Today's Image of the Day from the European Space Agency features a compilation of European cities that resemble stars. 



“Star-shaped cities are scattered across Europe, their geometric designs most appreciated when viewed from above,” noted <a href="https://www.esa.int/ESA_Multimedia/Images/2024/12/Earth_from_Space_Star_cities" target="_blank" rel="noreferrer noopener">ESA</a>. 



<h2 class="wp-block-heading" id="h-development-of-star-shaped-cities">Development of star-shaped cities</h2>



The development of star-shaped fortresses, also known as bastion forts, emerged during the Renaissance in Italy as a response to the rapidly evolving art of <a href="https://www.earth.com/news/migrating-eagles-have-been-rerouted-by-the-war-in-ukraine/" target="_blank" rel="noreferrer noopener">warfare</a>.&nbsp;



Traditional medieval fortifications, characterized by high, straight walls and square towers, became vulnerable with the advent of gunpowder weaponry. Cannons could easily reduce these structures to rubble, rendering them obsolete.



The star-shaped design addressed these vulnerabilities by incorporating wide moats and projecting bastions - angled structures that jutted outward from the main walls.&nbsp;



These bastions provided overlapping fields of fire, allowing defenders to cover blind spots and effectively repel attackers attempting to approach or scale the walls.&nbsp;



Additionally, the sloped walls of these fortresses, known as glacis, were designed to deflect cannonballs rather than absorb their impact, further enhancing their resilience.



This innovative design not only improved defensive capabilities but also transformed the battlefield, forcing attackers to develop new siege techniques. It marked a pivotal moment in military engineering, influencing fortress construction across Europe and beyond for centuries.



<h2 class="wp-block-heading" id="h-examples-of-star-shaped-cities">Examples of star-shaped cities</h2>



“Four examples of such cities can be seen here, arranged clockwise from the top left: Bourtange in the Netherlands, Palmanova in Italy, Almeida in Portugal, and Neuf-Brisach in France,” said ESA.



“The green and red hues evoke a Christmas vibe, achieved through different band combinations during image processing to generate true-color (green) and false-color (red) visuals.”



<h3 class="wp-block-heading" id="h-bourtange-netherlands">Bourtange, Netherlands </h3>



Fort Bourtange, nestled in the picturesque countryside of northeast Netherlands near the German border, is a remarkable example of Renaissance military architecture and urban planning.&nbsp;



Constructed in 1593 during the Eighty Years' War, it was strategically positioned to control the only road linking Germany to the Dutch city of Groningen - a vital route for military and trade purposes.&nbsp;



Its unique pentagonal, star-shaped design featured angled bastions, wide moats, and interconnected defensive structures, making it nearly impenetrable to enemy forces equipped with the era's artillery.



In 1851, after centuries of military service, Fort Bourtange was decommissioned and transformed into a peaceful village.&nbsp;



Despite the change in purpose, its original geometric layout, defined by precise angles and symmetrical patterns, remained intact. The pentagonal walls, surrounding waterways, and radial street design continue to showcase the ingenuity of its designers.



<h3 class="wp-block-heading" id="h-palmanova-italy">Palmanova, Italy </h3>



Palmanova, located in the Friuli-Venezia Giulia region of northeast Italy, is a masterpiece of Renaissance urban and military planning.&nbsp;



Designated as a UNESCO World Heritage site, it exemplifies the idealized city envisioned during the late Renaissance, combining beauty, functionality, and <a href="https://www.earth.com/news/preparing-u-s-military-bases-for-sea-level-rise/" target="_blank" rel="noreferrer noopener">military</a> innovation.&nbsp;



Constructed in 1593 by the Republic of Venice, Palmanova was strategically designed to protect the Republic’s northeastern borders from external threats - particularly the Ottoman Empire.



The city’s layout embodies the principles of symmetry and order characteristic of the Renaissance. Its unique radial design spreads out from the central hexagonal square, known as Piazza Grande or Piazza del Duomo, which serves as the civic and social heart of the city.&nbsp;



From this central hub, six straight avenues fan outward, connecting the square to the surrounding neighborhoods and gates. This design was not only aesthetically pleasing but also practical, allowing for efficient movement and communication within the city.



Today, Palmanova is celebrated not only for its historical and architectural significance but also as a rare example of a perfectly preserved star fortress.&nbsp;



<h3 class="wp-block-heading" id="h-almeida-portugal-nbsp">Almeida, Portugal&nbsp;</h3>



Perched on a high plain in northeast Portugal near the Spanish border, the fortress of Almeida is a striking example of military engineering and a symbol of Portugal’s resilience.&nbsp;



Built to secure the nation’s eastern frontier, Almeida has played a significant role in Portuguese history, particularly during its early years of independence and throughout various military conflicts, including the Peninsular War.



The fortress's defining star-shaped ramparts consist of twelve points, each projecting outward to eliminate blind spots and provide overlapping fields of fire against advancing enemies.&nbsp;



The thick walls, surrounding moats, and angular bastions made Almeida a formidable stronghold capable of withstanding prolonged sieges.



<h3 class="wp-block-heading" id="h-neuf-brisach-france">Neuf-Brisach, France</h3>



Neuf-Brisach, located in the Alsace region of northeastern <a href="https://www.earth.com/news/470-million-year-old-animal-fossils-discovered-in-frances-cabrieres-biota/" target="_blank" rel="noreferrer noopener">France</a> near the German border, is another fascinating example of military and urban design.&nbsp;



The town was constructed in 1697 after the loss of Breisach, which stood on the opposite bank of the Rhine River in Germany.&nbsp;



The name "Neuf" (meaning "new" in French) reflects its creation as a strategic replacement and fortification to strengthen France's defense along its eastern border.



Designed by Sébastien Le Prestre de Vauban, the renowned military engineer under King Louis XIV, Neuf-Brisach is part of the extensive network of fortifications that Vauban designed to protect France from external threats.&nbsp;



Vauban's expertise in defensive architecture is evident in the town's star-shaped layout, which was intended to optimize defense while accommodating civilian life within the fortifications.&nbsp;



The fortifications were built to withstand sieges and were strategically positioned to control movement across the Rhine River and defend against potential invasions. The outer star-shaped ramparts extend in a way that creates a nearly impenetrable defensive perimeter.



Image Credit: European Space Agency&nbsp;



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Star-shaped cities scattered across Europe

Today's Image of the Day from the European Space Agency features a compilation of European cities that resemble stars. “Star-shaped cities are scattered across Europe, their geometric designs most appreciated when viewed from above,” noted ESA.  Development of star-shaped cities The development of star-shaped fortresses, also known as bastion forts, emerged during the Renaissance in Italy as a response to the rapidly evolving art of warfare.&nbsp; Traditional medieval fortifications, characterized by high, straight walls and square towers, became vulnerable with the advent of...

Today's Image of the Day from the European Space Agency features a Copernicus Sentinel-2 photograph of Lake Maracaibo, located in the northwestern part of Venezuela. The lake is a significant geographical and ecological feature of South America. 



Lake Maracaibo is often considered more of a tidal bay due to its direct connection to the Caribbean Sea through the Tablazo Strait. It is one of the oldest lakes on Earth, formed approximately 36 million years ago.



"With an area of over 13,000 sq km, Lake Maracaibo is generally considered the largest lake in South America, although by some estimates it should be considered an inlet of the Caribbean Sea since much of its water is brought in by its direct connection to the ocean," explained <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.



"As a result, the water in the northern part of the lake is rather brackish, while the southern waters are fresh, owing to the many rivers that flow into the lake. The biggest, the Catatumbo River, can be seen entering the lake from southwest, where a large amount of sediment carried by the river appears as a yellowish plume."



<h2 class="wp-block-heading" id="h-the-catatumbo-lightning">The Catatumbo lightning</h2>



The lake is renowned for a unique weather phenomenon - the Catatumbo lightning. This natural spectacle occurs primarily where the Catatumbo River meets the <a href="https://www.earth.com/news/wildfire-smoke-has-affected-almost-every-lake-in-north-america/" target="_blank" rel="noreferrer noopener">lake</a>.



