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  

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; Antennae Galaxies in a deadly embrace “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...

Today's Image of the Day from the European Space Agency features a compilation of European cities that resemble stars. 



“Star-shaped cities are scattered across Europe, their geometric designs most appreciated when viewed from above,” noted <a href="https://www.esa.int/ESA_Multimedia/Images/2024/12/Earth_from_Space_Star_cities" target="_blank" rel="noreferrer noopener">ESA</a>. 



<h2 class="wp-block-heading" id="h-development-of-star-shaped-cities">Development of star-shaped cities</h2>



The development of star-shaped fortresses, also known as bastion forts, emerged during the Renaissance in Italy as a response to the rapidly evolving art of <a href="https://www.earth.com/news/migrating-eagles-have-been-rerouted-by-the-war-in-ukraine/" target="_blank" rel="noreferrer noopener">warfare</a>.&nbsp;



Traditional medieval fortifications, characterized by high, straight walls and square towers, became vulnerable with the advent of gunpowder weaponry. Cannons could easily reduce these structures to rubble, rendering them obsolete.



The star-shaped design addressed these vulnerabilities by incorporating wide moats and projecting bastions - angled structures that jutted outward from the main walls.&nbsp;



These bastions provided overlapping fields of fire, allowing defenders to cover blind spots and effectively repel attackers attempting to approach or scale the walls.&nbsp;



Additionally, the sloped walls of these fortresses, known as glacis, were designed to deflect cannonballs rather than absorb their impact, further enhancing their resilience.



This innovative design not only improved defensive capabilities but also transformed the battlefield, forcing attackers to develop new siege techniques. It marked a pivotal moment in military engineering, influencing fortress construction across Europe and beyond for centuries.



<h2 class="wp-block-heading" id="h-examples-of-star-shaped-cities">Examples of star-shaped cities</h2>



“Four examples of such cities can be seen here, arranged clockwise from the top left: Bourtange in the Netherlands, Palmanova in Italy, Almeida in Portugal, and Neuf-Brisach in France,” said ESA.



“The green and red hues evoke a Christmas vibe, achieved through different band combinations during image processing to generate true-color (green) and false-color (red) visuals.”



<h3 class="wp-block-heading" id="h-bourtange-netherlands">Bourtange, Netherlands </h3>



Fort Bourtange, nestled in the picturesque countryside of northeast Netherlands near the German border, is a remarkable example of Renaissance military architecture and urban planning.&nbsp;



Constructed in 1593 during the Eighty Years' War, it was strategically positioned to control the only road linking Germany to the Dutch city of Groningen - a vital route for military and trade purposes.&nbsp;



Its unique pentagonal, star-shaped design featured angled bastions, wide moats, and interconnected defensive structures, making it nearly impenetrable to enemy forces equipped with the era's artillery.



In 1851, after centuries of military service, Fort Bourtange was decommissioned and transformed into a peaceful village.&nbsp;



Despite the change in purpose, its original geometric layout, defined by precise angles and symmetrical patterns, remained intact. The pentagonal walls, surrounding waterways, and radial street design continue to showcase the ingenuity of its designers.



<h3 class="wp-block-heading" id="h-palmanova-italy">Palmanova, Italy </h3>



Palmanova, located in the Friuli-Venezia Giulia region of northeast Italy, is a masterpiece of Renaissance urban and military planning.&nbsp;



Designated as a UNESCO World Heritage site, it exemplifies the idealized city envisioned during the late Renaissance, combining beauty, functionality, and <a href="https://www.earth.com/news/preparing-u-s-military-bases-for-sea-level-rise/" target="_blank" rel="noreferrer noopener">military</a> innovation.&nbsp;



Constructed in 1593 by the Republic of Venice, Palmanova was strategically designed to protect the Republic’s northeastern borders from external threats - particularly the Ottoman Empire.



The city’s layout embodies the principles of symmetry and order characteristic of the Renaissance. Its unique radial design spreads out from the central hexagonal square, known as Piazza Grande or Piazza del Duomo, which serves as the civic and social heart of the city.&nbsp;



From this central hub, six straight avenues fan outward, connecting the square to the surrounding neighborhoods and gates. This design was not only aesthetically pleasing but also practical, allowing for efficient movement and communication within the city.



Today, Palmanova is celebrated not only for its historical and architectural significance but also as a rare example of a perfectly preserved star fortress.&nbsp;



<h3 class="wp-block-heading" id="h-almeida-portugal-nbsp">Almeida, Portugal&nbsp;</h3>



Perched on a high plain in northeast Portugal near the Spanish border, the fortress of Almeida is a striking example of military engineering and a symbol of Portugal’s resilience.&nbsp;



Built to secure the nation’s eastern frontier, Almeida has played a significant role in Portuguese history, particularly during its early years of independence and throughout various military conflicts, including the Peninsular War.



The fortress's defining star-shaped ramparts consist of twelve points, each projecting outward to eliminate blind spots and provide overlapping fields of fire against advancing enemies.&nbsp;



The thick walls, surrounding moats, and angular bastions made Almeida a formidable stronghold capable of withstanding prolonged sieges.



<h3 class="wp-block-heading" id="h-neuf-brisach-france">Neuf-Brisach, France</h3>



Neuf-Brisach, located in the Alsace region of northeastern <a href="https://www.earth.com/news/470-million-year-old-animal-fossils-discovered-in-frances-cabrieres-biota/" target="_blank" rel="noreferrer noopener">France</a> near the German border, is another fascinating example of military and urban design.&nbsp;



The town was constructed in 1697 after the loss of Breisach, which stood on the opposite bank of the Rhine River in Germany.&nbsp;



The name "Neuf" (meaning "new" in French) reflects its creation as a strategic replacement and fortification to strengthen France's defense along its eastern border.



Designed by Sébastien Le Prestre de Vauban, the renowned military engineer under King Louis XIV, Neuf-Brisach is part of the extensive network of fortifications that Vauban designed to protect France from external threats.&nbsp;



Vauban's expertise in defensive architecture is evident in the town's star-shaped layout, which was intended to optimize defense while accommodating civilian life within the fortifications.&nbsp;



The fortifications were built to withstand sieges and were strategically positioned to control movement across the Rhine River and defend against potential invasions. The outer star-shaped ramparts extend in a way that creates a nearly impenetrable defensive perimeter.



Image Credit: European Space Agency&nbsp;



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Star-shaped cities scattered across Europe

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

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a close-up view of Pluto captured by the New Horizons spacecraft in 2015. 

A new study published in Nature Communications has revealed that some of the mountains discovered on Pluto during the New Horizons flyby are covered by a blanket of methane ice. 

Using numerical simulations from the planet's climate, the scientists determined that the ice caps detected on Mars are created through very different processes than they are on Earth.

On Pluto, the atmosphere actually gets warmer with altitude, rather than colder like on Earth. However, the atmosphere of Pluto is too thin to affect the surface temperatures at high elevations. 

