Arizona’s Chiricahua poised to become 64th US National Park
A quiet national monument tucked into southeastern Arizona is poised to become North America’s newest national park. Chiricahua National Monument — which towers with rock formations and is home to animals such as the coatimundi — could soon become the 64th national park in the United States. Chiricahua National Park would join the three other national parks in Arizona: Petrified Forest, Saguaro and the Grand Canyon.
On September 30, 2026, the U.S. Congress passed legislation to redesignate the monument as a national park. Now the bill just awaits the U.S. president’s signature.
The legislation keeps the existing boundaries of the park. It also doesn’t change the federal ownership and management of the park. What it will do is draw many more visitors to the area, which can be both a benefit and a drawback, especially in this time of cuts to the National Park Service’s budget.
Chiricahua is a wonderland of rocks
Chiricahua, sitting in the Chiricahua Mountains, is famous for its bizarre collection of rock formations. The National Park Service describes the landscape as a collection of rhyolite pinnacles and balanced rocks. Ancient volcanic eruptions some 27 million years ago led to what we see today as a wonderland of rocks.
The eruptions layered ash and molten rock that compacted into what geologists call rhyolite tuff. Eventually water and wind erosion wore down the softer parts of the rock. What remains are the stacked pinnacles and hoodoos we see today.
Chiricahua National Monument in southeastern Arizona is poised to become the 64th U.S. national park. Read more about the unique land and animals of Chiricahua below. Image via NPS.
An International Dark Sky Park
Chiricahua National Monument is already designated an International Dark Sky Park. These parks conserve the night sky and are excellent for stargazing. And Arizona’s desert environment is already well-known for its night skies. It’s the home of many astronomy observatories.
Chiricahua is open 24 hours a day. The National Park Service suggests stargazing from locations such as Massai Point and Echo Canyon Trailhead. And, of course, campgrounds are another great spot. Just throw your sleeping bag under the stars!
A view from Massai Point Nature Trail in Chiricahua National Monument in September 2026. Image via Lucy Whitt. Used with permission.
What lives in these lands?
Chiricahua is home to a wide variety of animal life. Just a few of the many animals you might see here include black bears, white-tailed deer, rattlesnakes and the tiger salamander. Plus, some 200 species of birds have been documented here.
But one of the big draws for animal watchers in the park are the coatimundi. These long-tailed members of the raccoon family are more common in South America, but you can also find them here in the Chiricahua Mountains. Because coati are active during daylight hours and social animals, you have a good chance to see them playing together in the park.
A curious coatimundi walks toward the camera in Chiricahua. Image via Lucy Whitt. Used with permission.
Concerns with national park status
There are some concerns with changing the national monument to a national park. About 70,400 visitors came to Chiricahua in 2025. And it probably isn’t prepared for the increase in visitation once it receives national park status.
There is only one campground in Chiricahua, with 26 sites. There is no lodge. More tourism will mean more pressure on roads, trails, wildlife habitat, water resources and park staff. But more tourism could also be a boon to surrounding communities. And more visitors means more people will realize the value of this land and wish to protect it.
As always, the designation of land to a national park can have both benefits and drawbacks.
Have you visited Chiricahua National Monument? Let us know in the comments.
Bottom line: Chiricahua National Monument in the southeastern corner of Arizona is poised to become the U.S.’s 64th national park.
Arizona’s Chiricahua poised to become 64th US National Park
A quiet national monument tucked into southeastern Arizona is poised to become North America’s newest national park. Chiricahua National Monument — which towers with rock formations and is home to animals such as the coatimundi — could soon become the 64th national park in the United States. Chiricahua National Park would join the three other national parks in Arizona: Petrified Forest, Saguaro and the Grand Canyon.
On September 30, 2026, the U.S. Congress passed legislation to redesignate the monument as a national park. Now the bill just awaits the U.S. president’s signature.
The legislation keeps the existing boundaries of the park. It also doesn’t change the federal ownership and management of the park. What it will do is draw many more visitors to the area, which can be both a benefit and a drawback, especially in this time of cuts to the National Park Service’s budget.
Chiricahua is a wonderland of rocks
Chiricahua, sitting in the Chiricahua Mountains, is famous for its bizarre collection of rock formations. The National Park Service describes the landscape as a collection of rhyolite pinnacles and balanced rocks. Ancient volcanic eruptions some 27 million years ago led to what we see today as a wonderland of rocks.
The eruptions layered ash and molten rock that compacted into what geologists call rhyolite tuff. Eventually water and wind erosion wore down the softer parts of the rock. What remains are the stacked pinnacles and hoodoos we see today.
Chiricahua National Monument in southeastern Arizona is poised to become the 64th U.S. national park. Read more about the unique land and animals of Chiricahua below. Image via NPS.
An International Dark Sky Park
Chiricahua National Monument is already designated an International Dark Sky Park. These parks conserve the night sky and are excellent for stargazing. And Arizona’s desert environment is already well-known for its night skies. It’s the home of many astronomy observatories.
Chiricahua is open 24 hours a day. The National Park Service suggests stargazing from locations such as Massai Point and Echo Canyon Trailhead. And, of course, campgrounds are another great spot. Just throw your sleeping bag under the stars!
A view from Massai Point Nature Trail in Chiricahua National Monument in September 2026. Image via Lucy Whitt. Used with permission.
What lives in these lands?
Chiricahua is home to a wide variety of animal life. Just a few of the many animals you might see here include black bears, white-tailed deer, rattlesnakes and the tiger salamander. Plus, some 200 species of birds have been documented here.
But one of the big draws for animal watchers in the park are the coatimundi. These long-tailed members of the raccoon family are more common in South America, but you can also find them here in the Chiricahua Mountains. Because coati are active during daylight hours and social animals, you have a good chance to see them playing together in the park.
A curious coatimundi walks toward the camera in Chiricahua. Image via Lucy Whitt. Used with permission.
Concerns with national park status
There are some concerns with changing the national monument to a national park. About 70,400 visitors came to Chiricahua in 2025. And it probably isn’t prepared for the increase in visitation once it receives national park status.
There is only one campground in Chiricahua, with 26 sites. There is no lodge. More tourism will mean more pressure on roads, trails, wildlife habitat, water resources and park staff. But more tourism could also be a boon to surrounding communities. And more visitors means more people will realize the value of this land and wish to protect it.