Known as the most persistent lightning storm in the world, it produces frequent and dramatic flashes of lightning, illuminating the night sky for an average of 260 nights per year.



These storms generate thousands of lightning strikes in a single night, making the region one of the most electrified places on the planet. 



The phenomenon is so intense that it has been recognized by the Guinness World Records as the place with the highest <a href="https://www.earth.com/news/lightning-on-earth-can-influence-the-weather-in-space/" target="_blank" rel="noreferrer noopener">lightning</a> activity.



Scientists believe the lightning is influenced by the area's geography and climate, including the warm air rising from the lake and its surrounding mountains.



<h2 class="wp-block-heading" id="h-economical-significance-of-lake-maracaibo">Economical significance of Lake Maracaibo </h2>



Lake Maracaibo plays an important role in Venezuela’s economy, as it lies atop vast reserves of crude oil.



The discovery of petroleum in the early 20th century transformed the region into a major oil-producing area, leading to the establishment of numerous oil rigs and platforms. 



However, this economic activity has come at a cost. <a href="https://www.earth.com/news/half-of-the-worlds-largest-lakes-are-losing-their-resilience/" target="_blank" rel="noreferrer noopener">Pollution</a> from oil spills, industrial waste, and agricultural runoff has significantly degraded the lake's ecosystem.



The appearance of a green, slimy algae known as Lemna has further exacerbated environmental concerns, threatening marine life and the livelihoods of local communities.



<h2 class="wp-block-heading" id="h-cultural-ties-to-lake-maracaibo">Cultural ties to Lake Maracaibo </h2>



The cultural significance of Lake Maracaibo is deeply rooted in the traditions and lifestyle of the Indigenous Añu people, who have inhabited its shores for centuries. The Añu, also known as Paraujano, are known for their distinctive stilt houses, called palafitos.



These wooden structures are built directly over the water, connected by walkways or small boats, allowing the Añu to live harmoniously with their aquatic environment. The architectural style of these stilt houses inspired the early Spanish explorers to nickname the region "The Venice of the Americas."



The Añu's way of life is closely tied to the lake. They rely on <a href="https://www.earth.com/news/sustainable-fishing-must-be-redefined-to-halt-ocean-destruction/" target="_blank" rel="noreferrer noopener">fishing</a> as a primary source of food and income, using traditional methods passed down through generations.



For the Añu, the <a href="https://www.earth.com/news/wildfire-smoke-significantly-impacts-lake-ecosystems/" target="_blank" rel="noreferrer noopener">lake</a> is more than a resource; it is a spiritual and cultural cornerstone, shaping their identity and daily practices.



However, modernization and environmental challenges have disrupted their traditional lifestyle. The oil industry’s expansion around Lake Maracaibo has led to significant environmental degradation, which threaten the lake's biodiversity and the Añu’s primary sources of sustenance. 



<h2 class="wp-block-heading" id="h-lake-maracaibo-and-venezuelan-history">Lake Maracaibo and Venezuelan history</h2>



Lake Maracaibo also played a pivotal role in Venezuelan history, particularly during the Battle of Lake Maracaibo in 1823. 



This naval battle was a decisive conflict in Venezuela’s war for independence from Spain and marked one of the final military engagements of the South American liberation movements led by figures like Simón Bolívar.



Today, the lake represents a remarkable blend of natural beauty, industrial significance, and cultural heritage. 



<h2 class="wp-block-heading" id="h-ongoing-conservation-efforts">Ongoing conservation efforts </h2>



Ongoing efforts aim to harmonize ecological conservation with economic development, as both local and global stakeholders acknowledge the need to protect this extraordinary environment for generations to come.



Efforts to preserve the Añu culture and the lake's ecosystem have been initiated by local and international organizations. These initiatives focus on promoting sustainable development, preserving Indigenous languages and traditions, and mitigating the environmental damage caused by industrial activities. 



Despite these challenges, the Añu have shown remarkable resilience, maintaining their cultural identity and advocating for their rights and the health of their ancestral lands.



Image Credit: ESA



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Lake Maracaibo: One of the most electrified places on the planet

Today's Image of the Day from the European Space Agency...

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features an astronaut photograph of the Amazon River in Brazil. This particular stretch of river is located near the port city of Parintins.



"The river is the largest on Earth and allows seagoing ships to reach Parintins even though it is 800 kilometers (500 miles) inland from the Atlantic Ocean," says NASA.



"Seagoing ships can progress 3,600 kilometers (2,200 miles) up the Amazon River - more than halfway across the South American continent - to the port of Iquitos in Peru."&nbsp;



The muddy color of the river is tied to the Andes Mountains, a major source of sediments and mineral nutrients. According to NASA, the sediment erodes from the Andes Mountains located to the west and is carried generally eastward toward the ocean. 



The Amazon River is renowned for its vast biodiversity. It's home to a wide range of wildlife, including many species of fish like the piranha and the Amazonian manatee. The surrounding Amazon Rainforest is also one of the most biodiverse places on Earth.



The river plays a crucial role in regulating the local and global climate. The Amazon Rainforest, which it nourishes, is often referred to as the "Lungs of the Earth" because of its vast production of oxygen.



Numerous indigenous tribes live along the Amazon River, many of which have maintained traditional ways of life. The river has also been a focal point for explorers and scientists interested in its unique ecosystem.



Image Credit: NASA Earth Observatory&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The lower Amazon River in Brazil

Today's Image of the Day from NASA Earth Observatory features...

Today's Image of the Day from the <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">European Space Agency </a> features the colors of autumn across the islands of Japan. The photo was captured by the Copernicus Sentinel-3 mission on November 1, 2023.



"Japan is made up of thousands of islands stretching some 2500 km through the western Pacific Ocean. Almost all of the land area, however, is taken up by the country’s four main islands, three of which are pictured in this image," said ESA.



"From north to south we see Honshu, the largest island extending in a northeast–southwest arc, Shikoku, just beneath the lower part of Honshu, and Kyushu at the bottom."



According to ESA, the fall colors - visible in shades of red and brown - were triggered by cooler temperatures and fewer daylight hours.



"Urban areas and cultivated land stand out in sharp contrast in tones of grey. The largest area on the eastern coast of Honshu is Japan’s capital Tokyo. This metropolitan area – commonly known as Greater Tokyo – stretches around Tokyo Bay and is home to about 37 million people, making it the largest megacity in the world. Other urban areas, visible moving south along the Pacific coast of Honshu, are Nagoya and Osaka," said ESA.



"Honshu is also home to the country’s highest mountain Mount Fuji, a volcano that has been dormant since 1707. Its snow-capped summit can be spotted as a small white dot near the Pacific coast, about 100 km southwest of Tokyo."



Image Credit: ESA&nbsp;



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Fall colors emerge on the islands of Japan

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory </a> features salt flats in the Bolivian Andes, Salar de Coipasa and Salar de Uyuni. The photograph was captured by an astronaut aboard the International Space Station.



"Visible from low Earth orbit, the salt flats display stark white hues that contrast with the darker surrounding rock. Various volcanic cones are scattered through the image, such as Cerro Tetivilla, which divides the two salt lakes; Wila Pukarani, located within the Coipasa Salt Flat; and Paryani, on the northern edge of Coipasa," said NASA.



"In recent years, Andean salt flats have been the subject of climate and space-based analog studies, serving as a proxy for Earth’s climate history and the Martian environment. Salt textures tell the story of the landscape’s climatic and geologic history, while saltwater brines and hydrated clays beneath the salt crust are of interest to both Earth and Mars scientists."



Salt flats, or "salares" in Spanish, are expansive flat areas covered with salt and other minerals. They form in regions where water evaporates from a shallow lake or pond, leaving behind the salts. The most famous salt flat in the Bolivian Andes, and perhaps the world, is the Salar de Uyuni.