“It is particularly remarkable to see that two very similar landscapes on Earth and Pluto can be created by two very dissimilar processes,” said study lead author Tanguy Bertrand, who is a postdoctoral researcher at NASA’s Ames Research Center. “Though theoretically objects like Neptune’s moon Triton could have a similar process, no other place in our solar system has ice-capped mountains like this besides Earth.”

The research team determined that Pluto has more gaseous methane at its warmer, higher altitudes. This methane gas can saturate, condense, and then freeze directly on mountain peaks, which is the exact opposite of the sublimation process on Earth.

“Pluto really is one of the best natural laboratories we have to explore the physical and dynamic processes involved when compounds that regularly transition between solid and gas states interact with a planetary surface,” said Bertrand. “The New Horizons flyby revealed astonishing glacial landscapes we continue to learn from.”

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Ice-capped mountains discovered on Pluto

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

The peak of fall colors in Ottawa, Canada. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features the colorful leaves of fall in the Canadian capital of Ottawa. The peak of the autumn season is an event that is known locally as the "Fall Rhapsody." 

Just west of city in Gatineau Park, sugar maple leaves turn orange-red, while hickories turn golden-bronze.

Ottawa is located at the confluence of three important waterways: the Ottawa River, the Gatineau River, and the Rideau Canal. The peak of fall colors in Ottawa, Canada

The Ottawa River is a major source of fresh drinking water and connects to the Saint-Lawrence River further east. Various <a title="Indigenous peoples in Canada" href="https://en.wikipedia.org/wiki/Indigenous_peoples_in_Canada">Indigenous peoples inhabited what is now Canada</a> for thousands of years before European colonization. Beginning in the 16th century, <a title="British colonization of the Americas" href="https://en.wikipedia.org/wiki/British_colonization_of_the_Americas">British</a> and <a title="French colonization of the Americas" href="https://en.wikipedia.org/wiki/French_colonization_of_the_Americas">French</a> expeditions explored and later settled along the Atlantic coast. As a consequence of <a title="Military history of Canada" href="https://en.wikipedia.org/wiki/Military_history_of_Canada">various armed conflicts</a>, France ceded nearly all of <a title="New France" href="https://en.wikipedia.org/wiki/New_France">its colonies in North America</a> in 1763. 

In 1867, with the union of three <a title="British North America" href="https://en.wikipedia.org/wiki/British_North_America">British North American</a> colonies through <a title="Canadian Confederation" href="https://en.wikipedia.org/wiki/Canadian_Confederation">Confederation</a>, Canada was formed as a <a title="Federalism" href="https://en.wikipedia.org/wiki/Federalism">federal</a> <a class="mw-redirect" title="British Dominions" href="https://en.wikipedia.org/wiki/British_Dominions">dominion</a> of four provinces. This began an <a title="Territorial evolution of Canada" href="https://en.wikipedia.org/wiki/Territorial_evolution_of_Canada">accretion of provinces and territories</a> and a process of increasing autonomy from the <a title="United Kingdom" href="https://en.wikipedia.org/wiki/United_Kingdom">United Kingdom</a>. This widening autonomy was highlighted by the <a title="Statute of Westminster 1931" href="https://en.wikipedia.org/wiki/Statute_of_Westminster_1931">Statute of Westminster 1931</a> and culminated in the <a title="Canada Act 1982" href="https://en.wikipedia.org/wiki/Canada_Act_1982">Canada Act 1982</a>, which severed the vestiges of legal dependence on the <a title="Parliament of the United Kingdom" href="https://en.wikipedia.org/wiki/Parliament_of_the_United_Kingdom">British Parliament</a>.

The image was captured on October 14 by an astronaut onboard the International Space Station.

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

The peak of fall colors in Ottawa, Canada

The peak of fall colors in Ottawa, Canada. Today's Image...

August Complex fire leaves behind massive burn scar. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> shows the burn scar from the August Complex fire in Northern California.

The massive complex started out as 38 separate fires that were triggered by lightning on August 16 and 17.

The blaze consumed hundreds of thousands of acres of Mendocino National Forest, and impacted parts of the Shasta-Trinity and Six Rivers national forests as well. 

According to Cal Fire, more than 4.13 million acres have been consumed by fire so far this year in a total of 8,685 incidents that destroyed 9,200 structures and claimed the lives of 31 people. August Complex fire leaves behind massive burn scar. Northern California is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers include the San Francisco Bay Area, the Greater Sacramento area, and the Metropolitan Fresno area. Northern California also contains redwood forests, along with the Sierra Nevada, including Yosemite Valley and part of Lake Tahoe, Mount Shasta, and most of the Central Valley, one of the world's most productive agricultural regions.

The photo was captured on October 19, 2020 by the Operational Land Imager (OLI) on Landsat 8.

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

August Complex fire leaves behind massive burn scar

August Complex fire leaves behind massive burn scar. Today's Image...

Cameron Peak fire is now the largest in Colorado’s history. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> shows smoke plumes from the Cameron Peak fire in northern Colorado.

In mid-October, dry weather and strong winds significantly fueled the fire. By October 21, it had consumed 206,000 acres in the mountains west and northwest of Fort Collins and Estes Park.

The Cameron Peak fire has now become the largest in Colorado’s history, exceeding a new record set just last month by the Pine Gulch fire, which burned 139,007 acres. 

Meanwhile, a couple hours north of Denver, the East Troublesome Fire picked up momentum on Wednesday. The blaze is currently spreading so quickly that it is burning about 6,000 acres per hour. A typical fire in Larimer County is usually over within a few weeks but this fire came in waves over the course of four months, which was exhausting. The fire kept changing due to terrain and wind conditions, leading to the fire threatening every one of our mountain communities. As emergency managers, our job was to anticipate changing conditions and to plan for any impacts from the fire. We ended up utilizing every plan we have created over the last few years to manage this event, including emergency notifications, GIS (geographic information system mapping), evacuation and sheltering, feeding, public information management, resource management and credentialing for re-entry operations. This was the event that you plan for but always hope doesn’t happen.

The image was captured on October 16, 2020 by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite.

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Cameron Peak fire is now the largest in Colorado’s history

Cameron Peak fire is now the largest in Colorado’s history....

Winter arrives in the Dzhugdzhur Mountains. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features the Dzhugdzhur Mountains in the far east region of Siberia

By the time this natural-color photo was captured on October 9, 2020, the vibrant fall colors had faded to brown as winter began to arrive. 

Long shadows can be seen across the lower slopes as the sun sinks low on the horizon. Winter arrives in the Dzhugdzhur Mountains

In December, this part of Khabarovsk territory often sees average highs in the negative 20s and receives just 6 hours of Image Credit: NASA Earth Observatory The Dzhugdzhur Mountains or Jugjur Mountains, meaning 'big bulge' in <a title="Evenki language" href="https://en.wikipedia.org/wiki/Evenki_language">Evenki</a>[<a title="Wikipedia:Citation needed" href="https://en.wikipedia.org/wiki/Wikipedia:Citation_needed">citation needed</a>], are a mountain range in the far east of <a title="Siberia" href="https://en.wikipedia.org/wiki/Siberia">Siberia</a> that run along the entire northwest coast of the <a title="Sea of Okhotsk" href="https://en.wikipedia.org/wiki/Sea_of_Okhotsk">Sea of Okhotsk</a>. In the east, mountains emerge from the Stanovoy Range and run northeast for some 1500 kilometers before splitting three ways into the Chersky Range, Verkhoyansk Mountains, and Gydan Mountains. The mountains are quite deserted, the one exception being the <a title="Gold" href="https://en.wikipedia.org/wiki/Gold">gold</a> mines that have operated in the range since the 1920s.

