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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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Spiral galaxy NGC 1559 is a loner in outer space

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

<p>Today's <strong>Image of the Day</strong> from the European Space Agency features the barred spiral galaxy NGC 3783, which is located about 130 million light-years away in the constellation Centaurus. </p>



<p>NGC 3783 is also the most prominent of a galaxy group (by the same name) that contains 47 galaxies. </p>



<h2 class="wp-block-heading" id="h-galaxy-groups">Galaxy groups</h2>



<p>“Like galaxy clusters, galaxy groups are aggregates of gravitationally bound galaxies. Galaxy groups, however, are less massive and contain fewer members than <a href="https://www.earth.com/news/titanic-galaxy-cluster-collision-defies-all-current-understanding-of-the-universe/" target="_blank" rel="noreferrer noopener">galaxy clusters</a> do: where galaxy clusters can contain hundreds or even thousands of constituent galaxies, galaxy groups do not typically include more than 50,” noted <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.</p>



<p>“The Milky Way is actually part of a galaxy group, known as the Local Group, which contains two other large galaxies (Andromeda and the Triangulum galaxy), as well as several dozen satellite and dwarf galaxies.”</p>



<h2 class="wp-block-heading" id="h-hd-101274-a-blue-giant-star">HD 101274: A blue giant star</h2>



<p>The bright object that appears to the right of the galaxy is the star HD 101274. “The perspective in this image makes the star and the galaxy look like close companions, but this is an illusion. HD 101274 lies only about 1,530 light-years from Earth, meaning it is about 85 thousand times closer than NGC 3783,” explained ESA.&nbsp;</p>



<p>The star is part of the NGC 3766 cluster, which is sometimes referred to as the Pearl Cluster, an open cluster known for its richness in bright stars and its relatively young age.</p>



<p>HD 101274 is categorized as a blue giant star, characterized by its high temperature and luminosity. </p>



<p>Blue giants are massive stars that have left the main sequence phase of stellar evolution and are burning helium or heavier elements in their cores. These stars are known for their short lifespans relative to smaller stars due to their rapid consumption of nuclear fuel.</p>



<h2 class="wp-block-heading" id="h-significance-of-blue-giants">Significance of blue giants</h2>



<p><a href="https://www.earth.com/news/dark-stars-scientists-discover-a-new-type-of-star-powered-by-dark-matter/" target="_blank" rel="noreferrer noopener">Stars</a> like HD 101274 are important for astronomers because they help in studying the properties of stellar populations in clusters and the dynamics of stellar evolution in different environments. </p>



<p>The spectral and photometric observations of such stars can provide valuable insights into the characteristics of their atmospheres, internal structures, and the processes occurring within and around them.</p>



<h2 class="wp-block-heading" id="h-bright-central-region-of-ngc-3783">Bright central region of NGC 3783</h2>



<p>One of the most interesting aspects of NGC 3783 is that it harbors an active galactic nucleus, meaning its central region is exceptionally luminous, likely due to the presence of a supermassive black hole. This black hole is actively accreting material, which emits a substantial amount of radiation as it spirals inward and heats up.</p>



<p>The galaxy is particularly known for its bright central region and has been studied extensively in the ultraviolet and X-ray light spectra to understand better the properties of the accretion disk around the black hole and the complex dynamics of the material surrounding it. These studies are crucial for understanding the physics of active galactic nuclei and the role they play in <a href="https://www.earth.com/news/galaxies-like-our-own-milky-way-are-not-unique/" target="_blank" rel="noreferrer noopener">galaxy evolution</a>.</p>



<p>According to ESA, NGC 3783 is a&nbsp;Type I Seyfert galaxy. “In this image it is recorded by Hubble in incredible detail, from its glowing central bar to its narrow, winding arms and the dust threaded through them, thanks to five separate images taken in different wavelengths of light," noted ESA.</p>



<p>“In fact, the galactic center is bright enough to Hubble that it exhibits diffraction spikes, normally only seen on stars such as HD 101274.”</p>



<h2 class="wp-block-heading" id="h-more-about-the-ngc-3783-galaxy-group">More about the NGC 3783 galaxy group</h2>



<p>The NGC 3783 group is part of the larger Hydra-Centaurus Supercluster, which itself is a massive collection of <a href="https://www.earth.com/news/shapes-of-one-million-galaxies-hint-at-the-universes-origins/" target="_blank" rel="noreferrer noopener">galaxies</a> and galaxy clusters located primarily in the constellations of Hydra and Centaurus.</p>



<p>The NGC 3783 group consists of several galaxies that are gravitationally bound and interact with each other. These interactions can influence the galaxies' evolution through mechanisms like tidal forces and merger events, which can trigger star formation, fuel central black holes, and reshape the galaxies' structures.</p>



<p>Studying groups like the NGC 3783 group helps astronomers understand how <a href="https://www.earth.com/news/ceers-2112-ancient-galaxy-looks-strikingly-similar-to-ours/" target="_blank" rel="noreferrer noopener">galaxies</a> evolve together in a common gravitational environment, offering insights into the dynamics and evolution of structures on cosmic scales. </p>



