Latest news with #Landsat8
Yahoo
4 days ago
- Science
- Yahoo
10 bizarre 'dark voids' appear in the skies over uninhabited island near Antarctica — Earth from space
When you buy through links on our articles, Future and its syndication partners may earn a commission. QUICK FACTS Where is it? Heard Island, Indian Ocean [-53.116414344, 73.51793263] What's in the photo? An unusual stream of von Kármán vortices trailing off a hidden peak Which satellite took the photo? Landsat 8 When was it taken? May 3, 2016 This striking satellite photo shows 10 swirling "dark voids" that appeared above an uninhabited volcanic island in the Indian Ocean. The black spots are the result of atmospheric cloud vortices, but are oddly pronounced and significantly contorted compared to most other examples of this phenomenon. The spinning voids are trailing off Heard Island — an uninhabited Australian territory in the southern Indian Ocean, around 900 miles (1,500 kilometers) north of Antarctica. The cloud-obscured landmass has a surface area of around 142 square miles (368 square kilometers). On average, the dark spots are around 8 miles (13 km) wide, decreasing slightly in size the further they have traveled, according to NASA's Earth Observatory. They are initially moving away from the island in a northeasterly direction (left to right). The spinning holes are the result of a phenomenon known as von Kármán vortices, which occur when a prevailing wind encounters a landmass, disturbing the airflow and creating "a double row of vortices which alternate their direction of rotation," according to the National Oceanic and Atmospheric Administration. They are named for Theodore von Kármán, a Hungarian-American physicist, who was the first to describe this natural phenomenon. In this case, the vortices are being created by Mawson Peak, a 9,000-foot-tall (2,700 meters) active volcano sat at the heart of Heard Island. Related: See all the best images of Earth from space Normally, von Kármán vortices create long trails of swirling clouds that get caught up in the disrupted air flows. The cloud streams are normally perfectly straight, such as a series of parallel vortex streams that emerged side-by-side off the Atlantic coast of Africa in 2015 (see above). But in this case, the vortex stream appears to bend almost 90 degrees midway through the stream. This change in direction was most likely caused by a sporadic burst of the intense westerly winds that frequently blow across the area around Heard Island at speeds over 50 mph (80km/h), known as the "Furious Fifties," according to the Earth Observatory. In most examples of von Kármán vortices, the resulting cloud trails can be quite wispy, tracing out the subtle variations in the invisible air currents, such as examples observed over Mexico's Guadalupe Island in 2012 and above Svalbard's Bear Island in 2023. MORE EARTH FROM SPACE —Gravity waves spark pair of perfect cloud ripples above uninhabited islands —Mysterious, slow-spinning cloud 'cyclone' hugs the Iberian coast —Giant, near-perfect cloud ring appears in the middle of the Pacific Ocean However, in this photo, the wispy trails are replaced by a string of concentrated holes, or gaps, within the clouds. This is probably due to exceptionally thick cloud coverage, which can be disrupted only at the heart of each spinning section within the vortex stream. Mawson Peak is smaller than most of the peaks that regularly produce von Kármán vortices, making it slightly rarer for the cloud swirls to emerge there. However, Heard Island has produced more traditional vortex streams in the past, such as one showing in November 2015. Solve the daily Crossword
Newsweek
01-08-2025
- Climate
- Newsweek
NASA Satellite Shows Vast Spread of Utah Fire
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Striking satellite images released this week by NASA have revealed the full scale of the Monroe Canyon wildfire, which has scorched nearly 46,000 acres of land in central Utah. The images captured by the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA's Aqua satellite show a thick cloud of smoke stretching hundreds of miles northeast, creating hazy skies and degrading air quality in the region. The blaze erupted near the communities of Richfield, Monroe and Koosharem amid a stretch of hot, dry and windy weather. It then rapidly expanded over the afternoon of July 25, when firefighters reported wind gusts in the area exceeding 60 miles per hour. Within three days, the fire had more than doubled its size, prompting evacuations and partial closure of Fishlake National Forest. An image shared by NASA Earth Observatory shows a thick cloud of smoke over Utah following the wildfire. An image shared by NASA Earth Observatory shows a thick cloud of smoke over Utah following the