As always, the designation of land to a national park can have both benefits and drawbacks.
Have you visited Chiricahua National Monument? Let us know in the comments.
Bottom line: Chiricahua National Monument in the southeastern corner of Arizona is poised to become the U.S.’s 64th national park.
Here’s an easy way to use the prominent M or W shape of Cassiopeia to locate the Double Cluster in Perseus.
Double Cluster in Perseus
The Double Cluster in Perseus consists of two open star clusters near each other on the sky’s dome. Amateur astronomers know them as h Persei and chi Persei. The two clusters reside in the northern part of the constellation Perseus, quite close to the constellation Cassiopeia the Queen.
If you have a dark sky and find Cassiopeia – which is easy, because the constellation has a distinctive M or W shape – be sure to look for Perseus, too. Then just scan between the two constellations with your binoculars for two glittering groups of stars. The Double Cluster – a breathtaking pair of open clusters, each containing supergiant suns – will be there.
These two star clusters are located about 7,500 light-years away. It’s amazing that we can see these stars at all across this great span of space. Plus, we know they must be intrinsically bright stars, or we wouldn’t be able to see them. Each cluster contains a few hundred stars, and, indeed, these stars are young, hot supergiant suns. They are many thousands of times more luminous than our sun.
Astronomers tell us that the Double Cluster lies within the Perseus arm of the Milky Way galaxy. However, our solar system resides in the inner part of the Orion arm. Therefore, looking at the Double Cluster, we are looking through our local spiral arm and all the way to the next spiral arm outward from the galactic center.
How to find the Double Cluster in Perseus
To locate the Double Cluster, find the W- or M-shaped constellation Cassiopeia the Queen. If your sky is dark enough, you will be able to see the graceful pattern of Perseus the Hero nearby. Then scan between them with binoculars to find the Double Cluster.
The Perseus Double Cluster is located between Cassiopeia and Perseus. Scan the area between them with binoculars and you’ll find the 2 glittering star clusters. Image via Stellarium.org. Used with permission.
Starting at mid-northern latitudes, the Double Cluster is circumpolar, so it’s above the horizon every night of the year at any hour of the night. If you are farther south (but still in the Northern Hemisphere), try looking for the Double Cluster on any clear autumn or winter night.
But remember, the Double Cluster is harder to see when it’s close to the horizon. If you can’t spot it between Cassiopeia and Perseus, wait until later at night. Or look later in the year, when it’s higher in the sky.
For general reference, the Double Cluster is high in the sky when the Big Dipper is low, and vice versa. Because the Big Dipper is lowest in the northern sky on late autumn and early winter evenings, the Double Cluster is highest in the northern sky at these times. As a matter of fact, the Double Cluster is pretty much always visible in the evening except in late spring and summer.
The Double Cluster in Perseus is visible to the unaided eye
The Double Cluster rates among the most magnificent deep-sky objects not to be included in the famous Messier catalog. Of course, Charles Messier (1730-1817) was looking for deep-sky objects that could be mistaken for comets. Maybe he thought nobody would see this pair of glittery clusters as a comet in the sky.
Although considered a deep-sky jewel, the Double Cluster is visible to the unaided eye in a dark country sky.
If you zoom in on them with binoculars or a wide view telescope, you’ll see them as two glorious star clusters. Also they’re an easy target through a telescope and will wow your friends!
The position of h Persei is Right Ascension: 2h 19m; Declination: 57o 9′ north
The position of chi Persei is Right Ascension: 2h 22.4m; Declination: 57o 7′ north
The Double Cluster from our EarthSky Community
View at EarthSky Community Photos. | Makrem Larnaout in Tunisia made this 34-hour telescopic exposure of the Double Cluster in Perseus with surrounding nebulosity, on October 1, 2024. Makrem wrote: “Here’s a new image of the stunning Double Cluster in the constellation Perseus, captured over several nights with the Skywatcher ED80 Esprit and ZWO ASI 2600MC. This pair of open clusters shines with young, blue stars surrounded by subtle red hues, beautifully captured in hydrogen-alpha and RGB for maximum detail and contrast. Each imaging session brought out more depth and brilliance, highlighting the richness of this region of the sky.” That’s impressive. Thank you, Makrem!View at EarthSky Community Photos. | Jeremy Likness in Newport, Oregon, captured this telescopic view of the Double Cluster in the constellation Perseus on November 24, 2023. Jeremy wrote: “The Double Cluster is the beautiful pair of NGC 869 (h Persei) and NGC 884 (chi Persei), containing over 300 blue-white supergiants and a scattering of red supergiants. The cluster is also blue-shifted as it inches its way 24 miles [39 km] closer to Earth every second. It is visible to the unaided eye and lurks near the distinct ‘W’ of Cassiopeia.” Thank you, Jeremy!View at EarthSky Community Photos. | Mario Rana in Hampton, Virginia, captured this telescopic view of the Double Cluster in Perseus (NGC 869 and NGC 884) on September 18, 2023. Mario explained this could be his favorite deep-sky object. Thank you, Mario!
Bottom line: On any autumn or winter evening, scan between Cassiopeia and Perseus for the magnificent Double Cluster in Perseus. The stars in these two clusters are young, hot supergiant suns that are many thousands of times more luminous than our sun.
Here’s an easy way to use the prominent M or W shape of Cassiopeia to locate the Double Cluster in Perseus.
Double Cluster in Perseus
The Double Cluster in Perseus consists of two open star clusters near each other on the sky’s dome. Amateur astronomers know them as h Persei and chi Persei. The two clusters reside in the northern part of the constellation Perseus, quite close to the constellation Cassiopeia the Queen.
If you have a dark sky and find Cassiopeia – which is easy, because the constellation has a distinctive M or W shape – be sure to look for Perseus, too. Then just scan between the two constellations with your binoculars for two glittering groups of stars. The Double Cluster – a breathtaking pair of open clusters, each containing supergiant suns – will be there.
These two star clusters are located about 7,500 light-years away. It’s amazing that we can see these stars at all across this great span of space. Plus, we know they must be intrinsically bright stars, or we wouldn’t be able to see them. Each cluster contains a few hundred stars, and, indeed, these stars are young, hot supergiant suns. They are many thousands of times more luminous than our sun.