<p>Image Credit: ESA/Hubble &amp; NASA</p>



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Luminous galaxy NGC 3783 and a blue giant star

<p>Today's Image of the Day from NASA Earth Observatory features Cyclone Chido, an intense tropical cyclone that caused unprecedented devastation across Southeast Africa in December 2024.</p>



<p>On December 14, Chido struck the islands of Mayotte with wind speeds exceeding 200 km/h (124 mph) and gusts over 225 km/h (140 mph), marking it as the most powerful storm to hit the French territory in at least 90 years.&nbsp;</p>



<p>The <a href="https://www.earth.com/news/fast-moving-tropical-cyclones-are-becoming-more-powerful/" target="_blank" rel="noreferrer noopener">cyclone</a> ultimately made three landfalls - all with winds equivalent to those of a Category 4 tropical cyclone. According to media reports, authorities in Mayotte fear that hundreds and possibly thousands of people have died.</p>



<h2 class="wp-block-heading" id="h-rapid-intensification-of-chido">Rapid intensification of Chido</h2>



<p>“Chido formed in the southeastern Indian Ocean on December 5, 2024. The disturbance rapidly intensified before hitting the Mauritian islands of Agaléga on December 11. The next day, the cyclone peaked in intensity, with sustained winds of about 250 kilometers (155 miles) per hour - equivalent to a strong Category 4 hurricane on the Saffir-Simpson wind scale,” noted <a href="https://earthobservatory.nasa.gov/images/153708/cyclone-chido-pummels-mayotte" target="_blank" rel="noreferrer noopener">NASA</a>.&nbsp;&nbsp;</p>



<p>“According to the Joint Typhoon Warning Center, Cyclone Chido continued to move west in an environment favorable for sustaining storms. That included warm <a href="https://www.earth.com/news/ocean-warming-has-nearly-doubled-in-the-last-decade/" target="_blank" rel="noreferrer noopener">sea surface temperatures</a> of up to 29 degrees Celsius (84 degrees Fahrenheit) and low vertical wind shear.</p>



<h2 class="wp-block-heading" id="h-devastation-of-cyclone-chido-nbsp">Devastation of Cyclone Chido&nbsp;</h2>



<p>The cyclone obliterated entire neighborhoods, particularly in hillside shantytowns inhabited by undocumented migrants. Official reports confirm at least 31 fatalities and thousands of injuries - though the actual death toll may be significantly higher.&nbsp;</p>



<p>The destruction in Mayotte's capital, Mamoudzou, has left approximately 100,000 people homeless. The aftermath has been characterized by a lack of visible assistance from authorities, with residents relying on community support amid concerns over hunger, disease outbreaks, and lawlessness.&nbsp;</p>



<h2 class="wp-block-heading" id="h-landfall-in-mozambique-nbsp">Landfall in Mozambique&nbsp;</h2>



<p>Following its impact on Mayotte, Chido continued westward, making landfall in Mozambique on December 15 near the city of Pemba as a strong Category 4-equivalent intense tropical cyclone.&nbsp;</p>



<p>The storm resulted in at least 34 deaths and 43 injuries across three northern provinces. In neighboring Malawi, Chido claimed two lives.&nbsp;</p>



<p>The cyclone's ferocity, fueled by warmer ocean temperatures attributed to climate change, has raised concerns about the increasing frequency and <a href="https://www.earth.com/news/coastal-hurricanes-are-intensifying-faster-due-to-climate-change/" target="_blank" rel="noreferrer noopener">intensity</a> of such storms in the region.&nbsp;</p>



<h2 class="wp-block-heading" id="h-recovery-efforts-and-vulnerable-communities-nbsp">Recovery efforts and vulnerable communities&nbsp;</h2>



<p>The crisis has highlighted the vulnerabilities of affected regions, particularly Mayotte, which faces challenges of poverty, overcrowding, and inadequate infrastructure.&nbsp;</p>



<p>The lack of preparedness and insufficient emergency response have drawn criticism, highlighting the need for improved disaster management and investment in resilient infrastructure to mitigate the impacts of future climate-induced disasters.&nbsp;</p>



<p>In response to the disaster, French President Emmanuel Macron is scheduled to visit Mayotte, and relief efforts are underway, including the arrival of a ship carrying 180 tons of aid.&nbsp;</p>



<p>However, the scale of destruction and ongoing challenges in delivering assistance to remote and inaccessible areas continue to impede recovery efforts.&nbsp;</p>



<h2 class="wp-block-heading" id="h-climate-fueled-intensification-of-cyclones-nbsp">Climate-fueled intensification of cyclones&nbsp;</h2>



<p>The <a href="https://www.earth.com/news/the-rising-impact-of-tropical-cyclones-in-a-warming-world/" target="_blank" rel="noreferrer noopener">intensification of cyclones</a> due to climate change is a significant and concerning phenomenon. As global temperatures rise, warmer ocean waters provide the energy that fuels tropical cyclones, making them stronger and more destructive.&nbsp;</p>



<p>Higher <a href="https://www.earth.com/news/pacific-ocean-temperatures-highest-in-650-years-greatly-harming-coral-reefs/" target="_blank" rel="noreferrer noopener">sea surface temperatures</a> lead to increased evaporation, which adds more moisture to the atmosphere. This moisture can enhance the rainfall associated with cyclones, increasing the risk of flooding.&nbsp;</p>



