San Francisco Bay as climate change disrupts their Arctic food supply. But this ...