 Australia's capital is <a title="Canberra" href="https://en.wikipedia.org/wiki/Canberra">Canberra</a>, and its largest <a title="List of cities in Australia by population" href="https://en.wikipedia.org/wiki/List_of_cities_in_Australia_by_population">city</a> is <a title="Sydney" href="https://en.wikipedia.org/wiki/Sydney">Sydney</a>. The country's other major <a title="List of cities in Australia" href="https://en.wikipedia.org/wiki/List_of_cities_in_Australia">metropolitan areas</a> are <a title="Melbourne" href="https://en.wikipedia.org/wiki/Melbourne">Melbourne</a>, <a title="Brisbane" href="https://en.wikipedia.org/wiki/Brisbane">Brisbane</a>, <a title="Perth" href="https://en.wikipedia.org/wiki/Perth">Perth</a>, and <a title="Adelaide" href="https://en.wikipedia.org/wiki/Adelaide">Adelaide</a>.

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Winter arrives in the Dzhugdzhur Mountains

Winter arrives in the Dzhugdzhur Mountains. Today's Image of the...

Springtime in the central Andes mountains. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features early springtime in the central Andes mountains of South America.

In September and October, the snow begins to melt and transforms into a primary water source for major rivers, which provide water to nearby towns for drinking, agriculture, and hydroelectric power.

The Andes stretch out across seven countries along the western coast of South America. This photograph shows about 400 miles of the mountain range in Chile and Argentina.

The image was captured on October 11, 2020 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.

The Andes, Andes Mountains or Andean Mountains (<a title="Spanish language" href="https://en.wikipedia.org/wiki/Spanish_language">Spanish</a>: Cordillera de los Andes) are the longest continental mountain range in the world, forming a continuous highland along the western edge of <a title="South America" href="https://en.wikipedia.org/wiki/South_America">South America</a>. The range is 7,000 km (4,350 mi) long, 200 to 700 km (124 to 435 mi) wide (widest between 18°S - 20°S latitude), and has an average height of about 4,000 m (13,123 ft). The Andes extend from north to south through seven South American countries: Venezuela, Colombia, <a title="Ecuador" href="https://en.wikipedia.org/wiki/Ecuador">Ecuador</a>, Peru, <a title="Bolivia" href="https://en.wikipedia.org/wiki/Bolivia">Bolivia</a>, <a title="Chile" href="https://en.wikipedia.org/wiki/Chile">Chile</a>, and Argentina.

Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high <a title="Plateau" href="https://en.wikipedia.org/wiki/Plateau">plateaus</a>—some of which host major cities such as <a title="Quito" href="https://en.wikipedia.org/wiki/Quito">Quito</a>, <a title="Bogotá" href="https://en.wikipedia.org/wiki/Bogot%C3%A1">Bogotá</a>, <a title="Cali" href="https://en.wikipedia.org/wiki/Cali">Cali</a>, Arequipa, <a title="Medellín" href="https://en.wikipedia.org/wiki/Medell%C3%ADn">Medellín</a>, Bucaramanga, Sucre, Mérida and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the <a title="Tropical Andes" href="https://en.wikipedia.org/wiki/Tropical_Andes">Tropical Andes</a>, the <a title="Dry Andes" href="https://en.wikipedia.org/wiki/Dry_Andes">Dry Andes</a>, and the <a title="Wet Andes" href="https://en.wikipedia.org/wiki/Wet_Andes">Wet Andes</a>.

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Springtime in the central Andes mountains

Springtime in the central Andes mountains. Today's Image of the...

Hudson Bay in late summer. Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a late summer view of Hudson Bay, which is located in northeastern Canada just south of the Arctic Circle. The photo shows the southern side of the ocean inlet, where it is bordered by Ontario.

The Hudson Bay receives fresh water from more than 40 major rivers. As sediment and dissolved organic matter mix in from various types of ecosystems, the color of the bay's salty water is changed. 

The image captures a brown sediment plume around Partridge Island that was carried in by the Severn River.Founded on 2 May 1670, the Hudson's Bay Company opened its first department store in 1881 in <a title="Winnipeg" href="https://en.wikipedia.org/wiki/Winnipeg">Winnipeg</a>, <a title="Manitoba" href="https://en.wikipedia.org/wiki/Manitoba">Manitoba</a>. The chain operated under the company name before being rebranded to The Bay in 1965. It operated exclusively in <a title="Western Canada" href="https://en.wikipedia.org/wiki/Western_Canada">Western Canada</a> until the acquisitions and conversions of department stores <a title="Morgan's" href="https://en.wikipedia.org/wiki/Morgan%27s">Morgan's</a>, <a title="Freimans" href="https://en.wikipedia.org/wiki/Freimans">Freimans</a>, <a title="Simpsons (department store)" href="https://en.wikipedia.org/wiki/Simpsons_(department_store)">Simpsons</a>, <a title="Woodward's" href="https://en.wikipedia.org/wiki/Woodward%27s">Woodward's</a>, coupled with the opening of new locations, positioned its presence nationwide in the second half of the 20th century. After nearly 50 years with The Bay brand, the chain was rebranded to Hudson's Bay with a modernized logo in 2013.

The photo was taken on September 19, 2020 by the Operational Land Imager (OLI) on Landsat 8.

Image Credit: NASA Earth Observatory 

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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Hudson Bay in late summer

Hudson Bay in late summer. Today's Image of the Day...

<a href="http://www.earth.com/video/houseplants-reduce-indoor-air-pollution/">Euphorbia milii</a> Crown of thorns is a succulent subshrub or shrub growing to 5 ft 11 in tall, with densely spiny stems. The straight, slender spines, up to 1.2 in long, help it scramble over other plants.

The leaves are found mainly on new growth, and are up to 1.4 in long and 0.59 in broad. The flowers are small, subtended by a pair of conspicuous petal-like bracts, variably red, pink or white, up to 12 mm (0.47 in) broad. The sap is moderately poisonous, and causes irritation on contact with skin or eyes.