<p>Additionally, rising sea levels, driven by the melting of polar ice caps and thermal expansion of seawater, exacerbate storm surge impacts, causing more extensive and severe coastal flooding during cyclonic events.</p>



<p>Changes in atmospheric conditions also play a role. While climate change may not increase the overall frequency of cyclones, it is likely to shift the distribution and intensity of these storms. For instance, studies suggest that a larger proportion of cyclones are reaching the most intense categories.&nbsp;</p>



<p>Furthermore, slower-moving cyclones, a trend linked to weakened steering currents, can linger longer over vulnerable areas, compounding the damage with prolonged heavy rainfall and strong winds.</p>



<p>These changes in cyclone behavior present challenges for disaster preparedness and response. Coastal communities, particularly in low-lying regions, are becoming increasingly vulnerable to the compounded impacts of more powerful storms, highlighting the urgent need for climate mitigation and adaptation strategies.</p>



<p>The image was captured by the VIIRS (Visible Infrared Imaging Radiometer Suite) on the NOAA-20 satellite, about three hours after the storm made landfall.</p>



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



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Cyclone Chido’s path of destruction: A climate wake-up call

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

<p>Today's Image of the Day from NASA Earth Observatory features a 9.5-mile section of Pangong Lake on the western end of the Tibetan Plateau. The image was captured by a crew member onboard the International Space Station. </p>



<p>“In this winter scene, a sheet of cracked ice tops part of the lake,” noted <a href="https://earthobservatory.nasa.gov/" target="_blank" rel="noreferrer noopener">NASA</a>. “On the left side, open water appears blue. Shallow water offshore of a delta, formed by a small, winding river, appears green."</p>



<p>"Parallel lines along the coastlines of bays are visible in the high-resolution version of this image. These lines indicate raised beaches, which formed in the past when lake levels were higher.”</p>



<p>NASA pointed out that several roads cut across the landscape, including one with switchbacks that ascends a steep slope. "These roads facilitate tourist travel from both India and China.”&nbsp;</p>



<h2 class="wp-block-heading" id="h-migratory-birds-at-pangong-lake-nbsp">Migratory birds at Pangong Lake&nbsp;</h2>



<p>Pangong Lake and its surroundings are home to numerous bird species, particularly <a href="https://www.earth.com/news/migratory-birds-burn-unexpected-amounts-of-protein/" target="_blank" rel="noreferrer noopener">migratory birds</a>. Visitors can spot various waterfowl and waders that are rarely seen elsewhere.</p>



<p>“During the summer, species such as bar-headed geese and Brahminy ducks attract bird watchers to the lake, which is a major breeding ground for migrating birds,” said NASA.</p>



<p>Pangong Lake is one of the few places in India where the endangered black-necked crane is found during its breeding season. </p>



<p>Ruddy shelduck and brown-headed <a href="https://www.earth.com/news/gulls-are-shifting-their-habitats-to-urban-areas/" target="_blank" rel="noreferrer noopener">gulls</a> are also frequently spotted around the lake. The ruddy shelduck is known for its striking orange-brown body and creamy white head, while the brown-headed gulls are often seen flying or swimming in the lake.</p>



<h2 class="wp-block-heading" id="h-pangong-lake-nbsp">Pangong Lake&nbsp;</h2>



<p>Pangong Lake is a stunning high-altitude lake situated in the <a href="https://www.earth.com/news/temperatures-are-rising-unexpectedly-fast-on-the-tibetan-plateau/" target="_blank" rel="noreferrer noopener">Himalayas</a>, extending from India to the Tibetan Autonomous Region of China. It is renowned for its mesmerizing beauty and dramatic setting, with the lake lying at an elevation of about 4,350 meters.</p>



<p>One of the most distinctive features of Pangong Lake is its changing colors, ranging from shades of blue to green and even red, influenced by the sky's reflection and the lake's mineral content.</p>



<p>This saline water lake is approximately 134 kilometers long and 5 kilometers wide at its broadest point. Despite its considerable size, Pangong Lake is relatively shallow.&nbsp;</p>



<p>The lake gained additional popularity after being featured in several Indian films - most notably the Bollywood hit "3 Idiots." Its remote location requires a permit for visitors, especially due to its proximity to the Line of Actual Control between India and China.</p>



<p>Despite the geopolitical sensitivities surrounding its location, Pangong Lake remains a favorite among tourists for its unparalleled natural beauty and serene environment.</p>



<h2 class="wp-block-heading" id="h-high-altitude-lakes">High-altitude lakes</h2>



<p>High-altitude lakes are unique bodies of water found at elevations typically above 3,000 meters (about 10,000 feet) in mountain ranges like the <a href="https://www.earth.com/news/himalayan-glaciers-retreating-threat-is-much-worse-than-previously-believed/" target="_blank" rel="noreferrer noopener">Himalayas</a>, Andes, and Rockies. </p>



<p>These lakes are formed either by glacial activity, where glaciers erode the earth to create depressions that fill with melted snow and rainwater, or when natural dams created by landslides or moraines trap water in valleys.</p>



