Today's Image of the Day from the European Space Agency features the Cat's Eye Nebula (NGC 6543), located about 3,300 light-years from Earth in the constellation Draco.&nbsp;



The nebula's name comes from its eye-like appearance when viewed through a telescope. This particular image, which reveals the <a href="https://www.earth.com/news/horsehead-nebula-webb-telescope-captured-unprecedented-detail/" target="_blank" rel="noreferrer noopener">nebula</a> in stunning detail, was captured by the NASA/ESA Hubble Space Telescope.



<h2 class="wp-block-heading" id="h-planetary-nebulae-nbsp">Planetary nebulae&nbsp;</h2>



According to ESA, the Cat's Eye Nebula is one of the most complex planetary nebulae that has ever been discovered.



“A planetary nebula forms when Sun-like stars gently eject their outer gaseous layers to form bright nebulae with amazing twisted shapes," explained <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.



"Until recently, it was thought that shells around planetary nebulae were a rare phenomenon. However, astronomers have instead shown that these rings are likely to be the rule rather than the exception."



<h2 class="wp-block-heading" id="h-appearance-of-the-cat-s-eye-nebula-nbsp">Appearance of the Cat's Eye Nebula&nbsp;</h2>



The central focus of the Cat's Eye is a hot, dying star that has shed its outer layers to form the <a href="https://www.earth.com/news/dragons-egg-nebula-is-a-truly-stunning-sight-to-behold/" target="_blank" rel="noreferrer noopener">nebula</a>. It is surrounded by concentric gas shells, jets of high-speed gas, and unusual shock-induced knots of gas.



“Although the rings may be the key to explaining the final ‘gasp’ of the dying central star, the mystery behind the Cat’s Eye Nebula’s nested ‘Russian doll’ structure remains largely unsolved,” noted ESA.



<h2 class="wp-block-heading" id="h-rings-around-the-cat-s-eye">Rings around the Cat’s Eye</h2>



“This image, taken with Hubble's Advanced Camera for Surveys (ACS), reveals the full pattern of eleven or more concentric rings, or shells, around the Cat’s Eye. Each ‘ring’ is actually the edge of a spherical bubble seen projected onto the sky - which is why it appears bright along its outer edge.”



According to ESA, observations suggest that the star ejected its mass in a series of pulses at 1,500-year intervals. “These convulsions created dust shells that each contains as much mass as all of the planets in our solar system combined.”



Several explanations have been proposed for this phenomenon, including cycles of magnetic activity similar to our Sun's sunspot cycle, the influence of companion stars orbiting the <a href="https://www.earth.com/news/dying-stars-may-be-a-source-of-gravitational-waves/" target="_blank" rel="noreferrer noopener">dying star</a>, or stellar pulsations.&nbsp;



Another theory suggests that the material is ejected smoothly from the star, with the rings forming later due to the creation of waves in the outflowing material.



<h2 class="wp-block-heading" id="h-the-constellation-draco-nbsp">The constellation Draco&nbsp;</h2>



<a href="https://www.earth.com/news/extrasolar-ocean-planet-discovered-in-the-draco-constellation/" target="_blank" rel="noreferrer noopener">Draco</a> is a constellation in the northern sky that represents a dragon. It's one of the largest constellations, winding between the Big and Little Dippers.&nbsp;



In Greek mythology, Draco is often identified as the dragon Ladon, who guarded the golden apples in the garden of the Hesperides.



Draco is a circumpolar constellation for most northern hemisphere observers, meaning it never sets below the horizon and can be seen all year round.



<h2 class="wp-block-heading" id="h-famous-planetary-nebulae">Famous planetary nebulae </h2>



Planetary nebulae are some of the most beautiful and intriguing objects in the universe.&nbsp;



One of the most famous is the Ring Nebula, or M57, located in the constellation Lyra. This nebula is renowned for its nearly perfect ring shape, which is the result of a dying star shedding its outer layers.&nbsp;



Another well-known planetary nebula is the Helix Nebula, or NGC 7293, often referred to as the "Eye of God" due to its eye-like appearance. The Helix Nebula is one of the closest planetary nebulae to Earth, making it a popular target for amateur astronomers.&nbsp;



The Dumbbell Nebula, or M27, in the constellation Vulpecula, is another striking example. It is named for its resemblance to a dumbbell and is notable for being the first planetary nebula ever discovered, by Charles Messier in 1764.&nbsp;



The Butterfly Nebula, or NGC 6302, is located in the constellation Scorpius. Its name comes from its distinctive bipolar structure, resembling the wings of a butterfly. The nebula's central star is one of the hottest known, with a surface temperature of around 250,000 degrees Celsius.&nbsp;



The Eskimo Nebula, or NGC 2392, in the constellation Gemini, is known for its resemblance to a face surrounded by a fur parka, which gives it its name. Its intricate structure, including filaments and bubble-like shapes, makes it a fascinating object of study. 