Astronomers tell us that the Double Cluster lies within the Perseus arm of the Milky Way galaxy. However, our solar system resides in the inner part of the Orion arm. Therefore, looking at the Double Cluster, we are looking through our local spiral arm and all the way to the next spiral arm outward from the galactic center.
How to find the Double Cluster in Perseus
To locate the Double Cluster, find the W- or M-shaped constellation Cassiopeia the Queen. If your sky is dark enough, you will be able to see the graceful pattern of Perseus the Hero nearby. Then scan between them with binoculars to find the Double Cluster.
The Perseus Double Cluster is located between Cassiopeia and Perseus. Scan the area between them with binoculars and you’ll find the 2 glittering star clusters. Image via Stellarium.org. Used with permission.
Starting at mid-northern latitudes, the Double Cluster is circumpolar, so it’s above the horizon every night of the year at any hour of the night. If you are farther south (but still in the Northern Hemisphere), try looking for the Double Cluster on any clear autumn or winter night.
But remember, the Double Cluster is harder to see when it’s close to the horizon. If you can’t spot it between Cassiopeia and Perseus, wait until later at night. Or look later in the year, when it’s higher in the sky.
For general reference, the Double Cluster is high in the sky when the Big Dipper is low, and vice versa. Because the Big Dipper is lowest in the northern sky on late autumn and early winter evenings, the Double Cluster is highest in the northern sky at these times. As a matter of fact, the Double Cluster is pretty much always visible in the evening except in late spring and summer.
The Double Cluster in Perseus is visible to the unaided eye
The Double Cluster rates among the most magnificent deep-sky objects not to be included in the famous Messier catalog. Of course, Charles Messier (1730-1817) was looking for deep-sky objects that could be mistaken for comets. Maybe he thought nobody would see this pair of glittery clusters as a comet in the sky.
Although considered a deep-sky jewel, the Double Cluster is visible to the unaided eye in a dark country sky.
If you zoom in on them with binoculars or a wide view telescope, you’ll see them as two glorious star clusters. Also they’re an easy target through a telescope and will wow your friends!
The position of h Persei is Right Ascension: 2h 19m; Declination: 57o 9′ north
The position of chi Persei is Right Ascension: 2h 22.4m; Declination: 57o 7′ north
The Double Cluster from our EarthSky Community
View at EarthSky Community Photos. | Makrem Larnaout in Tunisia made this 34-hour telescopic exposure of the Double Cluster in Perseus with surrounding nebulosity, on October 1, 2024. Makrem wrote: “Here’s a new image of the stunning Double Cluster in the constellation Perseus, captured over several nights with the Skywatcher ED80 Esprit and ZWO ASI 2600MC. This pair of open clusters shines with young, blue stars surrounded by subtle red hues, beautifully captured in hydrogen-alpha and RGB for maximum detail and contrast. Each imaging session brought out more depth and brilliance, highlighting the richness of this region of the sky.” That’s impressive. Thank you, Makrem!View at EarthSky Community Photos. | Jeremy Likness in Newport, Oregon, captured this telescopic view of the Double Cluster in the constellation Perseus on November 24, 2023. Jeremy wrote: “The Double Cluster is the beautiful pair of NGC 869 (h Persei) and NGC 884 (chi Persei), containing over 300 blue-white supergiants and a scattering of red supergiants. The cluster is also blue-shifted as it inches its way 24 miles [39 km] closer to Earth every second. It is visible to the unaided eye and lurks near the distinct ‘W’ of Cassiopeia.” Thank you, Jeremy!View at EarthSky Community Photos. | Mario Rana in Hampton, Virginia, captured this telescopic view of the Double Cluster in Perseus (NGC 869 and NGC 884) on September 18, 2023. Mario explained this could be his favorite deep-sky object. Thank you, Mario!
Bottom line: On any autumn or winter evening, scan between Cassiopeia and Perseus for the magnificent Double Cluster in Perseus. The stars in these two clusters are young, hot supergiant suns that are many thousands of times more luminous than our sun.
View larger. | Artist’s concept of the ancient lake in Gale crater. A new study from researchers in Japan suggests that ancient rains on Mars likely brought atmospheric formaldehyde to the surface. And that could potentially have helped life get started on the Red Planet. Image via Kevin Gill/ Flickr.
We know that Mars once had lots of water on its surface. And a new study says there might have been formaldehyde in some of that water.
Atmospheric formaldehyde was likely brought down to the surface through rainfall, the researchers in Japan suggests.
In water, formaldehyde can kickstart the chemical reactions to produce the sugars and organic molecules needed for life.
Follow the ancient rains on Mars
Did life once exist on Mars? Various clues in recent years have moved the answer toward “quite likely.” But we still don’t know for sure. Now there’s another possible clue: formaldehyde.
Scientists said on October 1, 2026, that atmospheric formaldehyde could have mixed with rainwater billions of years ago. And in water, formaldehyde can help start chemical reactions that produce sugars, amino acids and other complex organic molecules needed to start life.
The researchers — from Tohoku University, the Earth-Life Science Institute and the Institute of Science Tokyo in Japan — wanted to know where this formaldehyde would have actually been present on Mars’ surface. The new study makes some interesting findings.
The intriguing new peer-reviewed results were published in The Planetary Science Journal on September 30, 2026.
Formaldehyde on ancient Mars
We know that Mars once had plentiful water on its surface, including rain, rivers, lakes and a probable ocean. And some studies have shown that the early atmosphere on Mars likely produced formaldehyde, a pungent, colorless gas.
Why is that important? When formaldehyde is mixed in water, something very interesting happens. Chemical reactions create sugars, amino acids and other complex organic molecules. These are the molecules needed to help give a kickstart to life.
View larger. | Distribution of atmospheric formaldehyde on ancient Mars. Darker colors show larger amounts on the surface. Various landing sites of landers and rovers are also marked. Image via Shungo Koyama et al./ The Planetary Science Journal.
Where was the formaldehyde?
If there was formaldehyde on Mars long ago, where exactly was it? The researchers created a global map showing where the gas would most likely have been located on the surface.
They simulated the warmer conditions of the time, about 3.8 to 3.6 billion years ago. With this model, the researchers studied how temperature, water vapor, pressure and ultraviolet (UV) light affected the formation of formaldehyde.
