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;



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

Star-shaped cities scattered across Europe

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

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



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



—--



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/">Eric Ralls</a> and <a href="https://www.earth.com/">Earth.com</a>.

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

Today's Image of the Day from NASA Earth Observatory features a satellite view of retreating glaciers in Alaska, where meltwater is rapidly expanding glacial lakes. The image was captured on August 4, 2024 by the Landsat 8 satellite.



“In parts of Alaska, water is replacing ice. As glaciers thin and <a href="https://www.earth.com/news/satellite-images-reveal-hidden-retreat-of-arctic-glaciers/" target="_blank" rel="noreferrer noopener">retreat</a>, meltwater collects at their fronts, forming proglacial lakes. According to an analysis by Mauri Pelto, a glaciologist at Nichols College, three such lakes in the southeastern part of the state have grown rapidly in recent decades,” said <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>.



<h2 class="wp-block-heading" id="h-retreating-glaciers-in-alaska">Retreating glaciers in Alaska</h2>



“A trio of glaciers - Yakutat, Alsek, and Grand Plateau - descend from inland mountains and flow onto the coastal plain southeast of Yakutat borough, ending at Harlequin Lake, Alsek Lake, and Grand Plateau Lake,” noted NASA.&nbsp;



The retreat of the glaciers, as well as the growth of the lakes, are visible in the image. When compared to an <a href="https://eoimages.gsfc.nasa.gov/images/imagerecords/153000/153638/fastestlake_tm5_19840705_lrg.jpg" target="_blank" rel="noreferrer noopener">image</a> captured by Landsat 5 in the summer of 1984, the changes are even more evident.



NASA elaborated on the extent of the glacier retreat from 1984 to 2024. “During this period, Yakutat Glacier’s main arm retreated 4.3 miles, while Alsek Glacier’s northern and southern arms retreated 3.3 miles and 3.4 miles, respectively. Grand Plateau Glacier’s northern arm lost the most, retreating 4.8 miles.”



<h2 class="wp-block-heading" id="h-glacial-lakes-doubled-in-size-nbsp">Glacial lakes doubled in size&nbsp;</h2>



“Collectively, the three lakes more than doubled in size over 40 years. In 1984, they covered about 50 square miles. By 2024, they spanned 90 square miles. That’s an area larger than Seneca Lake (67 square miles) - one of the Finger Lakes in New York, which also have a glacial origin,” said NASA.



Pelto noted that the lakes forming in this region are immense - starting at the mountains and spreading toward the coast - making this a new lake district that is unique in our nation.



“Millions of other lakes, named and unnamed, dot the state. But this system has grown fast, so much so that Pelto thinks it might represent the fastest lake growth in the United States this century,” said NASA.



<h2 class="wp-block-heading" id="h-understanding-glacier-retreat-nbsp">Understanding glacier retreat&nbsp;</h2>



Glacier retreat is a significant phenomenon driven primarily by global warming the results from rising greenhouse gas <a href="https://www.earth.com/news/global-carbon-dioxide-emissions-hit-a-record-high-in-2023/" target="_blank" rel="noreferrer noopener">emissions</a>.&nbsp;



As temperatures rise, glaciers lose more ice during the summer melt than they can regain in winter snowfall, causing them to shrink over time. This process has profound implications for ecosystems, water resources, and global sea levels.



<h3 class="wp-block-heading" id="h-glacial-lakes">Glacial lakes</h3>



When glaciers retreat, they often leave behind depressions in the landscape that can fill with meltwater, forming glacial lakes. These lakes are typically bounded by natural dams made of rock, ice, or moraine - accumulations of debris left behind by the glacier's movement.&nbsp;



Over the past century, the number and size of glacial lakes worldwide have increased significantly due to the accelerating pace of <a href="https://www.earth.com/news/tropical-glaciers-offer-a-glimpse-of-our-harsh-climate-reality/" target="_blank" rel="noreferrer noopener">glacier</a> retreat. This trend is especially evident in high-altitude regions like the Himalayas, the Andes, and the Alps, as well as in polar areas such as Alaska and Greenland.



<h3 class="wp-block-heading" id="h-positive-and-negative-impacts-nbsp">Positive and negative impacts&nbsp;</h3>



Glacial lakes can have both positive and negative impacts. They provide critical water sources for downstream communities, support biodiversity, and sometimes offer opportunities for hydropower development or tourism.&nbsp;



However, they also pose serious risks. The dams holding back these lakes can fail suddenly, causing glacial lake outburst floods (GLOFs). These catastrophic events can devastate downstream areas, destroying infrastructure, agricultural lands, and habitats while endangering human lives.