These nebulae not only captivate us with their beauty but also provide valuable insights into the life cycles of stars and the processes that shape our galaxy.



Image Credit: NASA/ESA Hubble Space Telescope



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Cat's Eye Nebula in the constellation Draco

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

Today's Image of the Day from the European Space Agency features a Copernicus Sentinel-2 photograph of South Georgia, a remote and rugged island located in the southern Atlantic Ocean. 



"Linked with the South Sandwich Islands to form a British Overseas Territory, this southern Atlantic island is a haven for a vast array of wildlife," said <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.



"Around five million seals call the islands home, as well as 65 million birds of 30 different species. Migrating whales and various fish species populate the surrounding waters and there is a large penguin population."



<h2 class="wp-block-heading" id="h-climate-and-wildlife-of-south-georgia">Climate and wildlife of South Georgia </h2>



The island is dominated by mountains, glaciers, and fjords. Its highest peak, Mount Paget, rises to 2,935 meters, making it one of the tallest in the region.



South Georgia’s location within the Antarctic Convergence gives it a cold, maritime climate. Although not part of the Antarctic Treaty System, its environment and <a href="https://www.earth.com/news/conservation-efforts-are-not-enough-to-save-antarctic-wildlife/" target="_blank" rel="noreferrer noopener">wildlife</a> are closely linked to Antarctica. 



The island is home to vast colonies of penguins, seals, and seabirds. The surrounding waters are rich with krill, providing an abundant food source for marine life.



<h2 class="wp-block-heading" id="h-penguins-adapted-to-harsh-environments">Penguins adapted to harsh environments </h2>



The most notable species found here are the king penguins, which are the second-largest penguin species in the world. South Georgia also hosts large populations of <a href="https://www.earth.com/news/what-makes-the-gentoo-penguin-the-worlds-fastest-swimming-bird/" target="_blank" rel="noreferrer noopener">gentoo</a> and macaroni penguins. 



The island's harsh climate, characterized by strong winds, snow, and cold temperatures, makes it a tough environment, but the penguins have adapted well. 



Their colonies - some of which number in the hundreds of thousands - can be found along the island's rugged coasts and beaches. 



The island’s isolation, combined with its plentiful food supply, makes it a critical breeding ground for these penguins.



<h2 class="wp-block-heading" id="h-history-of-south-georgia">History of South Georgia </h2>



The island has a history of exploration and exploitation. Captain James Cook first claimed South Georgia for Britain in 1775. 



During the late 19th and early 20th centuries, it became a hub for the <a href="https://www.earth.com/news/echoes-of-the-past-whalings-long-term-impact-on-genetic-diversity/" target="_blank" rel="noreferrer noopener">whaling</a> industry, with stations like Grytviken serving as operational centers. These stations have since been abandoned, and the island is now a haven for scientific research and ecotourism.



South Georgia is also notable for its role in Ernest Shackleton’s famed Endurance expedition. His crew reached the island in 1916 after an extraordinary open-boat journey from Elephant Island. Shackleton later died on South Georgia in 1922 and is buried in Grytviken.



<h2 class="wp-block-heading" id="h-pristine-nature-of-the-island">Pristine nature of the island</h2>



Today, South Georgia is a focus of conservation efforts. The eradication of invasive species, such as rats and reindeer, has been a significant success, allowing native wildlife to recover. 



Rats and mice were responsible for the decline of ground-nesting birds, including the South Georgia pipit, the island's only endemic bird. 



<a href="https://www.earth.com/news/reindeer-use-ultraviolet-vision-to-find-food-in-the-winter/" target="_blank" rel="noreferrer noopener">Reindeer</a>, which had been introduced for farming in the 19th century, caused extensive damage to the island’s vegetation, disrupting the habitat for native species.



South Georgia is uninhabited except for a small number of scientists and staff working at research stations and administrative facilities, emphasizing its role as a protected wilderness area and an essential site for understanding global environmental changes.



Its uninhabited status has helped preserve its pristine nature. Visitors to South Georgia must follow strict environmental guidelines to minimize human impact on this extraordinary island.



<h2 class="wp-block-heading" id="h-scientific-significance-of-remote-islands">Scientific significance of remote islands </h2>



Remote <a href="https://www.earth.com/news/plant-life-on-islands-loses-diversity-when-humans-arrive/" target="_blank" rel="noreferrer noopener">islands</a> are scientifically significant for several reasons. They often serve as unique ecosystems that can provide insights into evolutionary processes, biodiversity, and adaptation. 



Due to their isolation, species on remote islands may evolve differently from their mainland counterparts, resulting in the development of endemic species that exist nowhere else in the world. 



These islands also act as natural laboratories for studying the effects of climate change, human activity, and ecological interactions, as they are more vulnerable to disturbances. 



Moreover, remote islands can offer valuable information on the health of marine and terrestrial ecosystems, as their ecosystems are often less impacted by human-induced factors. This makes them ideal for studying natural processes in relatively undisturbed environments. 



