Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a natural-color photograph of north-central Kyushu, the southernmost of Japan’s four largest islands.&nbsp;



While the Northern Hemisphere had lost most of its fall color by late November, some parts of Japan were still hitting their autumn peak. In the image, colorful vegetation is still visible across the mountainous landscape of Aso-Kuju National Park.



According to NASA, it is not possible to know the exact sources of the color based on this satellite image alone, but it is likely a combination of evergreens, deciduous trees, grasses, shrubs, and agricultural fields.&nbsp;



The photograph of Kyushu was captured on November 29, 2021 by the Operational Land Imager (OLI) on Landsat 8.



Image Credit: NASA Earth Observatory&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

Fall colors persist in Kyushu, Japan

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

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features Frederikshåb Isblink, a glacier in southwest Greenland that flows downward from the Greenland Ice Sheet. After winding through a series of valleys, the glacier flattens out on a delta along the coast.&nbsp;



In this image xaotured by the Operational Land Imager (OLI) on Landsat 8, meltwater draining from Frederikshåb is mixing with the darker waters of the Labrador Sea.



According to ESA, Greenland’s glaciers function like bulldozers, grinding away and pulverizing rocks along the land surface. This produces a powder called glacial flour, made up of silt and clay, that builds up in the water around the glaciers.



Image Credit: NASA Earth Observatory&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

Frederikshåb Isblink meltwater colors the Labrador Sea

In 1959, NASA chose seven men to train for space exploration. It was an absolute honor to participate in such an elite task force, but Alan Shepard was the only one who actually succeeded in making it all the way to the moon. However while it may seem glamorous, Shepard’s journey was rife with trauma. After years of silence, he’s finally coming clean about the dark experiences he underwent—and the details are truly shocking. Photo Credit: NASA

Man Who Went To Space Twice Shares Troubling Secret

In 1959, NASA chose seven men to train for space...

Anyone who was alive during the late '60s remembers how intense the Apollo 11 launch was. The world watched in awe as three American astronauts — Neil Armstrong, Buzz Aldrin, and Michael Collins — piloted the Apollo Lunar Module Eagle with success. But this foray into space wouldn't have been possible without Alan Shepard. Photo Credit: Nasa/Getty Images

Only The Best Wanted

Anyone who was alive during the late '60s remembers how...

See, the 1969 Apollo 11 flight wouldn't have gotten off the ground if not for a dedicated group of seven astronauts chosen by NASA in 1959. Each individual had no idea what to expect, considering NASA was breaking into completely new territory, but they were all thrilled at the chance to participate. Photo Credit: NASA/Flickr

The Special Seven

See, the 1969 Apollo 11 flight wouldn't have gotten off...

In an ongoing study from the <a href="https://www.txbiomed.org/">Texas Biomedical Research Institute</a>, experts have found that after vaccination, COVID-19 antibody levels vary by age and sex. The researchers also found that antibody levels drop significantly within six months across all individuals.



The study participants were tested over the course of six months after receiving the Pfizer-BioNTech vaccine. The tests revealed that individuals under the age of 65 had more than twice the level of SARS-COV-2 antibodies than individuals 65 years and older. In addition, women had higher antibody levels than men, especially women under the age of 65.&nbsp;



The experts report that by the sixth month, antibody levels had decreased by more than 50 percent from peak levels for all study participants.&nbsp;



“While we see how well vaccines have helped keep people out of the hospital and prevent life-threatening disease, antibody levels are quickly declining in all persons regardless of age and sex,” said Dr. Brandon Michael Henry, a postdoctoral researcher at Texas Biomed who co-led the study. He emphasized that the decline in antibody level does not mean that the vaccines are not effective



The study was focused on 787 healthcare workers in Verona, Italy who received two doses of the Pfizer-BioNTech vaccine. The individuals ranged in age from 21 to 75.&nbsp;



The researchers theorize that the significant sex differences are linked to hormones. They noted that testosterone naturally suppresses the immune system, while estrogen is known to amplify immune responses.&nbsp;



Furthermore, some genes that code for certain immune proteins are on the X chromosome. Women have two X chromosomes, which could help increase immune activity.



“Normally, only one X chromosome is active and the other is mostly deactivated, but there is evidence that immune-related genes stay active on that redundant chromosome and help boost immune responses in women,” said Dr. Henry.



“We have observed throughout the pandemic more older people and men suffer the worst consequences of COVID-19. These studies point to weaker immune responses against SARS-CoV-2 as a contributing factor to this phenomenon.”



“Our study provides additional evidence that booster shots for all adults will be important to keep antibody levels up so we can continue to mount an effective immune response against COVID-19 infection and prevent COVID-19 fatalities.”



The study is published in the <a href="https://doaj.org/toc/1452-8266">Journal of Medical Biochemistry</a>.



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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

COVID-19 antibody levels are highest in women after vaccination

In an ongoing study from the Texas Biomedical Research Institute,...

