Reference Terms
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Circle of latitude
On the Earth, a circle of latitude or parallel is an imaginary east-west circle that connects all locations with a given latitude. The position on the circle of latitude is given by the longitude. Each is perpendicular to all meridians at the intersection points. Those parallels closer to the poles are smaller than those at or near the Equator.
For a low latitude a circle of latitude can be said to be a line around the Earth, while at a high latitude it is a circle around a pole. Circles of latitude are often used as boundaries between countries or regions.
The five major circles of latitude are, starting from the North Pole and finishing at the South Pole; the Arctic Circle, the Tropic of Cancer, the Equator, the Tropic of Capricorn and the Antarctic Circle.
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Earth & Climate News
December 12, 2025
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Dec. 12, 2025 Fossils from Qatar have revealed a small, newly identified sea cow species that lived in the Arabian Gulf more than 20 million years ago. The site contains the densest known collection of fossil sea cow bones, showing that these animals once thrived ...
Dec. 11, 2025 Researchers found that eroded lava rubble beneath the South Atlantic can trap enormous amounts of CO2 for tens of millions of years. These porous breccia deposits store far more carbon than previously sampled ocean crust. The discovery reshapes how ...
Dec. 11, 2025 Scientists tracking young Arizona Bald Eagles found that many migrate north during summer and fall, bucking the traditional southbound pattern of most birds. Their routes rely heavily on historic stopover lakes and rivers, and often extend deep into ...
Dec. 10, 2025 Researchers have uncovered surprising evidence that the deep ocean’s carbon-fixing engine works very differently than long assumed. While ammonia-oxidizing archaea were thought to dominate carbon fixation in the sunless depths, experiments show ...
Dec. 10, 2025 Researchers discovered that unusually high temperatures can hinder early childhood development. Children living in hotter conditions were less likely to reach key learning milestones, especially in reading and basic math skills. Those facing ...
Dec. 9, 2025 Scientists discovered a small protein region that determines whether plants reject or welcome nitrogen-fixing bacteria. By tweaking only two amino acids, they converted a defensive receptor into one that supports symbiosis. Early success in barley ...
Dec. 8, 2025 A newly analyzed set of climate data points to a major volcanic eruption that may have played a key role in the Black Death’s arrival. Cooling and crop failures across Europe pushed Italian states to bring in grain from the Black Sea. Those ...
Dec. 7, 2025 A century-old North Atlantic cold patch is now linked to a long-term slowdown in the AMOC, the climate-regulating conveyor belt of ocean water. Only weakened-AMOC models match observed temperature and salinity patterns, overturning recent model ...
Dec. 4, 2025 This year’s ozone hole over Antarctica ranked among the smallest since the early 1990s, reflecting steady progress from decades of global action under the Montreal Protocol. Declining chlorine levels and warmer stratospheric temperatures helped ...
Dec. 2, 2025 As the last Ice Age waned and the Holocene dawned, deep-ocean circulation around Antarctica underwent dramatic shifts that helped release long-stored carbon back into the atmosphere. Deep-sea sediments show that ancient Antarctic waters once trapped ...
Latest Headlines
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Dec. 10, 2025 New research reveals that Earth’s solid inner core is actually in a superionic state, where carbon atoms flow freely through a solid iron lattice. This unusual behavior makes the core soft, ...
Dec. 7, 2025 A new radiocarbon study has clarified the timing of the colossal Thera eruption, placing it before Egypt’s New Kingdom. Researchers analyzed artifacts tied to Pharaoh Ahmose, gaining rare access to ...
Dec. 6, 2025 Scientists have discovered that complex life began evolving much earlier than traditional models suggested. Using an expanded molecular clock approach, the team showed that crucial cellular features ...
Dec. 4, 2025 Fresh evidence suggests early Earth wasn’t locked under a rigid stagnant lid but was already experiencing intense subduction. Ancient melt inclusions and advanced simulations point to continents ...
Dec. 3, 2025 Researchers recreated conditions from billions of years ago and found that Earth’s young atmosphere could make key molecules linked to life. These sulfur-rich compounds, including certain amino ...
Dec. 2, 2025 Dolichospermum, a type of cyanobacteria thriving in Lake Erie’s warming waters, has been identified as the surprising culprit behind the lake’s dangerous saxitoxins—some of the most potent ...
Dec. 1, 2025 Two decades of satellite and GPS data show the Thwaites Eastern Ice Shelf slowly losing its grip on a crucial stabilizing point as fractures multiply and ice speeds up. Scientists warn this pattern ...
Nov. 30, 2025 New findings show that some coastal regions will become far more acidic than scientists once thought, with upwelling systems pulling deep, CO2-rich waters to the surface and greatly intensifying ...
Nov. 28, 2025 Long-term inhalation of toxic air appears to dull the protective power of regular workouts, according to a massive global study spanning more than a decade and over a million adults. While exercise ...
Nov. 27, 2025 Human development and climate-driven sea level rise are accelerating global beach erosion and undermining the natural processes that sustain coastal ecosystems. Studies reveal that urban activity on ...