The isolation of these islands can also help scientists study the patterns of species migration, colonization, and extinction.



Image Credit: ESA 



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South Georgia: One of the most remote islands in the world

Today's Image of the Day from NASA Earth Observatory features the Messak Settafet, a rocky plateau located in the central Sahara Desert. It is part of the greater Messak Plateau, which stretches between the Erg Uan Kasa and the Murzuq Sand Sea.&nbsp;



The plateau's surface is characterized by blackened sandstone, sculpted by thousands of years of wind erosion. This dark patina, often referred to as "desert varnish," adds to its distinctive appearance. The region is starkly beautiful but harsh, with extreme temperatures and minimal <a href="https://www.earth.com/news/even-desert-plants-are-not-immune-to-climate-stress/" target="_blank" rel="noreferrer noopener">vegetation</a>.



<h2 class="wp-block-heading" id="h-image-of-the-messak-settafet">Image of the Messak Settafet</h2>



“Towering over the desert in southwestern Libya, the Messak Settafet plateau resembles the wall of a giant fortress, with its dark, erosion-resistant sandstone separating the Ubari Sand Sea to the north and the Marzūq Sand Sea to the south,” noted NASA.



“The large outcrop of Cretaceous rock features a sharp escarpment on its north side. The cliff, some 300 meters (1,000 feet) high in places, is lined with a thin dark shadow.”&nbsp;



“Dark debris from rockfalls is visible to the north. Note that an optical illusion called relief inversion can make high-elevation areas appear low and vice versa when shadows appear on the northern side of a feature.”



<h2 class="wp-block-heading" id="h-archaeological-significance-of-the-plateau-nbsp">Archaeological significance of the plateau&nbsp;</h2>



Messak Settafet is often referred to as the "land of stone tools" because it is one of the world's largest sites for prehistoric tools.&nbsp;



The area is littered with countless <a href="https://search.app?link=https%3A%2F%2Fwww.earth.com%2Fnews%2Fstone-tool-discovery-challenges-entire-theory-of-human-evolution%2F&amp;utm_campaign=aga&amp;utm_source=agsadl2%2Csh%2Fx%2Fgs%2Fm2%2F4" target="_blank" rel="noreferrer noopener">stone tools</a> and artifacts dating back to various prehistoric periods, including the Acheulean and Neolithic. These tools offer insights into early human technology and adaptation to desert environments.



“Signs of ancient tool making cover much of the plateau’s surface,” said <a href="https://www.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>. “According to one archaeological survey, people discarded so many stone tools and rock fragments on the plateau over hundreds of thousands of years that roughly 75 artifacts per square meter now carpet the surface.”&nbsp;



“That makes this one of the earliest known examples of hominins modifying an entire landscape, according to the University of Cambridge archaeologists who conducted the survey.”



“Other signs of ancient activity include the bright spots that dot the image. These areas were likely quarrying pits where people dug up rocks and crafted them into tools, the archaeologists reported.”&nbsp;



<h2 class="wp-block-heading" id="h-rock-art-on-the-plateau-nbsp">Rock art on the plateau&nbsp;</h2>



The plateau is home to numerous petroglyphs and <a href="https://www.earth.com/news/negev-petroglyphs-ancient-art-rock-carvings-face-erosion-fungi-lichens/" target="_blank" rel="noreferrer noopener">carvings</a>. These engravings depict animals, humans, and symbolic designs, providing valuable clues about the lives, beliefs, and environments of the region's ancient inhabitants.&nbsp;



“For instance, Wadi Mathendous, a prehistoric archaeological site located in the southern part of the plateau, contains engravings of rhinoceroses, crocodiles, hippopotamuses, fighting cats, giraffes, long-horned buffaloes, and elephants. The art is thought to be about 8,000 years old,” said NASA.



Some of the animals depicted, such as giraffes and elephants, indicate that the Sahara was once a <a href="https://search.app?link=https%3A%2F%2Fwww.earth.com%2Fnews%2Fa-lush-green-sahara-desert-helped-early-humans-migrate-out-of-africa%2F&amp;utm_campaign=aga&amp;utm_source=agsadl2%2Csh%2Fx%2Fgs%2Fm2%2F4" target="_blank" rel="noreferrer noopener">much wetter</a> and more hospitable environment.



<h2 class="wp-block-heading" id="h-cultural-significance-of-the-messak-settafet">Cultural significance of the Messak Settafet</h2>



Messak Settafet forms part of the Rock-Art Sites of Tadrart Acacus, a UNESCO World Heritage Site since 1985. This designation highlights the area's importance for understanding early human culture and environmental changes in the Sahara.



The plateau has been a critical area for studying the migration and adaptation of early humans. Its archaeological richness offers a glimpse into how humans thrived in this region during periods when the climate was wetter.



“Although the plateau now receives less than 0.4 inches of rain annually, clues in the landscape make clear it was once much wetter,” noted NASA.