<h3 class="wp-block-heading" id="h-extreme-environments">Extreme environments</h3>



<p>The conditions at high altitudes make these lakes distinct in several ways. The climate is typically colder and harsher, with significant temperature variations between day and night. </p>



<p>This extreme environment affects both the physical characteristics of the <a href="https://www.earth.com/news/alarming-study-most-of-the-worlds-largest-lakes-are-quickly-losing-water/" target="_blank" rel="noreferrer noopener">lakes</a> and the types of ecosystems they support. For example, due to lower atmospheric pressure, the boiling point of water is reduced, which can affect the type of life that can survive in these regions.</p>



<h3 class="wp-block-heading" id="h-critical-habitats">Critical habitats</h3>



<p>Biologically, high-altitude lakes often have limited biodiversity because only certain types of plants and animals can tolerate the cold temperatures and lower oxygen levels in the water. </p>



<p>Despite this, these lakes are crucial habitats for some unique species of fish, birds, and other wildlife. They also serve as important indicators of climate change, as variations in their water levels and temperatures can reflect environmental shifts.</p>



<h3 class="wp-block-heading" id="h-significance-of-high-altitude-lakes">Significance of high-altitude lakes </h3>



<p>Lakes at high altitudes are often clear and pristine, due to the low density of human populations in these areas and minimal industrial activity, making them significant for ecological studies and attractive for tourism. </p>



<p>However, they are sensitive ecosystems, and increased tourist activity brings challenges like pollution and habitat disruption.</p>



<p>High-altitude lakes are not only beautiful and scientifically significant but also hold cultural importance for local communities, often considered sacred and associated with historical and spiritual significance.</p>



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



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Pangong Lake on the Tibetan Plateau

<p>Today's <strong>Image of the Day</strong> from the European Space Agency features the star-forming region NGC 604, which is located 2.73 million light-years away from Earth in the Triangulum Galaxy (M33). The image was captured by the James Webb Space Telescope.</p>



<p>By studying regions like NGC 604, astronomers can gain insights into the complex interactions between stars and the interstellar medium, as well as the conditions that lead to the birth of stars. This, in turn, helps in understanding the evolution of <a href="https://www.earth.com/news/galaxies-like-our-own-milky-way-are-not-unique/" target="_blank" rel="noreferrer noopener">galaxies</a> and the universe as a whole.</p>



<h2 class="wp-block-heading" id="h-massive-stars-of-ngc-604">Massive stars of NGC 604</h2>



<p>"Sheltered among NGC 604’s dusty envelopes of gas are more than 200 of the hottest, most massive kinds of stars, all in the early stages of their lives," said <a href="https://www.esa.int/" target="_blank" rel="noreferrer noopener">ESA</a>.</p>



<p>"These types of stars are known as B-types and O-types, the latter of which can be more than 100 times the mass of our own Sun. It’s quite rare to find this concentration of them in the nearby universe. In fact, there’s no similar region within our own Milky Way galaxy."</p>



<p>According to ESA, this concentration of massive stars, combined with its relatively close distance, means that NGC 604 gives astronomers an opportunity to study these objects at a fascinating time early in their life.</p>



<h2 class="wp-block-heading" id="h-gigantic-region-of-ionized-hydrogen">Gigantic region of ionized hydrogen</h2>



<p>NGC 604 is one of the largest known regions of ionized hydrogen, also known as an H II region. This nebula is significantly larger than the Orion Nebula, which is one of the most well-known H II regions in our own <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 galaxy</a>.&nbsp;</p>



<p>NGC 604 spans about 1,500 light-years across, making it one of the largest H II regions in the Local Group of galaxies. This group includes the Milky Way, the Andromeda Galaxy, and about 54 other smaller galaxies.&nbsp;</p>



<h2 class="wp-block-heading" id="h-ngc-604-starburst-phenomenon">NGC 604 starburst phenomenon </h2>



<p>Within NGC 604, there are hundreds of young, hot, massive <a href="https://www.earth.com/news/stars-at-the-edge-of-our-milky-way-galaxy-travel-more-slowly/" target="_blank" rel="noreferrer noopener">stars</a>. These stars have ionized the surrounding gas, causing it to glow and creating the nebula. The region is a prime example of a starburst phenomenon, where stars form at a much higher rate than in typical galactic conditions.</p>



<p>“The bright orange streaks in this image signify the presence of carbon-based molecules known as polycyclic aromatic hydrocarbons, or PAHs," explained ESA.</p>



<p>"As you travel further from the immediate cavities of dust where the star is forming, the deeper red signifies molecular hydrogen. This cooler gas is a prime environment for star formation. Ionized hydrogen from ultraviolet radiation appears as a white and blue ghostly glow."</p>



<h2 class="wp-block-heading" id="h-more-about-star-formation">More about star formation </h2>



<p>Star formation is crucial for the evolution of galaxies and the synthesis of heavy elements. In the cores of stars, elements heavier than helium are created.</p>