If ingested, <a href="http://www.earth.com/video/houseplants-reduce-indoor-air-pollution/">Euphorbia milii</a> Crown of thorns causes severe stomach pain, irritation of the throat and mouth, and vomiting. The poisonous ingredients have been identified as phorbol esters. Wat Phrik in Thailand claims to be the home of the world's tallest Christ thorn plant. Euphorbia milii, the crown of thorns, Christ plant, or Christ thorn, called Corona de Cristo in Latin America (coroa-de-cristo in Brazil), is a <a title="Species" href="https://en.wikipedia.org/wiki/Species">species</a> of <a title="Flowering plant" href="https://en.wikipedia.org/wiki/Flowering_plant">flowering plant</a> in the spurge <a title="Family (biology)" href="https://en.wikipedia.org/wiki/Family_(biology)">family</a> Euphorbiaciae, <a title="Native plant" href="https://en.wikipedia.org/wiki/Native_plant">native</a> to <a title="Madagascar" href="https://en.wikipedia.org/wiki/Madagascar">Madagascar</a>. The species name commemorates <a class="extiw" title="fr:Pierre Bernard Milius" href="https://fr.wikipedia.org/wiki/Pierre_Bernard_Milius">Baron Milius</a>, once Governor of Réunion, who introduced the species to France in 1821. It is imagined that the species was introduced to the Middle East in ancient times, and legend associates it with the <a title="Crown of thorns" href="https://en.wikipedia.org/wiki/Crown_of_thorns">crown of thorns</a> worn by Christ.&lt; It is commonly used as an ornamental houseplant that can be grown in warmer climates. The common name is due to the thorns and deep red bracts referring to the crown thorn Jesus had to wear during his crucification and his blood.

Euphorbia milii can be propagated from cuttings.

Euphorbia milii -- Crown of thorns

Euphorbia milii Crown of thorns is a succulent subshrub or...

The world’s largest iceberg has astonished scientists by shaking free from a spinning ocean trap and continuing its trek across remote southern waters.



Its journey, marked by twists and turns since it separated from Antarctica, has become a focus for research on the changing ocean and the ice’s influence on life beneath the surface.



<h2 class="wp-block-heading" id="h-a23a-iceberg-breaks-free">A23a iceberg breaks free</h2>



The icy slab covers about 1,418 square miles, which makes it bigger than Rhode Island. 



It originally broke away from <a href="https://eros.usgs.gov/earthshots/filchner-ice-shelf-antarctica" target="_blank" rel="noreferrer noopener">Antarctica’s Filchner-Ronne Ice Shelf</a> in 1986 and remained stuck close to the continent for decades. 



Ocean currents and seafloor topography restricted its path. After finally regaining momentum last year, the towering block ran into a swirling formation of water near the <a href="https://www.ndsu.edu/subantarctic/southorkney.htm">South Orkney Islands</a>, where it ended up spinning in place for months.



<h2 class="wp-block-heading" id="h-tracking-iceberg-movements">Tracking iceberg movements</h2>



“It’s exciting to see A23a on the move again after periods of being stuck,” said <a href="https://www.bas.ac.uk/media-post/worlds-largest-iceberg-a23a-breaks-free/">Dr Andrew Meijers</a>, an oceanographer at the <a href="https://www.bas.ac.uk/" target="_blank" rel="noreferrer noopener">British Antarctic Survey</a>.



Ocean experts have been monitoring this <a href="https://www.earth.com/news/worlds-largest-iceberg-a23a-undergoing-major-erosion/" target="_blank" rel="noreferrer noopener">iceberg’s</a> every move to understand how such massive blocks can influence sea circulation, temperature balance, and the distribution of nutrients.



<h2 class="wp-block-heading" id="h-new-chapter-for-the-a23a-iceberg">New chapter for the A23a iceberg</h2>



The <a href="https://www.earth.com/news/birth-of-an-iceberg-a-83-breaks-free-from-antarctica/" target="_blank" rel="noreferrer noopener">iceberg’s</a> latest departure from its watery prison has stirred up fresh discussions about its fate. 



As it progresses northward, warmer seas may take a toll on its bulk. Many large ice masses follow a similar route before gradually disintegrating. Scientists emphasize that ice already afloat in the water does not raise sea levels when it melts. That does not mean these events should be dismissed, though, since Antarctica’s overall health is a concern in a warming world.



<h2 class="wp-block-heading" id="h-a23a-iceberg-and-its-ocean-impacts-nbsp">A23a iceberg and its ocean impacts&nbsp;</h2>



Researchers have pointed out that although this particular <a href="https://www.earth.com/news/iceberg-that-weighs-more-than-the-eiffel-tower-is-floating-freely/" target="_blank" rel="noreferrer noopener">iceberg</a> calved naturally, Antarctic ice shelves are showing other, more concerning changes.



Experts worry that accelerated ice loss in certain areas could have far-reaching effects. Even small changes along coastal regions of the continent can result in shifts in glacial flow, which might eventually lead to an uptick in sea-level rise. 



Data gathered from icebergs like A23a helps build a clearer picture of these wider trends.



<h2 class="wp-block-heading" id="h-importance-of-antarctic-ice-shelves">Importance of Antarctic ice shelves</h2>



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



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



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



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



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



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



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



<h2 class="wp-block-heading" id="h-ecosystems-under-the-ice">Ecosystems under the ice</h2>



Observations have shown that drifting ice blocks can stir the waters they pass through, sometimes generating short-lived plankton blooms. 



These blooms support fish, krill, and other marine life in areas that might otherwise lack resources. "These icebergs provide different sources of nutrients," explained Professor <a href="https://www.bas.ac.uk/profile/gant/" target="_blank" rel="noreferrer noopener">Geraint Tarling</a>, Biopole's principal investigator. By sampling the water where the giant iceberg has traveled, scientists hope to gauge whether this berg’s size and origin play a notable part in shaping ocean communities.



<h2 class="wp-block-heading" id="h-what-the-future-holds">What the future holds</h2>



Many anticipate that <a href="https://www.earth.com/news/a23a-worlds-largest-iceberg-is-moving-after-30-years/" target="_blank" rel="noreferrer noopener">A23a</a> will continue meandering through the Southern Ocean currents. As it ventures closer to milder latitudes, the ice is expected to weaken and break into smaller chunks. 



Some fragments may persist for a while, but the main body of the iceberg will likely diminish.



<h2 class="wp-block-heading" id="h-a23a-iceberg-research-enhances-ocean-circulation">A23a iceberg research enhances ocean circulation</h2>



Ongoing research on these gargantuan ice blocks helps experts refine climate models, track ocean circulation patterns, and pinpoint areas most vulnerable to environmental changes. 



Observations from ships, satellites, and on-site measurements all combine to offer a clearer view of what is happening far from major population centers. The hope is that findings from the watery trails left by A23a will guide future decisions on how we manage and protect polar waters and fragile marine habitats.



<h2 class="wp-block-heading" id="h-moving-lab-for-ocean-studies">Moving lab for ocean studies</h2>



A23a’s odyssey is important because it shows how an individual iceberg can become a moving lab for oceanographers and climate scientists. 



The iceberg's escape from a rotating water column this month hints at nature’s complexity, from shifting ocean currents to unseen underwater topography.



While it has been around for nearly four decades, its path in the coming months may reveal more about the chain reactions set in motion when a piece of Antarctica sets sail for open waters.



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World’s largest iceberg breaks free from ocean cyclone

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

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

NASA’s Parker Solar Probe touched the Sun's atmosphere, flying within 3.8 million miles (around 6.1 million kilometers) from the surface of the Sun on Tuesday, Dec. 24, at 6:53 a.m. EST. 