Located in southwest Bolivia, the Salar de Uyuni is the world's largest salt flat, spanning over 10,000 square kilometers. It was formed as a result of prehistoric lakes evaporating over thousands of years. It's a major tourist attraction and offers one of the most unique landscapes on Earth.&nbsp;



When it rains, the surface becomes a giant mirror, reflecting the sky. The Salar de Uyuni also contains 50-70% of the world's lithium reserves, which is becoming increasingly important due to the rise of electric vehicles.



Image Credit: NASA Earth Observatory&nbsp;



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Salt flats in the Bolivian Andes

Today's Image of the Day from NASA Earth Observatory  features...

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features bright autumn colors along the banks of the Amur River, which forms the border between the Russian Far East and Northeastern China (Manchuria).



"Fall color reaches its “peak” when air temperatures drop and shortened daylight triggers plants to slow and stop the production of chlorophyll - the molecule that plants use to synthesize food," explained NASA.&nbsp;



"Without chlorophyll, the green pigment fades and various yellow and red pigments become visible. Northernmost latitudes see these changes first, with fall color appearing as early as September. Areas farther south can see peak color as late as mid-November."



The Amur is the world's tenth longest river, flowing about 1,755 miles from its origins to its mouth in the Strait of Tartary, which connects to the Sea of Okhotsk. The river is known in China as the Heilong Jiang, which means "Black Dragon River."



The Amur River basin is home to a variety of wildlife, including the Amur leopard and the Amur tiger, which are among the rarest large cats in the world. The river's ecology supports a rich biodiversity, although it faces environmental threats such as pollution, overfishing, and the impact of dams on water flow and aquatic life.



The image was captured on September 30, 2019 by the Operational Land Imager on Landsat 8.



Image Credit: NASA Earth Observatory&nbsp;



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Bright fall colors on the banks of the Amur River

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features an ash plume from an explosive eruption of the Klyuchevskoy volcano. 



The ash plume reached as high as 40,000 feet above sea level and extended 1,000 miles to the east-southeast, according to the Kamchatka Volcanic Eruption Response Team (KVERT).



"Eruption activity escalated at the Klyuchevskoy volcano on Russia’s Kamchatka Peninsula in autumn 2023," said NASA. "As a precaution, authorities ordered the closure of schools in two nearby towns, according to news reports. The aviation color code was elevated to red, the highest warning level, due to the significant emissions of ash into the atmosphere."



"Located along the Pacific Ring of Fire, the Kamchatka Peninsula is home to more than 300 volcanoes, including several that are frequently active."&nbsp;



"The current eruption at Klyuchevskoy, Eurasia’s tallest active volcano, has been ongoing since June 2023, when KVERT noted the start of Strombolian eruptions. Explosive eruptions and lava flows continued in the ensuing months."



The false-color image was captured by the OLI (Operational Land Imager) on Landsat 8 on November 1, 2023.&nbsp;



Image Credit: NASA Earth Observatory&nbsp;



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Klyuchevskoy volcano erupts on Russia’s Kamchatka Peninsula

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features Rio Negro in the Brazilian province of Amazonas near the city of Manaus.



Rio Negro is one of the largest tributaries of the Amazon River and the largest blackwater river in the world.



When this photograph was captured on October 3, 2023, the river had dropped to 50.52 feet, according to data collected by the Port of Manaus.&nbsp;



"July through October fall within the dry season in the western and northern Amazon rainforest, but a particularly acute lack of rain during this period in 2023 has pushed the region into a severe drought," said NASA.



"Some areas in the Amazon River’s watershed have received less rain between July and September than any year since 1980, Reuters reported. The drought has been particularly severe in the Rio Negro watershed in northern Amazonas, as well as parts of southern Venezuela and southern Colombia."



René Garreaud, an atmospheric scientist at the University of Chile, said that this is a pretty unusual and extreme situation. “The primary culprit exacerbating the drought appears to be El Niño.”&nbsp;



According to the Associated Press,&nbsp; diminishing river levels in the Brazilian Amazon have left hundreds of communities isolated and struggling to get access to drinkable water.&nbsp;



The image was captured by the OLI (Operational Land Imager) instrument on Landsat 8.



Image Credit: NASA Earth Observatory/Wanmei Liang/ Landsat/ U.S. Geological Survey



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Rio Negro is shrinking as drought strikes the Brazilian Amazon

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a phytoplankton bloom off the coast of Argentina, which became visible in satellite images as summer approached in the southern hemisphere.



“The color of the ocean provides us with important information about phytoplankton, the health of the ocean, and the global climate,” said Ivona Cetinić, the science lead of ocean biogeochemistry for an upcoming NASA satellite called the Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission.



Cetinić said that the color of the swirls can tell us something about the type of plankton present in the bloom. She explained that it is difficult to tell immediately the types of phytoplankton present.



Identifying the different types of phytoplankton present in seawater can help scientists understand more about carbon and nutrient cycling in the ocean. While satellites still have some limitations for understanding ocean ecology, some of these limitations could soon be resolved, said Cetinić.



“PACE is hyperspectral, which means it will be able to see many different hues and will help us tease apart which types of phytoplankton are present. It will also help us quickly identify and forecast harmful algal blooms."&nbsp;



Cetinić said that moving to PACE to understand ocean ecology will be like "switching from a flip phone to the latest smart phone."



The image was captured on November 21, 2022 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.&nbsp;



Image Credit: NASA Earth Observatory



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Plankton colors provide information about ocean health

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA Earth Observatory</a> features what appears to be a ghostly face peering out of Trou au Natron, a deep volcanic pit in northern Chad.&nbsp;



Trou au Natron is a volcanic crater (or maar) located in the Sahara desert. It's part of the Tibesti Mountains, a chain of volcanic formations.&nbsp;



The crater is filled with natron, a naturally occurring mixture of sodium carbonate decahydrate (Na2CO3·10H2O) and around 17% sodium bicarbonate (also called baking soda) along with small quantities of sodium chloride (salt) and sodium sulfate.&nbsp;



This mixture gives the crater its name, as "natron" refers to this type of salt, which was historically used in a variety of ways, including mummification by the ancient Egyptians.&nbsp;



Trou au Natron is noteworthy for its stark and impressive landscape, with steep crater walls surrounding the salt flat inside. The photo was captured by an astronaut on the International Space Station on February 12, 2023.



"The edge of the 'face' is partly formed by shadows cast by the rim of a caldera - a type of volcanic crater formed after an explosive eruption or the collapse of the surface into a partially-emptied magma chamber," said NASA.



"The 'eyes' and 'nose' are cinder cones - steep conical hills built around volcanic vents. The cinder cones are thought to be relatively young in geological terms, likely forming within the past few million years and possibly as recently as the past few thousand years."



"The white area around the 'mouth' is a mineral crust made of a salt known as natron - a mixture of sodium carbonate, sodium bicarbonate, sodium chloride, and sodium sulfate. It forms as hot spring water pools on the surface and evaporates, and mineral-rich steam rises from the surface of the geothermally active area."



Image Credit: NASA Earth Observatory&nbsp;



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Ghostly face peering out of Trou au Natron

The world’s largest iceberg has astonished scientists by shaking free from a spinning ocean trap and continuing its trek across remote southern waters.



Its journey, marked by twists and turns since it separated from Antarctica, has become a focus for research on the changing ocean and the ice’s influence on life beneath the surface.



<h2 class="wp-block-heading" id="h-a23a-iceberg-breaks-free">A23a iceberg breaks free</h2>



The icy slab covers about 1,418 square miles, which makes it bigger than Rhode Island. 



It originally broke away from <a href="https://eros.usgs.gov/earthshots/filchner-ice-shelf-antarctica" target="_blank" rel="noreferrer noopener">Antarctica’s Filchner-Ronne Ice Shelf</a> in 1986 and remained stuck close to the continent for decades. 