wildfire. NASA Earth Observatory In false-color images captured by Landsat 8's Operational Land Imager, NASA scientists were able to distinguish burning zones and scorched land from untouched areas. Bright orange patches on the below image mark areas that are still ablaze, while brown tones show all the dead vegetation left behind by the fire. More than 1,000 firefighting personnel have been deployed to fight the blaze—and local authorities have confirmed the loss of several buildings. Conditions remain volatile. As of July 31st, a red flag warning was in effect for central and southern Utah as a result on ongoing low humidity and breezy weather, which can interfere with containment efforts. An image shared by NASA Earth Observatory shows areas that are still burning in Utah. An image shared by NASA Earth Observatory shows areas that are still burning in Utah. NASA Earth Observatory Data from the U.S. Environmental Protection Agency (EPA) shows that the extent of area burned by wildfires each year has increased since the 1980s, with the largest acreage of burns occurring after 2004—including peaks in 2015 and 2020, aligning with many of the warmest years on record. Land area burned by wildfires varies by state, with more burns in the Western part of the country than in the East. The most significant increases have happened during spring and summer, with peak fires in August. Since 1983, the National Interagency Fire Center has documented an average of approximately 70,000 wildfires per year, although data from the Forest Service suggest that the number could be even higher. Over the past decade, the USDA Forest Service has used prescribed burns and mechanical thinning in and around Monroe Canyon to promote aspen regeneration and reduce accumulated brush and dead vegetation. According to Utah's Department of Natural Resources, the intensity of the Monroe Canyon fire decreased near treated zones. This helped firefighters add more blackline around the southeastern perimeter of the fire and increase containment on that side. However, despite all the efforts, only 11 percent of the ire has so far been contained, and official continue to warn residents to remains alert and follow evacuation orders. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about wildfires? Let us know via science@
11-07-2025
- Science
Iliamna volcano in Alaska rumbling despite being dormant for over 100 years, scientists say
An Alaskan volcano that has been inactive for more than 100 years is showing signs of rumbling, according to scientists. However, there's a chance that the activity could be signs of a pending avalanche, rather than a volcanic eruption, NASA said. The Iliamna volcano, located near the Cook Inlet in southern Alaska, last erupted in 1867, but would still rumble every few years due to avalanches large enough to register on nearby seismic and infrasound instruments, according to NASA. The region has recently experienced a "flurry of shaking," according to the Alaska Volcano Observatory. On June 15, seismic activity ramped up at a "nearly continuous" rate for several hours, the observatory reported. The Operational Land Imager, a sensor aboard the Landsat 8 satellite, acquired an image of the volcano on June 10, prior to when the rumblings began. The seismic activity was similar to those caused by the initial slipping between rock and ice that preceded large avalanches on the volcano in the past, according to the AVO. Iliamna often experiences massive avalanches due to the combination of glacial ice weakened rock and volcanic heat, scientists say. Its peak is covered in glaciers, snow and ice and it sits on a base of Jurassic-era granite, according to the NPS. Since its last eruption, the volcano was recorded ejecting smoke and light ash in 1876, 1933, 1941 and 1947, according to the NPS. More reports of smoke and light ash were recorded for the late winter of 1956 or early spring of 1957, but those reports were not confirmed, the NPS said. In 1958, four columns of vapor were shooting out of vents on the eastern side of the volcano, according to the NPS. But that was the last time smoke appeared to be ejected by the volcano. Although Iliamna is remote -- located in the Chigmit Mountains within Lake Clark National Park and Preserve -- it is monitored closely be volcanologists due to its potential hazards. There are several communities within a 200-mile radius of the volcano that could be impacted in the event of an eruption, including Pedro Bay, Port Alsworth and Anchorage, according to the NPS. The AVO monitors 51 other active volcanos within the state, including the Redoubt Volcano, Iliamna's more eruptive neighbor, which is also located within the preserve. The U.S. Geological Survey currently has Iliamna at a "normal" volcano alert level.
NDTV
09-07-2025
- Science
- NDTV
Here's Why NASA Is Watching Volcanoes From Space
NASA is closely monitoring volcanoes from space to better understand and predict volcanic eruptions, which can have significant impacts on the environment, climate and human populations. NASA is also studying the changing tree leaves, which can indicate the eruption of a nearby volcano. Scientists believe they can detect these changes from space by monitoring these changes. The US-based space agency has deployed satellites and instruments to monitor the volcanoes, such as Landsat 8 and 9 gives high-resolution images of volcanic activity and ash deposits, Sentinel-5P tracks sulfur dioxide and other volcanic gases, GOES-R Series provides real-time imagery of volcanic eruptions and ash clouds, MODIS monitors volcanic ash and aerosols in the atmosphere. Why Is Watching Volcanoes From Space Important? "Volcano early warning systems exist," volcanologist Florian Schwandner, chief of the Earth Science Division at NASA's Ames Research Center in California's Silicon Valley, who had teamed up with climate scientist Josh Fisher of Chapman University in Orange, California and volcanologist Robert Bogue of McGill University in Montreal a decade ago, said as quoted by NASA in a report published on May 15, 2025. "The aim here is to make them better and make them earlier." NASA reported that volcanic hazards pose a threat to approximately 10 per cent of the global population, particularly those living or working near active volcanoes and constant tracking can enable the authorities to prepare and respond accordingly. NASA's satellite instruments can detect volcanic ash and gases, such as sulfur dioxide, which can affect global climate patterns and pose hazards to aviation and human health. The observations also help to understand the climate impacts. Studying volcanoes from space helps scientists get a better understanding of geological processes, the Earth's interior and the interactions between volcanoes and the atmosphere.
News18
24-06-2025
- Science
- News18
Satellite Catches Alaska Volcano Stirring Mid-Rumble With Earthquakes Hitting Every Minute
Last Updated: Alaska's Iliamna volcano last erupted in 1867, but its slopes often trigger seismic spikes due to falling rock and glacial ice. A satellite image showing Alaska's Iliamna Volcano 'ready to rumble" has sparked renewed interest in the snow-covered peak, just as scientists recorded a spike in earthquakes on its slopes. The image, taken on June 10 by the Operational Land Imager (OLI) on NASA and USGS's Landsat 8 satellite, captured the volcano days before it saw an increase in seismicity around 4:30 am local time on June 15. An increase in seismicity means frequently occurring small earthquakes, according to a report by US-based magazine Newsweek which first reported the development. NASA satellite photo of Alaska's Iliamna Volcano which towers more than 10,000 feet (3,000 meters) over Cook Inlet. The volcano can be seen lower slightly left of center. Regular seismic activity causes the mountain to rumble and cause avalanches. — Black Hole (@konstructivizm) June 24, 2025 'Initially, the earthquake rate was nearly continuous, with several earthquakes per minute," said the Alaska Volcano Observatory (AVO) in a post on its website, 'but this has since slowed to a rate of about one earthquake per minute". Despite the flurry of tremors, scientists say the activity is likely not linked to an impending eruption. 'This activity is likely not caused by volcanic unrest," the AVO explained, 'but is instead caused by avalanches thundering down the volcano slopes". Iliamna last erupted in 1867 but still generates seismic activity roughly once every two years. 'Its murmurs tend not to be signs of volcanic unrest but rather the signature of avalanches large enough to register on nearby seismic and infrasound instruments," NASA highlighted in a blog post on its page. 'Although steam plumes occur on its eastern flanks, there has been no historical volcanic activity at Iliamna," the AVO added. As of June 16, the AVO said it didn't yet have enough data to confirm the size or location of any specific slide that may have taken place. However, the recent quake pattern resembles what has been observed during previous avalanches on Iliamna and especially in early summer. 'The outcome of the current activity remains uncertain," the AVO said. First Published: June 24, 2025, 23:49 IST
