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GLP-1 Pill Fails to Slow Alzheimer’s Progression in Clinical Trial
Top-line results from two large clinical trials by Novo Nordisk, the company behind Ozempic and Wegovy, found oral semaglutide failed to slow down Alzheimer's progression
NASA, NOAA Rank 2025 Ozone Hole as 5th Smallest Since 1992
5 min read
NASA, NOAA Rank 2025 Ozone Hole as 5th Smallest Since 1992 Earth (ESD)- Earth
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While continental in scale, the ozone hole over the Antarctic was small in 2025 compared to previous years and remains on track to recover later this century, NASA and the National Oceanic and Atmospheric Administration (NOAA) reported. The hole this year was the fifth smallest since 1992, the year a landmark international agreement to phase out ozone-depleting chemicals began to take effect.
At the height of this year’s depletion season from Sept. 7 through Oct. 13, the average extent of the ozone hole was about 7.23 million square miles (18.71 million square kilometers) — that’s twice the area of the contiguous United States. The 2025 ozone hole is already breaking up, nearly three weeks earlier than usual during the past decade.
This map shows the size and shape of the ozone hole over the South Pole on the day of its 2025 maximum extent. Moderate ozone losses (orange) are visible amid areas of more potent ozone losses (red). Scientists describe the ozone “hole” as the area in which ozone concentrations drop below the historical threshold of 220 Dobson units.NASA Earth Observatory image by Lauren Dauphin, using data courtesy of NASA Ozone Watch and GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFCThe hole reached its greatest one-day extent for the year on Sept. 9 at 8.83 million square miles (22.86 million square kilometers). It was about 30% smaller than the largest hole ever observed, which occurred in 2006, and had an average area of 10.27 million square miles (26.60 million square kilometers).
“As predicted, we’re seeing ozone holes trending smaller in area than they were in the early 2000s,” said Paul Newman, a senior scientist with the University of Maryland, Baltimore County, and leader of the ozone research team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “They’re forming later in the season and breaking up earlier. But we still have a long way to go before it recovers to 1980s levels.”
NASA and NOAA scientists say this year’s monitoring showed that controls on ozone-depleting chemical compounds established by the Montreal Protocol and subsequent amendments are driving the gradual recovery of the ozone layer in the stratosphere, which remains on track to recover fully later this century.
The ozone-rich layer acts as a planetary sunscreen that helps shield life from harmful ultraviolet (UV) radiation from the Sun. It is located in the stratosphere, which is found between 7 and 31 miles above the Earth’s surface. Reduced ozone allows more UV rays to reach the surface, resulting in crop damage as well as increased cases of skin cancer and cataracts, among other adverse health impacts.
The ozone depletion process starts when human-made compounds containing chlorine and bromine rise high into the stratosphere miles above Earth’s surface. Freed from their molecular bonds by the more intense UV radiation, the chlorine and bromine-containing molecules then participate in reactions that destroy ozone molecules. Chlorofluorocarbons and other ozone-depleting compounds were once widely used in aerosol sprays, foams, air conditioners, and refrigerators. The chlorine and bromine from these compounds can linger in the atmosphere for decades to centuries.
“Since peaking around the year 2000, levels of ozone-depleting substances in the Antarctic stratosphere have declined by about a third, relative to pre-ozone-hole levels,” said Stephen Montzka, a senior scientist with NOAA’s Global Monitoring Laboratory.
As part of the 1987 Montreal Protocol, countries agreed to replace ozone-depleting substances with less harmful alternatives.
“This year’s hole would have been more than one million square miles larger if there was still as much chlorine in the stratosphere as there was 25 years ago,” Newman said.
Still, the now-banned chemicals persist in old products like building insulation and in landfills. As emissions from those legacy uses taper off over time, projections show the ozone hole over the Antarctic recovering around the late 2060s.