Tsunamis are giant waves that are produced by explosive underwater activity, such as <a href="https://www.earth.com/news/melting-glaciers-are-fueling-earthquakes-in-alaska/">earthquakes</a> and volcanic eruptions. While there are some detection techniques that can warn of tsunamis as they develop, a new study from <a href="https://www.cardiff.ac.uk/">Cardiff University</a> is focused on identifying methods that could lead to earlier detection.&nbsp;



“Tsunamis have a devastating impact on communities. Developing accurate methods to detect them quickly is key to saving lives,” said Dr. Usama Kadri, an expert in Cardiff University’s School of Mathematics.&nbsp;



The researchers analyzed deep sound recordings in the wake of 201 earthquakes in the Pacific and Indian oceans. Earthquakes usually trigger tsunamis when tectonic plates move vertically rather than horizontally, replacing large volumes of water and causing tsunami waves. This unique movement in turn creates unique sounds, and sound can be used to pinpoint the location of such earthquakes.&nbsp;



Bernabe Gomez, a PhD student on the research team, used this data to train artificial intelligence to alert the scientists when a vertical earthquake has happened and predict a tsunami quickly.&nbsp;



“Our findings show we are able to classify the type of earthquake and retrieve its main properties from acoustic signals, in near real time. These methods will complement existing technology for real-time tsunami analysis and provide another tool for experts working to detect them," said Dr. Kadri.



"This work is an integral part of a larger project for creating a more reliable early tsunami warning system.”



Dr. Kadri elaborated on the study, emphasizing that the research is a step toward even better technical mastery of tsunami prediction.



“Tectonic movements are very complicated, with horizontal and vertical elements. Some earthquakes have higher capability to generate tsunamis than others," explained Dr. Kadri.



"Employing digital signal processing techniques, we can analyse sound recordings of underwater earthquakes, that train artificial intelligence (AI) algorithms to classify the type of earthquake and its moment magnitude. This is a significant step for a reliable early tsunami warning system since the type of earthquake can dictate if a tsunami will be generated at all.”



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By <a href="mailto:zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Machine learning may help with earlier tsunami detection

Tsunamis are giant waves that are produced by explosive underwater...

One of the advantages of electric vehicles is that they make less noise and thus decrease levels of noise <a href="https://www.earth.com/news/noise-pollution-is-changing-which-birds-visit-your-backyard/">pollution</a> in cities. However, this may make electric vehicles a safety concern as pedestrians are less likely to hear them advancing. In order to address this risk, particularly for visually impaired pedestrians, many governments have mandated that artificial sounds be added to electric vehicles.



In the United States, for example, regulations require vehicle sounds to be detectable at certain distances for various vehicle speeds. A vehicle that is traveling faster has to make more noise so that it can be detected while still relatively far from a pedestrian.&nbsp;



A recent study led by Michael Roan of Penn State University tested how well people detect electric vehicle sounds in terms of these requirements.



Participants in the study had to sit next to a lane of the Virginia Tech Transportation Institute's Smart Road facility and press a button when they heard an approaching electric vehicle. This allowed the researchers to measure the probability of detection of vehicles at different distances, rather than calculating mean detection distance, which has been the accepted measurement standard in the past.



"All of the cases had mean detection ranges that exceeded the National Highway Transportation Safety Administration minimum detection distances. However, there were cases where probability of detection, even at close ranges, never reached 100%," said Roan. "While the additive sounds greatly improve detection distances over the no sound condition, there are cases where pedestrians still missed detections."



The sounds produced by electric vehicles are typically quieter than the sounds of vehicles with standard, internal combustion engines. Even after adding sounds, as required by government regulations, electric vehicles remain relatively quiet.&nbsp;



Roan said further studies are still needed to investigate detection success when all vehicles at an intersection are electric. Additive sounds could create a complex interference pattern that may result in some loud locations and other locations with very little sound, as the sound waves add to, or cancel out each other.



Roan will discuss the methods and results in the talk,"Electric Vehicle Additive Sounds: Detection results from an outdoor test for 16 participants," as part of the 181st Meeting of the <a href="https://acousticalsociety.org/">Acoustical Society of America</a>.



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Electric vehicles are too quiet for pedestrian safety

One of the advantages of electric vehicles is that they...

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Tanezrouft Basin in the Sahara Desert Today&#8217;s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the Tanezrouft Basin, which is one of the most barren parts of the Sahara Desert. 
Tanezrouft is located in southern Algeria and northern Mali. The region is often referred to as the &#8220;Land of Terror&#8221; due to its extreme lack of water and vegetation, as well as its scorching hot temperatures.
Tanezrouft, region of the Sahara lying in southern Algeria and northern Mali. This are covers majority and  part of a plateau eastward toward the Ahaggar (Hoggar) uplands, it curves down to lower ground in the west, and farther away in the  southward swamp areas. The region lacks to have much water, landmarks, and vegetation. Therefore it has a very dry climate and weather with very  little to no humidity but extremely hot weather patterns leaving it more dry than others. In this part of the Sahara, known as the Tanezrouft Basin, this land and area is especially parched, with annual rainfall measured in millimeters , very low amounts if any.  This is a hyperarid place of soaring temperatures and scarce access to water or vegetation.
Video Credit: European Space Agency 
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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