“Deeply incised dried stream valleys, or wadis, crisscross the plateau, indicating significant past water flow. The small, bright features scattered across the plateau are sand and silt deposits left where water once pooled.”



The Messak Settafet, like many remote <a href="https://www.earth.com/news/sahara-desert-dust-storms-carry-harmful-bacteria-and-fungi-around-the-globe/" target="_blank" rel="noreferrer noopener">desert</a> regions, faces challenges such as erosion, vandalism of ancient rock art, and the potential impacts of development. 



Efforts to preserve its archaeological treasures are vital for protecting its cultural and scientific significance.



The image was captured November 17, 2024 by the Operational Land Imager-2 (OLI-2) on Landsat 9 on&nbsp;



Image Credit: NASA Earth Observatory



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Messak Settafet plateau in the Sahara Desert

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

Today's Image of the Day from the European Space Agency features NGC 6744 - a large, barred spiral galaxy located approximately 30 million light-years away in the constellation Pavo.&nbsp;



The galaxy is often considered a close analog to the <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> due to its similar structure and size, spanning about 175,000 light-years across.&nbsp;



<h2 class="wp-block-heading" id="h-euclid-space-mission-nbsp">Euclid space mission&nbsp;</h2>



The image was captured by the <a href="https://www.esa.int/Science_Exploration/Space_Science/Euclid" target="_blank" rel="noreferrer noopener">Euclid</a> space telescope. NGC 6744 stands out as a prime example of the galaxies currently forming the majority of stars in the nearby universe, making it an ideal subject for study with the Euclid mission.&nbsp;



Euclid’s extensive field-of-view allows it to capture the entire galaxy, showcasing not only its large-scale spiral structure but also revealing intricate details on smaller scales across various wavelengths. These details include feather-like dust lanes, known as “spurs,” emerging from the spiral arms.



<h2 class="wp-block-heading" id="h-star-formation-in-ngc-6744">Star formation in NGC 6744</h2>



Euclid's observations enable scientists to count individual stars within NGC 6744, trace the distribution of stars and dust throughout the galaxy, and map the dust associated with the gas that fuels the development of new stars. 



<a href="https://www.earth.com/news/baby-stars-release-sneezes-of-gas-and-dust-as-they-develop/" target="_blank" rel="noreferrer noopener">Star formation</a> is a key process in the growth of galaxies, making these studies crucial for understanding galaxy evolution.



Researchers are utilizing Euclid’s data to explore the relationship between dust, gas, and star formation; to map the distribution of different stellar populations and identify regions of active star formation; and to investigate the underlying physics of spiral galaxy structures.&nbsp;



Spiral arms play a significant role in star formation by compressing gas, yet the precise mechanisms behind this process are still unclear. The presence of “spurs” along NGC 6744’s spiral arms offers valuable insights into the dynamics of star formation within these structures.



<h2 class="wp-block-heading" id="h-discovering-new-dwarf-galaxies-nbsp">Discovering new dwarf galaxies&nbsp;</h2>



Additionally, Euclid's dataset will help scientists identify clusters of old stars (globular clusters) and discover new dwarf galaxies around NGC 6744. Remarkably, Euclid has already identified a new dwarf satellite galaxy of NGC 6744 - a surprising discovery given that the galaxy has been studied extensively.



With Euclid’s detailed observations, scientists are gaining a deeper understanding of the processes shaping galaxies, providing essential clues to the evolution and appearance of the <a href="https://www.earth.com/news/universes-expansion-rate-hubble-tension-puzzles-astronomers/" target="_blank" rel="noreferrer noopener">universe</a>.



<h2 class="wp-block-heading" id="h-more-about-ngc-6744">More about NGC 6744</h2>



NGC 6744's disk is rich in star-forming regions and contains numerous young, bright blue stars. The galaxy's nucleus is slightly elongated and has a bar structure, which influences the motion of the stars and gas within it.&nbsp;



The spiral arms of NGC 6744 are well-defined and extend outward, wrapping around the central bar. Additionally, NGC 6744 has a smaller companion galaxy, NGC 6744A, which is interacting with it, adding to the complexity and interest of this distant system.&nbsp;



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



<a href="https://www.earth.com/news/the-mesmerizing-beauty-of-spiral-galaxies/" target="_blank" rel="noreferrer noopener">Spiral galaxies</a> are one of the most common types of galaxies in the universe, characterized by their distinct, spiral-shaped structure.&nbsp;



The galaxies typically consist of a flat, rotating disk containing stars, gas, and dust, along with a central concentration of stars known as the bulge. This bulge is often surrounded by a halo of older stars.&nbsp;



The spiral arms, which extend from the central bulge, are regions of active star formation and are rich in young, hot stars, giving them a bright, bluish appearance.&nbsp;



These arms are also sites where interstellar gas and dust are concentrated, leading to the formation of new stars.&nbsp;



Spiral galaxies are classified into different types based on the tightness of their spirals and the size of their central bulge, with classifications ranging from tightly wound arms in Sa galaxies to more loosely wound arms in Sc galaxies. The <a href="https://www.earth.com/news/large-amount-of-dark-matter-may-be-missing-from-the-milky-way/" target="_blank" rel="noreferrer noopener">Milky Way</a>, our home galaxy, is a prime example of a spiral galaxy.