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



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



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



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



<h2 class="wp-block-heading" id="h-going-where-no-human-made-object-has-gone">Going where no human-made object has gone</h2>



This approach is unlike anything previously accomplished by a human-made spacecraft, marking a landmark in solar science that may rewrite much of what we know about our star.



Arik Posner, <a href="https://parkersolarprobe.jhuapl.edu/" target="_blank" rel="noreferrer noopener">Parker Solar Probe</a> program scientist at NASA Headquarters in Washington, sees this effort as a new window into solar research. “This is one example of NASA’s bold missions, doing something that no one else has ever done before to answer longstanding questions about our universe,” said <a href="https://science.nasa.gov/people/dr-arik-posner/" target="_blank" rel="noreferrer noopener">Arik</a>. The Johns Hopkins Applied Physics Laboratory (<a href="https://www.jhuapl.edu/" target="_blank" rel="noreferrer noopener">APL</a>) in Laurel, Maryland, manages mission operations and is keeping a watchful eye on every step as Parker speeds by.



<h2 class="wp-block-heading" id="h-breathtaking-pace-of-the-parker-solar-probe">Breathtaking pace of the Parker solar probe</h2>



The spacecraft is moving at approximately <a href="https://www.nasa.gov/feature/goddard/parker-solar-probe" target="_blank" rel="noreferrer noopener">430,000 miles per hour</a>. At that velocity, Parker could zip from New York to Los Angeles in about 20 seconds. 



By <a href="https://www.earth.com/news/parker-solar-probe-will-fly-through-suns-atmosphere-tomorrow-for-the-first-time/" target="_blank" rel="noreferrer noopener">approaching the Sun</a> so closely, mission teams hope to retrieve data that no earlier craft could access. Particles in the corona -- where temperatures can exceed a few million degrees -- tend to behave in puzzling ways. 



Scientists aim to see how these intense conditions might shape <a href="https://science.nasa.gov/sun/what-is-the-solar-wind/" target="_blank" rel="noreferrer noopener">solar wind</a>, which jets out at more than one million miles per hour.



Engineers designed Parker’s trajectory with careful flybys of Venus to shrink its orbit gradually around the Sun. This path has taken years to perfect since launch in 2018. 



Each loop demanded detailed calculations to ensure the craft can survive the approach, collect the right measurements, and keep sending updates back to Earth.



<h2 class="wp-block-heading" id="h-solar-probe-battling-extreme-heat">Solar probe battling extreme heat</h2>



Because the Sun’s heat is punishing at such a short distance, Parker Solar Probe relies on a <a href="https://parkersolarprobe.jhuapl.edu/Spacecraft/index.php#Extreme-Environments" target="_blank" rel="noreferrer noopener">carbon-composite shield</a> 4.5 inches thick.



This protective layer keeps sensitive instruments near room temperature while the shield’s front side can face extreme temperatures above 2,500 degrees Fahrenheit.



Sophisticated cooling systems also channel heat away from the core of the <a href="https://www.earth.com/news/meet-the-fastest-human-made-object-ever-nasas-parker-solar-probe/" target="_blank" rel="noreferrer noopener">spacecraft</a>, helping to sustain the electronics that record measurements of plasma, magnetic fields, and solar wind particles.



Inside, the instruments are scanning for clues to explain the corona’s unusual temperatures, which skyrocket to levels far higher than the Sun’s visible surface. 



Those same instruments are also watching for charged particle bursts and fluctuations in magnetic fields that might help answer big questions about what accelerates the solar wind.



<h2 class="wp-block-heading" id="h-crucial-timing-and-limited-contact">Crucial timing and limited contact</h2>



Today’s perihelion means Parker is currently skimming the outer atmosphere of the <a href="https://www.earth.com/news/solar-orbiter-spacecraft-sees-the-sun-through-three-different-lenses/" target="_blank" rel="noreferrer noopener">Sun</a> while in autonomous mode, out of immediate radio contact.



This window of silence is standard because powerful solar emissions prevent reliable communication. Mission operators anticipate a beacon tone on December 27, which should confirm Parker has survived.



Scientists believe that data from this flyby could provide <a href="https://www.earth.com/news/parker-solar-probe-will-fly-through-suns-atmosphere-tomorrow-for-the-first-time/" target="_blank" rel="noreferrer noopener">unprecedented detail on solar activity</a>. Periods of heightened activity, known as solar maxima, produce more flares and coronal mass ejections. These events can spawn auroras at unexpected latitudes and threaten satellites with bursts of charged particles. 



By collecting data from close range, Parker might reveal new insights into how these explosive happenings form and evolve.



<h2 class="wp-block-heading" id="h-visionary-behind-the-parker-solar-probe">Visionary behind the Parker solar probe</h2>



This trailblazer of solar research is named after <a href="https://news.uchicago.edu/story/eugene-parker-legendary-figure-solar-science-and-namesake-parker-solar-probe-1927-2022" target="_blank" rel="noreferrer noopener">Dr. Eugene N. Parker</a>, the late astrophysicist from the University of Chicago who proposed the existence of the solar wind back in the 1950s.



He changed our understanding of how stars interact with their surroundings. In 2018, he became the first person to witness the launch of a spacecraft bearing his name. 



Though he passed away in 2022, his legacy lives on in every close pass the probe completes.



<h2 class="wp-block-heading" id="h-a-closer-look-at-solar-wind">A closer look at solar wind</h2>



One of the main motivations behind Parker Solar Probe mission is to figure out how <a href="https://www.earth.com/news/strong-solar-storm-warning-issued-as-two-cmes-will-hit-earth-tomorrow/" target="_blank" rel="noreferrer noopener">solar wind</a>, that stream of charged particles racing from the Sun, accelerates to incredible speeds. Scientists hope Parker will pinpoint where and how energy is transferred to these particles. Such information could refine space weather forecasts, which are critical for protecting satellites, power grids, and astronauts in orbit.



<a href="https://www.plasmacoalition.org/plasma_writeups/solar_plasmas.pdf" target="_blank" rel="noreferrer noopener">Plasma</a> behavior at these altitudes can also inform theories about stellar physics beyond the Sun. 



Many stars release similar particle streams, so unraveling the inner workings of the solar wind could offer a template for understanding events happening light-years away.



<h2 class="wp-block-heading" id="h-high-stakes-data-for-space-weather-predictions">High-stakes data for space weather predictions</h2>



Operators know that space weather can have major effects here on Earth. Sudden geomagnetic storms have been known to disrupt radio signals, damage satellites, and even cause power outages. By studying the Sun’s activity from the inside, Parker could lead to more accurate warnings for regions of the world vulnerable to blackouts. 



Air traffic, GPS services, and communication infrastructure may all benefit from improved predictions of <a href="https://science.nasa.gov/science-research/heliophysics/space-weather/solar-flares/what-is-a-solar-flare/" target="_blank" rel="noreferrer noopener">solar flares</a> and <a href="https://www.swpc.noaa.gov/phenomena/solar-radiation-storm#:~:text=Solar%20radiation%20storms%20occur%20when,of%20the%20speed%20of%20light." target="_blank" rel="noreferrer noopener">particle storms</a>.