The results indicated that water vapor was of particular importance. First, UV light broke down the water molecules. This released reactive hydrogen , which was needed to form the formaldehyde.
Then, rains brought the formaldehyde down to the surface. Based on this, the researchers concluded that areas with more water had more formaldehyde. So basically, the water cycle determined which areas would have more formaldehyde.
Lead author Shungo Koyama at the Institute of Science Tokyo and Tohoku University said:
By comparing our map with findings from rovers, we can begin to test whether places that received more H2CO were also more favorable for early life-related chemistry. If future observations confirm this relationship, our map could help identify promising targets for future Mars missions.
Shungo Koyama at the Institute of Science Tokyo and Tohoku University led the new study about formaldehyde and rain on ancient Mars. Image via ResearchGate.
Mountainous regions get the most formaldehyde
As it turned out, mountainous regions received the most rainfall and had the most formaldehyde. In fact, regions like Tharsis and Elysium had 10 times more formaldehyde than the global average. Both areas have huge towering volcanoes.
To note, this estimate is for how much formaldehyde Mars had way back then, not now.
Did formaldehyde help start life on Earth?
Back in 2011, another study published in Proceedings of the National Academy of Sciences showed that formaldehyde might have also helped start life on Earth.
Scientists think that billions of years ago, a Mars-sized object slammed into the Earth, blasting out debris that formed the moon. The collision, most experts say, caused huge numbers of organic molecules to flee our planet. But sticky formaldehyde molecules held onto a fair chunk of Earth’s carbon that we might have otherwise lost. We might owe our existence to that ancient formaldehyde.
Bottom line: Formaldehyde in the ancient rains on Mars might have provided crucial chemical reactions needed for life to begin on the red planet billions of years ago.
View larger. | Artist’s concept of the ancient lake in Gale crater. A new study from researchers in Japan suggests that ancient rains on Mars likely brought atmospheric formaldehyde to the surface. And that could potentially have helped life get started on the Red Planet. Image via Kevin Gill/ Flickr.
We know that Mars once had lots of water on its surface. And a new study says there might have been formaldehyde in some of that water.
Atmospheric formaldehyde was likely brought down to the surface through rainfall, the researchers in Japan suggests.
In water, formaldehyde can kickstart the chemical reactions to produce the sugars and organic molecules needed for life.
Follow the ancient rains on Mars
Did life once exist on Mars? Various clues in recent years have moved the answer toward “quite likely.” But we still don’t know for sure. Now there’s another possible clue: formaldehyde.
Scientists said on October 1, 2026, that atmospheric formaldehyde could have mixed with rainwater billions of years ago. And in water, formaldehyde can help start chemical reactions that produce sugars, amino acids and other complex organic molecules needed to start life.
The researchers — from Tohoku University, the Earth-Life Science Institute and the Institute of Science Tokyo in Japan — wanted to know where this formaldehyde would have actually been present on Mars’ surface. The new study makes some interesting findings.
The intriguing new peer-reviewed results were published in The Planetary Science Journal on September 30, 2026.
Formaldehyde on ancient Mars
We know that Mars once had plentiful water on its surface, including rain, rivers, lakes and a probable ocean. And some studies have shown that the early atmosphere on Mars likely produced formaldehyde, a pungent, colorless gas.
Why is that important? When formaldehyde is mixed in water, something very interesting happens. Chemical reactions create sugars, amino acids and other complex organic molecules. These are the molecules needed to help give a kickstart to life.
View larger. | Distribution of atmospheric formaldehyde on ancient Mars. Darker colors show larger amounts on the surface. Various landing sites of landers and rovers are also marked. Image via Shungo Koyama et al./ The Planetary Science Journal.
Where was the formaldehyde?
If there was formaldehyde on Mars long ago, where exactly was it? The researchers created a global map showing where the gas would most likely have been located on the surface.
They simulated the warmer conditions of the time, about 3.8 to 3.6 billion years ago. With this model, the researchers studied how temperature, water vapor, pressure and ultraviolet (UV) light affected the formation of formaldehyde.
The results indicated that water vapor was of particular importance. First, UV light broke down the water molecules. This released reactive hydrogen , which was needed to form the formaldehyde.
Then, rains brought the formaldehyde down to the surface. Based on this, the researchers concluded that areas with more water had more formaldehyde. So basically, the water cycle determined which areas would have more formaldehyde.
Lead author Shungo Koyama at the Institute of Science Tokyo and Tohoku University said:
By comparing our map with findings from rovers, we can begin to test whether places that received more H2CO were also more favorable for early life-related chemistry. If future observations confirm this relationship, our map could help identify promising targets for future Mars missions.
Shungo Koyama at the Institute of Science Tokyo and Tohoku University led the new study about formaldehyde and rain on ancient Mars. Image via ResearchGate.
Mountainous regions get the most formaldehyde
As it turned out, mountainous regions received the most rainfall and had the most formaldehyde. In fact, regions like Tharsis and Elysium had 10 times more formaldehyde than the global average. Both areas have huge towering volcanoes.
To note, this estimate is for how much formaldehyde Mars had way back then, not now.
Did formaldehyde help start life on Earth?
Back in 2011, another study published in Proceedings of the National Academy of Sciences showed that formaldehyde might have also helped start life on Earth.
Scientists think that billions of years ago, a Mars-sized object slammed into the Earth, blasting out debris that formed the moon. The collision, most experts say, caused huge numbers of organic molecules to flee our planet. But sticky formaldehyde molecules held onto a fair chunk of Earth’s carbon that we might have otherwise lost. We might owe our existence to that ancient formaldehyde.
Bottom line: Formaldehyde in the ancient rains on Mars might have provided crucial chemical reactions needed for life to begin on the red planet billions of years ago.
View at EarthSky Community Photos. | Paul Shouse captured this photo on December 12, 2025, in Japan and wrote: “An old garden bench under a Japanese maple tree.” Thank you, Paul!
Why do leaves change color in the autumn?
With autumn setting in for those in the Northern Hemisphere, the leaves on the trees are beginning their miraculous yearly color transformation. Why do leaves change color in fall?
Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. So the vivid yellows and oranges of fall leaves are there, but hidden.