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



Pavo, which means "peacock" in Latin, is a constellation in the southern sky. It was named by the Dutch astronomer Petrus Plancius in the late 16th century, based on observations made during the Dutch explorations of the southern hemisphere. 



Pavo is one of the 12 constellations created by Plancius from the records of explorers Pieter Dirkszoon Keyser and Frederick de Houtman. 



The constellation is known for its distinctive shape, resembling a peacock with a long, curved tail. Pavo is not visible from most of the northern hemisphere, but it can be seen from the southern hemisphere, particularly during the winter months.



The constellation contains several interesting celestial objects, including the star Peacock, also known as Alpha Pavonis, which is the brightest star in the constellation. This star is a blue-white subgiant located about 179 light-years from Earth.



Image Credit: <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>/Euclid/Euclid Consortium/NASA&nbsp;



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Spiral galaxy NGC 6744 in the constellation Pavo

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



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The violent clash of the Antennae Galaxies  

Most of the plastic that pollutes our oceans comes from an unexpected source: rivers. Strangely enough, research on plastic pollution has been primarily focused on ocean environments - leaving freshwater sources a bit neglected.



Enter a team of innovative scientists from the University of Minnesota, Twin Cities, who are turning the tide with their novel research.



Published in the journal Nature, the study explores the use of remote sensing technology to monitor and remove plastic debris from rivers like the Mississippi.



<h2 class="wp-block-heading" id="h-growing-concern-of-plastic-pollution">Growing concern of plastic pollution</h2>



Plastic pollution in oceans has become a global <a href="https://www.earth.com/news/plastic-pollution-is-changing-the-entire-earth-system/" target="_blank" rel="noreferrer noopener">environmental crisis</a>. The United Nations Environment Program (<a href="https://www.unep.org" target="_blank" rel="noreferrer noopener">UNEP</a>) ranks it among the top pollution challenges of our time.



Yet, freshwater environments - rivers and lakes - have received far less attention, despite being the primary conduits for plastic waste flowing into oceans. Recognizing this gap, the researchers set out to find innovative solutions for freshwater plastic pollution.



Traditional methods of monitoring and removing plastic debris rely on manual sampling. These techniques, while effective, are time-consuming and expensive. 



The new study addresses these limitations with advanced remote sensing technology, offering a more cost-effective and scalable solution.



<h2 class="wp-block-heading" id="h-remote-sensing-to-detect-plastic-pollution">Remote sensing to detect plastic pollution</h2>



The researchers utilized spectral reflectance properties - specific wavelengths of the electromagnetic spectrum - to detect different types of <a href="https://www.earth.com/news/could-this-breakthrough-finally-solve-the-plastic-crisis/" target="_blank" rel="noreferrer noopener">plastic</a> debris.



By isolating the unique spectral signatures of plastics, the technology can distinguish them from natural materials commonly found in freshwater - such as sediments, driftwood, and algae.



Study lead author Mohammadali Olyaei is a Ph.D. student in the <a href="https://cse.umn.edu/cege" target="_blank" rel="noreferrer noopener">Department of Civil, Environmental, and Geo-Engineering</a>.



“We could use this technology to identify different types of plastics in the water simultaneously. This is key information that we need when employing other technology, like drones, to capture and remove plastic debris in natural environments,” explained Olyaei.



<h2 class="wp-block-heading" id="h-testing-in-real-world-conditions">Testing in real-world conditions</h2>



The research team conducted their experiments at the St. Anthony Falls Laboratory, where the Mississippi River flows through the facility. 



This setting allowed the team to test their theories in real river conditions. They combined a remote sensing platform, called a spectroradiometer, with a digital single-lens reflex (DSLR) camera to classify and monitor various types of debris based on their spectral signatures.



This approach not only helps identify plastic debris but also lays the foundation for deploying technologies, like drones, for cleanup efforts. This dual capability of monitoring and removing debris makes remote sensing a promising tool in the fight against <a href="https://www.earth.com/news/how-can-we-combat-the-escalating-plastic-crisis/" target="_blank" rel="noreferrer noopener">plastic pollution</a>.



<h2 class="wp-block-heading" id="h-broader-environmental-impact">Broader environmental impact</h2>



Study co-author Ardeshir Ebtehaj is an associate professor in the Department of Civil, Environmental, and Geo-Engineering.



“If we can develop technology at the Mississippi headwaters, in a place like Minnesota, to catch plastic debris, we can protect the downstream states and the entire ocean from plastic pollution," said Professor Ebtehaj.



"As soon as these plastics begin to spread more and more, their control becomes more and more challenging.” 