NASA and NOAA previously ranked ozone hole severity using a time frame dating back to 1979, when scientists began tracking Antarctic ozone levels with satellites. Using that longer record, this year’s hole area ranked 14th smallest over 46 years of observations.
Factors like temperature, weather, and the strength of the wind encircling Antarctica known as the polar vortex also influence ozone levels from year to year. A weaker-than-normal polar vortex this August helped keep temperatures above average and likely contributed to a smaller ozone hole, said Laura Ciasto, a meteorologist with NOAA’s Climate Prediction Center.
Researchers monitor the ozone layer around the world using instruments on NASA’s Aura satellite, the NOAA-20 and NOAA-21 satellites, and the Suomi National Polar-orbiting Partnership satellite, jointly operated by NASA and NOAA.
NOAA scientists also use instruments carried on weather balloons and upward-looking surface-based instruments to measure stratospheric ozone directly above the South Pole Atmospheric Baseline Observatory. Balloon data showed that the ozone concentration reached its lowest value of 147 Dobson Units this year on Oct. 6. The lowest value ever recorded over the South Pole was 92 Dobson Units in October 2006.
NOAA scientists launch a weather balloon carrying an ozonesonde near the South Pole in September 2025.Simeon Bash/IceCube – courtesy of NOAAThe Dobson Unit is a measurement that indicates the total number of ozone molecules present throughout the atmosphere above a certain location. A measurement of 100 Dobson Units corresponds to a layer of pure ozone 1 millimeter thick — about as thick as a dime — at standard temperature and pressure conditions.
View the latest status of the ozone layer over the Antarctic with NASA’s ozone watch.
By Sally Younger
NASA’s Earth Science News Team
News Media Contacts:
Elizabeth Vlock
NASA Headquarters, Washington
202-358-1600
elizabeth.a.vlock@nasa.gov
Peter Jacobs
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-3308
peter.jacobs@nasa.gov
Theo Stein
NOAA Communications
303-819-7409
theo.stein@noaa.gov
Astronomers have revolutionized our understanding of a collection of stars in the northern sky called…
Article 5 days ago 5 min read Webb First to Show 4 Dust Shells ‘Spiraling’ Apep, Limits Long Orbit Article 6 days ago Keep Exploring Discover More Topics From NASA EarthYour home. Our Mission. And the one planet that NASA studies more than any other.
Explore Earth Science
Earth Science at WorkNASA Earth Science helps Americans respond to challenges and societal needs — such as wildland fires, hurricanes, and water supplies…
Climate ChangeNASA is a global leader in studying Earth’s changing climate.
NASA, NOAA Rank 2025 Ozone Hole as 5th Smallest Since 1992
5 min read
NASA, NOAA Rank 2025 Ozone Hole as 5th Smallest Since 1992 Earth (ESD)- Earth
- Explore
- Science at Work
- Multimedia
- Data
- For Researchers
- About Us
While continental in scale, the ozone hole over the Antarctic was small in 2025 compared to previous years and remains on track to recover later this century, NASA and the National Oceanic and Atmospheric Administration (NOAA) reported. The hole this year was the fifth smallest since 1992, the year a landmark international agreement to phase out ozone-depleting chemicals began to take effect.
At the height of this year’s depletion season from Sept. 7 through Oct. 13, the average extent of the ozone hole was about 7.23 million square miles (18.71 million square kilometers) — that’s twice the area of the contiguous United States. The 2025 ozone hole is already breaking up, nearly three weeks earlier than usual during the past decade.
This map shows the size and shape of the ozone hole over the South Pole on the day of its 2025 maximum extent. Moderate ozone losses (orange) are visible amid areas of more potent ozone losses (red). Scientists describe the ozone “hole” as the area in which ozone concentrations drop below the historical threshold of 220 Dobson units.NASA Earth Observatory image by Lauren Dauphin, using data courtesy of NASA Ozone Watch and GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFCThe hole reached its greatest one-day extent for the year on Sept. 9 at 8.83 million square miles (22.86 million square kilometers). It was about 30% smaller than the largest hole ever observed, which occurred in 2006, and had an average area of 10.27 million square miles (26.60 million square kilometers).