In the fall, trees break down the green pigments and nutrients stored in their leaves. Then, the nutrients move into the tree’s roots for reuse in the spring. It’s then that the trees take on their autumn hues.
As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, a former professor of chemistry and biochemistry at DePauw University who studies plant pigments. For example, some tree leaves turn mostly brown, indicating that all pigments are gone.
VIew at EarthSky Community Photos. | Lois Vanbroekhoven captured this image of colorful autumn leaves and the full Harvest Moon from Michigan on September 26, 2026. Thank you, Lois!
What brings out the reds in leaves?
Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:
The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves, especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.
View at EarthSky Community Photos. | Sharon Kizer, who is mother to EarthSky’s Kelly Kizer Whitt, took this image of fiery maples and rain clouds on October 9, 2022, in Madison, Wisconsin. It illustrates some of the vivid reds of autumn as leaves change color. Thank you, Sharon!
Sometimes there is a mixture of colors when leaves change
In some cases, about half of a tree’s leaves are red or orange and the other half green. Dudle says that results from micro-environmental factors, such as only half the tree being exposed to sunlight or cold.
Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.
When leaves turn color they might be protecting the tree
The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?
Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:
It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.
Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:
In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.
Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.
EarthSky’s roving nature reporter, Kelly Kizer Whitt, spent October 3 to 5, 2024, at Minnesota’s North Shore, where the arrowhead of Minnesota meets Lake Superior. She hiked around and took in some of the area’s most popular sights, while the fall colors were at their peak. Watch a video that captures the best of this autumn explosion.
Bottom line: Why do leaves change color in the autumn? Here’s what biologists say.
View at EarthSky Community Photos. | Paul Shouse captured this photo on December 12, 2025, in Japan and wrote: “An old garden bench under a Japanese maple tree.” Thank you, Paul!
Why do leaves change color in the autumn?
With autumn setting in for those in the Northern Hemisphere, the leaves on the trees are beginning their miraculous yearly color transformation. Why do leaves change color in fall?
Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. So the vivid yellows and oranges of fall leaves are there, but hidden.
In the fall, trees break down the green pigments and nutrients stored in their leaves. Then, the nutrients move into the tree’s roots for reuse in the spring. It’s then that the trees take on their autumn hues.
As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, a former professor of chemistry and biochemistry at DePauw University who studies plant pigments. For example, some tree leaves turn mostly brown, indicating that all pigments are gone.
VIew at EarthSky Community Photos. | Lois Vanbroekhoven captured this image of colorful autumn leaves and the full Harvest Moon from Michigan on September 26, 2026. Thank you, Lois!
What brings out the reds in leaves?
Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:
The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves, especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.
View at EarthSky Community Photos. | Sharon Kizer, who is mother to EarthSky’s Kelly Kizer Whitt, took this image of fiery maples and rain clouds on October 9, 2022, in Madison, Wisconsin. It illustrates some of the vivid reds of autumn as leaves change color. Thank you, Sharon!
Sometimes there is a mixture of colors when leaves change
In some cases, about half of a tree’s leaves are red or orange and the other half green. Dudle says that results from micro-environmental factors, such as only half the tree being exposed to sunlight or cold.
Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.
When leaves turn color they might be protecting the tree
The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?
Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:
It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.
Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:
In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.
Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.
EarthSky’s roving nature reporter, Kelly Kizer Whitt, spent October 3 to 5, 2024, at Minnesota’s North Shore, where the arrowhead of Minnesota meets Lake Superior. She hiked around and took in some of the area’s most popular sights, while the fall colors were at their peak. Watch a video that captures the best of this autumn explosion.
Bottom line: Why do leaves change color in the autumn? Here’s what biologists say.
NASA’s Curiosity rover captured this view of a Martian dawn on August 11, 2026. NASA just released it to the public on Tuesday. Now, Curiosity is headed toward those distant, sunlit crags. See the full panorama below. Image via NASA/ JPL-Caltech/ MSSS.
NASA’s Curiosity rover has been exploring the Mount Sharp region of Mars since it arrived in 2012. Now, on October 6, 2026, NASA has released this new pic of a Martian dawn, which illuminates the play of light on the cliffs and crags of the region.
The Mars Curiosity rover captured this image back on August 11, 2026, which was the 4,982nd Martian day, or sol. And since then, Curiosity has surpassed the 5,000 sol mark and is still going strong!
An odd feature on Mars
NASA said the crags on the horizon are known as yardangs. These are landscape protrusions carved out of bedrock. The yardangs protrude on the northwestern reaches of Mount Sharp.
Mount Sharp is a 3-mile-tall (5-km-tall) mountain, while the yardangs extend horizontally about 10 miles (16 km) across.
But scientists think something is odd about this yardang layer on Mars. Ashwin Vasavada, Curiosity project scientist of NASA’s Jet Propulsion Laboratory, said:
The yardang layer looks out of place. It’s the wrong color, the layers tilt at an odd angle, and it almost appears plastered on. But that’s what makes it exciting to reach.
No one is sure exactly what created this layer, but one idea is it may be ash deposited by ancient volcanic eruptions.
View larger. | Here’s the full panorama of the Martian dawn with all 6 shots from NASA’s Curiosity rover. NASA said: “Unlike most images from the rover’s Mastcam, this one was processed without the usual white balancing; an artistic choice that preserves the early morning appearance.” Image via NASA/ JPL-Caltech/ MSSS.
More about Mount Sharp
Mount Sharp lies within Gale Crater. And it makes up the crater’s central peak. Curiosity has now climbed 0.6 miles (1 km) of elevation as it ascends toward Mount Sharp. In fact, that’s the highest ever climbed on Mars, and the rover is still going.
Scientists say Mount Sharp is made of layers that formed over time. Lakes and streams once flowed here. But eventually, the water dried up and left behind salty deposits. The wind then eroded away some of the material, leaving behind the crags or yardangs.
Now the little Curiosity rover will roll onward, perhaps reaching the base of the yardangs by 2027. We look forward to seeing these jagged formations from a closer point of view!
This is an artist’s concept looking down at Mount Sharp on Mars. The circled area denotes the location of the yardangs, or crags, in the top image. Image via NASA/ JPL-Caltech/ ESA/ DLR/ FU Berlin/ MSSS.
Bottom line: On October 6, 2026, NASA released an image of Martian dawn from the Curiosity rover. The image captures a pale light illuminating distant cliffs and crags.