By stopping plastics at the source, the researchers hope to mitigate the downstream effects of pollution. 



The study emphasizes the importance of addressing freshwater systems to prevent <a href="https://www.earth.com/news/is-it-still-possible-to-save-the-ocean-from-plastic-pollution/" target="_blank" rel="noreferrer noopener">plastic</a> from reaching oceans, where it becomes far more difficult to manage.



<h2 class="wp-block-heading" id="h-next-steps-scaling-up-the-research">Next steps: Scaling up the research</h2>



The team plans to expand their research to larger river systems in order to understand the movement of plastic debris across freshwater networks and to refine removal strategies.



This broader scope will also shed light on the origins of <a href="https://www.earth.com/news/can-we-win-the-battle-of-planet-vs-plastic-drastic-changes-are-needed/" target="_blank" rel="noreferrer noopener">plastic</a> pollution, which will enable more targeted interventions.



In addition to Olyaei and Professor Ebtehaj, the research team included Christopher R. Ellis, a senior research associate at the St. Anthony Falls Laboratory.



The work was funded by the Minnesota Environment and Natural Resources Trust Fund (<a href="https://www.legacy.mn.gov/environment-natural-resources-trust-fund" target="_blank" rel="noreferrer noopener">ENTRF</a>), a permanent fund dedicated to protecting Minnesota's natural resources.



<h2 class="wp-block-heading" id="h-importance-of-early-intervention">Importance of early intervention</h2>



The study represents a significant step forward in tackling the often-overlooked issue of freshwater plastic pollution with remote sensing.



By leveraging advanced remote sensing technology, the researchers offer a scalable, efficient solution that can benefit both local ecosystems and the global environment.



The research highlights the importance of early intervention in freshwater systems to prevent plastics from spreading uncontrollably. 



With continued research and development, this technology could become a critical tool in protecting rivers, lakes, and ultimately, the oceans.



The study is published in the journal <a href="https://www.nature.com/articles/s41597-024-03974-x" target="_blank" rel="noreferrer noopener">Nature Scientific Data</a>.



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Remote sensing can help prevent plastic from reaching the ocean

Most of the plastic that pollutes our oceans comes from...

California’s vibrant native wildflowers face a growing threat: invasive grasses that form dense, suffocating layers of debris and prevent seed germination. 



According to a new study by the University of California, Riverside (UCR), a simple solution could lie in raking away this “thatch” - a layer of dead leaves and debris that blankets the ground.



This technique not only encourages biodiversity but also helps reduce fire risk in these ecosystems.



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



Raking involves using a tool, like a rake, to physically remove surface debris, including leaves, dead grass, and other organic material, from the soil. This process, often part of gardening or land management, has the following applications beyond basic cleanup.



<ol class="wp-block-list">
<li>Prepares soil for planting: By exposing bare soil, raking allows better water infiltration and nutrient absorption for seeds.</li>



<li>Improves soil aeration: Removing dense organic layers lets air circulate, enhancing microbial activity that is essential for healthy soil.</li>



<li>Prevents pest build-up: Thatch and debris can harbor pests and diseases; raking removes these potential threats.</li>



<li>Aids erosion control: By managing debris strategically, raking can prevent water runoff from eroding topsoil.</li>



<li>Enhances aesthetic appeal: In landscaped areas, raking maintains a neat, manicured appearance.</li>
</ol>



It’s a versatile, low-tech method that benefits both small-scale gardens and larger ecological restoration projects.



<h2 class="wp-block-heading" id="h-raking-for-grass-management">Raking for grass management </h2>



The study, published in the journal Restoration Ecology, compared raking with other invasive grass <a href="https://www.earth.com/news/un-report-calls-for-global-change-to-stop-biodiversity-loss/">mana</a><a href="https://www.earth.com/news/un-report-calls-for-global-change-to-stop-biodiversity-loss/" target="_blank" rel="noreferrer noopener">gement</a> techniques like controlled burns, hand weeding, and herbicide application.



The results? Raking stands out as a low-cost, less labor-intensive, and ecologically friendly alternative.



“In these ecosystems, native seeds often fall on thick layers of thatch and can’t germinate. Raking the thatch lets light in and gives native plants a chance to grow,” explained <a href="https://profiles.ucr.edu/app/home/profile/markos" target="_blank" rel="noreferrer noopener">Marko Spasojevic</a>, the study's lead author and UCR associate professor of plant ecology.



<h2 class="wp-block-heading" id="h-the-return-of-native-wildflowers">The return of native wildflowers</h2>



The research was conducted on grasslands near the UCR campus. The team used a grid of paired plots - one raked and one left untouched - to observe changes in plant communities over three years.



The findings revealed that raking significantly increased overall plant <a href="https://www.earth.com/news/what-are-the-biggest-drivers-of-biodiversity-loss/" target="_blank" rel="noreferrer noopener">diversity</a>. Invasive grasses like ripgut brome declined, while native and exotic wildflowers, collectively known as forbs, thrived.