<p>The elements are spread throughout the <a href="https://www.earth.com/news/ancient-stars-shakti-shiva-shaped-milky-way-galaxy/" target="_blank" rel="noreferrer noopener">galaxy</a> when stars reach the end of their lives and expel their material - either gently through winds or violently via supernova explosions. This enriching process allows for the formation of new stars and planets, and ultimately, the potential for life.</p>



<h3 class="wp-block-heading">Cloud collapse</h3>



<p>The process begins when part of a molecular cloud becomes unstable and starts to collapse under its own gravity. This can be triggered by events like shock waves from nearby <a href="https://www.earth.com/news/supernova-explosions-could-damage-distant-planets/" target="_blank" rel="noreferrer noopener">supernovae</a>, galactic collisions, or the influence of other massive stars.</p>



<h3 class="wp-block-heading">Formation of a protostar</h3>



<p>As the cloud collapses, it fragments into smaller clumps. Each clump will eventually form one or more stars. </p>



<p>The material within these clumps continues to fall inward, heating up as it does so, eventually forming a warm core called a protostar. At this stage, the protostar is not yet hot enough for nuclear fusion (the process that powers stars) to occur.</p>



<h3 class="wp-block-heading">Accretion disk</h3>



<p>Around the protostar, material from the surrounding cloud continues to fall inward, forming a rotating disk. This material slowly accretes onto the protostar, increasing its mass.</p>



<h3 class="wp-block-heading">Nuclear fusion begins</h3>



<p>Once the core of the protostar reaches a high enough temperature and pressure, hydrogen atoms begin to fuse into helium, releasing energy in the process. This marks the transition from a protostar to a main sequence star, like our sun.</p>



<h3 class="wp-block-heading">Main sequence and beyond</h3>



<p>The star will spend the majority of its life in the main sequence stage, where it balances the gravitational forces trying to collapse it and the outward pressure from nuclear fusion. </p>



<p>Eventually, the star will exhaust its hydrogen fuel. Its subsequent evolution will depend on its initial mass, leading to various end stages such as red giants, supernovae, neutron stars, or black holes.</p>



<p>Image Credit: NASA/ESA/CSA James Webb Space Telescope</p>



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



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

Young, massive stars in the Triangulum Galaxy

<p>The Winter Solstice, often referred to as “the shortest day of the year,” is an astronomical event that marks the beginning of winter in the Northern Hemisphere.</p>



<p>In this region of the world, the solstice also marks the turning point when days gradually grow longer.</p>



<p>While the solstice represents the start of <a href="https://www.earth.com/news/why-winters-are-getting-colder-while-world-is-getting-warmer/" target="_blank" rel="noreferrer noopener">winter</a>, the coldest temperatures often occur weeks later due to the “seasonal lag,” as the Earth continues losing heat.</p>



<p>Beyond its scientific significance, the winter solstice has profound cultural, spiritual, and historical importance across the globe.</p>



<h2 class="wp-block-heading" id="h-what-is-the-winter-solstice">What is the Winter Solstice?</h2>



<p>The winter solstice occurs when one of Earth’s poles is tilted farthest away from the Sun, resulting in the least amount of <a href="https://www.earth.com/news/do-we-actually-benefit-from-daylight-saving-time/" target="_blank" rel="noreferrer noopener">daylight</a>. This happens because Earth's axis is tilted at approximately 23.5 degrees relative to its orbit around the Sun.&nbsp;</p>



<p>“Earth’s axis may be imagined as an imaginary pole going right through the center of our planet from ‘top’ to ‘bottom.’ Earth spins around this pole, making one complete turn each day. That is why we have day and night,” explained <a href="https://blogs.nasa.gov/Watch_the_Skies/tag/solstice/" target="_blank" rel="noreferrer noopener">NASA</a>.</p>



<p>In the Northern Hemisphere, the Winter Solstice typically occurs between December 20 and 23, with December 21 being the most common date.</p>



<p>On this day, the Sun appears to travel its shortest path across the sky. For those at the Arctic Circle, the Sun may not rise at all, creating 24 hours of darkness. Conversely, the Antarctic Circle experiences 24 hours of daylight.</p>



<h2 class="wp-block-heading" id="h-cultural-significance-of-the-winter-solstice">Cultural significance of the Winter Solstice </h2>



<p>The Winter Solstice has been celebrated across cultures for thousands of years. Early humans observed the solstice as a critical marker of <a href="https://www.earth.com/news/peoples-moral-values-literally-change-with-the-weather/" target="_blank" rel="noreferrer noopener">seasonal change</a>, signifying the gradual return of longer daylight hours and the promise of spring.</p>



<h3 class="wp-block-heading" id="h-stonehenge">Stonehenge</h3>



<p>This ancient monument in England aligns with the solstices, suggesting its builders may have used it as a calendar to track astronomical events.</p>



<p>Constructed in several phases between roughly 3000 BCE and 2000 BCE, <a href="https://www.earth.com/news/stonehenges-famous-altar-stone-has-surprising-origins/" target="_blank" rel="noreferrer noopener">Stonehenge</a> remains a mystery regarding its exact purpose. It may have served as a burial ground or a ceremonial site.</p>



<h3 class="wp-block-heading" id="h-yule-in-norse-tradition">Yule in Norse tradition</h3>