Ocean currents and seafloor topography restricted its path. After finally regaining momentum last year, the towering block ran into a swirling formation of water near the <a href="https://www.ndsu.edu/subantarctic/southorkney.htm">South Orkney Islands</a>, where it ended up spinning in place for months.



<h2 class="wp-block-heading" id="h-tracking-iceberg-movements-in-the-ocean">Tracking iceberg movements in the ocean</h2>



“It’s exciting to see A23a on the move again after periods of being stuck,” said <a href="https://www.bas.ac.uk/media-post/worlds-largest-iceberg-a23a-breaks-free/">Dr Andrew Meijers</a>, an oceanographer at the British Antarctic Survey.



Ocean experts have been monitoring this <a href="https://www.earth.com/news/worlds-largest-iceberg-a23a-undergoing-major-erosion/" target="_blank" rel="noreferrer noopener">iceberg’s</a> every move to understand how such massive blocks can influence sea circulation, temperature balance, and the distribution of nutrients.



<h2 class="wp-block-heading" id="h-new-chapter-for-the-a23a-iceberg">New chapter for the A23a iceberg</h2>



The <a href="https://www.earth.com/news/birth-of-an-iceberg-a-83-breaks-free-from-antarctica/" target="_blank" rel="noreferrer noopener">iceberg’s</a> latest departure from its watery prison has stirred up fresh discussions about its fate. 



As it progresses northward, warmer seas may take a toll on its bulk. Many large ice masses follow a similar route before gradually disintegrating. Scientists emphasize that ice already afloat in the water does not raise sea levels when it melts. That does not mean these events should be dismissed, though, since Antarctica’s overall health is a concern in a warming world.



<h2 class="wp-block-heading" id="h-a23a-iceberg-and-its-ocean-impacts-nbsp">A23a iceberg and its ocean impacts&nbsp;</h2>



Researchers have pointed out that although this particular <a href="https://www.earth.com/news/iceberg-that-weighs-more-than-the-eiffel-tower-is-floating-freely/" target="_blank" rel="noreferrer noopener">iceberg</a> calved naturally, Antarctic ice shelves are showing other, more concerning changes.



Experts worry that accelerated ice loss in certain areas could have far-reaching effects. Even small changes along coastal regions of the continent can result in shifts in glacial flow, which might eventually lead to an uptick in sea-level rise. 



Data gathered from icebergs like A23a helps build a clearer picture of these wider trends.



<h2 class="wp-block-heading" id="h-ecosystems-under-the-ice">Ecosystems under the ice</h2>



Observations have shown that drifting ice blocks can stir the waters they pass through, sometimes generating short-lived plankton blooms. 



These blooms support fish, krill, and other marine life in areas that might otherwise lack resources. "These icebergs provide different sources of nutrients," explained Professor <a href="https://www.bas.ac.uk/profile/gant/" target="_blank" rel="noreferrer noopener">Geraint Tarling</a>, Biopole's principal investigator. By sampling the water where the giant iceberg has traveled, scientists hope to gauge whether this berg’s size and origin play a notable part in shaping ocean communities.



<h2 class="wp-block-heading" id="h-what-the-future-holds">What the future holds</h2>



Many anticipate that <a href="https://www.earth.com/news/a23a-worlds-largest-iceberg-is-moving-after-30-years/" target="_blank" rel="noreferrer noopener">A23a</a> will continue meandering through the Southern Ocean currents. As it ventures closer to milder latitudes, the ice is expected to weaken and break into smaller chunks. 



Some fragments may persist for a while, but the main body of the iceberg will likely diminish.



<h2 class="wp-block-heading" id="h-a23a-iceberg-research-enhances-ocean-circulation">A23a iceberg research enhances ocean circulation</h2>



Ongoing research on these gargantuan ice blocks helps experts refine climate models, track ocean circulation patterns, and pinpoint areas most vulnerable to environmental changes. 



Observations from ships, satellites, and on-site measurements all combine to offer a clearer view of what is happening far from major population centers. The hope is that findings from the watery trails left by A23a will guide future decisions on how we manage and protect polar waters and fragile marine habitats.



<h2 class="wp-block-heading" id="h-moving-lab-for-ocean-studies">Moving lab for ocean studies</h2>



A23a’s odyssey is important because it shows how an individual iceberg can become a moving lab for oceanographers and climate scientists. 



The iceberg's escape from a rotating water column this month hints at nature’s complexity, from shifting ocean currents to unseen underwater topography.



While it has been around for nearly four decades, its path in the coming months may reveal more about the chain reactions set in motion when a piece of Antarctica sets sail for open waters.



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World’s largest iceberg breaks free from ocean cyclone

The world’s largest iceberg has astonished scientists by shaking free...

NASA’s Parker Solar Probe touched the Sun's atmosphere, flying within 3.8 million miles (around 6.1 million kilometers) from the surface of the Sun on Tuesday, Dec. 24, at 6:53 a.m. EST. 



During its closest approach, also called perihelion, mission operations will be out of contact with the spacecraft. 



Parker will transmit another beacon tone on Friday, Dec. 27, to confirm its health following the close flyby.



<h2 class="wp-block-heading" id="h-going-where-no-human-made-object-has-gone">Going where no human-made object has gone</h2>



This approach is unlike anything previously accomplished by a human-made spacecraft, marking a landmark in solar science that may rewrite much of what we know about our star.



Arik Posner, <a href="https://parkersolarprobe.jhuapl.edu/" target="_blank" rel="noreferrer noopener">Parker Solar Probe</a> program scientist at NASA Headquarters in Washington, sees this effort as a new window into solar research. “This is one example of NASA’s bold missions, doing something that no one else has ever done before to answer longstanding questions about our universe,” said <a href="https://science.nasa.gov/people/dr-arik-posner/" target="_blank" rel="noreferrer noopener">Arik</a>. The Johns Hopkins Applied Physics Laboratory (<a href="https://www.jhuapl.edu/" target="_blank" rel="noreferrer noopener">APL</a>) in Laurel, Maryland, manages mission operations and is keeping a watchful eye on every step as Parker speeds by.



<h2 class="wp-block-heading" id="h-breathtaking-pace-of-the-parker-solar-probe">Breathtaking pace of the Parker solar probe</h2>



The spacecraft is moving at approximately <a href="https://www.nasa.gov/feature/goddard/parker-solar-probe" target="_blank" rel="noreferrer noopener">430,000 miles per hour</a>. At that velocity, Parker could zip from New York to Los Angeles in about 20 seconds. 



By <a href="https://www.earth.com/news/parker-solar-probe-will-fly-through-suns-atmosphere-tomorrow-for-the-first-time/" target="_blank" rel="noreferrer noopener">approaching the Sun</a> so closely, mission teams hope to retrieve data that no earlier craft could access. Particles in the corona -- where temperatures can exceed a few million degrees -- tend to behave in puzzling ways. 



Scientists aim to see how these intense conditions might shape <a href="https://science.nasa.gov/sun/what-is-the-solar-wind/" target="_blank" rel="noreferrer noopener">solar wind</a>, which jets out at more than one million miles per hour.



Engineers designed Parker’s trajectory with careful flybys of Venus to shrink its orbit gradually around the Sun. This path has taken years to perfect since launch in 2018. 



Each loop demanded detailed calculations to ensure the craft can survive the approach, collect the right measurements, and keep sending updates back to Earth.



<h2 class="wp-block-heading" id="h-solar-probe-battling-extreme-heat">Solar probe battling extreme heat</h2>



Because the Sun’s heat is punishing at such a short distance, Parker Solar Probe relies on a <a href="https://parkersolarprobe.jhuapl.edu/Spacecraft/index.php#Extreme-Environments" target="_blank" rel="noreferrer noopener">carbon-composite shield</a> 4.5 inches thick.



This protective layer keeps sensitive instruments near room temperature while the shield’s front side can face extreme temperatures above 2,500 degrees Fahrenheit.



Sophisticated cooling systems also channel heat away from the core of the <a href="https://www.earth.com/news/meet-the-fastest-human-made-object-ever-nasas-parker-solar-probe/" target="_blank" rel="noreferrer noopener">spacecraft</a>, helping to sustain the electronics that record measurements of plasma, magnetic fields, and solar wind particles.