NASA’s Curiosity rover captured this view of a Martian dawn on August 11, 2026. NASA just released it to the public on Tuesday. Now, Curiosity is headed toward those distant, sunlit crags. See the full panorama below. Image via NASA/ JPL-Caltech/ MSSS.
NASA’s Curiosity rover has been exploring the Mount Sharp region of Mars since it arrived in 2012. Now, on October 6, 2026, NASA has released this new pic of a Martian dawn, which illuminates the play of light on the cliffs and crags of the region.
The Mars Curiosity rover captured this image back on August 11, 2026, which was the 4,982nd Martian day, or sol. And since then, Curiosity has surpassed the 5,000 sol mark and is still going strong!
An odd feature on Mars
NASA said the crags on the horizon are known as yardangs. These are landscape protrusions carved out of bedrock. The yardangs protrude on the northwestern reaches of Mount Sharp.
Mount Sharp is a 3-mile-tall (5-km-tall) mountain, while the yardangs extend horizontally about 10 miles (16 km) across.
But scientists think something is odd about this yardang layer on Mars. Ashwin Vasavada, Curiosity project scientist of NASA’s Jet Propulsion Laboratory, said:
The yardang layer looks out of place. It’s the wrong color, the layers tilt at an odd angle, and it almost appears plastered on. But that’s what makes it exciting to reach.
No one is sure exactly what created this layer, but one idea is it may be ash deposited by ancient volcanic eruptions.
View larger. | Here’s the full panorama of the Martian dawn with all 6 shots from NASA’s Curiosity rover. NASA said: “Unlike most images from the rover’s Mastcam, this one was processed without the usual white balancing; an artistic choice that preserves the early morning appearance.” Image via NASA/ JPL-Caltech/ MSSS.
More about Mount Sharp
Mount Sharp lies within Gale Crater. And it makes up the crater’s central peak. Curiosity has now climbed 0.6 miles (1 km) of elevation as it ascends toward Mount Sharp. In fact, that’s the highest ever climbed on Mars, and the rover is still going.
Scientists say Mount Sharp is made of layers that formed over time. Lakes and streams once flowed here. But eventually, the water dried up and left behind salty deposits. The wind then eroded away some of the material, leaving behind the crags or yardangs.
Now the little Curiosity rover will roll onward, perhaps reaching the base of the yardangs by 2027. We look forward to seeing these jagged formations from a closer point of view!
This is an artist’s concept looking down at Mount Sharp on Mars. The circled area denotes the location of the yardangs, or crags, in the top image. Image via NASA/ JPL-Caltech/ ESA/ DLR/ FU Berlin/ MSSS.
Bottom line: On October 6, 2026, NASA released an image of Martian dawn from the Curiosity rover. The image captures a pale light illuminating distant cliffs and crags.
This image, which the European Southern Observatory (ESO) released on March 27, 2024, shows the supermassive black hole at the center of our Milky Way in polarized light. It depicts the hot material surrounding the black hole. We can’t see the black hole itself at the center. A new study suggests that planets could form in these outer dusty regions. Image via EHT Collaboration/ ESO.
Could black holes have planets? New research says yes, they could.
New simulations suggest massive planets could form in the outer dusty regions around supermassive black holes.
The planets could form through a similar mechanism to how planets form around stars.
Astronomers have found thousands of planets orbiting other stars. They’ve even found some rogue planets, or planets without a star. Now, fascinating new research says more planets could be lurking elsewhere. They could, the study says, be forming around black holes.
Astrophysicists Bhupendra Mishra and Wladimir Lyra discussed the possibility on a SETI livestream on September 21, 2026. They revealed that massive planets could form in the dusty regions around supermassive black holes, similarly to how planets form around stars.
The simulations suggest these planet-mass objects could start around the mass of Jupiter and then keep growing. And, incredibly, a single active black hole could spawn millions of planets at a time.
The new peer-reviewed paper was originally published in The Astrophysical Journal on June 29, 2026.
Scientists think supermassive black holes can be found in the central regions of almost all large galaxies. This study focuses on supermassive black holes that are actively feeding on the gas and dust around them. These incredibly violent objects are known as active galactic nuclei, or AGNs.
When these AGNs pull in matter to devour, the gas and dust start to collect and move around the black hole in a blazingly hot accretion disk. These are similar to the accretion disks that form around stars and create planets.
Noticing this, astrophysicist Barry McKernan — a co-author of the new study — asked Lyra whether the processes that form planets around stars could also occur around an active galactic nucleus.
They found that it could happen, at least theoretically. This is because the same physics should underly the process even in the different environments. If so, black holes could have planets.
The scales are vastly different though. A supermassive black hole could be a million times more massive than the sun. And baby planets forming around it could start out with the mass of Jupiter, our solar system’s biggest planet.
They would also form farther out from the black hole, in the dusty outer region of the disk. That is analogous to the outer region of our solar system, where comets form.
How would planets form?
So just how would one of these massive planets form? The researchers say the process would be similar to the way planets in regular solar systems do: from colliding dust. Dust grains would accumulate in increasingly dense concentrations. That’s the beginning of a baby planet.
Streaming instability — when drag on solid particles within a disk of gas and dust causes them to spontaneously clump — is the process behind this accumulation.
It’s even possible that some of them could grow beyond the planet stage and become brown dwarfs. These “failed stars” are larger than typical planets, but not massive enough to sustain nuclear fusion and shine like stars.
And, incredibly, some of those could keep growing until they became true stars.
How long would they last?
But some black hole planets might face a dire fate. Gravity from the black hole could move some of them inward. The temperatures in that region closer to the black would be far too hot. The planets would disintegrate. This, in turn, would create more dust.
That said, there could be a lot of planets to go round. The researchers estimated that a million planets could form during a single active episode of an active galactic nucleus. One of these bursts is typically about 2 million years long. And a black hole can go through many of these periods in its lifetime. Add that up over billions of years, and the number of planets formed from a black hole could be immense.
View larger. | The accretion disk of dusty material around a black hole could be the birthplace for millions of planets, or planetary-mass objects. Image via NASA/ JPL-Caltech.
Can black hole planets be detected?