<h3 class="wp-block-heading" id="h-monitoring-changes">Monitoring changes</h3>



Understanding glacier retreat and glacial lake formation requires a multidisciplinary approach, combining climate science, hydrology, and geology.&nbsp;



Monitoring these changes is essential to mitigate associated risks and adapt to the evolving landscape shaped by a <a href="https://search.app?link=https%3A%2F%2Fwww.earth.com%2Fnews%2Fperu-has-lost-over-half-of-its-glaciers-in-six-decades%2F&amp;utm_campaign=aga&amp;utm_source=agsadl2%2Csh%2Fx%2Fgs%2Fm2%2F4" target="_blank" rel="noreferrer noopener">warming planet</a>.



<h2 class="wp-block-heading" id="h-glacier-retreat-worldwide">Glacier retreat worldwide</h2>



Studies and satellite observations show that most glaciers in almost all regions of the world are shrinking.&nbsp;



Melting glaciers contribute significantly to global <a href="https://www.earth.com/news/emergency-meeting-reveals-the-alarming-extent-of-antarcticas-ice-loss/" target="_blank" rel="noreferrer noopener">sea level rise</a>, which threatens coastal communities and ecosystems.



The retreat of glaciers is considered one of the clearest indicators of climate change.&nbsp;Some glaciers are retreating at unprecedented rates, indicating accelerating climate impacts.



Image Credit: NASA Earth Observatory



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

Retreating glaciers and expanding meltwater lakes in Alaska

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

Today's Image of the Day from NASA Earth Observatory features the Gobi Altai Mountains and neighboring plains covered in snow and illuminated by sunlight. 



The photograph was captured on January 25, 2024 as the International Space Station (ISS) passed over central Mongolia.



<h2 class="wp-block-heading" id="h-mountain-peaks-and-plains">Mountain peaks and plains</h2>



“Late-afternoon sunlight casts long shadows of mountain peaks onto the plains below. Numerous steep gullies cut into the massif, or mass of mountains, whose rugged appearance contrasts with the flat plains stretching along the top of the image,” said <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>. “The plains are a semidesert grassland, or steppe, which provides pasture for livestock herders in the region.”



“The grassland surrounding the massif is classified by scientists as a cold semidesert. At an elevation of about 1,250 meters, annual temperatures are much lower there than in the mountains. The highest peak in the massif, Ikh Bogd (also known as Tergun Bogd), reaches nearly 4,000 meters.”&nbsp;



According to NASA, the climate on the peaks is classified as a polar tundra because the average annual temperature is below freezing. "Asia’s main tundra zone is located in Siberia, along the coast of the Arctic Ocean, 2,800 kilometers (1,750 miles) to the north.”



<h2 class="wp-block-heading" id="h-harsh-winters-and-livestock-in-mongolia">Harsh winters and livestock in Mongolia</h2>



Harsh <a href="https://www.earth.com/news/why-winters-are-getting-colder-while-world-is-getting-warmer/" target="_blank" rel="noreferrer noopener">winters</a> in Mongolia, locally known as "dzud," pose significant challenges for livestock and the herders who depend on them for their livelihood. These winters can be particularly severe, characterized by extreme cold, heavy snowfall, and ice, which can block access to grazing grounds, leaving animals without enough food.&nbsp;



The cold temperatures and nutritional shortages result in high mortality rates among livestock, which are crucial to the Mongolian economy and the nomadic lifestyle of many of its people.



The impact of these harsh winters extends beyond immediate animal welfare. As <a href="https://www.earth.com/news/bacteria-in-livestock-are-major-drivers-of-antibiotic-resistance/" target="_blank" rel="noreferrer noopener">livestock</a> numbers dwindle, herders face financial hardships, and the ripple effects can be felt throughout the entire community.&nbsp;



To combat these challenges, various strategies have been employed, including the development of better forecasting and early warning systems, the stockpiling of fodder, and improved veterinary care. These measures aim to strengthen the resilience of herding communities and ensure the survival of their livestock during Mongolia's most challenging seasons.



<h2 class="wp-block-heading" id="h-diverse-wildlife-of-mongolia">Diverse wildlife of Mongolia</h2>



Mongolia is renowned for its diverse wildlife, adapted to its unique landscapes ranging from vast steppes to rugged <a href="https://www.earth.com/news/mountains-both-carbon-sinks-and-carbon-sources/" target="_blank" rel="noreferrer noopener">mountains</a> and arid deserts. Among the most iconic species is the Bactrian camel, native to the region and crucial to nomadic herders.&nbsp;



The resilient Mongolian horse, integral to local culture, is celebrated for its endurance across the vast, open landscapes. Predators such as the snow leopard roam the high altitudes, playing a key role in the ecosystem, while the elusive Gobi bear survives in the sparse vegetation of the Gobi Desert.