Inside, the instruments are scanning for clues to explain the corona’s unusual temperatures, which skyrocket to levels far higher than the Sun’s visible surface. 



Those same instruments are also watching for charged particle bursts and fluctuations in magnetic fields that might help answer big questions about what accelerates the solar wind.



<h2 class="wp-block-heading" id="h-crucial-timing-and-limited-contact">Crucial timing and limited contact</h2>



Today’s perihelion means Parker is currently skimming the outer atmosphere of the <a href="https://www.earth.com/news/solar-orbiter-spacecraft-sees-the-sun-through-three-different-lenses/" target="_blank" rel="noreferrer noopener">Sun</a> while in autonomous mode, out of immediate radio contact.



This window of silence is standard because powerful solar emissions prevent reliable communication. Mission operators anticipate a beacon tone on December 27, which should confirm Parker has survived.



Scientists believe that data from this flyby could provide <a href="https://www.earth.com/news/parker-solar-probe-will-fly-through-suns-atmosphere-tomorrow-for-the-first-time/" target="_blank" rel="noreferrer noopener">unprecedented detail on solar activity</a>. Periods of heightened activity, known as solar maxima, produce more flares and coronal mass ejections. These events can spawn auroras at unexpected latitudes and threaten satellites with bursts of charged particles. 



By collecting data from close range, Parker might reveal new insights into how these explosive happenings form and evolve.



<h2 class="wp-block-heading" id="h-visionary-behind-the-parker-solar-probe">Visionary behind the Parker solar probe</h2>



This trailblazer of solar research is named after <a href="https://news.uchicago.edu/story/eugene-parker-legendary-figure-solar-science-and-namesake-parker-solar-probe-1927-2022" target="_blank" rel="noreferrer noopener">Dr. Eugene N. Parker</a>, the late astrophysicist from the University of Chicago who proposed the existence of the solar wind back in the 1950s.



He changed our understanding of how stars interact with their surroundings. In 2018, he became the first person to witness the launch of a spacecraft bearing his name. 



Though he passed away in 2022, his legacy lives on in every close pass the probe completes.



<h2 class="wp-block-heading" id="h-a-closer-look-at-solar-wind">A closer look at solar wind</h2>



One of the main motivations behind Parker Solar Probe mission is to figure out how <a href="https://www.earth.com/news/strong-solar-storm-warning-issued-as-two-cmes-will-hit-earth-tomorrow/" target="_blank" rel="noreferrer noopener">solar wind</a>, that stream of charged particles racing from the Sun, accelerates to incredible speeds. Scientists hope Parker will pinpoint where and how energy is transferred to these particles. Such information could refine space weather forecasts, which are critical for protecting satellites, power grids, and astronauts in orbit.



<a href="https://www.plasmacoalition.org/plasma_writeups/solar_plasmas.pdf" target="_blank" rel="noreferrer noopener">Plasma</a> behavior at these altitudes can also inform theories about stellar physics beyond the Sun. 



Many stars release similar particle streams, so unraveling the inner workings of the solar wind could offer a template for understanding events happening light-years away.



<h2 class="wp-block-heading" id="h-high-stakes-data-for-space-weather-predictions">High-stakes data for space weather predictions</h2>



Operators know that space weather can have major effects here on Earth. Sudden geomagnetic storms have been known to disrupt radio signals, damage satellites, and even cause power outages. By studying the Sun’s activity from the inside, Parker could lead to more accurate warnings for regions of the world vulnerable to blackouts. 



Air traffic, GPS services, and communication infrastructure may all benefit from improved predictions of <a href="https://science.nasa.gov/science-research/heliophysics/space-weather/solar-flares/what-is-a-solar-flare/" target="_blank" rel="noreferrer noopener">solar flares</a> and <a href="https://www.swpc.noaa.gov/phenomena/solar-radiation-storm#:~:text=Solar%20radiation%20storms%20occur%20when,of%20the%20speed%20of%20light." target="_blank" rel="noreferrer noopener">particle storms</a>.



<h2 class="wp-block-heading" id="h-a-milestone-for-parker-solar-probe">A milestone for Parker Solar Probe</h2>



Now that the probe is at perihelion, mission managers will hold their breath for a few days.



“No human-made object has ever passed this close to a star, so Parker will truly be returning data from uncharted territory,” explained <a href="https://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=205" target="_blank" rel="noreferrer noopener">Nick Pinkine</a>, Parker Solar Probe mission operations manager at <a href="https://www.jhuapl.edu/" target="_blank" rel="noreferrer noopener">APL</a>. 



He added that the team is eager to see how Parker managed the flyby when the link reopens.



This moment is a milestone for solar science. If everything goes as planned, Parker will maintain its orbit for future close passes, each offering a renewed chance to investigate the corona’s strange properties.



Researchers anticipate more discoveries that will fill in knowledge gaps about the Sun’s extreme environment.



Far from being an isolated phenomenon, the Sun’s behavior plays a significant role in shaping conditions on Earth. 



Today’s brush with solar fury signals the continuing progress of human exploration -- and the promise of deeper insight into the star that illuminates our world.



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Mission accomplished? Solar Probe just touched the Sun, but we don't know if it survived

NASA’s Parker Solar Probe touched the Sun's atmosphere, flying within...

Giant sloths once roamed across much of the Americas. Modern humans often picture sloths as slow animals clinging to tree branches, but their prehistoric relatives weighed more than 8,000 pounds and sometimes reacted aggressively if they felt threatened. At the same time, ancient mastodons grazed across plains and wetlands, forming part of a landscape filled with towering mammals that would turn heads in any museum exhibit.



<h2 class="wp-block-heading" id="h-humans-coexistence-with-sloths">Humans coexistence with sloths</h2>



For many years, scientists believed that <a href="https://www.earth.com/news/when-did-early-humans-first-start-wearing-clothes-and-why-parasites-lice/" target="_blank" rel="noreferrer noopener">humans</a> set foot in the Americas around 13,000 years ago and rapidly hunted massive creatures like giant ground sloths and saber-toothed cats into extinction.



This theory, called <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC6202698/" target="_blank" rel="noreferrer noopener">Pleistocene overkill</a>, painted a picture of speedy destruction. 



However, <a href="https://www.researchgate.net/publication/383692589_Anthropogenic_modification_of_a_giant_ground_sloth_tooth_from_Brazil_supported_by_a_multi-disciplinary_approach" target="_blank" rel="noreferrer noopener">researchers</a> from different archaeological sites have recently suggested that people may have arrived much earlier and may have coexisted with these animals for thousands of years.



<h2 class="wp-block-heading" id="h-ancient-footprints-in-new-mexico">Ancient footprints in New Mexico</h2>



<a href="https://pubmed.ncbi.nlm.nih.gov/34554787/" target="_blank" rel="noreferrer noopener">Daniel Odess</a>, an archaeologist at White Sands National Park in New Mexico, is among those revisiting the old timeline. 



His team has analyzed evidence from footprints and geological layers that could date <a href="https://www.earth.com/news/early-humans-preferred-the-mountains-and-it-changed-our-evolution/" target="_blank" rel="noreferrer noopener">human presence</a> in North America to more than 20,000 years ago.



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/giant-sloth_skeleton_coexisted-with-humans_1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/giant-sloth_skeleton_coexisted-with-humans_1s.webp" alt="Giant Ground Sloth skeleton at the Brevard Museum of History and Natural Science. Credit: BMHNS" class="wp-image-1954670"/></a><figcaption class="wp-element-caption">Giant Ground Sloth skeleton at the Brevard Museum of History and Natural Science. Credit: BMHNS</figcaption></figure>



These footprints appear alongside the tracks of mammoths, giant ground sloths, and other ancient creatures. Some experts question why footprints remain but few other artifacts have turned up. 