<p>The Norse people celebrated Yule, lighting fires to symbolize the Sun's rebirth and feasting to mark the turning of the season.</p>



<p>Yule coincided with the darkest days of the year. The festival celebrated the return of the Sun and the lengthening of days, symbolizing hope and renewal.</p>



<p>Yule was dedicated to the gods, particularly Odin, who was associated with wisdom, magic, and the Wild Hunt - a ghostly procession believed to occur during this time. Offerings, feasts, and sacrifices were made to gain their favor.</p>



<h3 class="wp-block-heading" id="h-saturnalia-in-ancient-rome-nbsp">Saturnalia in ancient Rome&nbsp;</h3>



<p>Saturnalia was one of the most popular festivals in ancient Rome, held in honor of Saturn, the god of agriculture, wealth, and time.&nbsp;</p>



<p>Celebrated annually in mid-December, the festival originally lasted for a single day (December 17) but eventually expanded to a week. The celebration involved feasting, gift-giving, and a temporary social reversal where traditional roles were upended.</p>



<h3 class="wp-block-heading" id="h-dongzhi-in-east-asia">Dongzhi in East Asia </h3>



<p>Dongzhi (冬至), meaning "Winter Solstice" in Chinese, is an important festival in East Asia.&nbsp;</p>



<p>Rooted in the philosophy of Yin and Yang, Dongzhi symbolizes the balance and transformation of natural energies as the days begin to lengthen, bringing more light and warmth.</p>



<p>Modern celebrations like Christmas and Hanukkah incorporate elements of these ancient traditions, emphasizing light and hope during the darkest days of the year.</p>



<h2 class="wp-block-heading" id="h-a-universal-reminder">A universal reminder</h2>



<p>The Winter Solstice is more than just an astronomical event; it serves as a reminder of nature’s rhythms and humanity’s enduring connection to the <a href="https://www.earth.com/news/anthropic-principle-we-live-in-a-universe-fine-tuned-to-support-life/" target="_blank" rel="noreferrer noopener">universe</a>. It symbolizes resilience, as the darkest day paves the way for the return of light.&nbsp;</p>



<p>Across millennia, it has inspired wonder, reflection, and celebration - a testament to the timeless bond between Earth, its inhabitants, and the heavens.</p>



<h2 class="wp-block-heading" id="h-a-spiritual-turning-point">A spiritual turning point</h2>



<p>The solstice encourages people to look inward, reflect on the past year, and set intentions for the year ahead, aligning with the natural pause of winter.</p>



<p>This occasion represents the balance and cycles of life, urging us to embrace both light and shadow in our personal journeys.</p>



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



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Winter Solstice: The shortest day of the year has arrived

The Winter Solstice, often referred to as “the shortest day...

<p>In the depths of planet Earth, a hidden microbial world thrives under extreme conditions that are beyond the reach of our regular perception.</p>



<p>This extraordinary and invisible ecosystem harbors an abundance of life forms that flourish in environments such as gold mines, aquifers, and deep boreholes in the seafloor.</p>



<p>But how do these below-the-surface microbiomes compare to the vibrant ecosystems bathed in Earth's sunlight?</p>



<h2 class="wp-block-heading" id="h-discovering-the-microbial-deep-dwellers">Discovering the microbial deep dwellers</h2>



<p>Researchers have now investigated this question in a first-of-its-kind comprehensive endeavor undertaken at the <a href="https://www.mbl.edu/" target="_blank" rel="noreferrer noopener">Marine Biological Laboratory</a> (MBL).</p>



<p>What they found was incredibly rich <a href="https://www.earth.com/news/microbial-life-soil-planet-warming-global-carbon-cycle/" target="_blank" rel="noreferrer noopener">microbial diversity</a> in certain subsurface habitats, which extended up to 491 meters (1,610 feet) below the seafloor and 4,375 meters (14,300 feet) below ground level in terrestrial habitats.</p>



<p>This unprecedented revelation hints at vast, unexplored, subsurface sources of diversity, and presents possible opportunities for finding new compounds and medicines.</p>



<p>The study holds potential for identifying how cells adapt to extremely energy-scarce environments. The findings may also be useful in the search for <a href="https://www.earth.com/news/expanding-the-search-for-extraterrestrial-life/" target="_blank" rel="noreferrer noopener">extraterrestrial life</a>.</p>



<h2 class="wp-block-heading" id="h-microbial-diversity-below-the-surface">Microbial diversity below the surface</h2>



<p>The study's lead scientist, MBL associate scientist Emil Ruff, addressed some of the common assumptions about life below the Earth's surface.</p>



<p>“It’s commonly assumed that the deeper you go below the <a href="https://www.earth.com/news/mystery-of-how-diamonds-reach-the-earths-surface-finally-solved/" target="_blank" rel="noreferrer noopener">Earth’s surface</a>, the less energy is available, and the lower is the number of cells that can survive,” noted Ruff. </p>



<p>“Whereas the more energy present, the more diversity can be generated and maintained - as in tropical forests or coral reefs, where there’s lots of sun and warmth."</p>



<p>However, the study’s findings tell a different story. In some subsurface habitats, microbial diversity can easily match or surpass the diversity on the surface.</p>



