Today's Image of the Day from the European Space Agency features a pair of interacting spiral galaxies known as the Antennae Galaxies. They are located approximately 45 million light-years away in the constellation Corvus.&nbsp;



<h2 class="wp-block-heading" id="h-antennae-galaxies-in-a-deadly-embrace">Antennae Galaxies in a deadly embrace </h2>



“The NASA/ESA Hubble Space Telescope has snapped the best ever image of the Antennae Galaxies. Hubble has released images of these stunning galaxies twice before, once using observations from its Wide Field and Planetary Camera 2 (WFPC2) in 1997, and again in 2006 from the Advanced Camera for Surveys (ACS),” noted <a href="https://esahubble.org/images/potw1345a/" target="_blank" rel="noreferrer noopener">ESA</a>.



“The galaxies - also known as NGC 4038 and NGC 4039 - are locked in a deadly embrace. Once normal, sedate spiral galaxies like the Milky Way, the pair have spent the past few hundred million years sparring with one another.”



According to ESA, the clash of the Antennae Galaxies is so violent that stars have been ripped from their host <a href="https://www.earth.com/news/galaxy-collision-2-million-mph-stephans-quintet-captured-unprecedented-detail/" target="_blank" rel="noreferrer noopener">galaxies</a> to form a streaming arc between the two.&nbsp;



The name "Antennae" comes from this long stream of stars and gas, which resembles insect antennae.



<h2 class="wp-block-heading" id="h-intense-bursts-of-star-formation-nbsp">Intense bursts of star formation&nbsp;</h2>



The collision has triggered intense bursts of star formation, making the Antennae Galaxies one of the nearest and most dramatic examples of a starburst galaxy.&nbsp;



Many of the newly formed stars are concentrated in massive star clusters, some of which are expected to evolve into globular clusters over millions of years.



“This new image of the Antennae Galaxies shows obvious signs of chaos. Clouds of gas are seen in bright pink and red, surrounding the bright flashes of blue star-forming regions - some of which are partially obscured by dark patches of dust,” explained ESA.



“The rate of star formation is so high that the Antennae Galaxies are said to be in a state of starburst, a period in which all of the gas within the galaxies is being used to form stars.”&nbsp;



“This cannot last forever and neither can the separate galaxies; eventually the nuclei will coalesce, and the galaxies will begin their retirement together as one large elliptical galaxy.”



<h2 class="wp-block-heading" id="h-significance-of-the-antennae-galaxies">Significance of the Antennae Galaxies</h2>



The Antennae Galaxies are one of the most well-studied examples of galaxy collisions, offering insight into the processes that shape galaxies over time.



Astronomers study the Antennae Galaxies using a range of telescopes across different wavelengths, including visible light, infrared, and X-rays.&nbsp;



Observations in X-rays have revealed evidence of supernovae and <a href="https://www.earth.com/news/black-holes-may-talk-to-galaxies-through-energetic-winds/" target="_blank" rel="noreferrer noopener">black holes</a>, while infrared studies highlight regions of dust and star formation.&nbsp;



<h2 class="wp-block-heading" id="h-the-milky-way-s-collision-course-nbsp">The Milky Way's collision course&nbsp;</h2>



The Antennae Galaxies provide a glimpse into the future of our <a href="https://www.earth.com/news/uma3-u1-faintest-star-system-found-orbiting-milky-way-galaxy/" target="_blank" rel="noreferrer noopener">Milky Way</a>, which is expected to eventually merge with the Andromeda Galaxy - our closest spiral galaxy neighbor.



The cosmic collision course of the Milky Way and Andromeda will reshape both galaxies over billions of years.&nbsp;



This event is expected to occur in about 4.5 billion years. Both galaxies are part of the Local Group, a cluster of galaxies bound together by gravity. Their mutual gravitational pull is drawing them closer at a speed of approximately 110 kilometers per second.