Yet the discovery suggests that humans spent many generations adapting to a dramatic environment, rather than simply arriving and wiping out large species in a short period.



<h2 class="wp-block-heading" id="h-sloth-fossils-reveal-human-presence">Sloth fossils reveal human presence</h2>



Sloth fossils from <a href="https://www.researchgate.net/publication/383692589_Anthropogenic_modification_of_a_giant_ground_sloth_tooth_from_Brazil_supported_by_a_multi-disciplinary_approach" target="_blank" rel="noreferrer noopener">Santa Elina</a>, an archaeological site in central Brazil, have stirred fresh discussions about the timeline.



<a href="https://www.researchgate.net/publication/383692589_Anthropogenic_modification_of_a_giant_ground_sloth_tooth_from_Brazil_supported_by_a_multi-disciplinary_approach" target="_blank" rel="noreferrer noopener">Researchers</a> there have unearthed the fossilized remains of giant ground sloths that show signs of human handiwork. These prehistoric bones feature small holes and polished edges that differ from untouched remains.



“We believe it was intentionally altered and used by ancient people as jewelry or adornment,” said researcher <a href="https://www.researchgate.net/profile/Mirian-Pacheco" target="_blank" rel="noreferrer noopener">Mírian Pacheco</a>.



<h2 class="wp-block-heading" id="h-jewelry-from-fresh-bones">Jewelry from ‘fresh bones’</h2>



One puzzle centered on whether this jewelry came from old fossils or from bones that were still fresh and relatively new. 



Laboratory analysis suggests these <a href="https://www.researchgate.net/figure/Study-area-and-fossil-material-a-Map-of-the-location-of-the-tank-deposit-where-the_fig1_383692589" target="_blank" rel="noreferrer noopener">sloth bones</a> were shaped and drilled not long after the animals died, hinting at a human presence in South America more than 25,000 years ago. 



Some bones also show dark coloration. Early findings point to possible burning at campfires, though researchers continue to explore alternative explanations, such as chemical changes in the soil.



<h2 class="wp-block-heading" id="h-debates-and-different-interpretations">Debates and different interpretations</h2>



The site at Santa Elina is only one example among several that point to the idea of an older human presence in the Western Hemisphere. 



In Chile, Monte Verde gained worldwide attention when stone tools and preserved vegetation were <a href="https://pubmed.ncbi.nlm.nih.gov/17773106/" target="_blank" rel="noreferrer noopener">dated to about 14,500 years ago</a>. <a href="https://www.arroyodelvizcaino.org/en/el-lugar/" target="_blank" rel="noreferrer noopener">Uruguay’s Arroyo del Vizcaíno site</a> has yielded animal bones with possible cut marks that may date back 30,000 years. 



Older dates consistently generate skepticism from some experts. People often ask whether there might be errors in dating techniques or whether non-human processes could explain the markings. Scientists like Odess remain open to these critiques and emphasize that it takes time and multiple confirmations for a hypothesis to gain acceptance.



<h2 class="wp-block-heading" id="h-living-among-ice-age-giants">Living among Ice Age giants</h2>



As research grows, a new picture emerges of <a href="https://www.earth.com/news/early-humans-felt-emotions-in-unusual-body-parts/" target="_blank" rel="noreferrer noopener">humans</a> who spent millennia wandering with mastodons, giant sloths, and other imposing animals. 



Paleontologist <a href="https://www.researchgate.net/profile/Thais-Pansani-2" target="_blank" rel="noreferrer noopener">Thais Pansani</a> and her colleagues note that early campsites may have included hearths that left burn marks on large bones.



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/american-mastodon_skeleton_coexisted-with-humans_1-1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/american-mastodon_skeleton_coexisted-with-humans_1s.webp" alt="Skeleton of an American mastodon, the elephant's Ice Age relative that went extinct around 13,000 years ago on display at the Natural History Museum in London. Credit: NHM London" class="wp-image-1954668"/></a><figcaption class="wp-element-caption">Skeleton of an American mastodon, the elephant's Ice Age relative that went extinct around 13,000 years ago on display at the Natural History Museum in London. Credit: NHM London</figcaption></figure>



These details give us a sense of daily life in a time when massive creatures ambled across landscapes quite different from modern farms and highways.



Although the popular view once held that people showed up and immediately caused extinctions, the latest findings propose a longer period of coexistence.



<h2 class="wp-block-heading" id="h-climate-shifts-disrupted-habitats">Climate shifts disrupted habitats</h2>



If <a href="https://www.earth.com/news/worlds-oldest-wooden-structure-completely-rewrites-early-human-history/" target="_blank" rel="noreferrer noopener">humans</a> arrived earlier, why didn’t they drive giant mammals to immediate extinction? Scientists have started to suggest a wider web of factors, including changes in climate. 



When the Ice Age ended, shifting habitats may have disrupted food sources and water supplies for large herbivores and the predators that hunted them.



People may have contributed to the extinctions, but it appears that climate shifts played a role, too. The timing of events is still under scrutiny, and not every site’s data line up perfectly, but the story is growing more complex.



<h2 class="wp-block-heading" id="h-challenges-in-dating-and-evidence">Challenges in dating and evidence</h2>



Dating techniques rely on methods such as radiocarbon analysis of charcoal or bones, geological correlations, and DNA tests that reveal genetic timelines. 



Each tool has strengths and weaknesses, so researchers weigh multiple approaches. Unusual finds, like footprints without additional artifacts, make some archaeologists cautious. 



Yet repeated patterns of evidence are shifting attitudes toward the possibility that <a href="https://www.earth.com/news/early-humans-impacted-earth-than-previously-thought-2/" target="_blank" rel="noreferrer noopener">humans</a> reached the Americas well before the traditional 13,000-year mark.



<h2 class="wp-block-heading" id="h-humans-sloths-and-mastodons">Humans, sloths, and mastodons</h2>



No single discovery will settle the debates. Instead, each new fossil sample and archaeological layer adds a piece to a changing puzzle. 



Researchers continue to test bones, re-check radiocarbon dates, and compare footprints to the surrounding sediments. 



Whether the first arrivals journeyed by land, sea, or both, many specialists agree that older dates are worth taking seriously. Giant sloths, mastodons, saber-toothed cats, and even ancient horses likely shared vast grasslands and wetlands with humans, at least for a while. 



Their interactions remain difficult to trace, but our understanding of the distant past grows richer as new investigations move forward.



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Discovery: Early humans in America coexisted with giant sloths and mastodons

Giant sloths once roamed across much of the Americas. Modern...

This,Man-made,Vehicle,Reached,A,Record,Speed,Of,635,Thousand

NASA’s Parker Solar Probe is set to achieve its most dangerous feat yet tomorrow, December 24, 2024. After a six-year journey of spiraling closer to the star at the heart of our solar system, the spacecraft is expected to come within 3.8 million miles of the Sun’s surface. 



This tiny distance in cosmic terms lets scientists capture a new type of information, revealing secrets about solar winds, extreme heat, and magnetic fields.



<h2 class="wp-block-heading" id="h-solar-probe-on-the-sun-s-doorstep">Solar probe on the Sun's doorstep</h2>



Engineers have spent years carefully adjusting <a href="https://blogs.nasa.gov/parkersolarprobe/" target="_blank" rel="noreferrer noopener">Parker’s flight path</a> using multiple Venus gravity assists. These flybys reshape the spacecraft’s orbit and tighten its looping path around the Sun. “This is one example of NASA’s bold missions, doing something that no one else has ever done before to answer longstanding questions about our universe,” explained <a href="https://science.nasa.gov/people/dr-arik-posner/" target="_blank" rel="noreferrer noopener">Arik Posner</a>, Parker Solar Probe program scientist at NASA Headquarters, describing this mission’s significance.