<p>This was found to be especially true for marine environments and for <a href="https://www.earth.com/news/living-microbes-discovered-in-2-billion-year-old-rocks/" target="_blank" rel="noreferrer noopener">microbes</a> in the Archaea domain.</p>



<h2 class="wp-block-heading" id="h-a-tale-of-two-realms">A tale of two realms</h2>



<p>The study, which took almost a decade to complete, was also one of the first to compare marine and terrestrial environments in terms of microbial diversity and community composition.</p>



<p>While the experts found that the marine and terrestrial microbiomes differed greatly in composition, their level of diversity was similar. This finding gives rise to a fundamental ecological principle.</p>



<p>“There’s a very clear divide between <a href="https://www.earth.com/news/diverse-life-forms-from-800-million-years-ago-redefine-evolution/" target="_blank" rel="noreferrer noopener">life forms</a> in the marine and in the terrestrial realms, not just in the surface, but also in the subsurface. The selective pressures are very different on land and in the sea, and they select for different organisms that have a hard time living in both realms," explained Ruff.</p>



<h2 class="wp-block-heading" id="h-microbes-in-low-energy-environments">Microbes in low-energy environments</h2>



<p>The existence of a vast reservoir of microbes kilometers deep - both under our feet and beneath the seafloor - was first broadly recognized by scientists in the mid-1990s.</p>



<p>Now, scientists estimate that between 50 and 80 percent of Earth’s microbial cells live in the subsurface sediments, where energy availability is significantly lower than on the sunlit surface.</p>



<p>The study suggests that potentially half of Earth's microbial diversity can be found in <a href="https://www.earth.com/news/human-activities-great-harm-earth-subsurface-deep-interior/" target="_blank" rel="noreferrer noopener">subsurface zones</a>.</p>



<p>In addition, the findings point towards a fascinating phenomenon: in these low-energy environments, life appears to be slowed down to an absolute minimum. Some subsurface cells are estimated to divide only once every 1,000 years. </p>



<p>These microbes live on completely different timescales and could provide intriguing insights about aging.</p>



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



<p>If planets like <a href="https://www.earth.com/news/hidden-water-found-on-mars-would-cover-the-planet-over-one-mile-deep/" target="_blank" rel="noreferrer noopener">Mars had liquid water</a> at some point in their history, the rocky ecosystems below their surface could resemble those currently on Earth.</p>



<p>“The energy would be very low; the organisms’ generation times would be very long. Understanding deep life on Earth could be a model for discovering if there was life on Mars, and if it has survived,” said Ruff.</p>



<h2 class="wp-block-heading" id="h-microbiomes-of-diverse-locations-on-earth">Microbiomes of diverse locations on Earth</h2>



<p>Past studies of microbial life on Earth’s surface and subsurface aren't scarce, but synthesizing the data was challenging due to inconsistencies in methodology across different research groups.</p>



<p>However, in 2016, a breakthrough method allowed for a consistent dataset to compare more than 1,000 samples from 50 marine and terrestrial ecosystems.</p>



<p>Samples from around the world were sent to MBL, where scientists used identical routines to sequence and analyze the microbial DNA present. </p>



<p>This consistent methodology allowed for the first direct comparison of microbiomes from vast and diverse locations.</p>



<p>Ultimately, the research serves as a foundation for exposing the rich tapestry of life forms that inhabit the invisible worlds below the Earth’s crust.</p>



<p>As we continue to explore these subsurface habitats, we stand to learn much about the adaptability and resilience of life in its myriad forms.</p>



<p>The full study was published in the journal <em><a href="https://www.science.org/doi/10.1126/sciadv.adq0645" target="_blank" rel="noreferrer noopener">Science Advances</a></em>.</p>



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



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Half of Earth's microbial life may be hiding beneath the surface

In the depths of planet Earth, a hidden microbial world...

<p>Despite their reputation as buzzing nuisances, flies serve a critical role as some of the Earth's most prolific pollinators. A new study led by Penn State scientists suggests that flies are increasingly at risk due to rising global temperatures.</p>



<p>An international team of researchers examined the heat tolerance of various bee and fly species in tropical and subtropical regions of the Americas.&nbsp;</p>



<p>The results indicate that flies are more vulnerable to <a href="https://www.earth.com/news/how-climate-change-is-buzzing-off-bumblebee-senses/" target="_blank" rel="noreferrer noopener">warming climates</a> than bees, since bees can handle significantly higher temperatures and occupy a broader range of habitats.</p>



<p>“Bees and flies are essential for pollinating plants, both in the wild and in agriculture,” said Margarita López-Uribe, an expert in pollinator health at <a href="https://www.psu.edu/" target="_blank" rel="noreferrer noopener">Penn State</a> and lead author on the study. “However, these vital insects are declining due to habitat loss, pesticides, disease and the growing threat of climate change.”</p>



<h2 class="wp-block-heading" id="h-flies-are-underappreciated-yet-vital-pollinators">Flies are underappreciated yet vital pollinators</h2>