Right now, we can’t directly detect any of these planets, if they exist. That will require new methods. The black holes are too massive to use the radial velocity technique, which detects the slight movement of a star caused by an orbiting planet.
The transit method — when a planet passes in front of its star as seen from Earth — might work, but the planets, big as they are, would be vanishingly small compared to the accretion disk of dust around the black hole. And that would be the only background light source available, since the black hole itself doesn’t emit light.
Gravitational microlensing could also work. But you would need several planets around the same black hole to produce a strong enough lensing signal, along with a favorable alignment. In gravitational microlensing, the mass of the planet distorts the spacetime around it, which astronomers can detect.
It would also be difficult to discern a planet from all the other noise that is around a supermassive black hole.
Pretty much the last place in the universe I'd expect to find planets is in the incredibly violent and radiation-laden accretion disks around supermassive black holes.And yet… maybe? ? ?www.scientificamerican.com/article/plan…[thanks to @saavikford.bsky.social for a convo about this]? ?
Even though the underlying physics is similar, these planets still form in a very different environment than those that form around stars. So should we call them planets? The peer-review team for the paper actually objected to calling them planets. So Lyra suggested the term “blanets.”
But that term hasn’t come into use yet, so they are still just calling them planetary-mass objects.
If black holes can have planets orbiting them, then it’s natural to wonder if those objects could have moons. The researchers say that these worlds would be more likely to form as binaries. That is, two bodies of similar mass orbiting each other, rather than one body having a smaller body orbiting it as a moon. There are binary asteroids and minor planets like this in our solar system.
Angular momentum could cause this to happen. When the planets are first forming, angular momentum would produce binary systems in which two objects orbit one another. The same process occurs in the Kuiper Belt in our solar system. In fact, astronomers have discovered a growing number of binary objects there.
What about life?
Could any of these hypothetical planets support life? We don’t know, but it’s not impossible. The simulations suggest that they would have energy, even though black holes don’t emit light like a star. The energy would come from hot gas in the black hole’s accretion disk.
It’s fun to ponder what kind of light might be possible on such worlds. And what would it be like to stand on one of them and look at the glowing accretion disk swirling around the black hole.
Bottom line: New simulations by two astrophysicists suggest that supermassive black holes could have planets orbiting them, much like planets orbit stars.
This image, which the European Southern Observatory (ESO) released on March 27, 2024, shows the supermassive black hole at the center of our Milky Way in polarized light. It depicts the hot material surrounding the black hole. We can’t see the black hole itself at the center. A new study suggests that planets could form in these outer dusty regions. Image via EHT Collaboration/ ESO.
Could black holes have planets? New research says yes, they could.
New simulations suggest massive planets could form in the outer dusty regions around supermassive black holes.
The planets could form through a similar mechanism to how planets form around stars.
Astronomers have found thousands of planets orbiting other stars. They’ve even found some rogue planets, or planets without a star. Now, fascinating new research says more planets could be lurking elsewhere. They could, the study says, be forming around black holes.
Astrophysicists Bhupendra Mishra and Wladimir Lyra discussed the possibility on a SETI livestream on September 21, 2026. They revealed that massive planets could form in the dusty regions around supermassive black holes, similarly to how planets form around stars.
The simulations suggest these planet-mass objects could start around the mass of Jupiter and then keep growing. And, incredibly, a single active black hole could spawn millions of planets at a time.
The new peer-reviewed paper was originally published in The Astrophysical Journal on June 29, 2026.
Scientists think supermassive black holes can be found in the central regions of almost all large galaxies. This study focuses on supermassive black holes that are actively feeding on the gas and dust around them. These incredibly violent objects are known as active galactic nuclei, or AGNs.
When these AGNs pull in matter to devour, the gas and dust start to collect and move around the black hole in a blazingly hot accretion disk. These are similar to the accretion disks that form around stars and create planets.
Noticing this, astrophysicist Barry McKernan — a co-author of the new study — asked Lyra whether the processes that form planets around stars could also occur around an active galactic nucleus.
They found that it could happen, at least theoretically. This is because the same physics should underly the process even in the different environments. If so, black holes could have planets.
The scales are vastly different though. A supermassive black hole could be a million times more massive than the sun. And baby planets forming around it could start out with the mass of Jupiter, our solar system’s biggest planet.
They would also form farther out from the black hole, in the dusty outer region of the disk. That is analogous to the outer region of our solar system, where comets form.
How would planets form?
So just how would one of these massive planets form? The researchers say the process would be similar to the way planets in regular solar systems do: from colliding dust. Dust grains would accumulate in increasingly dense concentrations. That’s the beginning of a baby planet.
Streaming instability — when drag on solid particles within a disk of gas and dust causes them to spontaneously clump — is the process behind this accumulation.
It’s even possible that some of them could grow beyond the planet stage and become brown dwarfs. These “failed stars” are larger than typical planets, but not massive enough to sustain nuclear fusion and shine like stars.
And, incredibly, some of those could keep growing until they became true stars.
How long would they last?
But some black hole planets might face a dire fate. Gravity from the black hole could move some of them inward. The temperatures in that region closer to the black would be far too hot. The planets would disintegrate. This, in turn, would create more dust.
That said, there could be a lot of planets to go round. The researchers estimated that a million planets could form during a single active episode of an active galactic nucleus. One of these bursts is typically about 2 million years long. And a black hole can go through many of these periods in its lifetime. Add that up over billions of years, and the number of planets formed from a black hole could be immense.
View larger. | The accretion disk of dusty material around a black hole could be the birthplace for millions of planets, or planetary-mass objects. Image via NASA/ JPL-Caltech.
Can black hole planets be detected?
Right now, we can’t directly detect any of these planets, if they exist. That will require new methods. The black holes are too massive to use the radial velocity technique, which detects the slight movement of a star caused by an orbiting planet.
The transit method — when a planet passes in front of its star as seen from Earth — might work, but the planets, big as they are, would be vanishingly small compared to the accretion disk of dust around the black hole. And that would be the only background light source available, since the black hole itself doesn’t emit light.
Gravitational microlensing could also work. But you would need several planets around the same black hole to produce a strong enough lensing signal, along with a favorable alignment. In gravitational microlensing, the mass of the planet distorts the spacetime around it, which astronomers can detect.
It would also be difficult to discern a planet from all the other noise that is around a supermassive black hole.