“As predicted, we’re seeing ozone holes trending smaller in area than they were in the early 2000s,” said Paul Newman, a senior scientist with the University of Maryland, Baltimore County, and leader of the ozone research team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “They’re forming later in the season and breaking up earlier. But we still have a long way to go before it recovers to 1980s levels.”
NASA and NOAA scientists say this year’s monitoring showed that controls on ozone-depleting chemical compounds established by the Montreal Protocol and subsequent amendments are driving the gradual recovery of the ozone layer in the stratosphere, which remains on track to recover fully later this century.
The ozone-rich layer acts as a planetary sunscreen that helps shield life from harmful ultraviolet (UV) radiation from the Sun. It is located in the stratosphere, which is found between 7 and 31 miles above the Earth’s surface. Reduced ozone allows more UV rays to reach the surface, resulting in crop damage as well as increased cases of skin cancer and cataracts, among other adverse health impacts.
The ozone depletion process starts when human-made compounds containing chlorine and bromine rise high into the stratosphere miles above Earth’s surface. Freed from their molecular bonds by the more intense UV radiation, the chlorine and bromine-containing molecules then participate in reactions that destroy ozone molecules. Chlorofluorocarbons and other ozone-depleting compounds were once widely used in aerosol sprays, foams, air conditioners, and refrigerators. The chlorine and bromine from these compounds can linger in the atmosphere for decades to centuries.
“Since peaking around the year 2000, levels of ozone-depleting substances in the Antarctic stratosphere have declined by about a third, relative to pre-ozone-hole levels,” said Stephen Montzka, a senior scientist with NOAA’s Global Monitoring Laboratory.
As part of the 1987 Montreal Protocol, countries agreed to replace ozone-depleting substances with less harmful alternatives.
“This year’s hole would have been more than one million square miles larger if there was still as much chlorine in the stratosphere as there was 25 years ago,” Newman said.
Still, the now-banned chemicals persist in old products like building insulation and in landfills. As emissions from those legacy uses taper off over time, projections show the ozone hole over the Antarctic recovering around the late 2060s.
NASA and NOAA previously ranked ozone hole severity using a time frame dating back to 1979, when scientists began tracking Antarctic ozone levels with satellites. Using that longer record, this year’s hole area ranked 14th smallest over 46 years of observations.
Factors like temperature, weather, and the strength of the wind encircling Antarctica known as the polar vortex also influence ozone levels from year to year. A weaker-than-normal polar vortex this August helped keep temperatures above average and likely contributed to a smaller ozone hole, said Laura Ciasto, a meteorologist with NOAA’s Climate Prediction Center.
Researchers monitor the ozone layer around the world using instruments on NASA’s Aura satellite, the NOAA-20 and NOAA-21 satellites, and the Suomi National Polar-orbiting Partnership satellite, jointly operated by NASA and NOAA.
NOAA scientists also use instruments carried on weather balloons and upward-looking surface-based instruments to measure stratospheric ozone directly above the South Pole Atmospheric Baseline Observatory. Balloon data showed that the ozone concentration reached its lowest value of 147 Dobson Units this year on Oct. 6. The lowest value ever recorded over the South Pole was 92 Dobson Units in October 2006.
NOAA scientists launch a weather balloon carrying an ozonesonde near the South Pole in September 2025.Simeon Bash/IceCube – courtesy of NOAAThe Dobson Unit is a measurement that indicates the total number of ozone molecules present throughout the atmosphere above a certain location. A measurement of 100 Dobson Units corresponds to a layer of pure ozone 1 millimeter thick — about as thick as a dime — at standard temperature and pressure conditions.
View the latest status of the ozone layer over the Antarctic with NASA’s ozone watch.