Ripgut brome, one of the dominant invasive species, is notorious for its sharp bristles that can injure grazing animals. 



“It’s super nasty for sheep and cattle to eat,” said Spasojevic. On the other hand, native flowers like the common fiddleneck, a species prevalent in Riverside, showed modest improvement when raking was applied.



<h2 class="wp-block-heading" id="h-growth-of-exotic-flowers">Growth of exotic flowers</h2>



However, the study revealed a trade-off. While raking reduced invasive grasses, it also encouraged the growth of certain exotic wildflowers, such as mustard, which can be highly invasive.



“Raking boosted native wildflowers by about 5% and exotic forbs by 7 to 10%,” said Advyth Ramachandran, co-leader of the project. 



“This doesn’t mean raking isn’t worthwhile. It’s a simple, low-cost method that could be a first step for restoring these systems,” noted Ramachandran, a former UCR undergraduate who is now studying plant ecology at the <a href="https://www.colorado.edu" target="_blank" rel="noreferrer noopener">University of Colorado, Boulder</a>.



<h2 class="wp-block-heading" id="h-the-seeds-initiative">The SEEDS initiative </h2>



This study represents more than just ecological research; it’s a proof of student-led innovation. The project traces its origins to the 1980s, when the study plots were created for an introductory biology class and later abandoned. 



During the COVID-19 pandemic, Ramachandran and fellow UCR students revived the site through the university’s SEEDS club, a grassroots research initiative.



“We built this project from scratch, writing protocols, identifying species, and involving over 25 undergraduates,” Ramachandran said. “It’s rare for undergraduates to initiate and lead publishable research like this.”



Spasojevic credited the project’s success to its accessibility. “The research site is on campus, so students could sample between classes. It lowered barriers for involvement and became a rich mentorship opportunity,” he said.



The SEEDS initiative continues to thrive, with students now collecting data for a fifth consecutive year.



<h2 class="wp-block-heading" id="h-practical-implications-for-land-managers">Practical implications for land managers</h2>



The findings offer a practical, low-cost method for land managers seeking to restore <a href="https://www.earth.com/news/polar-light-sustains-biodiversity-over-millions-of-years/" target="_blank" rel="noreferrer noopener">biodiversity</a> in California’s grasslands and coastal sage ecosystems. 



Native plants play a critical role in these ecosystems by providing food and habitat for local wildlife, supporting pollinators like bees, and preventing soil erosion. Meanwhile, invasive grasses pose multiple threats: outcompeting native plants, reducing biodiversity, and increasing wildfire risk with their dense, flammable layers.



“This project shows how small actions - like raking - can make meaningful differences in our ecosystems,” Ramachandran said. “It’s a promising step toward restoring California’s native landscapes.”



<h2 class="wp-block-heading" id="h-restoring-california-s-native-wildflowers">Restoring California’s native wildflowers</h2>



The UCR team’s research highlights the importance of simple yet effective interventions in combating ecological challenges. As California continues to face threats from invasive grass species and wildfires, methods like raking could play a key role in preserving the state’s natural heritage.



Land managers and conservationists alike can take inspiration from the study’s findings, and apply this technique to boost native biodiversity while promoting community involvement in ecological <a href="https://www.earth.com/news/plant-diversity-darkspots-need-urgent-attention/" target="_blank" rel="noreferrer noopener">restoration</a> efforts.



The success of the SEEDS initiative also underscores the power of student-driven research to address real-world environmental issues.



Restoring California’s wildflowers may not require monumental efforts. Sometimes, it’s as simple as picking up a rake.



The study is published in the journal <a href="https://onlinelibrary.wiley.com/doi/10.1111/rec.14340" target="_blank" rel="noreferrer noopener">Restoration Ecology</a>.



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California’s native wildflowers can be restored by raking dead grass

California’s vibrant native wildflowers face a growing threat: invasive grasses...

Carrying too much visible fat around the waist and hips is a well-known health risk. However, unseen fat around the heart also poses significant dangers. 



Scientists at the University of Virginia (UVA) Health System are developing a non-invasive method to assess these risks, potentially transforming how doctors diagnose and treat heart disease.



Led by Dr. Frederick H. Epstein of UVA’s Department of Biomedical Engineering, the researchers are using magnetic resonance imaging (MRI) to analyze the composition of epicardial adipose tissue - the fat surrounding the heart.



This technique could help doctors pinpoint patients who are at risk for severe heart conditions, such as coronary artery disease, atrial fibrillation, and heart failure. It may also help predict patient responses to treatments, which would enhance care strategies.



<h2 class="wp-block-heading" id="h-progress-in-heart-imaging">Progress in heart imaging</h2>



Initial testing has shown promising results. The new MRI technique offers insights that were previously unavailable.