<p>Flies, second only to <a href="https://www.earth.com/news/bees-do-not-learn-to-be-cooperative-it-is-in-their-genes/" target="_blank" rel="noreferrer noopener">bees</a> in terms of the volume of crops and habitats they pollinate, play a crucial role in sustaining wild ecosystems.&nbsp;</p>



<p>By facilitating the reproduction of numerous plant species, flies help maintain biodiversity and provide resources for countless other organisms. They also increasingly contribute to agriculture - for example, flies serve as the primary pollinators of cocoa trees, the source of chocolate.</p>



<p>A 2020 analysis of global crops found that the 105 most widely planted crops benefiting from pollinators represent more than $800 billion in gross economic value. Among these pollinators, flies, specifically hoverflies and blowflies, consistently ranked just behind bees.</p>



<p>“It's time we gave flies some more recognition of their role as pollinators,” López-Uribe said. “Flies have a significant role, but they don't get as much attention - and they are vulnerable in all the same ways that bees are.”</p>



<h2 class="wp-block-heading" id="h-flies-bees-and-climate-change">Flies, bees, and climate change </h2>



<p>Because insects cannot easily control their body temperatures, rising global temperatures present a serious challenge. </p>



<p>To assess how different <a href="https://www.earth.com/news/pollinators-face-extinction-risk-due-to-climate-change/" target="_blank" rel="noreferrer noopener">pollinators</a> might cope, the research team measured the “critical thermal maximum” (CTMax) - the highest temperature at which insects can still move - of both bees and flies.</p>



<p>They found that bees can tolerate substantially warmer conditions than flies. On average, bees had a CTMax 2.3 degrees Celsius higher than that of flies.&nbsp;</p>



<p>Additionally, bees foraging in cooler morning hours proved more heat-tolerant than those active in warmer afternoons.&nbsp;</p>



<p>Geographic factors also mattered - pollinators living at high-elevation tropical sites showed lower CTMax values than their counterparts in subtropical areas.</p>



<h2 class="wp-block-heading" id="h-data-collection-across-the-americas">Data collection across the Americas</h2>



<p>The study’s data collection occurred during COVID-19 lockdowns, so international students from Penn State and other universities conducted research in their home countries.&nbsp;</p>



<p>Instead of traveling, students worked with equipment sent to them, gathering measurements in their own kitchens and backyards.</p>



<p>“We sent out all of the equipment to do the study to students throughout the U.S. and South America,” López-Uribe said. “These students were collecting the data in their houses, using their kitchens to understand the thermal ecology these insects could withstand.”</p>



<p>“We effectively were able to provide an international research experience without being able to travel internationally.”</p>



<h2 class="wp-block-heading" id="h-flies-battling-climate-change">Flies battling climate change </h2>



<p>The findings suggest that insects from cooler, high-altitude environments, such as Cajicá in Colombia, are particularly susceptible to even slight temperature increases.&nbsp;</p>



<p>Since flies are often the primary pollinators in alpine and subarctic regions, their reduced ability to withstand warming could jeopardize entire ecosystems.</p>



<p>“In alpine and subarctic environments, flies are the primary pollinator,” López-Uribe said. “This study shows us that we have entire regions that could lose their primary pollinator as the <a href="https://www.earth.com/news/how-climate-change-is-buzzing-off-bumblebee-senses/" target="_blank" rel="noreferrer noopener">climate</a> warms, which could be catastrophic for those ecosystems.”</p>



<p>As climate change continues to reshape global temperatures, understanding the vulnerabilities of flies - as well as bees - will be key in guiding conservation efforts.&nbsp;</p>



<p>Without recognizing and protecting the essential pollination services flies provide, communities may face declining biodiversity, reduced crop yields, and unstable ecological networks in the years to come.</p>



<p>The study is published in the <a href="https://dx.doi.org/10.17161/jom.vi122.22505" target="_blank" rel="noreferrer noopener"><em>Journal of Melittology</em></a>.</p>



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



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Flies are more vulnerable to climate change than bees

Despite their reputation as buzzing nuisances, flies serve a critical...


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<p>Today’s <strong>Video of the Day</strong> from the <a href="https://www.esa.int/">European Space Agency</a> describes why satellite images and measurements of our planet have become &#8220;essential to our survival, offering a new outlook of our world.&#8221;&nbsp;</p>



<p>Rising sea levels pose one of the biggest societal threats associated with climate change. According to ESA, satellite altimeter missions such as Copernicus Sentinel-6 are essential in monitoring global and regional changes in sea level.</p>



<p>&#8220;Unbeknown to many, the island of Crete, Greece, plays an important role in the Copernicus satellite altimetry constellation and on an international stage,&#8221; reports ESA.</p>



<p>&#8220;Satellite altimetry data have to be continuously monitored at the ESA’s Permanent Facility for Altimetry Calibration where different techniques have pioneered the use of transponders to provide the best measurements to validate satellite altimeters in space soon after launch.&#8221;</p>



<p>Dr. Craig Donlon explains that, by understanding planet Earth through satellite measurements, we are able to find evidence of change.&nbsp;</p>



<p><em>Video Credit: European Space Agency&nbsp;</em></p>



<p><em>&#8211;</em><em>&#8212;</em></p>



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


Satellites have become essential to our survival