<h2 class="wp-block-heading" id="h-the-birth-of-an-elliptical-galaxy-nbsp">The birth of an elliptical galaxy&nbsp;</h2>



When the two galaxies collide, their individual stars will largely avoid direct collisions due to the vast distances between them. However, the gravitational forces involved will create dramatic effects.&nbsp;



These forces will distort the galaxies' <a href="https://www.earth.com/news/shapes-of-one-million-galaxies-hint-at-the-universes-origins/" target="_blank" rel="noreferrer noopener">shapes</a>, triggering intense bursts of star formation as gas clouds collide and compress. Over time, the galaxies will settle into a new, larger elliptical galaxy often referred to as "Milkomeda" or "Milkdromeda" by astronomers.



<h2 class="wp-block-heading" id="h-galaxy-merger-and-the-solar-system">Galaxy merger and the solar system</h2>



Despite the seemingly destructive nature of the collision, the solar system is unlikely to face direct harm. Our Sun may find itself flung into a new orbit within the merged galaxy or even cast into intergalactic space.&nbsp;



The merger will also significantly alter the night sky, with the Andromeda Galaxy becoming increasingly prominent before blending into the unified structure.



This event is part of the natural <a href="https://www.earth.com/news/galaxies-are-much-bigger-than-we-originally-believed-gas-clouds/" target="_blank" rel="noreferrer noopener">evolution of galaxies</a> and serves as a fascinating reminder of the dynamic and ever-changing nature of the universe. 



While the collision is still billions of years away, studying it helps astronomers understand galactic interactions and the long-term future of our cosmic neighborhood.



Image Credit: ESA/Hubble &amp; NASA



-----



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.



-----

The violent clash of the Antennae Galaxies  

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

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 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 

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">Tracking iceberg movements</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 <a href="https://www.bas.ac.uk/" target="_blank" rel="noreferrer noopener">British Antarctic Survey</a>.



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-importance-of-antarctic-ice-shelves">Importance of Antarctic ice shelves</h2>



These massive floating ice platforms act as natural barriers, holding back glaciers from flowing too quickly into the ocean, while playing a crucial role in our planet's climate system.



By doing this, they help regulate sea levels and prevent dramatic rises that could flood coastal communities around the world. 



Additionally, ice shelves influence <a href="https://www.earth.com/news/antarctica-ice-shelves-melting-faster-due-to-ocean-currents/" target="_blank" rel="noreferrer noopener">ocean currents</a> and the global climate by interacting with surrounding water and air, helping to maintain temperature and weather patterns. 



Without these ice shelves, we could see much faster ice loss from the Antarctic, leading to significant changes in our global climate.



Beyond their impact on climate, <a href="https://www.earth.com/news/antarctic-ice-shelves-are-fracturing-from-meltwater-weight/" target="_blank" rel="noreferrer noopener">Antarctic ice shelves</a> are vital indicators of environmental health. Scientists closely monitor these ice structures to understand the effects of global warming and to predict future changes in ice behavior. 



When ice shelves start to thin or collapse, it signals shifts in climate trends, providing valuable data for researchers working on climate models and sea-level rise projections.



Moreover, the areas beneath and around ice shelves host unique marine ecosystems that support a variety of wildlife, contributing to Earth’s biodiversity. 



<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.



-----



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.



-----

World’s largest iceberg breaks free from ocean cyclone

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

Parker,Solar,Probe,Near,The,Sun.,Elements,Of,This,Image

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. 



To approach the sun so closely, the Parker Solar Probe had to withstand extreme heat and intense radiation like no other spacecraft before it. 



"It is breaking all of these records and it's a, just a total 'Yay! We did it!' moment," <a href="https://science.nasa.gov/people/nicola-fox/" target="_blank" rel="noreferrer noopener">Nicola Fox</a>, the associate administrator for NASA Science Mission Directorate, said in a <a href="https://x.com/NASASun/status/1871524544306909200" target="_blank" rel="noreferrer noopener">video</a> on Dec. 24.