By Sally Younger
NASA’s Earth Science News Team
News Media Contacts:
Elizabeth Vlock
NASA Headquarters, Washington
202-358-1600
elizabeth.a.vlock@nasa.gov
Peter Jacobs
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-3308
peter.jacobs@nasa.gov
Theo Stein
NOAA Communications
303-819-7409
theo.stein@noaa.gov
Astronomers have revolutionized our understanding of a collection of stars in the northern sky called…
Article 5 days ago 5 min read Webb First to Show 4 Dust Shells ‘Spiraling’ Apep, Limits Long Orbit Article 6 days ago Keep Exploring Discover More Topics From NASA EarthYour home. Our Mission. And the one planet that NASA studies more than any other.
Explore Earth Science
Earth Science at WorkNASA Earth Science helps Americans respond to challenges and societal needs — such as wildland fires, hurricanes, and water supplies…
Climate ChangeNASA is a global leader in studying Earth’s changing climate.
NASA Citizen Science Toolkit for Librarians
2 min read
NASA Citizen Science Toolkit for Librarians Librarians: NASA Citizen Science has something for you!Our new Toolkit for Librarians can help you share NASA citizen science opportunities with your patrons and community members. Rural and urban libraries, informal educators, youth group leaders, and retirement community coordinators can all benefit from this resource. Together, we can open the door for more people to join the fun, learning, and thrill of doing NASA science.
The toolkit prepares a program leader to lead a NASA Science event for people ages 8 and up. The toolkit includes:
- A guide to help you prepare for the event, from choosing and equipping the space, to becoming familiar with the citizen science project that will be the focus of the event
- An editable 8.5” by 11” poster to advertise your event
- A model agenda to follow during your event
- A handout for you and your participants to help you explore NASA-sponsored citizen science project opportunities
The toolkit creators, Sarah Kirn (Participatory Science Strategist, NASA, from the Gulf of Maine Research Institute) and Kara Reiman (librarian), together with NASA’s Citizen Science Officer Marc Kuchner, also recorded a video walk-through of this Toolkit.
“I appreciate this so much!” said one participant. “I have started Citizen Science Kits for circulation over this past year and am excited to share new opportunities with our patrons!”
“Living in a very rural and primarily native community, the kids here are limited with their nearby opportunities, so sharing this with them is a huge win…” said another.
Which NASA citizen project is best for you? You’ll find all these projects at science.nasa.gov/citizen-science, and you’ll find more resources like this in our Toolkit for Librarians! Sarah Kirn, GMRI + Marc Kuchner, NASA Learn More and Get Involved NASA Citizen Science Toolkit for LibrariansPlease share this toolkit – or use it yourself – to invite more people to do NASA science with us – who knows what they will discover?!
Facebook logo @nasascience_ @nasascience_ Instagram logo @nasascience_ Linkedin logo @nasascience_ Share Details Last Updated Nov 24, 2025 Related Terms Explore More 2 min read Catch a Comet Using Early Data from the Vera Rubin Observatory
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3 min read New Citizen Science Proposals Funded in 2025
NASA has selected 10 new citizen science proposals for funding in 2025. These selections provide…
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NASA Citizen Science Toolkit for Librarians
2 min read
NASA Citizen Science Toolkit for Librarians Librarians: NASA Citizen Science has something for you!Our new Toolkit for Librarians can help you share NASA citizen science opportunities with your patrons and community members. Rural and urban libraries, informal educators, youth group leaders, and retirement community coordinators can all benefit from this resource. Together, we can open the door for more people to join the fun, learning, and thrill of doing NASA science.
The toolkit prepares a program leader to lead a NASA Science event for people ages 8 and up. The toolkit includes:
- A guide to help you prepare for the event, from choosing and equipping the space, to becoming familiar with the citizen science project that will be the focus of the event
- An editable 8.5” by 11” poster to advertise your event
- A model agenda to follow during your event
- A handout for you and your participants to help you explore NASA-sponsored citizen science project opportunities
The toolkit creators, Sarah Kirn (Participatory Science Strategist, NASA, from the Gulf of Maine Research Institute) and Kara Reiman (librarian), together with NASA’s Citizen Science Officer Marc Kuchner, also recorded a video walk-through of this Toolkit.