Ever since the launch in 2018, Parker’s main goal has been to study the Sun’s outer atmosphere, known as the corona. Tomorrow’s approach, often called <a href="https://cneos.jpl.nasa.gov/glossary/perihelion.html" target="_blank" rel="noreferrer noopener">perihelion</a>, marks a new milestone in that quest. The probe moves at speeds around 430,000 miles per hour, faster than any other spacecraft. At such high velocity, it can swing around our star without getting swallowed. Even so, mission managers won’t receive immediate updates once Parker hits its closest point because signals cannot travel through the intense solar environment.



<h2 class="wp-block-heading" id="h-extreme-heat-and-lasting-protection">Extreme heat and lasting protection</h2>



What sets Parker apart is its resilient heat shield. This 4.5-inch-thick carbon-composite barrier enables the spacecraft’s instruments to continue functioning in an environment where temperatures can reach roughly 2,500 degrees Fahrenheit. Despite the harsh surroundings, the precious science instruments remain near room temperature, thanks to expert engineering by Johns Hopkins University Applied Physics Laboratory (<a href="https://parkersolarprobe.jhuapl.edu/" target="_blank" rel="noreferrer noopener">APL</a>).



During every close approach, Parker is pelted by gusts of solar wind and bathed in radiation. Still, it keeps sending back readings about magnetic fields, <a href="https://www.plasmacoalition.org/plasma_writeups/solar_plasmas.pdf" target="_blank" rel="noreferrer noopener">plasma</a> behavior, and energetic <a href="https://www.swpc.noaa.gov/phenomena/solar-radiation-storm#:~:text=Solar%20radiation%20storms%20occur%20when,of%20the%20speed%20of%20light." target="_blank" rel="noreferrer noopener">particles</a>. The probe’s data illuminates reasons behind the corona’s blazing heat, which can climb into the millions of degrees, significantly hotter than the visible surface of the Sun. Such puzzling behavior has fascinated scientists for decades.



<h2 class="wp-block-heading" id="h-chasing-the-solar-wind-s-origins">Chasing the solar wind’s origins</h2>



Solar wind, a stream of charged particles flowing away from the Sun at speeds topping one million miles per hour, plays a major role in <a href="https://science.nasa.gov/sun/what-is-the-solar-wind/">space weather</a>. 



By skimming through the corona, Parker records fresh evidence of how these particles speed up and scatter across the solar system. The answers may help experts forecast disturbances that affect satellites and astronaut safety. Surges of these charged particles can disable communication systems or even disrupt power grids on Earth.



For researchers, big questions remain. How does the <a href="https://science.nasa.gov/sun/what-is-the-solar-wind/">solar wind</a> pick up its pace so dramatically? Is there a specific region in the corona that triggers bursts of fast-moving particles? 



Parker’s measurements bring us closer to unraveling these mysteries. Officials at NASA say that by tomorrow’s approach, new layers of data will help them see patterns not possible to detect from a greater distance.



<h2 class="wp-block-heading" id="h-solar-probe-and-the-sun-s-active-cycle">Solar probe and the Sun's active cycle</h2>



The Sun moves through an 11-year activity cycle. Right now, it is in an active phase, meaning increased sunspots, <a href="https://www.earth.com/news/secondary-peak-extreme-geomagnetic-solar-storm-expected-today/" target="_blank" rel="noreferrer noopener">solar flares</a>, and <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections" target="_blank" rel="noreferrer noopener">coronal mass ejections</a>. 



Researchers are tracking not only Parker’s journey but also the Sun’s changing patterns. Sometimes these outbursts interact with Earth’s magnetosphere and spark colorful auroras, even in places unused to such displays. And although most solar weather events are harmless for life on Earth, severe storms can interfere with GPS systems or satellites.



This is why Parker’s findings are so relevant. Gaining a better understanding of how energetic solar events begin could lead to timelier warnings, giving operators on Earth a heads-up to power down sensitive instruments or adjust satellite orbits.



<h2 class="wp-block-heading" id="h-paying-tribute-to-eugene-parker">Paying tribute to Eugene Parker</h2>



In 2017, NASA renamed the probe after <a href="https://news.uchicago.edu/story/eugene-parker-legendary-figure-solar-science-and-namesake-parker-solar-probe-1927-2022">Dr. Eugene N. Parker</a>, the first person to predict the solar wind in the 1950s. He introduced key ideas about how stars interact with their surroundings. The mission’s name honors his influential work. Dr. Parker passed away in 2022, but his legacy continues. 



The data this spacecraft is sending back not only expands knowledge of <a href="https://www.earth.com/news/tracing-solar-wind-directly-to-its-source-for-the-first-time/" target="_blank" rel="noreferrer noopener">solar physics</a> but also shows how correct Dr. Parker’s early theories were.



<h2 class="wp-block-heading" id="h-record-setting-solar-probe-flyby">Record-setting Solar Probe flyby</h2>



Mission operations expect Parker to reach perihelion at 6:53 a.m. EST on December 24. 



At that time, the spacecraft will run autonomously, and engineers at APL will wait until December 27 for a beacon tone confirming a safe passage around the Sun. “No human-made object has ever passed this close to a star, so Parker will truly be returning data from uncharted territory. We’re excited to hear back from the spacecraft when it swings back around the Sun,” explained <a href="https://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=205" target="_blank" rel="noreferrer noopener">Nick Pinkine</a>, Parker Solar Probe mission operations manager. 



When that update arrives, scientists will study Parker’s recent measurements to identify potential clues about solar wind origins and coronal heating. Each orbit is another chance to witness the scorching conditions near our star. At the same time, the probe helps refine predictions about solar eruptions that might drive future storms toward Earth.



<h2 class="wp-block-heading" id="h-why-does-any-of-this-matter">Why does any of this matter?</h2>



Beyond the scientific breakthroughs, Parker’s success can have practical benefits for technology we rely on every day. Our society depends on GPS signals and stable power systems, and <a href="https://www.earth.com/news/team-creates-video-showing-the-sun-in-gamma-rays-over-a-14-year-period/" target="_blank" rel="noreferrer noopener">major solar events</a> can disrupt both. By learning how to anticipate strong solar winds or flares, experts might one day keep satellites out of harm’s way or shield power grids from unexpected surges.



Tomorrow’s close approach continues a streak of remarkable achievements for NASA. As Parker zips through the corona, it gathers observations that no other mission could obtain. The craft appears ready for another sizzling pass, thanks to the robust thermal design and careful planning. 



Whether it’s helping forecast solar tempers or refining our knowledge of basic astrophysical processes, Parker remains on track to change the way we see the Sun.



Learn more about <a href="https://science.nasa.gov/mission/parker-solar-probe/" target="_blank" rel="noreferrer noopener">NASA's Parker Solar Probe here...</a>



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Spacecraft flew through the Sun's atmosphere today for the first time ever

NASA’s Parker Solar Probe is set to achieve its most...

If all the world's a stage, and all the species merely players, then their exits and entrances can be found in the rock record. This poetic perspective highlights the continuous evolution and unfolding of life’s history, a narrative that is etched into fossils and the layers of sediment in which they are found.



A recent Virginia Tech analysis has now extended this narrative back to nearly 2 billion years ago, offering a more complete picture of life's origin, diversification, and extinction.



<h2 class="wp-block-heading" id="h-expanding-the-chart-of-life">Expanding the chart of life</h2>



Fossil evidence has charted evolutionary milestones over the past half-billion years, but researchers have now pushed this timeline even further back.



The study, led by <a href="https://www.vt.edu" target="_blank" rel="noreferrer noopener">Virginia Tech</a> geobiologist Shuhai Xiao, expands our <a href="https://www.earth.com/news/discovery-evolution-not-random-gene-families-pangenome-influence-called-revolutionary/" target="_blank" rel="noreferrer noopener">understanding of ancient life</a> to the Proterozoic Eon, which spans 2,500 million to 539 million years ago. 



During this era, life forms were typically smaller and softer, such as sea sponges without mineral skeletons, which were less likely to leave fossil traces.



“This is the most comprehensive and up-to-date analysis of this period to date,” said Xiao. "And more importantly, we’ve used a graphic correlation program that allowed us to achieve greater temporal resolution.”



The team’s findings provide a high-resolution analysis of the global diversity and evolution of Proterozoic life. This chart now offers valuable insights into how life’s story played out during this vast period.



<h2 class="wp-block-heading" id="h-understanding-proterozoic-life-the-basics">Understanding proterozoic life -- the basics</h2>



During the <a href="https://www.earth.com/news/rewrite-the-textbooks-life-on-earth-did-not-arise-due-to-increased-oxygen-levels/" target="_blank" rel="noreferrer noopener">Proterozoic eon</a>, which lasted from about 2.5 billion to 541 million years ago, life on Earth was mostly simple and microscopic. Imagine tiny single-celled organisms like bacteria and algae swimming in the oceans. 



These early life forms played a huge role in shaping our planet. For example, they produced oxygen through photosynthesis, which gradually filled the atmosphere and made it possible for more complex life to develop later on. 



Around the middle of the Proterozoic, more advanced cells called <a href="https://www.earth.com/news/earths-oldest-organisms-ever-discovered-show-dazzling-diversity-and-complexity/" target="_blank" rel="noreferrer noopener">eukaryotes</a> appeared. These cells are the building blocks of all plants and animals today, featuring a nucleus and other specialized structures inside them.



As the Proterozoic eon progressed, life started to get a bit more interesting. Towards the end of this time, some of these eukaryotic cells began to form simple multicellular organisms, laying the groundwork for the incredible diversity of life we see today. 



Fossils from this era show the first signs of tiny colonies of cells and simple sea creatures. Even though life was still mostly confined to the oceans, these early innovations set the stage for the explosion of life that would happen in the next eon, the Phanerozoic.



<h2 class="wp-block-heading" id="h-evolution-of-proterozoic-marine-eukaryotes">Evolution of proterozoic marine eukaryotes</h2>



Xiao and his team studied the evolution of ancient marine eukaryotes, which are organisms with cells that have a nucleus. 



These early eukaryotes were the ancestors of animals, <a href="https://www.earth.com/news/ferns-evolving-backward-a-new-look-at-the-evolution-of-life/" target="_blank" rel="noreferrer noopener">plants</a>, and fungi, and thus they paved the way for complex life on Earth.



The researchers found that eukaryotes first appeared at least 1.8 billion years ago. For the next billion years, often called the "boring billion," not much changed.



Species evolved slowly, and diversity remained stable, with few new species emerging or old ones going extinct.



This calm period eventually ended as Earth experienced dramatic changes. Shifts in the environment and evolution then brought a surge in diversity and set the stage for the development of the complex ecosystems we know today.



<h2 class="wp-block-heading" id="h-snowball-earth-s-impact-on-the-evolution-of-life">Snowball Earth's impact on the evolution of life</h2>



Between 720 million and 635 million years ago, the planet experienced at least two severe ice ages, known as Snowball Earth events. These global glaciations plunged Earth into an icy grip, and reshaped <a href="https://www.earth.com/news/how-life-and-environment-co-evolved-over-500-million-years/" target="_blank" rel="noreferrer noopener">life’s trajectory</a>.



“The ice ages were a major factor that reset the evolutionary path in terms of diversity and dynamics,” Xiao explained. “We see rapid turnover of eukaryotic species immediately after glaciation. That’s a major finding.”



When the ice melted, evolutionary activity surged, marking the end of the “boring billion” and ushering in a more dynamic era of biodiversity.



<h2 class="wp-block-heading" id="h-more-questions-than-answers">More questions than answers</h2>



The study on eukaryotic evolution raises important questions about how environmental and evolutionary forces influenced the development of life on Earth. 



For instance, why did eukaryotic evolution remain so slow and stable during the "boring billion," a period marked by low species turnover?



What triggered the rapid evolutionary changes after the <a href="https://www.earth.com/news/snowball-earth-event-set-the-stage-for-complex-life/" target="_blank" rel="noreferrer noopener">Snowball Earth events</a>, when the planet thawed from extreme glaciation?



Key factors under consideration include whether changes in climate and rising atmospheric oxygen levels played a role in accelerating evolution. 



Additionally, scientists wonder whether competition and interactions among organisms created an "evolutionary arms race," that drove species to evolve faster. 



According to Xiao, the team's findings create a foundation for future research. By analyzing the patterns revealed in this study, scientists can delve deeper into the complex relationship between Earth's changing environments and the evolution of life.



<h2 class="wp-block-heading" id="h-new-perspective-on-the-evolution-of-life">New perspective on the evolution of life</h2>



The study of proterozoic life enhances our understanding of how early eukaryotes - the ancestors of modern animals, plants, and fungi - evolved.



The research also reveals how living organisms and Earth’s environment influenced each other in <a href="https://www.earth.com/news/earths-evolution-was-shaped-by-environmental-crises-land-and-sea/" target="_blank" rel="noreferrer noopener">complex and interconnected ways</a> over billions of years.



By extending the timeline of life’s history, this research gives scientists a detailed framework to explore unanswered questions about Earth’s ancient past. It helps us see how events from billions of years ago shaped the planet and life as we know it today.



The study is published in the journal <a href="https://www.science.org/doi/10.1126/science.adm9137" target="_blank" rel="noreferrer noopener">Science</a>.



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Timeline of life’s evolution extended by nearly 1.5 billion years

If all the world's a stage, and all the species...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Nushagak Bay, a large estuary in southwest Alaska. Nushagak runs mainly north to south and exits in Bristol Bay, a large body of water in the Bering Sea.



"The bay is primarily fed by the Nushagak River, which begins in the Alaska Range and flows southwest approximately 450 km. The bay is also fed by several additional rivers including the Wood, Igushik, Snake and Weary rivers," says ESA.



"The dark colors of the Nushagak River are most likely due to tannins or lignins (chemical substances found in plants). Tannins and lignins from roots, leaves, seeds, bark and soil can leach into the water and give it a brown or even black colour. The sediments then flow southwards where it is mixed with the bluer waters of the bay."



Video/ Image Credit: ESA



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Nushagak Bay in southwest Alaska

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> (ACS) reveals that proteins on flu viruses are actually flexible, tilting and waving in a “breath-like” motion. According to the experts, these proteins could be used to better defend against the flu.



"The main antigenic targets of influenza virus are two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Whereas the structural and dynamical properties of both glycoproteins have been studied previously, the understanding of their plasticity in the whole-virion context is fragmented," wrote the researchers.



To investigate, the team conducted detailed simulations of the influenza A H1N1 virion, or the swine flu. The experts concluded that the visualizations show many new vulnerable states of flu viruses, which could improve future vaccines and antiviral drugs.



Video/ Image Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Flu viruses are more flexible than expected

[sendtonews key="G9bUoxcjr4-2511624-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Trasimeno, which is located west of Perugia in central Italy. It is the fourth largest lake in the country. While Trasimeno’s water level varies, it has a maximum depth of approximately six meters.&nbsp;



"In this Copernicus Sentinel-2 image, captured on 6 August 2022, the lake’s emerald green colour is likely due to the presence of phytoplankton. Streaks in the water, particularly visible in the west, indicate the presence of soil and sediments which have been stirred up by winds. Dark colored waters in the southern part of the lake indicate a presence of submerged and floating macrophytes (aquatic plants) as well as algae," says ESA.



"Surrounded by hills on three sides, Trasimeno is subject to heavy storms created by winds, especially from the north and west. There are three islets in the lake: Maggiore, Minore and Polvese (the largest). The lake’s shores are sparsely inhabited with only two popular villages: Castiglione del Lago and Passignano sul Trasimeno."



"Italy is experiencing its worst drought in 70 years which has affected drinking water supplies, hydroelectric power and agricultural production. High temperatures, hot winds and lack of rainfall are the main causes of drought in the Umbrian region which saw Lake Trasimeno’s drop 1.3 m, reaching the limit of the hydrometric zero in July 2022."



Video/Image Credit: ESA&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Lake Trasimeno in Central Italy

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