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



Scientists won’t know if Parker survived or what condition it’s in until Friday, when it's expected to send its first signal back to Earth since its close fly-by. Lots of fingers will remain crossed until then.



<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.



-----



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.



-----

Solar Probe touched the Sun, now scientists wait for a signal and "proof of life"

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

Scientists have long looked to oxygen when searching for signs of life beyond Earth. This gas sustains breathing and enables animals and plants to flourish. Now, researchers suggest that oxygen might also point to advanced technology. 



If an exoplanet’s atmosphere holds enough oxygen, it may not only support organisms but also help them spark fire, build structures, and craft machinery.



A study in Nature Astronomy presents this view, highlighting oxygen’s value as more than just a sign of biology. 



<h2 class="wp-block-heading" id="h-oxygen-civilization-and-technology">Oxygen, civilization, and technology</h2>



Leading this research are <a href="https://www.pas.rochester.edu/people/faculty/frank_adam/index.html" target="_blank" rel="noreferrer noopener">Adam Frank</a>, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy at the University of Rochester, and <a href="https://www-en.fisica.uniroma2.it/phone-directory/balbia_en/" target="_blank" rel="noreferrer noopener">Amedeo Balbi</a>, an associate professor of astronomy and astrophysics at the University of Roma Tor Vergata, Italy.



Together with their team, they set out to explore whether oxygen is a key factor in allowing extraterrestrial civilizations to emerge and thrive through the development of technology.



“We are ready to find signatures of life on alien worlds,” Frank says. “But how do the [oxygen] conditions on a planet tell us about the possibilities for intelligent, technology-producing life?” 



This question drives efforts to examine oxygen’s role beyond respiration and metabolism, especially in relation to large-scale industrial activities.



<h2 class="wp-block-heading" id="h-why-oxygen-matters-for-civilizations">Why oxygen matters for civilizations</h2>



<a href="https://www.earth.com/news/animal-cells-capable-of-photosynthesis-created-for-the-first-time/" target="_blank" rel="noreferrer noopener">Photosynthesis</a> on Earth accounts for the bulk of our oxygen on our planet, thanks to countless organisms that use sunlight to make food. 



Because this process produces so much oxygen, it has been considered a biosignature. A planet with significant oxygen levels hints that life may be present, but Frank and Balbi argue that oxygen also has a second function.



“<a href="https://www.nature.com/articles/s41550-023-02112-8" target="_blank" rel="noreferrer noopener">In our paper</a>, we explore whether any atmospheric composition would be compatible with the presence of advanced technology,” Balbi says. “We found that the atmospheric requirements may be quite stringent.”



The link to technology comes from open-air combustion. Smelting metals, cooking food, and powering engines all rely on oxygen. 



Any alien civilization that forges metals would need a certain percentage of oxygen in its air to keep fires burning reliably. That percentage, according to Earth’s history, appears to be around 18 percent.



<h2 class="wp-block-heading" id="h-fire-and-the-18-threshold">Fire and the 18% threshold</h2>



“You might be able to get biology -- you might even be able to get intelligent creatures -- in a world that doesn’t have oxygen,” Frank says, “but without a ready source of fire, you’re never going to develop higher technology because higher technology requires fuel and melting.” 



He calls attention to fire’s role in shaping tools, infrastructure, and <a href="https://www.earth.com/news/human-wellbeing-is-a-more-effective-focus-area-when-discussing-energy-solutions/" target="_blank" rel="noreferrer noopener">energy production</a>. Metalworking, for instance, depends on sustaining flames hot enough to melt ore and craft refined structures.



Frank and Balbi refer to this requirement as an “oxygen bottleneck.” A planet might host life forms of various kinds, yet remain stuck without the combustion needed to fuel industrial breakthroughs. 



“The presence of high degrees of oxygen in the atmosphere is like a bottleneck you have to get through in order to have a technological species,” Frank says. 



“You can have everything else work out, but if you don’t have <a href="https://www.earth.com/news/it-took-200-million-years-for-earth-to-get-its-oxygen/" target="_blank" rel="noreferrer noopener">oxygen in the atmosphere</a>, you’re not going to have a technological species.”



<h2 class="wp-block-heading" id="h-oxygen-technology-create-technosignatures">Oxygen + technology create "technosignatures"</h2>



Frank thinks that exoplanets with oxygen levels at or above 18 percent should be at the top of our search list. 



“Targeting planets with high oxygen levels should be prioritized because the presence or absence of high oxygen levels in exoplanet atmospheres could be a major clue in finding potential technosignatures,” Frank says. 



Planets that exceed this level may have the capacity for factories, infrastructure, or communication networks.



Balbi notes that interpreting any possible signal of intelligent life will be challenging. 



“The implications of discovering intelligent, technological life on another planet would be huge,” adds Balbi. “Therefore, we need to be extremely cautious in interpreting possible detections. 



Their study suggests that astronomers should be skeptical of potential technosignatures from a planet with insufficient <a href="https://www.earth.com/news/earths-ancient-breath-study-links-atmospheric-oxygen-and-mantle-chemistry/" target="_blank" rel="noreferrer noopener">atmospheric oxygen</a>.



<h2 class="wp-block-heading" id="h-technosphere-vs-biotechnosphere">Technosphere vs. biotechnosphere</h2>



Frank and Balbi’s perspective also covers the idea of a technosphere, which is the collective output of an advanced civilization. 



Factories, vehicles, and power grids all fit under this label. They rely on resources provided by the planet’s biosphere but stretch beyond purely natural processes. 



<a href="https://www.earth.com/news/bronze-age-technology-is-a-modern-solution-for-clean-energy/" target="_blank" rel="noreferrer noopener">Burning fuels in open air</a> has been central to every major industrial leap, from forging steel to generating electricity.



When these technologies reach a global scale, they form a biotechnosphere. This term applies to the interplay of living systems and technology -- essentially, how organisms and machines coexist. 



On Earth, that includes everything from smartphones to farms, all running side by side. A well-established biotechnosphere might produce clear signals in the atmosphere: waste gases, <a href="https://www.earth.com/news/mapping-2024s-record-heat-unveiling-earths-climate-danger-zones/" target="_blank" rel="noreferrer noopener">unusual heat patterns</a>, or <a href="https://www.earth.com/news/forever-chemicals-found-in-tap-and-bottled-water-worldwide/" target="_blank" rel="noreferrer noopener">chemicals not normally found in nature</a>.



<h2 class="wp-block-heading" id="h-balancing-machines-and-ecosystems">Balancing machines and ecosystems</h2>



History shows that as technology expands, it can sometimes damage or alter environments. Factories might pump pollutants into the air, while deforestation removes habitats that produce oxygen. 



Yet there is an ongoing move toward cleaner energy and more efficient resource use. If any alien civilization follows a similar path, we might detect certain byproducts in the form of <a href="https://www.earth.com/news/2023-climate-change-report-record-high-temperatures-greenhouse-gases-sea-level-rise/" target="_blank" rel="noreferrer noopener">greenhouse gases</a> or <a href="https://www.earth.com/news/banning-forever-chemicals-may-threaten-us-national-security/" target="_blank" rel="noreferrer noopener">engineered molecules</a>.



Though the focus is on oxygen, other factors matter too, such as temperature and access to metals or fuels. A planet may need stable conditions for life to progress to a point where industry becomes possible.



That said, Frank and Balbi’s findings highlight how oxygen stands out among these factors, because it directly enables combustion processes.



<h2 class="wp-block-heading" id="h-fire-and-progress-in-earth-s-past">Fire and progress in Earth’s past</h2>



Earth’s own development through advances in technology offers insight into how vital oxygen has been for technical achievements.



Once our atmosphere had enough of it, humans learned to manipulate fire for cooking and for <a href="https://www.earth.com/news/worlds-oldest-wooden-structure-completely-rewrites-early-human-history/" target="_blank" rel="noreferrer noopener">making stronger materials</a>. 



From simple smithing to modern manufacturing, every stage of growth involved open-air combustion.



“You can have everything else work out, but if you don’t have oxygen in the atmosphere, you’re not going to have a technological species,” Frank says. 



This idea underlines how a single factor -- oxygen -- can open or close the door to industrial progress, altering a <a href="https://www.earth.com/news/decarbonizing-worlds-industrial-emissions-possible-with-current-technology/" target="_blank" rel="noreferrer noopener">planet’s entire future path</a>.



<h2 class="wp-block-heading" id="h-oxygen-technology-and-next-steps">Oxygen, technology, and next steps</h2>



Observatories now in the works may soon gather data about exoplanet atmospheres in detail. Detecting a high oxygen content could mark a world that supports advanced living organisms. 



The next task is to look for proof of industry or technology, sometimes called technosignatures. These might appear as chemical emissions, <a href="https://www.earth.com/news/deep-space-radio-signal-reaches-earth-after-8-billion-years-frb-20220610a/" target="_blank" rel="noreferrer noopener">radio signals</a>, or specific spectral lines.



If these two checks-- oxygen above 18 percent and evidence of artificial activity -- both yield results, we will have a strong indication that we share the universe with another technological civilization. 



That reality could reshape how we see ourselves and our place among the stars.



<h2 class="wp-block-heading" id="h-why-does-any-of-this-matter-0">Why does any of this matter?</h2>



Understanding the significance of atmospheric oxygen can also inspire reflection on our home planet. Human industries <a href="https://www.earth.com/news/air-pollution-from-fossil-fuels-kills-5-million-people-each-year/" target="_blank" rel="noreferrer noopener">rely heavily on combustion</a>, from running cars to powering factories. This has changed Earth’s ecosystems. 



As we learn more about how oxygen in an atmosphere enables or limits technology, we might gain new ideas on how to manage our own balance between growth and <a href="https://www.earth.com/news/un-report-calls-for-global-change-to-stop-biodiversity-loss/" target="_blank" rel="noreferrer noopener">environmental health</a>.



Ultimately, Frank and Balbi’s argument shows that oxygen may do far more than keep living cells alive. It might be the clearest signal of whether a planet can support the technologies that shape modern societies. 



By recognizing the 18 percent threshold, scientists can refine their search for advanced life and possibly move closer to answering the age-old question: Are we alone, or is someone else using fire to reshape their world?



The full study was published in the journal <a href="https://www.nature.com/articles/s41550-023-02112-8" target="_blank" rel="noreferrer noopener">Nature Astronomy</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.



-----

Oxygen levels on exoplanets reveal presence of alien technology

Scientists have long looked to oxygen when searching for signs...

<div class="vdb_player vdb_591c9e3c9efa894c3c6e150b58d96b98cd4fed198a0d2a49">
</div>

Today’s Video of the Day comes thanks to <a href="http://www.esa.int/">European Space Agency</a> astronaut Thomas Pesquet on board the International Space Station. The clip features a breathtaking look at the stars and city lights on Earth at night.
&#8220;Stars and city lights revolve and seem to form from a point behind the green <a href="https://www.earth.com/news/antacids-atmosphere-global-warming/">atmosphere</a> of our planet,” Pesquet commented.
Pesquet will be on the International Space Station for six months while he completes his Proxima mission.
&#8212;
By <a href="mailto:rarnold@earth.com">Rory Arnold</a>, <a href="https://www.earth.com/staff">Earth.com</a>
Source: <a href="http://www.esa.int/spaceinvideos/Videos/2017/05/Stars_and_city_lights">ESA</a>

Stars and city lights on Earth at night