The steppes are home to the fast-moving Mongolian gazelle and the critically endangered saiga antelope, known for its distinctive nose. The mountains support populations of argali sheep, the world's largest wild sheep, and the ibex, which has mastered the art of navigating rocky terrains. 



<h2 class="wp-block-heading" id="h-valley-of-lakes">Valley of Lakes</h2>



“Part of a small dry lake appears in the top left of the image. In wetter years, water from this lake feeds Orog Lake (also photographed by astronauts), out of frame to the upper right. This and other nearby lakes are part of the Valley of Lakes waterfowl conservation habitat, protected as a Ramsar site,” noted NASA.



The Valley of Lakes is known for its expansive <a href="https://www.earth.com/news/the-potential-of-tidal-wetlands-as-blue-carbon-ecosystems/" target="_blank" rel="noreferrer noopener">wetlands</a> and diverse ecosystems that support a variety of bird species, especially migratory waterfowl. This area serves as a crucial stopover for birds during their migration periods, providing them with essential resources such as food and shelter.&nbsp;



The conservation efforts in the Valley of Lakes focus on maintaining and restoring these <a href="https://www.earth.com/news/coastal-wetlands-are-inching-closer-to-extinction-as-the-world-heats-up/" target="_blank" rel="noreferrer noopener">wetlands</a> to ensure they continue to offer a safe haven for waterfowl. These efforts include controlling invasive plant species that threaten the natural vegetation and managing water levels to create optimal conditions for bird populations.&nbsp;



Education and community involvement are also key components of the conservation strategy, aiming to raise awareness about the importance of these habitats and encourage sustainable practices that help protect the local wildlife.



Image Credit: NASA Earth Observatory&nbsp;



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

Mountain peaks and plains of central Mongolia 

Today's Image of the Day from the European Space Agency features the barred spiral galaxy NGC 1559, located around 35 million light-years away in the southern constellation Reticulum. The image was captured by the James Webb Space Telescope. 



<h2 class="wp-block-heading" id="h-fuel-for-star-formation">Fuel for star formation </h2>



"The data featured in this portrait make use of two of Webb’s instruments: the Mid-InfraRed Instrument (MIRI) and Near-InfraRed Camera (NIRCam)," noted <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.



"Here MIRI captures the glow of interstellar dust grains, which trace out the interstellar medium, the fuel for future star formation. NIRCam shows the light from stars, even young stars hidden behind prodigious amounts of dust. NIRCam also captures emission from ionised nebulae around young stars."



<h2 class="wp-block-heading" id="h-webb-reveals-galaxies-in-new-light">Webb reveals galaxies in new light</h2>



According to ESA, the data was collected by the <a href="https://sites.google.com/view/phangs/home">PHANGS team</a> as part of a program in which Webb will observe 55 <a href="https://www.earth.com/news/james-webb-captures-galaxies-that-are-too-old-to-exist/">galaxies</a> that have also been mapped by the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope, the Hubble Space Telescope, and more.&nbsp;



"By combining Webb’s unprecedented view of the dust and stars with data from these other facilities, the team aims to obtain a new, highly detailed view of how stars are born, live, and die in galaxies across the Universe."



<h2 class="wp-block-heading" id="h-ngc-1559-a-loner-in-space">NGC 1559: A loner in space</h2>



Although NGC 1559 appears to sit close to one of our nearest neighbors in the sky - the Large Magellanic Cloud (LMC) - this is just a trick of perspective, noted ESA.



While it is part of the Reticulum constellation, NGC 1559 is not part of the Local Group of galaxies but instead resides in a more distant region of space.



"In reality, NGC 1559 is physically nowhere near the LMC in space; in fact it truly is a loner, lacking the company of any nearby galaxies or membership of any galaxy cluster."



<h2 class="wp-block-heading" id="h-star-formation-in-ngc-1559">Star formation in NGC 1559</h2>



NGC 1559 is notable for its active star formation and strong magnetic fields. It has also been the site of several <a href="https://www.earth.com/news/supernova-explosions-could-damage-distant-planets/" target="_blank" rel="noreferrer noopener">supernovae</a>, making it of particular interest to astronomers studying stellar evolution and the lifecycle of stars.