<h2 class="wp-block-heading" id="h-a-milestone-for-parker-solar-probe">A milestone for Parker Solar Probe</h2>



Now that the probe is at perihelion, mission managers will hold their breath for a few days.



“No human-made object has ever passed this close to a star, so Parker will truly be returning data from uncharted territory,” explained <a href="https://parkersolarprobe.jhuapl.edu/News-Center/Show-Article.php?articleID=205" target="_blank" rel="noreferrer noopener">Nick Pinkine</a>, Parker Solar Probe mission operations manager at <a href="https://www.jhuapl.edu/" target="_blank" rel="noreferrer noopener">APL</a>. 



He added that the team is eager to see how Parker managed the flyby when the link reopens.



This moment is a milestone for solar science. If everything goes as planned, Parker will maintain its orbit for future close passes, each offering a renewed chance to investigate the corona’s strange properties.



Researchers anticipate more discoveries that will fill in knowledge gaps about the Sun’s extreme environment.



Far from being an isolated phenomenon, the Sun’s behavior plays a significant role in shaping conditions on Earth. 



Today’s brush with solar fury signals the continuing progress of human exploration -- and the promise of deeper insight into the star that illuminates our world.



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

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

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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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



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Oxygen levels on exoplanets reveal presence of alien technology

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

Picture a landscape on Mars where frost covers the ground, and the crisp sound of icy surfaces breaking underfoot fills the air. Above, sunlight filters through clouds mixed with ice and dust, creating a warm, golden glow. This is the Australe Scopuli region, located at the southern pole of Mars.



It offers a striking contrast - its alien features are shaped by the Red Planet's unique environment, yet its serene beauty evokes scenes that feel almost Earth-like.



This blend of the otherworldly and the familiar makes it a captivating subject for scientific exploration and visual fascination.



<h2 class="wp-block-heading" id="h-australe-scopuli-unique-polar-landscape-on-mars">Australe Scopuli: Unique polar landscape on Mars</h2>



The High Resolution Stereo Camera (HRSC) aboard the&nbsp;<a href="https://www.esa.int/Science_Exploration/Space_Science/Mars_Express" target="_blank" rel="noreferrer noopener">Mars Express</a>&nbsp;captured stunning images of Australe Scopuli, displaying its distinctive polar deposits.



This region lies near the "cryptic terrain," a puzzling area previously explored by few scientists. Here, layers of carbon dioxide ice and dust swirl together, creating a white, frosty terrain that contrasts sharply with the iconic red <a href="https://www.earth.com/news/how-mars-became-uninhabitable-after-being-life-supporting-ocean-world/" target="_blank" rel="noreferrer noopener">Martian soil</a>.



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_frost_ice_Mars-Express_1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_frost_ice_Mars-Express_1s.webp" alt="Swirls of light and dark layers mark the boundaries between ice and dust layers exposed in this icy scene from the Australe Scopuli region of Mars. The right side of the image has a lot of ice coverage compared with the left hand side that has numerous dark fan-shaped deposits tracing the horizontal layers. Credit: Mars Express/ESA" class="wp-image-1954353"/></a><figcaption class="wp-element-caption">Swirls of light and dark layers mark the boundaries between ice and dust layers exposed in this icy scene from the Australe Scopuli region of Mars. The right side of the image has a lot of ice coverage compared with the left hand side that has numerous dark fan-shaped deposits tracing the horizontal layers. Credit: Mars Express/ESA</figcaption></figure>



These layered polar deposits result from seasonal cycles, with ice forming and trapping varying amounts of dust. 



The contrasting light and dark layers are particularly visible on hills and in valleys, painting the landscape with striking textures.



When viewed through 3D glasses, the region’s topography resembles Earthly ski resorts, with smooth slopes, sharp turns, and steep hillsides.



But skiing on Mars would require preparation for extreme cold: temperatures here plunge to a bone-chilling -125°C (-193°F).



<h2 class="wp-block-heading" id="h-changing-seasons-and-martian-spiders">Changing seasons and Martian "spiders"</h2>



The images, taken on June 16, 2022, during the <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">Martian</a> summer solstice, showcase how Mars’s southern pole transitions with the changing seasons.



Dark patches in the imagery reveal areas where carbon dioxide ice has sublimated, a process where the ice turns directly from solid to vapor without melting.



This sublimation is driven by sunlight, which warms the ice. As the ice evaporates, it leaves behind trails of dark dust spread across the surface. 



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_perspective_Mars-Express_1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_perspective_Mars-Express_1s.webp" alt="Perspective view across undulating terrain at the Australe Scopuli region of Mars, with exposed layers of ice and dust. Numerous dark dusty fan-shaped features follow the pattern of the layers. Credit: Mars Express/ESA" class="wp-image-1954355"/></a><figcaption class="wp-element-caption">Perspective view across undulating terrain at the Australe Scopuli region of Mars, with exposed layers of ice and dust. Numerous dark dusty fan-shaped features follow the pattern of the layers. Credit: Mars Express/ESA</figcaption></figure>



These fan-shaped patterns, sculpted by prevailing winds, provide a remarkable look at the seasonal dynamics in <a href="https://www.earth.com/news/mars-gravity-pulls-earth-closer-to-the-sun-warming-our-climate-scientists-say/" target="_blank" rel="noreferrer noopener">Mars</a>'s polar regions.



As summer progresses, sunlight penetrates the translucent carbon dioxide ice, heating the ground beneath it. This leads to the formation of gas pockets as the underlying ice sublimates. 



When the gas pressure becomes too high, the ice cracks, releasing bursts of gas and dust into the atmosphere. These jets create fan-shaped deposits that can stretch for hundreds of meters.



This process resembles the formation of <a href="https://www.earth.com/news/marss-space-debris-should-be-regarded-as-historical-artifacts/" target="_blank" rel="noreferrer noopener">Martian</a> "spiders," another fascinating feature observed in recent&nbsp;Mars Express imagery, where similar sublimation mechanisms create spider-like patterns on the surface.



<h2 class="wp-block-heading" id="h-dynamic-australe-scopuli-of-mars">Dynamic Australe Scopuli of Mars</h2>



A detailed look at Australe Scopuli shows that the dust jets typically emerge along the edges of layered polar deposits. These boundaries may act as fragile zones, allowing the jets to break through with less resistance.



This phenomenon, shaped by seasonal temperature changes and the region’s topography, creates a dynamic and evolving <a href="https://www.earth.com/news/air-samples-from-mars-could-reveal-fascinating-secrets/" target="_blank" rel="noreferrer noopener">Martian</a> landscape. 



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_topography_Mars-Express_1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/mars_south-pole_Australe-Scopuli-region_topography_Mars-Express_1s.webp" alt="A topography map of Australe Scopuli region of Mars color-coded according to relative heights. The scale goes from red (highest terrain) through yellow, green, blue and purple (lowest terrain). Credit: Mars Express/ESA" class="wp-image-1954357"/></a><figcaption class="wp-element-caption">A topography map of Australe Scopuli region of Mars color-coded according to relative heights. The scale goes from red (highest terrain) through yellow, green, blue and purple (lowest terrain). Credit: Mars Express/ESA</figcaption></figure>



The interplay between the shifting ice and dust patterns highlights the complexity of Mars’s natural processes.



Although building a snowman on Mars might not be possible, the Australe Scopuli region captures the essence of the planet’s unique beauty. 



It offers scientists and explorers a fascinating glimpse into the changing polar environment of the Red Planet.



<h2 class="wp-block-heading" id="h-science-behind-the-images">Science behind the images</h2>



The HRSC on&nbsp;Mars Express&nbsp;is a remarkable piece of engineering, designed and developed by the German Aerospace Center (DLR).



After the camera captured detailed images of Mars, the <a href="https://www.dlr.de/en/pf/about-us/departments" target="_blank" rel="noreferrer noopener">DLR Institute for Planetary Research</a> in Berlin-Adlershof processed the data. 



Using this data, the Planetary Science and Remote Sensing group at <a href="https://www.fu-berlin.de/en/index.html" target="_blank" rel="noreferrer noopener">Freie Universität Berlin</a> created the stunning final images we see today.



In conclusion, the images of Australe Scopuli offer much more than just stunning visuals of the Martian southern pole. 



They serve as powerful proof of the intricate and ever-changing processes that sculpt the Red Planet's icy polar regions.



Every layer of ice and dust preserved in these photographs tells a unique story about <a href="https://www.earth.com/news/mars-curiosity-rover-makes-surprising-find-under-martian-rock-sulfur-crystals/" target="_blank" rel="noreferrer noopener">Mars</a>'s geological and climatic history. 



By studying these features in detail, researchers can piece together the planet's evolving climate and uncover the mysteries of its geological past.



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White Christmas on Mars with its changing polar landscapes

Picture a landscape on Mars where frost covers the ground,...

Geometry,Of,Space,Series.,Backdrop,Of,Conceptual,Grids,,Curves,And

Dark energy has long been seen as the invisible force behind our Universe’s accelerating expansion. This mysterious component was thought to make up nearly 70 percent of the cosmic energy budget. A new study, however, raises a different idea: maybe the Universe is expanding in a “lumpy” manner, which means dark energy might not be needed to explain those puzzling measurements of distant supernovae.



<h2 class="wp-block-heading" id="h-dark-energy-and-expansion">Dark energy and expansion</h2>



For almost a century, scientists have assumed that the <a href="https://www.earth.com/news/new-evidence-suggests-that-dark-energy-comes-from-black-holes/" target="_blank" rel="noreferrer noopener">cosmos</a> spreads out uniformly in every direction, with dark energy speeding up that expansion. The notion was adopted after researchers saw exploding stars, known as supernovae, appearing farther away than expected. 



When calculations showed that galaxies seemed to be drifting apart too quickly, dark energy became an easy placeholder for the unknown physics.



Professor <a href="https://profiles.canterbury.ac.nz/David-Wiltshire" target="_blank" rel="noreferrer noopener">David Wiltshire</a> from the <a href="https://www.canterbury.ac.nz/" target="_blank" rel="noreferrer noopener">University of Canterbury</a> in Christchurch, New Zealand has been examining this challenge in more detail. 



His research team’s <a href="https://academic.oup.com/mnrasl/article/537/1/L55/7926647" target="_blank" rel="noreferrer noopener">analysis</a> of supernova light curves suggests the <a href="https://www.earth.com/news/mapping-the-universe-may-reveal-secrets-of-dark-energy/" target="_blank" rel="noreferrer noopener">Universe</a> may be more uneven than we assumed.



Their approach leads to a fresh explanation for the changes in light we see, one that focuses on how time passes differently in various gravitational conditions rather than appealing to an unseen substance.



<h2 class="wp-block-heading" id="h-why-many-have-relied-on-dark-energy">Why many have relied on dark energy</h2>



Dark energy has been tied to the so-called Lambda Cold Dark Matter model, or <a href="https://lambda.gsfc.nasa.gov/education/graphic_history/univ_evol.html" target="_blank" rel="noreferrer noopener">ΛCDM model</a>. 



This model has served as the bedrock of modern cosmology for decades. Scientists had no direct means to detect or measure dark energy, so they relied on the <a href="https://iopscience.iop.org/article/10.3847/1538-4357/aca5fa" target="_blank" rel="noreferrer noopener">apparent acceleration</a> seen in distant supernovae. They also looked to patterns in the <a href="https://www.esa.int/Science_Exploration/Space_Science/Cosmic_Microwave_Background_CMB_radiation" target="_blank" rel="noreferrer noopener">Cosmic Microwave Background</a>, which is often described as the faint afterglow of the Big Bang. 



Over the years, more data have hinted that there could be tension between early and recent <a href="https://www.earth.com/news/dark-energy-could-explain-the-rapid-expansion-of-the-early-universe/" target="_blank" rel="noreferrer noopener">expansion</a> rates, sparking serious questions about whether we are missing some major puzzle piece.



<h2 class="wp-block-heading" id="h-enter-the-timescape-model">Enter the timescape model</h2>



The new work supports something called the timescape model, which does not need dark energy to explain cosmic acceleration. Instead, it notes that local physics can vary depending on how mass is distributed. One clock drifting through a sparse region of the cosmos might tick faster than the same clock inside a galaxy packed with more gravitational pull. 



<figure class="wp-block-image aligncenter size-full"><a href="https://www.earth.com/wp-content/uploads/2024/12/dark-energy_doesnt-exist_history-of-universe-graphic_credit-NASA_1m.jpg" target="_blank" rel="noreferrer noopener"><img src="https://www.earth.com/wp-content/uploads/2024/12/dark-energy_doesnt-exist_history-of-universe-graphic_credit-NASA_1s.webp" alt="This graphic offers a glimpse of the history of the universe, as we currently understand it. The cosmos began expanding with the Big Bang but then around 10 billion years later it strangely began to accelerate thanks to a theoretical phenomenon termed dark energy. Credit: NASA" class="wp-image-1954661"/></a><figcaption class="wp-element-caption">This graphic offers a glimpse of the history of the universe, as we currently understand it. The cosmos began expanding with the Big Bang but then around 10 billion years later it strangely began to accelerate thanks to a theoretical phenomenon termed dark energy. Credit: NASA</figcaption></figure>



The team’s findings were featured in the journal Monthly Notices of the Royal Astronomical Society Letters.



“Our findings show that we do not need dark energy to explain why the <a href="https://www.earth.com/news/study-dark-matter-does-not-exist-and-the-universe-is-27-billion-years-old/" target="_blank" rel="noreferrer noopener">Universe</a> appears to expand at an accelerating rate,” noted Professor David Wiltshire, who led the study. 



He sees this approach as an opportunity to rethink the way we average cosmic expansion. “The Universe’s biggest mystery could be settled by the end of the decade,” Professor Wiltshire claimed.



<h2 class="wp-block-heading" id="h-hubble-tension-and-the-lumpy-universe">Hubble tension and the lumpy Universe</h2>



Part of the growing dispute involves something called the <a href="https://www.earth.com/news/unknown-factors-are-accelerating-the-expansion-of-the-universe/" target="_blank" rel="noreferrer noopener">Hubble tension</a>.



<a href="https://www.aanda.org/articles/aa/full_html/2020/09/aa33910-18/aa33910-18.html" target="_blank" rel="noreferrer noopener">Measurements</a> of the early cosmos from the Cosmic Microwave Background suggest a certain rate of expansion, while observations of supernovae in the present day reveal a faster pace. This inconsistency has triggered re-examinations of old assumptions. Adding to that, the Dark Energy Spectroscopic Instrument (<a href="https://iopscience.iop.org/article/10.3847/1538-4357/aca5fa" target="_blank" rel="noreferrer noopener">DESI</a>) has discovered that the standard ΛCDM model may not line up perfectly with some of its new high-precision data. Researchers are looking into models where dark energy <a href="https://www.earth.com/news/dark-energy-is-ripping-the-universe-apart-but-we-arent-sure-how/" target="_blank" rel="noreferrer noopener">might change over time</a>, but the timescape idea takes a different path: it challenges the uniformity assumption at its core.



<h2 class="wp-block-heading" id="h-rethinking-dark-energy">Rethinking dark energy </h2>



If the Universe is lumpy, with matter clumping in some regions and emptier voids in others, then local gravitational effects might skew the calculations that gave dark energy its place in cosmic theory. <a href="https://www.astro.uvic.ca/~jwillis/teaching/astr405/astr405_lecture6.pdf?utm_blank" target="_blank" rel="noreferrer noopener">Traditional equations</a> used to describe expansion were first introduced almost a hundred years ago, so some researchers argue that the Universe’s complex structures were overlooked. This new study insists that a <a href="https://www.earth.com/news/universe-expansion-rate-dark-energy-measured-11-billion-years-ago/" target="_blank" rel="noreferrer noopener">uniform expansion</a> might not be the full story. When you allow for different gravitational influences, dark energy becomes optional.



<h2 class="wp-block-heading" id="h-looking-ahead-to-fresh-data">Looking ahead to fresh data</h2>



Several upcoming projects are on the horizon. 



The European Space Agency’s <a href="https://www.esa.int/Science_Exploration/Space_Science/Euclid" target="_blank" rel="noreferrer noopener">Euclid</a> satellite launched in July 2023, and future missions like the <a href="https://science.nasa.gov/mission/roman-space-telescope/" target="_blank" rel="noreferrer noopener">Nancy Grace Roman Space Telescope</a> promise more comprehensive observations of supernovae. The timescape team believes that at least 1,000 high-quality supernova measurements could be enough to show if their approach really works. 



If timescape ideas pass these tests, the so-called “biggest mystery” might get resolved sooner than people think.



<h2 class="wp-block-heading" id="h-what-does-all-of-this-mean">What does all of this mean?</h2>



To sum it all up, the Universe is more intricate than any simple map might reveal. If the <a href="https://ui.adsabs.harvard.edu/abs/2011MNRAS.413..367S/abstract" target="_blank" rel="noreferrer noopener">timescape model</a> holds up under further scrutiny, there could be wide-ranging effects on cosmic models, especially those that rely on dark energy as a key ingredient. Astronomers, physicists, and cosmologists will be watching closely as more data come in from cutting-edge surveys and instruments. 



These results might bring clarity to the <a href="https://www.earth.com/news/dark-energy-could-explain-the-rapid-expansion-of-the-early-universe/" target="_blank" rel="noreferrer noopener">Hubble tension</a> or uncover new clues about the structure and history of everything around us.



Dark energy has been the leading explanation for cosmic acceleration for decades. Yet, if local gravitational differences and variable clock speeds can account for what we see, the door may be open to a more nuanced story of cosmic growth. There is no shortage of skepticism within the scientific community, but unexpected solutions to old puzzles are often how we expand our understanding of the Universe. 



If the timescape approach stands the test of fresh observations, future textbooks might look a little different.



The full study is published in the <a href="https://academic.oup.com/mnrasl/article/537/1/L55/7926647" target="_blank" rel="noreferrer noopener">Monthly Notices of the Royal Astronomical Society: Letters</a>.



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Wrong again? Dark energy doesn't exist and the universe is "lumpy"

Dark energy has long been seen as the invisible force...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Nushagak Bay, a large estuary in southwest Alaska. Nushagak runs mainly north to south and exits in Bristol Bay, a large body of water in the Bering Sea.



"The bay is primarily fed by the Nushagak River, which begins in the Alaska Range and flows southwest approximately 450 km. The bay is also fed by several additional rivers including the Wood, Igushik, Snake and Weary rivers," says ESA.



"The dark colors of the Nushagak River are most likely due to tannins or lignins (chemical substances found in plants). Tannins and lignins from roots, leaves, seeds, bark and soil can leach into the water and give it a brown or even black colour. The sediments then flow southwards where it is mixed with the bluer waters of the bay."



Video/ Image Credit: ESA



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

Nushagak Bay in southwest Alaska

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> (ACS) reveals that proteins on flu viruses are actually flexible, tilting and waving in a “breath-like” motion. According to the experts, these proteins could be used to better defend against the flu.



"The main antigenic targets of influenza virus are two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Whereas the structural and dynamical properties of both glycoproteins have been studied previously, the understanding of their plasticity in the whole-virion context is fragmented," wrote the researchers.



To investigate, the team conducted detailed simulations of the influenza A H1N1 virion, or the swine flu. The experts concluded that the visualizations show many new vulnerable states of flu viruses, which could improve future vaccines and antiviral drugs.



Video/ Image Credit: American Chemical Society&nbsp;



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



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Flu viruses are more flexible than expected

[sendtonews key="G9bUoxcjr4-2511624-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Trasimeno, which is located west of Perugia in central Italy. It is the fourth largest lake in the country. While Trasimeno’s water level varies, it has a maximum depth of approximately six meters.&nbsp;



"In this Copernicus Sentinel-2 image, captured on 6 August 2022, the lake’s emerald green colour is likely due to the presence of phytoplankton. Streaks in the water, particularly visible in the west, indicate the presence of soil and sediments which have been stirred up by winds. Dark colored waters in the southern part of the lake indicate a presence of submerged and floating macrophytes (aquatic plants) as well as algae," says ESA.



"Surrounded by hills on three sides, Trasimeno is subject to heavy storms created by winds, especially from the north and west. There are three islets in the lake: Maggiore, Minore and Polvese (the largest). The lake’s shores are sparsely inhabited with only two popular villages: Castiglione del Lago and Passignano sul Trasimeno."



"Italy is experiencing its worst drought in 70 years which has affected drinking water supplies, hydroelectric power and agricultural production. High temperatures, hot winds and lack of rainfall are the main causes of drought in the Umbrian region which saw Lake Trasimeno’s drop 1.3 m, reaching the limit of the hydrometric zero in July 2022."



Video/Image Credit: ESA&nbsp;



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

Lake Trasimeno in Central Italy

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