“I appreciate this so much!” said one participant. “I have started Citizen Science Kits for circulation over this past year and am excited to share new opportunities with our patrons!”
“Living in a very rural and primarily native community, the kids here are limited with their nearby opportunities, so sharing this with them is a huge win…” said another.
Which NASA citizen project is best for you? You’ll find all these projects at science.nasa.gov/citizen-science, and you’ll find more resources like this in our Toolkit for Librarians! Sarah Kirn, GMRI + Marc Kuchner, NASA Learn More and Get Involved NASA Citizen Science Toolkit for LibrariansPlease share this toolkit – or use it yourself – to invite more people to do NASA science with us – who knows what they will discover?!
Facebook logo @nasascience_ @nasascience_ Instagram logo @nasascience_ Linkedin logo @nasascience_ Share Details Last Updated Nov 24, 2025 Related Terms Explore More 2 min read Catch a Comet Using Early Data from the Vera Rubin Observatory
Join the Rubin Comet Catchers project, and help scientists discover comets and other active objects…
Article
3 days ago
3 min read New Citizen Science Proposals Funded in 2025
NASA has selected 10 new citizen science proposals for funding in 2025. These selections provide…
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1 min read Help Map the Moon’s Molten Flows!
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City Lights and Atmospheric Glow
JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui captured this photo of southern Europe and the northwestern Mediterranean coast from the International Space Station as it orbited 261 miles above Earth on Aug. 30, 2025. At left, the Po Valley urban corridor in Italy shines with the metropolitan areas of Milan and Turin and their surrounding suburbs.
Crew members aboard the orbital lab have produced hundreds of thousands of images of the land, oceans, and atmosphere of Earth, and even of the Moon through Crew Earth Observations. Their photographs of Earth record how the planet changes over time due to human activity and natural events. This allows scientists to monitor disasters and direct response on the ground and study a number of phenomena, from the movement of glaciers to urban wildlife.
Image credit: JAXA/Kimiya Yui
City Lights and Atmospheric Glow
JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui captured this photo of southern Europe and the northwestern Mediterranean coast from the International Space Station as it orbited 261 miles above Earth on Aug. 30, 2025. At left, the Po Valley urban corridor in Italy shines with the metropolitan areas of Milan and Turin and their surrounding suburbs.
Crew members aboard the orbital lab have produced hundreds of thousands of images of the land, oceans, and atmosphere of Earth, and even of the Moon through Crew Earth Observations. Their photographs of Earth record how the planet changes over time due to human activity and natural events. This allows scientists to monitor disasters and direct response on the ground and study a number of phenomena, from the movement of glaciers to urban wildlife.
Image credit: JAXA/Kimiya Yui
City Lights and Atmospheric Glow
A new understanding of causality could fix quantum theory’s fatal flaw
A new understanding of causality could fix quantum theory’s fatal flaw
Thirty Meter Telescope Considers Move to Spain
Spain’s offer to host the powerful observatory, mired in funding obstacles and local controversies, might promise a new path forward.
The post Thirty Meter Telescope Considers Move to Spain appeared first on Sky & Telescope.
The Box vs The Bulldozer: The Story of Two Space Gas Stations
Using in-situ propellant has been a central pillar of the plan to explore much of the solar system. The logic is simple - the less mass (especially in the form of propellant) we have to take out of Earth’s gravity well, the less expensive, and therefore more plausible, the missions requiring that propellant will be. However, a new paper from Donald Rapp, the a former Division Chief Technologist at NASA’s JPL and a Co-Investigator of the successful MOXIE project on Mars, argues that, despite the allure of creating our own fuel on the Moon, it might not be worth it to develop the systems to do so. Mars, on the other hand, is a different story.