The structure of NGC 1559 includes well-defined spiral arms that are rich in young, hot stars and regions of ionized gas, indicative of ongoing <a href="https://www.earth.com/news/black-hole-is-starving-its-host-galaxy-of-star-forming-fuel/" target="_blank" rel="noreferrer noopener">star formation</a>.



The galaxy’s central bar is believed to play a role in driving gas towards the core, fueling both the star formation and the activity around its nucleus.



<h2 class="wp-block-heading" id="h-an-extragalactic-wonder">An extragalactic wonder</h2>



Despite being relatively small compared to larger galaxies like the Milky Way, NGC 1559 is an important object for understanding how barred spiral galaxies evolve and the processes that trigger supernovae.



The galaxy’s remote location and active nature make it a fascinating subject of study in the field of extragalactic astronomy. The isolation of NGC 1559 allows for a clearer view of its structure without much interference from neighboring galaxies.



<h2 class="wp-block-heading" id="h-barred-spiral-galaxies">Barred spiral galaxies</h2>



Barred spiral galaxies are a type of spiral galaxy characterized by a central bar-shaped structure composed of stars. This bar extends out from the core and connects to the galaxy's spiral arms, which swirl outward in a graceful pattern.



Scientists believe that the bar plays a crucial role in the evolution of the galaxy, funneling gas towards the core and potentially triggering star formation or feeding a central black hole. 



The <a href="https://www.earth.com/news/newly-discovered-stars-milky-way-are-old-as-universe/" target="_blank" rel="noreferrer noopener">Milky Way</a>, our own galaxy, is an example of a barred spiral. These galaxies are quite common in the universe, making up about two-thirds of all observed spiral galaxies.



The bar itself is thought to be a temporary feature, developing as the galaxy matures and possibly disappearing over time as the dynamics of the stars change. 



<h2 class="wp-block-heading" id="h-the-reticulum-constellation">The Reticulum constellation</h2>



The Reticulum constellation is a small, faint constellation in the southern sky. Its name means "the reticle" in Latin, which refers to the crosshairs in an eyepiece of a telescope. 



The constellation was named in the 18th century by the French astronomer Nicolas Louis de Lacaille to honor the reticle he used in his scientific instruments. It is one of the 88 modern constellations recognized by the International Astronomical Union.



Image Credit: ESA/Webb, NASA &amp; CSA, A. Leroy, J. Lee and the PHANGS Team



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

Spiral galaxy NGC 1559 is a loner in outer space

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.



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.&nbsp;



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.earth.com/author/eralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

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>



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.earth.com/author/eralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

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>.



-----



Like what you read? <a href="https://www.earth.com/subscribe/" target="_blank" rel="noreferrer noopener">Subscribe to our newsletter</a> for engaging articles, exclusive content, and the latest updates.



Check us out on <a href="https://www.earth.com/earthsnap/" target="_blank" rel="noreferrer noopener">EarthSnap</a>, a free app brought to you by <a href="https://www.linkedin.com/in/eric-ralls/" target="_blank" rel="noreferrer noopener">Eric Ralls</a> and Earth.com.



-----

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

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

<div id="58e3ebce955a315103d39bd1" class="vdb_player vdb_58e3ebce955a315103d39bd158d96b98cd4fed198a0d2a49" data-placeholder="//img.vidible.tv/prod/2021-06/25/60d5eb93671aa54b253e4b62/60d5ecc3beaecd00013919ed_768x432_FES_v1.jpg?w=1600&amp;h=900&amp;q=60"><script src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" type="text/javascript"></script></div>
 
Lake Mar Chiquita in Argentina Today&#8217;s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Mar Chiquita, South America&#8217;s largest salt lake. Mar Chiquita is a protected wilderness area in the northeast province of Córdoba, Argentina.
The lake is around 70 kilometers long and 24 kilometers wide. It is fed by the Primero and Segundo rivers from the southwest, and by the Dulce river from the north. 
Even though water flows in, there is no outlet for water to flow out of the lake. This makes Lake Mar Chiquita an endorheic lake that only loses water through evaporation. Lake Mar Chiquita, saline lake at the southern edge of the Gran Chaco in northeastern Córdoba provincia (province), north-central Argentina. It is about 45 miles (70 km) long and 15 miles (24 km) wide with an area of almost 775 square miles (2,000 square km). Lake Mar Chiquita is fed by the rivers
According to ESA, the lake’s surface area, as well as its salinity, varies considerably between 2,000 and 6,000 square kilometers &#8211; although it is slowly diminishing in size owing to evaporation.
Lake Mar Chiquita contains several small islands, including is El Médano, and is surrounded by salt marshes on its northern shore.
Video Credit: ESA 
&#8211;&#8212;
By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer