<p>Today's Image of the Day from the European Space Agency features UGC 5460, a spiral galaxy that is located about 60 million light-years away in the constellation Ursa Major.&nbsp;</p>



<p>“This image combines four different wavelengths of light to reveal UGC 5460’s central bar of stars, winding spiral arms and bright blue star clusters. Also captured in the upper left-hand corner of this image is a far closer object: a star just 577 light-years away in our own galaxy,” said <a href="https://www.esa.int/ESA_Multimedia/Images" target="_blank" rel="noreferrer noopener">ESA</a>.</p>



<p>“UGC 5460 has hosted two recent supernovae named SN 2011ht and SN 2015as. It’s because of these two stellar explosions that Hubble targeted this galaxy, collecting data for three observing programmes that aim to study various kinds of supernovae.”&nbsp;</p>



<h2 class="wp-block-heading" id="h-a-core-collapse-supernova-nbsp">A core-collapse supernova&nbsp;</h2>



<p>SN 2015as is an example of a core-collapse supernova. This type of <a href="https://www.earth.com/news/supernova-explosions-could-damage-distant-planets/" target="_blank" rel="noreferrer noopener">supernova</a> occurs when the core of a massive star - typically with more than 8 times the mass of the sun - can no longer support its own gravity after exhausting its nuclear fuel. </p>



<p>This causes the core to collapse under its own weight, leading to an extremely violent explosion. The collapse triggers the release of an enormous amount of energy, expelling the outer layers of the star into space.</p>



<p>In the aftermath of the explosion, a dense <a href="https://www.earth.com/news/shockingly-bright-carbon-monoxide-detected-in-supernova-remnant/" target="_blank" rel="noreferrer noopener">remnant</a> is created. This is often a neutron star or black hole, depending on the mass of the original star. Core-collapse supernovae are some of the most powerful events in the universe.</p>



<p>According to ESA, Hubble observations of SN 2015as will help researchers understand what happens when the expanding shockwave of a <a href="https://www.earth.com/news/supernova-dandelion-year-1181-leaves-behind-zombie-star-defying-death/" target="_blank" rel="noreferrer noopener">supernova</a> collides with the gas that surrounds the exploded star.</p>



<h2 class="wp-block-heading" id="h-rare-stars-with-large-eruptions-nbsp">Rare stars with large eruptions&nbsp;</h2>



<p>“SN 2011ht might have been a core-collapse supernova as well, but it could also be an impostor called a luminous blue variable. Luminous blue variables are rare stars that experience eruptions so large that they can mimic supernovae,” noted ESA.</p>



<p>“Crucially, luminous blue variables emerge from these eruptions unscathed, while stars that go supernova do not. Hubble will search for a stellar survivor at SN 2011ht’s location, and the explosion’s identity may be revealed at last.”</p>



<h2 class="wp-block-heading" id="h-what-is-a-spiral-galaxy">What is a spiral galaxy?</h2>



<p>Spiral galaxies are some of the most recognizable and beautiful structures in the universe. They are known for their distinctive arms that spiral outward from a central bulge.&nbsp;</p>



<p>These galaxies are typically composed of stars, gas, dust, and dark matter. The arms are often sites of intense <a href="https://www.earth.com/news/fluffy-molecular-clouds-may-change-our-understanding-of-star-formation/" target="_blank" rel="noreferrer noopener">star formation</a>, where clouds of gas collapse to form new stars. </p>



<p>In the center of a spiral galaxy lies a dense concentration of older stars and, often, a supermassive black hole.</p>



<h2 class="wp-block-heading" id="h-structure-of-a-spiral-galaxy-nbsp">Structure of a spiral galaxy&nbsp;</h2>



<p>The structure of a spiral galaxy is generally divided into three main components: the disk, the bulge, and the halo.&nbsp;</p>



<p>The disk is where the spiral arms are located and contains most of the galaxy's visible stars and interstellar medium.&nbsp;</p>



<p>The bulge is a tightly packed region of older stars at the core, and the halo consists of a sparse collection of stars and globular clusters that surround the galaxy.&nbsp;</p>



<p>Spiral galaxies can be classified into different types based on the tightness and number of their spiral arms, as well as the size of their central bulge.</p>



<h2 class="wp-block-heading" id="h-the-milky-way-galaxy">The Milky Way galaxy</h2>



<p>Our solar system is located within a large spiral galaxy known as the Milky Way. The name refers to its appearance as a dim, milky band of light stretching across the night sky.&nbsp;</p>



<p>The term "Milky Way" comes from ancient Greek mythology, where it was associated the goddess Hera's milk spilling into the sky. In Greek, it was called "Galaxias Kyklos," meaning "milky circle."&nbsp;</p>



<p>Spanning about 100,000 light-years in diameter, the Milky Way is composed of stars, gas, dust, and dark matter. The galaxy has a distinct disk shape with spiral arms that wind outward from a central bulge, which houses a supermassive <a href="https://www.earth.com/news/milky-ways-black-hole-unleashes-mysterious-flares/" target="_blank" rel="noreferrer noopener">black hole</a>. </p>



<p>Our sun is located in one of the spiral arms - known as the Orion Arm - positioned roughly halfway from the center to the outer edge.&nbsp;</p>



<p>The Milky Way is part of a small group of galaxies called the Local Group, which includes the Andromeda Galaxy and several smaller galaxies.</p>



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Hubble views a spiral galaxy with stellar explosions

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

<p>Today's Image of the Day from the European Space Agency features an incredible image of the Crab Nebula in bright neon colors.&nbsp;</p>



<p>“The unusual image was produced by combining data from telescopes spanning nearly the entire electromagnetic spectrum, from radio waves to X-rays,” noted <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.&nbsp;</p>



<p>Colored in red, the Karl G. Jansky Very Large Array (VLA) provided information about the nebula gathered in the radio regime.</p>



<p>NASA’s Spitzer Space Telescope took infrared images, which appear yellow, while the NASA/ESA <a href="https://www.earth.com/news/hubble-captures-another-cosmic-masterpiece-in-galaxy-ngc-2217/" target="_blank" rel="noreferrer noopener">Hubble</a> Space Telescope provided images made in optical wavelengths, colored in green.&nbsp;</p>



<p>Blue colors represent ultraviolet observations made by ESA’s XMM-Newton telescope, and the purple colors are X-ray radiation data from NASA’s Chandra X-ray Observatory.</p>



<h2 class="wp-block-heading" id="h-what-is-the-crab-nebula">What is the Crab Nebula? </h2>



<p>The Crab Nebula, located in the constellation Taurus, contains the remnants of a <a href="https://www.earth.com/news/supernova-explosions-could-damage-distant-planets/" target="_blank" rel="noreferrer noopener">supernova explosion</a> first observed on Earth in 1054 AD. This explosion was recorded by Chinese astronomers and possibly by Native American rock art.&nbsp;</p>



<p>The nebula spans about 11 light-years across and lies approximately 6,500 light-years away from Earth. It is one of the most <a href="https://www.earth.com/news/unraveling-the-mysterious-origins-of-the-crab-nebula/" target="_blank" rel="noreferrer noopener">studied objects</a> in the sky, largely due to its status as a bright and dynamic supernova remnant.&nbsp;</p>



<h2 class="wp-block-heading" id="h-the-crab-pulsar">The Crab Pulsar</h2>



<p>The Crab Nebula contains a pulsar at its center, which is a rapidly rotating <a href="https://www.earth.com/news/slow-spinning-neutron-star-completely-defies-our-expectations/" target="_blank" rel="noreferrer noopener">neutron star</a> that emits pulses of radiation. This pulsar, known as the Crab Pulsar, spins about 30 times per second and is a significant source of gamma rays and other forms of high-energy radiation.&nbsp;</p>



<p>The nebula itself is a complex structure of filaments and synchrotron radiation. The filaments are remnants of the original star's outer layers, while the synchrotron radiation emerges from electrons spiraling in the magnetic fields produced by the pulsar.</p>



<p>“Surrounding the pulsar lies a mix of material; some of it was originally expelled from the star before it went supernova, and the rest was ejected during the explosion itself,” explained ESA.&nbsp;</p>



<p>“Fast-moving winds of particles fly off from the neutron star, energizing the dust and gas around it. These different layers and intricacies of the nebula can be observed in all of the different wavelengths of light.”</p>



<h2 class="wp-block-heading" id="h-crab-nebula-observations-nbsp">Crab Nebula observations&nbsp;</h2>



<p>Throughout its history, the Crab Nebula has provided critical insights into the processes of stellar death, the behavior of <a href="https://www.earth.com/news/pulsars-are-helping-astronomers-pinpoint-dark-matter/" target="_blank" rel="noreferrer noopener">pulsars</a>, and the mechanics of supernova remnants.&nbsp;</p>



<p>Its continuous observation has revealed changes over time, such as the expansion of its filaments and variations in its brightness, offering a dynamic laboratory for astrophysical studies.</p>



<p>Overall, the Crab Nebula is a highly energetic and object, providing valuable insights into the processes following a supernova explosion.</p>



<h2 class="wp-block-heading" id="h-fascinating-facts-about-nebulae">Fascinating facts about nebulae</h2>



<p>Nebulae are some of the most breathtaking and intriguing structures in the universe. They are vast clouds of gas and dust, often considered stellar nurseries where new stars are born. </p>



<h3 class="wp-block-heading" id="h-colors-of-nebulae">Colors of nebulae </h3>



<p>One of the most fascinating aspects of nebulae is their ability to glow in different colors. This occurs because they either reflect the light of nearby stars or emit light due to the ionization of gases within them, particularly hydrogen. </p>



<p>Some nebulae, like the famous Orion Nebula, are visible to the naked eye and serve as one of the nearest regions of active star formation.</p>



<h3 class="wp-block-heading" id="h-planetary-nebulae">Planetary nebulae </h3>



<p>Stars are born in dense regions of nebulae, and when they die, some will expel their outer layers, creating stunning structures known as planetary nebulae. The colorful clouds left behind can shine brightly for thousands of years. </p>



<h3 class="wp-block-heading" id="h-massive-size">Massive size</h3>



<p>Another amazing fact is that some nebulae are so vast that light can take years to travel from one side to the other, stretching across hundreds of light-years.</p>



<h3 class="wp-block-heading" id="h-star-remnants">Star remnants </h3>



<p>Perhaps even more mind-boggling is the fact that nebulae are the remnants of previous generations of stars. Supernova explosions of massive stars can create these glowing clouds of gas and dust, seeding the cosmos with the elements necessary for the formation of new stars and planets.</p>



<p>Image Credit: NASA, ESA, G. Dubner (IAFE, CONICET-University of Buenos Aires) et al.; A. Loll et al.; T. Temim et al.; F. Seward et al.; VLA/NRAO/AUI/NSF; Chandra/CXC; Spitzer/JPL-Caltech; XMM-Newton/ESA; and Hubble/STScI</p>



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Crab Nebula: The remains of a massive star explosion

<p>Today's <strong>Image of the Day</strong> from NASA Earth Observatory features an astronaut photograph of Fayzabad, a culturally diverse city in the Kokcha River valley of Northern Afghanistan. </p>



<p>The photo was captured as the International Space Station passed over central Asia.</p>



<p>Fayzabad is the capital of the Badakhshan Province. It is located in a mountainous part of northeastern Afghanistan at an elevation of about 4,000 feet.</p>



<p>“The city is situated along the Kokcha River, which flows northward within a deep river valley surrounded by the Hindu Kush Mountains and eventually discharges into the Amu Darya River,” noted NASA.</p>



<h2 class="wp-block-heading" id="h-climate-of-fayzabad-nbsp">Climate of Fayzabad&nbsp;</h2>



<p>The climate of Fayzabad varies from cold semi-arid to Mediterranean-influenced warm-summer humid continental, according to <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>.</p>



<p>The summer months are warm, with average high temperatures ranging from 77 to 86 degrees Fahrenheit.&nbsp;</p>



<p>The winter months are cold, with average low temperatures often dropping below freezing - sometimes reaching as low as 14 degrees Fahrenheit.&nbsp;</p>



<p>The region receives moderate precipitation, mostly during the spring and winter. Snowfall is common in winter, adding to the picturesque landscape.&nbsp;</p>



<h2 class="wp-block-heading" id="h-fayzabad-culture">Fayzabad culture</h2>



<p>Historically, Fayzabad has been a center of learning and culture, though its development has been hampered by years of conflict.&nbsp;</p>



<p>Despite these challenges, <a href="https://www.earth.com/news/humans-started-cumulative-culture-around-600000-years-ago/" target="_blank" rel="noreferrer noopener">culture</a> remains a vital component of the region, which is known for its traditional crafts including weaving and embroidery.</p>



<p>Cultural life in Fayzabad is influenced by its predominantly Tajik population, along with other ethnic groups such as Uzbeks and Hazaras. The local cuisine is a blend of traditional Afghan flavors, incorporating ingredients like rice, meat, and a variety of spices.</p>



<h2 class="wp-block-heading" id="h-land-use-changes-nbsp">Land use changes&nbsp;</h2>



<p>“This territory has experienced notable changes in its land use in recent decades, especially with commercial and administrative growth near the airport,” noted NASA.</p>



<p>“Among the changes: a new airstrip built west of the Kokcha River. However, mountains hem in the city and limit how much development is possible.”</p>



<p>“Despite these topographical barriers, some development has spread into hilly areas south of Fayzabad. Green vegetation is mostly confined to mountain valleys, stream channels, and the Kokcha River floodplain.”&nbsp;</p>



<p>“The Kokcha River meanders through the valley, providing a vital water resource for the region. Fields of predominantly wheat and rice cover much of the floodplain, though these flat areas are mixed with residential, industrial, and commercial activity as well.”</p>



<h2 class="wp-block-heading" id="h-kokcha-river-nbsp">Kokcha River&nbsp;</h2>



<p>The Kokcha River originates in the Hindu Kush mountains. It stretches approximately 360 kilometers before joining the Amu Darya, one of Central Asia's major <a href="https://www.earth.com/news/hypoxia-is-a-serious-problem-in-rivers-worldwide/" target="_blank" rel="noreferrer noopener">rivers</a>.&nbsp;</p>



<p>The Kokcha River traverses rugged terrain, providing vital irrigation for agriculture in the region and supporting local communities' livelihoods.&nbsp;The <a href="https://www.earth.com/news/what-amount-of-water-do-earths-rivers-hold/" target="_blank" rel="noreferrer noopener">river</a> basin features diverse landscapes that include mountainous areas and fertile valleys.&nbsp;</p>



<p>Throughout history, the Kokcha River has played a crucial role in the region's cultural and economic development, serving as a natural resource for the inhabitants and influencing settlement patterns.</p>



<h2 class="wp-block-heading" id="h-northern-afghanistan">Northern Afghanistan </h2>



<p>Northern Afghanistan is known for its diverse landscape, featuring fertile plains, rugged mountains, and strategic rivers such as the Amu Darya. </p>



<p>Historically, northern Afghanistan has been an important cultural and trade center. The city of Balkh, often referred to as "the mother of cities," is a hub of early civilization and a major stop on the Silk Road.</p>



<p>Northern Afghanistan has experienced periods of relative stability compared to the rest of the country, though it has also seen conflict - particularly during the Soviet invasion, the civil war of the 1990s, and the more recent Taliban resurgence.</p>



<p>The region's economy traditionally revolves around agriculture. Wheat, cotton, and fruits are key crops. In addition, there are vast mineral resources, although instability has hindered their full exploitation. </p>



<h2 class="wp-block-heading" id="h-wildlife-of-northern-afghanistan">Wildlife of Northern Afghanistan </h2>



<p>In mountainous regions of Northern Afghanistan, such as the Hindu Kush, you can find species like the elusive snow leopard, which is well-adapted to the rugged terrain. </p>



<p>Other mountain-dwelling animals include the Asiatic black bear and the Siberian ibex, both of which thrive in the high-altitude environments.</p>



<p>The plains and valleys are home to various species of antelope, such as the goitered gazelle, as well as foxes, wolves, and smaller mammals like hares. </p>



<p>Birdlife is also abundant, with species ranging from eagles and vultures in the mountains to waterfowl along rivers and wetlands. The region’s rivers and lakes, though under environmental pressure, support fish species and amphibians.</p>



<p>However, many of these species are under threat. Decades of war and instability have impacted conservation efforts, with illegal hunting and habitat destruction taking a toll on populations. </p>



<p>Some areas, such as the Wakhan Corridor in the northeast, remain relatively untouched and serve as crucial refuges for wildlife where rare species like the Marco Polo sheep still roam. These havens are increasingly important for conservation efforts in the region.</p>



<p>Image Credit: NASA Earth Observatory&nbsp;</p>



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Fayzabad and the Kokcha River valley 

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

<p>Today's Image of the Day from the European Space Agency features the spiral galaxy NGC 5643, which is located roughly 40 million light-years away in the constellation Lupus.&nbsp;</p>



<p>NGC 5643 belongs to the Hubble classification SBc, indicating that it is a barred spiral galaxy with loosely wound arms.&nbsp;</p>



<p>Its orientation, nearly face-on to Earth, provides astronomers with an exceptional view of its detailed spiral structure and central bar.</p>



<h2 class="wp-block-heading" id="h-ngc-5643-a-grand-design-spiral-nbsp">NGC 5643: A grand design spiral&nbsp;</h2>



<p>“NGC 5643 is what’s known as a grand design spiral, referring to how the galaxy’s two large, winding spiral arms are clear to see,” noted <a href="https://www.esa.int/ESA_Multimedia/Images">ESA</a>. “The spiral arms are defined by bright blue stars, lacy reddish-brown dust clouds and pink star-forming regions.”</p>



<p>“As fascinating as the galaxy appears at visible wavelengths, some of NGC 5643’s most interesting features are invisible to the human eye.”&nbsp;</p>



<h2 class="wp-block-heading" id="h-intense-activity-in-ngc-5643">Intense activity in NGC 5643</h2>



<p>This galaxy is notable for its Seyfert 2 nucleus, a type of active galactic nucleus (AGN). The intense activity in its core is powered by a supermassive <a href="https://www.earth.com/news/awakening-of-a-black-hole-witnessed-for-the-first-time/">black hole</a> that accretes surrounding material, emitting energy across a wide range of wavelengths.&nbsp;</p>



<p>“When a supermassive black hole ensnares gas from its surroundings, the gas collects in a disc that heats up to hundreds of thousands of degrees. The superheated gas shines brightly across the electromagnetic spectrum, but especially at X-ray wavelengths,” said ESA.</p>



<p>Observations have revealed jets and outflows of material emanating from the nucleus, likely driven by the black hole’s activity.&nbsp;</p>



<p>NGC 5643’s AGN has been studied extensively for its role in galactic evolution, particularly in how its energetic processes interact with the galaxy’s interstellar medium.</p>



<h2 class="wp-block-heading" id="h-the-mystery-of-ngc-5643-x-1">The mystery of NGC 5643 X-1</h2>



<p>ESA pointed out that NGC 5643’s active galactic nucleus isn’t the brightest source of X-rays in the galaxy. </p>



<p>“Researchers using ESA’s XMM-Newton discovered an even brighter X-ray-emitting object, called NGC 5643 X-1, on the galaxy’s outskirts. What could be a more powerful source of X-rays than a <a href="https://www.earth.com/news/how-do-black-holes-become-supermassive/">supermassive black hole</a>?”&nbsp;</p>



<p>“Surprisingly, the answer appears to be a much smaller black hole! While the exact identity of NGC 5643 X-1 is not yet known, evidence points to a black hole that is about 30 times more massive than the Sun.”&nbsp;</p>



<p>“Locked in an orbital dance with a companion star, the black hole ensnares gas from its stellar companion, creating a superheated disc that outshines the galactic center,” said ESA.</p>



<h2 class="wp-block-heading" id="h-star-formation-in-ngc-5643">Star formation in NGC 5643</h2>



<p>NGC 5643 also exhibits prominent regions of <a href="https://www.earth.com/news/six-rogue-worlds-discovered-inside-a-young-star-forming-nebula/">star formation</a> within its spiral arms. These areas are rich in gas and dust - the raw materials for birthing new stars - and glow brightly in ultraviolet and infrared light.&nbsp;</p>



<p>Observations from the Hubble Space Telescope and the Very Large Telescope (VLT) have helped uncover the complex interplay between star formation and the galaxy's central activity.</p>



<h2 class="wp-block-heading" id="h-extended-ionized-gas-regions-nbsp">Extended ionized gas regions&nbsp;</h2>



<p>A defining feature of NGC 5643 is the presence of its extended ionized gas regions, which are shaped by the galaxy's AGN activity and star-forming regions.&nbsp;</p>



<p>These structures have been mapped through optical spectroscopy, revealing intricate patterns that help astronomers understand the physical conditions of the gas, such as density, temperature, and composition.</p>



<p>The galaxy also has a dust lane that crosses its nucleus, partially obscuring direct observations of the central region in visible light.&nbsp;</p>



<p>Overall, NGC 5643 offers a fascinating glimpse into the dynamics of barred <a href="https://www.earth.com/news/the-mesmerizing-beauty-of-spiral-galaxies/">spiral galaxies</a> with active nuclei, serving as a valuable resource for studying the interactions between supermassive black holes, star formation, and galactic evolution.</p>



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



<p>Lupus is a constellation located in the southern sky, its name meaning "wolf" in Latin. It has been known since antiquity and was cataloged by the Greek astronomer Ptolemy.&nbsp;</p>



<p>Once part of the larger constellation Centaurus, Lupus was later recognized as a distinct constellation. It is relatively faint but holds historical significance in mythology, often associated with a sacrificial wolf in ancient stories.</p>



<p>Lupus is bordered by other constellations like Scorpius, Centaurus, and Libra. Its stars do not form a particularly striking pattern, but it contains a variety of interesting astronomical features. Among them are numerous double stars, globular clusters, and other deep-sky objects, visible through telescopes.&nbsp;</p>



<p>For observers in the Southern Hemisphere, Lupus is best seen in the winter and spring months, while it appears closer to the horizon for those in northern latitudes.</p>



<p>This constellation also lies along the <a href="https://www.earth.com/news/stars-at-the-edge-of-our-milky-way-galaxy-travel-more-slowly/">Milky Way</a>, offering a rich field of stars and nebulae for stargazers. Despite its modest brightness, Lupus holds a special place in the science of astronomy.</p>



<p>Image Credit<strong>: </strong>NASA/ESA Hubble Space Telescope</p>



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Secrets of a spiraling galactic powerhouse

<p>Today's <strong>Image of the Day</strong> from NASA Earth Observatory features an astronaut view of the northeast coast of Somalia. This region, which borders the Indian Ocean, has a mix of sandy beaches and rugged terrain, including the Cal Madow mountain range.</p>



<h2 class="wp-block-heading" id="h-a-closer-look-at-northeast-somalia">A closer look at Northeast Somalia </h2>



<p>"The detailed image reveals a desert landscape etched by wind and water," said NASA. "Over time, streams have cut canyons into the earth. But streams in this region are ephemeral, making groundwater the main source of fresh water."&nbsp;</p>



<p>"The water table is shallow (wells are typically drilled less than 20 meters deep) and meets the surface toward the coast, creating springs."</p>



<p>According to <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>, bidirectional winds sculpted the tan, brown, and reddish sand into transverse <a href="https://www.earth.com/news/sand-dunes-hold-a-record-of-fire-history/" target="_blank" rel="noreferrer noopener">sand dunes</a> visible near the stream’s deltas. "The orientation of the sand dunes indicates that they were likely formed by summer winds blowing up the coast from the southwest."</p>



<h2 class="wp-block-heading" id="h-economy-of-northeast-somalia">Economy of Northeast Somalia </h2>



<p>The economy of northeast Somalia, specifically the autonomous region of Puntland, is primarily based on fishing, livestock, and trade. </p>



<p>Puntland has a long coastline along the Gulf of Aden and the Indian Ocean, and the waters are home to various types of fish, including tuna, mackerel, and lobster. </p>



<p>However, the fishing industry is underdeveloped and faces challenges such as illegal, unreported, and unregulated (IUU) <a href="https://www.earth.com/news/dark-fleets-hidden-industrial-fishing-activity-exposed/" target="_blank" rel="noreferrer noopener">fishing</a> by foreign vessels.</p>



<p>The arid landscape is well-suited for raising goats, sheep, camels, and cattle. <a href="https://www.earth.com/news/bacteria-in-livestock-are-major-drivers-of-antibiotic-resistance/" target="_blank" rel="noreferrer noopener">Livestock</a> is the main export, with animals being sold to markets in the Middle East.</p>



<p>The region is home to important port cities like Bosaso, which is a hub for trade and commerce. These ports are vital for both the local and national economy.</p>



<h2 class="wp-block-heading" id="h-wildlife-of-northeast-somalia">Wildlife of Northeast Somalia </h2>



<p>The region includes a mix of desert-adapted <a href="https://www.earth.com/news/even-desert-plants-are-not-immune-to-climate-stress/" target="_blank" rel="noreferrer noopener">species</a> and those that thrive in the more fertile areas near the coast and highlands. </p>



<h3 class="wp-block-heading" id="h-mammals">Mammals</h3>



<p>Large mammals such as the Somali wild ass, a critically endangered species, and the gerenuk, a long-necked antelope, are among the most notable inhabitants. </p>



<p>The Somali wild ass is particularly suited to the harsh desert environment, while the gerenuk can survive long periods without water by feeding on moisture-rich vegetation.</p>



<h3 class="wp-block-heading" id="h-birds">Birds</h3>



<p>Birdlife in Northeast Somalia is also abundant, with a variety of species adapted to different habitats ranging from coastal areas to dry savannahs. </p>



<p>Raptors such as the Somali ostrich and various eagles can be spotted, along with <a href="https://www.earth.com/news/how-do-migratory-birds-navigate-with-such-accuracy/" target="_blank" rel="noreferrer noopener">migratory birds</a> that pass through the region during seasonal changes. </p>



<h3 class="wp-block-heading" id="h-marine-life-reptiles-and-insects">Marine life, reptiles, and insects</h3>



<p>The coastal waters, especially along the Gulf of Aden, are home to dolphins, whales, and a variety of fish species.</p>



<p>The region's reptiles include various species of lizards, snakes, and tortoises, many of which are well-adapted to the arid conditions. Insects, particularly locusts and butterflies, play significant roles in the local ecosystem.</p>



<h3 class="wp-block-heading" id="h-wildlife-conservation">Wildlife conservation </h3>



<p>Despite its arid climate, Northeast Somalia's diverse ecosystems support a surprising range of wildlife, although many species face threats from habitat loss, overgrazing, and hunting. </p>



<p>Conservation efforts are ongoing, but the region's political instability has often hampered effective wildlife management and protection.</p>



<h2 class="wp-block-heading" id="h-culture-of-northeast-somalia">Culture of Northeast Somalia </h2>



<p>Northeast Somalia's culture is a mosaic of tradition, religion, and external influences, reflecting the resilience and adaptability of its people.</p>



<p>The region's culture is deeply intertwined with Islam, which influences daily life, social norms, and celebrations. Poetry and storytelling are highly valued, with oral traditions serving as a key method for passing down history and values. </p>



<p>Somalis from this region are known for their hospitality, with the concept of "sooryo" emphasizing the importance of welcoming guests.</p>



<p>Family ties and clan affiliations play a significant role in the social structure, dictating everything from marriage to conflict resolution. </p>



<p>The people of Northeast Somalia have a strong sense of identity and pride, which is often expressed through traditional dances, music, and clothing. Despite modern influences, there is a conscious effort to preserve traditional customs, especially in rural areas.</p>



<p>The photograph was captured on August 9, 2023 as the International Space Station orbited over the Horn of Africa.</p>



<p><em>Image Credit: NASA Earth Observatory&nbsp;</em></p>



<p>-----</p>



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Northeast Somalia: A landscape shaped by wind and water

<p>For decades, scientists believed modern humans descended from a single ancestral lineage. However, new research has not only challenged this view, it has simultaneously spawned a new mystery surrounding human evolution.</p>



<p>Using full genome sequencing, researchers discovered that modern humans originated from two distinct populations that diverged around 1.5 million years ago and later merged.</p>



<p>This genetic reunion, occurring roughly 300,000 years ago, resulted in one group contributing 80% of modern human DNA, while the other provided the remaining 20%. </p>



<p>These findings suggest human evolution was <a href="https://www.earth.com/news/stone-tool-flint-discovery-challenges-theory-of-human-cultural-evolution/" target="_blank" rel="noreferrer noopener">far more intricate</a> than previously assumed.</p>



<h2 class="wp-block-heading" id="h-genetic-mixing-and-complex-evolution">Genetic mixing and complex evolution</h2>



<p>“The question of where we come from is one that has fascinated humans for centuries,” said Dr. Trevor Cousins from the University of Cambridge <a href="https://www.gen.cam.ac.uk" target="_blank" rel="noreferrer noopener">Department of Genetics</a>.</p>



<p>He emphasized that while a single continuous lineage was the dominant theory, genetic evidence now reveals a more complicated history.</p>



<p>Professor Richard Durbin, co-author of the study, noted that these ancient groups remained separate for over a million years before recombining to form the genetic foundation of modern humans. </p>



<p>This suggests our species' origins were shaped by deep evolutionary interactions rather than a straightforward lineage.</p>



<h2 class="wp-block-heading" id="h-humans-and-neanderthals-the-basics">Humans and Neanderthals - the basics</h2>



<p>Humans and Neanderthals didn’t just coexist - they mingled, competed, and even <a href="https://www.earth.com/news/dna-analysis-reveals-most-recent-modern-human-to-interbreed-with-neanderthals/" target="_blank" rel="noreferrer noopener">had children together</a>. </p>



<p>Neanderthals lived in Europe and Asia for hundreds of thousands of years before modern humans migrated out of Africa around 60,000–70,000 years ago. </p>



<p>For at least 5,000–10,000 years, the two species overlapped, sharing landscapes, caves, and possibly even knowledge. </p>



<p>Archaeological evidence suggests Neanderthals created tools, used fire, and may have practiced symbolic behaviors like <a href="https://www.earth.com/news/tinshemet-cave-more-evidence-neanderthals-and-early-humans-interacted-socially/" target="_blank" rel="noreferrer noopener">burying their dead</a>. </p>



<p>Some of their cultural traits look strikingly similar to those of early humans, which hints at possible interactions - maybe even trade or shared ideas.</p>



<p>However, this new research highlights an earlier, more significant genetic mixing event around 300,000 years ago. </p>



<p>Unlike Neanderthal DNA, which comprises roughly 2% of non-African modern human genomes, this earlier event contributed up to 20% of the genetic makeup found in all humans today.</p>



<h2 class="wp-block-heading" id="h-decoding-the-past-with-dna">Decoding the past with DNA</h2>



<p>The research team used modern human DNA rather than ancient fossils to reconstruct this evolutionary history. </p>



<p>They analyzed data from the <a href="https://www.internationalgenome.org/" target="_blank" rel="noreferrer noopener">1000 Genomes Project</a>, which includes genetic samples from populations worldwide. </p>



<p>Their approach enabled them to infer the presence of ancestral populations that left no direct fossil evidence.</p>



<p>By developing an advanced computational tool called cobraa, the researchers modeled how human populations split and later merged. </p>



<p>They first tested the algorithm on simulated data before applying it to real human genetic sequences.</p>



<p>This method provided fresh insights into the genetic diversity of early humans.</p>



<h2 class="wp-block-heading" id="h-one-human-population-nearly-disappeared">One human population nearly disappeared</h2>



<p>“Immediately after the two ancestral populations split, we see a severe bottleneck in one of them - suggesting it shrank to a very small size before slowly growing over a period of one million years,” said Professor Aylwyn Scally from the Department of Genetics.</p>



<p>This smaller group later contributed most of the genetic material found in modern humans and was also the ancestral population from which Neanderthals and <a href="https://www.earth.com/news/mysterious-denisovan-species-humans-lived-undisturbed-tibetan-plateau-160000-years/" target="_blank" rel="noreferrer noopener">Denisovans</a> evolved.</p>



<p>Meanwhile, the second population, which contributed a minority of modern human DNA, carried genes related to brain function and neural processing. </p>



<p>“Some of the genes from the population which contributed a minority of our genetic material may have played a crucial role in human evolution,” said Cousins.</p>



<h2 class="wp-block-heading" id="h-natural-selection-and-genetic-compatibility">Natural selection and genetic compatibility</h2>



<p>The experts found that genes inherited from the second <a href="https://www.earth.com/news/early-humans-had-surprising-diets-3-5-million-years-ago/" target="_blank" rel="noreferrer noopener">population</a> were often located in regions of the genome unrelated to primary gene functions. This suggests natural selection filtered out less compatible genetic traits over time.</p>



<p>The process, known as purifying selection, gradually removed harmful mutations, ensuring only beneficial genetic changes persisted.</p>



<h2 class="wp-block-heading" id="h-expanding-the-study-beyond-humans">Expanding the study beyond humans</h2>



<p>Beyond human <a href="https://www.earth.com/news/human-ancestors-homo-erectus-thrived-in-extreme-desert-landscapes-1-million-years-ago/" target="_blank" rel="noreferrer noopener">evolution</a>, the researchers applied their computational model to genetic data from species such as bats, dolphins, chimpanzees, and gorillas.</p>



<p>They found evidence of similar ancestral population structures in some species, reinforcing the idea that evolutionary history is more intertwined than previously thought.</p>



<p>“What’s becoming clear is that the idea of species evolving in clean, distinct lineages is too simplistic,” Cousins explained. </p>



<p>He suggested that interbreeding and genetic exchange likely influenced species development across the animal kingdom.</p>



<h2 class="wp-block-heading" id="h-identifying-our-ancestral-candidates">Identifying our ancestral candidates</h2>



<p>The identities of these ancestral human populations remain uncertain. </p>



<p>Fossil evidence indicates that species such as Homo erectus and Homo heidelbergensis lived in Africa and other regions during this period. </p>



<p>These species could be potential candidates for the populations identified in the genetic study, but more research is needed.</p>



<p>Future studies aim to refine the genetic model to account for gradual genetic exchanges rather than abrupt splits and reunions. </p>



<p>Scientists also plan to integrate their findings with fossil records to build a clearer picture of early <a href="https://www.earth.com/news/humans-lived-in-rainforests-80000-years-earlier-than-we-thought/" target="_blank" rel="noreferrer noopener">human diversity</a>.</p>



<h2 class="wp-block-heading" id="h-our-understanding-of-human-evolution">Our understanding of human evolution</h2>



<p>“The fact that we can reconstruct events from hundreds of thousands or millions of years ago just by looking at DNA today is astonishing,” said Scally. </p>



<p>He emphasized that our evolutionary history is far richer and more <a href="https://www.earth.com/news/what-animal-will-replace-humans-as-earths-dominant-species-this-scientist-has-an-idea/" target="_blank" rel="noreferrer noopener">complex</a> than previously imagined.</p>



<p>This remarkable research reshapes our understanding of human origins, proving that our past was shaped by intricate genetic interconnections rather than a single ancestral line. </p>



<p>The findings open new avenues for studying evolutionary history across multiple species, offering a deeper appreciation of the forces that shaped modern life.</p>



<p>The study is published in the journal<em> <a href="https://www.nature.com/articles/s41588-025-02117-1" target="_blank" rel="noreferrer noopener">Nature Genetics</a>.</em></p>



<p>-----</p>



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Who were they? "Mystery ancestor" gave humans 20% of our current DNA

For decades, scientists believed modern humans descended from a single...

<p>A recent study has discovered a surprising behavior in lemon leafcutter ants (<em>Atta sexdens</em>). These ants not only exhibit social immunity - the ability to detect and remove pathogens to protect their colony - but also appear to remember past infections and respond more aggressively to familiar threats.</p>



<p>The research, led by <a href="https://www.international.unesp.br/" target="_blank" rel="noreferrer noopener">São Paulo State University</a> (UNESP), reveals that leafcutter ants can recognize a pathogenic fungus they have previously encountered, even 30 days after the initial exposure. </p>



<p>When re-exposed, they intensify their cleaning behaviors and recruit more workers, a phenomenon researchers suggest could be considered a form of “social immune memory.”</p>



<h2 class="wp-block-heading" id="h-a-superorganism-s-defense-mechanism">A superorganism’s defense mechanism</h2>



<p>“If we think of the <a href="https://www.earth.com/news/larger-ant-colonies-drove-the-evolution-of-worker-castes/" target="_blank" rel="noreferrer noopener">colony</a> as a superorganism, these behaviors would be like the immune system,” said first author Aryel Goes, a former bioscience student at UNESP. “In the same way that our defense cells attack invaders, such as viruses and bacteria, the workers fight infections that could harm the colony.”</p>



<p>The study shows that, unlike individual <a href="https://www.earth.com/news/covid-19-lockdowns-weakened-our-immune-systems/" target="_blank" rel="noreferrer noopener">immune systems</a> in animals, ants respond to infections collectively.&nbsp;</p>



<p>“What we’re showing is that the social immune system of ants can store information about previous infections with the same pathogen, a phenomenon seen in our immune cells, but which occurs at a behavioral level in ant colonies,” Goes said.</p>



<p>To test this idea, the researchers conducted several experiments to observe how ants responded to repeated exposures to the same pathogen.</p>



<h2 class="wp-block-heading" id="h-a-stronger-response-to-familiar-threats">A stronger response to familiar threats</h2>



<p>In one experiment, the team exposed <a href="https://www.earth.com/news/dinosaur-extinction-led-to-the-emergence-of-ant-agriculture/" target="_blank" rel="noreferrer noopener">ant colonies</a> to a pathogen, then reintroduced it after seven days and again after a month. The ants' response became significantly stronger over time, with the most intense reaction occurring at the 30-day mark. </p>



<p>More ants participated in cleaning activities, both grooming themselves and removing the harmful fungus from the fungi they cultivate for food.</p>



<p>Lemon leafcutters belong to a group of ants that maintain a mutualistic relationship with fungi, cultivating them inside their colonies as a food source. In return, the fungi provide essential nutrients for the ants.</p>



<p>As part of the study, researchers tested four different pathogens - two harmful to the ants themselves and two that targeted their cultivated <a href="https://www.earth.com/news/fungus-farming-ants-work-hard-to-maintain-healthy-gardens/" target="_blank" rel="noreferrer noopener">fungi</a>.&nbsp;</p>



<p>In another experiment, the scientists exposed separate colonies to a pathogen, then reintroduced it after seven days and again after 60 days. This time, the ants' responses were noticeably weaker compared to those that encountered the pathogen after 30 days.</p>



<p>“Unlike our immune system, which in some cases responds expressively to a specific pathogen even many years after initial exposure, ants’ social immune memory has a shorter time frame, so they need to be constantly exposed to the pathogen for the information to persist,” explained Goes.</p>



<h2 class="wp-block-heading" id="h-do-ants-recognize-specific-pathogens">Do ants recognize specific pathogens?</h2>



<p>The researchers also tested whether the ants' memory-like response was pathogen-specific. In a third experiment, they exposed the ants to one pathogen, then introduced a different pathogen after seven days. The ants' response to the second pathogen was much weaker than their reaction to the original one.</p>



<p>The following week, the researchers reintroduced the first pathogen. While the ants reacted, their response was only moderate - similar to their first encounter with the pathogen, but far less intense than when the pathogen had been reintroduced after 30 days.</p>



<p>Rodrigues suggested that this behavior could be a strategy to prevent accidentally spreading a new pathogen within the colony. “One hypothesis is that the lemon leafcutter reduced its hygienic response to avoid spreading the new pathogen to the rest of the colony.&nbsp;</p>



<p>This is because cleaning altruism, in which ants lick each other to get rid of pathogens, can also spread new contaminants. That’s why they would have been more careful with a second infection that was completely new to the colony,” he explained.</p>



<h2 class="wp-block-heading" id="h-do-ants-respond-to-unknown-substance">Do ants respond to unknown substance?</h2>



<p>To ensure that the ants’ response was indeed triggered by pathogens and not simply by exposure to an unfamiliar substance, the researchers applied a harmless solution to five colonies as a control.&nbsp;</p>



<p>The ants in this group showed the weakest response of all the experiments, suggesting that the ants can distinguish between different substances and respond more aggressively to harmful pathogens.</p>



<p>The study raises the possibility that social immunity in leafcutter ants could increase the efficiency of pathogen removal, improving the colony’s overall survival. However, more research is needed to determine whether this actually qualifies as a form of immune memory.</p>



<h2 class="wp-block-heading" id="h-implications-for-pest-control">Implications for pest control</h2>



<p>Leafcutter ants, including <em>Atta sexdens</em>, thrive in open environments and have adapted well to agricultural landscapes, making them a common <a href="https://www.earth.com/news/urgent-need-to-protect-earths-forests-from-non-native-pests/" target="_blank" rel="noreferrer noopener">pest</a> in monoculture farming.&nbsp;</p>



<p>Their strong cleaning behaviors pose a challenge to biological control methods that rely on natural pathogens rather than chemical pesticides.</p>



<p>“Lemon leafcutters are adapted to open areas, so they benefit from monocultures and are a pest. Their cleaning behavior is one of the obstacles to effective biological control without the use of chemical insecticides. Understanding the social immunity of leafcutters can help to develop more effective and ecologically correct controls,” Rodrigues concluded.</p>



<p>The study is published in the journal <a href="http://dx.doi.org/10.1098/rspb.2024.1097" target="_blank" rel="noreferrer noopener"><em>Proceedings of the Royal Society B</em></a>.</p>



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Leafcutter ants remember past infections, strengthening colony defenses

A recent study has discovered a surprising behavior in lemon...

<p>For more than 20 years, scientists have puzzled over an unusual trait in thorny skates in the North Atlantic. </p>



<p>In some parts of their range, these fish appear in two distinctly different sizes, regardless of their sex. Researchers were unable to determine the cause of this phenomenon - until now.</p>



<p>A new study led by Jeff Kneebone and a team from the <a href="https://www.floridamuseum.ufl.edu/" target="_blank" rel="noreferrer noopener">Florida Museum of Natural History</a> has finally solved the mystery, thanks in part to unexpected disruptions caused by the COVID-19 pandemic.</p>



<h2 class="wp-block-heading" id="h-a-longstanding-conservation-puzzle">A longstanding conservation puzzle</h2>



<p>The size discrepancy among thorny skates has been noted for nearly a century, but the issue became especially significant in the 1970s when their populations began to plummet. Suspecting <a href="https://www.earth.com/news/overfishing-has-caused-a-50-decline-in-sharks-and-rays/" target="_blank" rel="noreferrer noopener">overfishing</a> as the main culprit, authorities implemented a strict fishing ban on thorny skates and barndoor skates in 2003.</p>



<p>“The barndoor skate rebounded to the point where they’re now allowed to be harvested again, but for whatever reason, the thorny skate has remained low, despite 20 years of protection,” said Kneebone, a senior scientist at the <a href="https://www.neaq.org/conservation-and-research/anderson-cabot-center-for-ocean-life/" target="_blank" rel="noreferrer noopener">Anderson Cabot Center for Ocean Life</a> at the New England Aquarium.</p>



<p>Data from the <a href="https://www.noaa.gov/" target="_blank" rel="noreferrer noopener">National Oceanic and Atmospheric Administration</a> indicates that thorny skate populations have declined by 80% to 95% in some regions, particularly in the Gulf of Maine and Canadian waters off the Scotian Shelf.</p>



<h2 class="wp-block-heading" id="h-the-mystery-of-thorny-skates">The mystery of thorny skates </h2>



<p>Thorny skates have an extensive distribution, ranging from South Carolina to the Arctic Circle and across to Europe and Russia. However, the size variation appears to be unique to North American waters; in the Arctic and Europe, thorny skates only appear in one size.</p>



<p>“No one could understand what the deal was with these skates,” said study co-author Gavin Naylor, director of the <a href="https://www.floridamuseum.ufl.edu/sharks/" target="_blank" rel="noreferrer noopener">Florida Program for Shark Research</a> at the Florida Museum of Natural History. </p>



<p>Researchers had previously analyzed thorny skate DNA, searching for genetic differences between the two size variants, but found nothing.&nbsp;</p>



<p>“The big forms are twice the size, and it takes them 11 years to reach adulthood. The small forms are mature by the time they’re six years old. There’s got to be genetic differences.”</p>



<p>Naylor believed a more detailed genetic analysis could uncover the answer.</p>



<h2 class="wp-block-heading" id="h-samples-from-hundreds-of-thorny-skates">Samples from hundreds of thorny skates </h2>



<p>Previous attempts to solve the mystery involved sequencing short DNA fragments from a small number of individuals.&nbsp;</p>



<p>While a reasonable approach, Naylor suspected it had failed because not enough of the genome had been examined. Instead, he proposed a gene capture method, an intensive approach that collects DNA sequences from thousands of genes across an organism’s <a href="https://www.earth.com/news/how-does-genome-size-impact-evolutionary-success/" target="_blank" rel="noreferrer noopener">genome</a>.&nbsp;</p>



<p>This would require analyzing samples from hundreds of thorny skates to gather a comprehensive dataset.</p>



<p>Researchers from around the world responded to Naylor’s request for samples, providing more than 600 tissue specimens spanning much of the Northern Hemisphere and helping him prepare for an extensive lab analysis.</p>



<p>Then, the <a href="https://www.earth.com/news/hidden-death-toll-of-covid-19-pandemic-revealed/" target="_blank" rel="noreferrer noopener">COVID-19 pandemic</a> shut down lab operations, halting their work indefinitely.</p>



<p>At that point, postdoctoral researcher Shannon Corrigan devised an alternative plan. Instead of conducting a labor-intensive gene capture study on hundreds of skates, they would sequence the full genome of just a handful - four or five individuals. While less comprehensive, it would still allow them to search for significant genetic differences.</p>



<p>It was a gamble. If the genome sequencing approach failed, the team would have used up their funding with no results.</p>



<p>“It was a Hail Mary,” Naylor said. But it paid off. In fact, had they stuck with the original plan, “we would have missed it entirely.”</p>



<h2 class="wp-block-heading" id="h-a-key-genetic-difference">A key genetic difference</h2>



<p>The breakthrough came when lead author Pierre Lesturgie analyzed the genome - comprising 2.5 billion base pairs. As he sifted through the data, he noticed something unusual.</p>



<p>“There was a large region on chromosome two that we thought was weird. Since it was behaving in a way we didn’t understand, we considered removing it from the analysis,” Lesturgie said.</p>



<p>Initially, he suspected the anomaly was a sequencing error and worried it might skew their results. But before discarding it, Naylor recognized a pattern - it resembled a gene inversion, where a segment of DNA is flipped in the opposite direction.</p>



<p>Gene inversions are common across many species, including humans, but they rarely result in such dramatic physical differences. Still, the team decided to check if this inverted DNA sequence was present in both small and large thorny skates.</p>



<p>It wasn’t. Only the larger skates had the inversion. They had finally uncovered the genetic basis for the size difference.</p>



<h2 class="wp-block-heading" id="h-implications-for-conservation">Implications for conservation</h2>



<p>Now that scientists understand why thorny skates appear in two distinct sizes, Kneebone believes they can develop more effective conservation strategies.&nbsp;</p>



<p>The next step is to study the skates' life histories more closely - something that has been challenging due to the difficulty of distinguishing between the two types.</p>



<p>“We could identify the large males and females because they’re bigger than anything else,” Naylor said. Both large and small males develop distinctive long claspers on either side of their tails when they reach maturity.&nbsp;</p>



<p>“So when you’ve got a small male with large claspers, we know it’s an adult. But we can’t do anything with the small females because we don’t know whether they’re just babies on their way to getting big.”</p>



<p>This has complicated research on the species. “The big question has always been, what do the life histories of the two morphs look like? Currently, they’re not discriminated in the stock assessment, so a thorny skate is a thorny skate is a thorny skate,” Kneebone said.</p>



<h2 class="wp-block-heading" id="h-the-role-of-climate-change">The role of climate change</h2>



<p>Even with this discovery, thorny skates are still struggling in parts of their range, particularly in the Gulf of Maine. One potential factor is <a href="https://www.earth.com/news/climate-change-is-impacting-marine-life-more-than-we-realized/" target="_blank" rel="noreferrer noopener">climate change</a>.</p>



<p>Current evidence suggests that the two size variants may have difficulty interbreeding in areas where populations are declining. Warming ocean temperatures could be exacerbating this natural reproductive barrier.</p>



<p>The Gulf of Maine has experienced some of the fastest ocean warming on the planet, with sea surface temperatures rising at a rate faster than 99% of the world's oceans. This has already led to significant ecological changes, such as the collapse of cod fisheries.</p>



<p>Scientists are now investigating whether climate change is disproportionately affecting thorny skates compared to other skate species in the region.</p>



<p>“We’re trying to use the best available science to make decisions about how to best manage and sustain populations,” Kneebone concluded.</p>



<p>The study is published in the journal <a href="http://dx.doi.org/10.1038/s41467-025-56126-z" target="_blank" rel="noreferrer noopener"><em>Nature Communications</em></a>.</p>



<p>Image Credit: Illustration by Jorge Machuski</p>



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DNA twist reveals why some thorny skates grow twice as large

For more than 20 years, scientists have puzzled over an...


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<p>An estimated two million people die each year due to human-caused pollution.</p>


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