“Using this new MRI technique, we now for the very first time have the ability to know the composition of the fat that accumulates around the <a href="https://www.earth.com/news/heart-disease-patients-have-a-unique-vulnerability-to-air-pollution/" target="_blank" rel="noreferrer noopener">heart</a>,” said Dr. Amit R. Patel, a cardiologist at <a href="https://uvahealth.com" target="_blank" rel="noreferrer noopener">UVA Health</a>.



“This is important because, depending on its makeup, the fat which surrounds the heart has the potential to release damaging substances directly into the heart muscle, leading to serious heart problems.”



Dr. Patel noted that the research could enable patients to convert unhealthy fat into healthier forms using lifestyle changes or medications.



“We believe that by doing so, we will be able to reduce some of the complications associated with heart disease,” he added.



<h2 class="wp-block-heading" id="h-dual-nature-of-epicardial-fat">Dual nature of epicardial fat</h2>



Epicardial adipose tissue is a type of fat that surrounds the heart. In healthy individuals, this fat plays an important protective role, helping the <a href="https://www.earth.com/news/eating-more-plant-protein-lowers-the-risk-of-heart-disease/" target="_blank" rel="noreferrer noopener">heart function</a> properly.



However, in people with conditions like obesity, diabetes, high blood pressure, or unhealthy habits like smoking and poor diets, this fat can accumulate excessively. In this case, it may become inflamed and undergo changes that can harm the heart instead of protecting it.



Scientists can now study the composition of this fat by analyzing the types of fatty acids it contains - saturated, monounsaturated, and polyunsaturated.



These insights help doctors identify people at risk of heart disease before symptoms appear. Finding and addressing these risks early can slow down the progression of heart disease, which is one of the leading causes of death worldwide.



<h2 class="wp-block-heading" id="h-tackling-the-challenges-of-heart-scans">Tackling the challenges of heart scans</h2>



Capturing clear images of heart fat posed significant technical challenges due to constant heart and lung motion. To overcome this, the team developed advanced computational methods and innovative imaging approaches.



“The ability to make these measurements in epicardial adipose tissue required the use of advanced computational methods that can extract the unique signature of saturated fatty acids from an overall noisy signal,” said Dr. Epstein.



He commended&nbsp;Jack Echols, a biomedical engineering graduate student, for his pivotal contributions.



With these advances, the team can now obtain precise images in a single breath hold, paving the way for real-world applications.



<h2 class="wp-block-heading" id="h-early-findings-from-heart-scans">Early findings from heart scans</h2>



Tests revealed that the fat surrounding the <a href="https://www.earth.com/news/new-blood-test-accurately-predicts-cardiovascular-heart-disease-risk-30-years-into-future/" target="_blank" rel="noreferrer noopener">heart</a> in obese patients with prior heart attacks contained excessive saturated fatty acids. 



This discovery suggests that the new MRI technique could help identify at-risk individuals and improve patient outcomes.



“Being able to see the composition of the fat that surrounds the <a href="https://www.earth.com/news/climate-change-worsens-cardiovascular-health-risks/" target="_blank" rel="noreferrer noopener">heart</a> will improve our understanding of heart disease and may lead to the development of new treatment strategies in the future,” noted Dr. Patel.



<h2 class="wp-block-heading" id="h-heart-scans-and-early-interventions">Heart scans and early interventions</h2>



The new MRI technique represents a significant leap in heart disease care. 



"Epicardial adipose tissue (EAT), the adipose depot positioned between the myocardium and the visceral pericardium, has emerged as an important contributor to cardiovascular disease, particularly in obesity and metabolic heart disease," explained the researchers.



By providing a clearer picture of this fat composition around the heart, the new imaging technique could empower doctors to intervene earlier and more effectively, reducing the burden of heart disease worldwide.



The findings were published in the journal <a href="https://onlinelibrary.wiley.com/doi/10.1002/mrm.30285" target="_blank" rel="noreferrer noopener">Magnetic Resonance in Medicine</a>. 



The study received funding from the&nbsp;National Institutes of Health,&nbsp;National Institute on Aging,&nbsp;American Heart Association, and other organizations.



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Simple scan can predict risks of serious heart problems

Carrying too much visible fat around the waist and hips...

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Today’s Video of the Day from the <a href="https://www.jpl.nasa.gov/">NASA Jet Propulsion Laboratory</a> describes all of the exciting things that we can see in the night sky during the month of December 2021.



On December 6th through the 10th, look westward following sunset to see the Moon visiting Venus, Saturn, and Jupiter in turn. According to NASA, the Moon&#8217;s crescent fills out as it appears higher in the sky each evening.



A recently discovered comet known as Comet Leonard will fly by this month, making its closest approach to Earth on December 12th.



NASA reports that in the first couple of weeks of December, Comet Leonard can be found in the east before sunrise, passing between Arcturus and the handle of the Big Dipper.&nbsp;



In addition, the annual Geminid meteor shower peaks overnight on the 13th and 14th.&nbsp;



Video Credit: NASA JPL



&#8211;&#8212;



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

Skywatching in December 2021: planets, comet, and a meteor shower