Pretty much the last place in the universe I'd expect to find planets is in the incredibly violent and radiation-laden accretion disks around supermassive black holes.And yet… maybe? ? ?www.scientificamerican.com/article/plan…[thanks to @saavikford.bsky.social for a convo about this]? ?
Even though the underlying physics is similar, these planets still form in a very different environment than those that form around stars. So should we call them planets? The peer-review team for the paper actually objected to calling them planets. So Lyra suggested the term “blanets.”
But that term hasn’t come into use yet, so they are still just calling them planetary-mass objects.
If black holes can have planets orbiting them, then it’s natural to wonder if those objects could have moons. The researchers say that these worlds would be more likely to form as binaries. That is, two bodies of similar mass orbiting each other, rather than one body having a smaller body orbiting it as a moon. There are binary asteroids and minor planets like this in our solar system.
Angular momentum could cause this to happen. When the planets are first forming, angular momentum would produce binary systems in which two objects orbit one another. The same process occurs in the Kuiper Belt in our solar system. In fact, astronomers have discovered a growing number of binary objects there.
What about life?
Could any of these hypothetical planets support life? We don’t know, but it’s not impossible. The simulations suggest that they would have energy, even though black holes don’t emit light like a star. The energy would come from hot gas in the black hole’s accretion disk.
It’s fun to ponder what kind of light might be possible on such worlds. And what would it be like to stand on one of them and look at the glowing accretion disk swirling around the black hole.
Bottom line: New simulations by two astrophysicists suggest that supermassive black holes could have planets orbiting them, much like planets orbit stars.
El Niño could soon trigger coastal flooding along the western coast of North America, through Kelvin waves. But what are Kelvin waves? Image via Connor Scott McManus/ Pexels.
A strong El Niño formed over the summer, and has immediately had an impact on tropical weather.
The Atlantic Ocean has had a below-average hurricane season. In fact, this is the first season in the modern, satellite era to have not recorded a hurricane at this point of the June 1st through November 30th season. Meanwhile, in the Pacific Ocean, the hurricane season has been more active than average with 18 named storms, including nine hurricanes. A typical full hurricane season in the eastern Pacific Ocean normally brings 15 named storms and eight hurricanes.
But El Niño isn’t set to only affect tropical storms. Forecasters are warning that El Niño could now help trigger coastal flooding along the western coast of North America. How? Through the formation of Kelvin waves.
What is a Kelvin wave?
A Kelvin wave is not a wave that crashes along the coast. Instead, it’s a planetary wave that moves from west to east along the equator in a trip that can take up to three months.
While higher than the surface of the water, it doesn’t have a crest like a typical wave. It’s more like a large ripple. Once it arrives in Central and South America, the Kelvin wave continues its journey up the western coast of the Americas. There, it can bring higher water temperatures and water levels, sometimes for months on end.
Kelvin waves were reported to have impacted parts of California back in the spring, but will be more impactful through the fall and winter.
Kelvin waves and El Niño
So, what’s the relationship between El Niño and these Kelvin waves?
El Niño is the warm phase of the global climate pattern called El Niño Southern Oscillation, or ENSO. ENSO has two main phases: El Niño and La Niña, but also a third neutral phase.
El Niño is considered the “warm phase” because that is when the waters of the tropical Pacific Ocean are warmer than average. One reason for the warmer than normal water is due to weaker easterly trade winds, or winds that flow east to west. Weaker trade winds mean the deeper, cold ocean water doesn’t as easily reach the water’s surface, keeping the water warmer.
But the weaker surface winds can also allow the surface layer of the water to propagate back eastward, creating a Kelvin wave. Because this surface layer of the ocean water is warmer than average, it can continue to warm the ocean water. And that includes the temperature of the water off the North American coastline as it moves up.
Kelvin waves can bring warmer waters and higher water levels on the North American West Coast. Image via Yajun Dong/ Pexels.
Strengthening El Niño
El Niño in the Pacific this year is strong. The latest update from NOAA’s Climate Prediction Center says that this current El Niño has a 75% chance of being historically strong, topping the strength of previous El Niño events since 1950, when reliable records began.
This means the likelihood of more significant impacts due to El Niño are much higher. For decades, NOAA scientists have been studying the impact of El Niño on high tide flooding, which is when water covers roads and lower lying areas due to high tide and higher sea levels. They have noticed an increase in high tide flooding during El Niño years.
With sea levels already rising over the decades, Kelvin waves could see coastal communities — especially along the western coast of North America — dealing with more flooding through the fall and winter.
Bottom line: As El Niño continues to strengthen, it could cause Kelvin waves to move east and eventually trigger coastal flooding in the North American west.
El Niño could soon trigger coastal flooding along the western coast of North America, through Kelvin waves. But what are Kelvin waves? Image via Connor Scott McManus/ Pexels.
A strong El Niño formed over the summer, and has immediately had an impact on tropical weather.
The Atlantic Ocean has had a below-average hurricane season. In fact, this is the first season in the modern, satellite era to have not recorded a hurricane at this point of the June 1st through November 30th season. Meanwhile, in the Pacific Ocean, the hurricane season has been more active than average with 18 named storms, including nine hurricanes. A typical full hurricane season in the eastern Pacific Ocean normally brings 15 named storms and eight hurricanes.
But El Niño isn’t set to only affect tropical storms. Forecasters are warning that El Niño could now help trigger coastal flooding along the western coast of North America. How? Through the formation of Kelvin waves.
What is a Kelvin wave?
A Kelvin wave is not a wave that crashes along the coast. Instead, it’s a planetary wave that moves from west to east along the equator in a trip that can take up to three months.
While higher than the surface of the water, it doesn’t have a crest like a typical wave. It’s more like a large ripple. Once it arrives in Central and South America, the Kelvin wave continues its journey up the western coast of the Americas. There, it can bring higher water temperatures and water levels, sometimes for months on end.
Kelvin waves were reported to have impacted parts of California back in the spring, but will be more impactful through the fall and winter.
Kelvin waves and El Niño
So, what’s the relationship between El Niño and these Kelvin waves?
El Niño is the warm phase of the global climate pattern called El Niño Southern Oscillation, or ENSO. ENSO has two main phases: El Niño and La Niña, but also a third neutral phase.
El Niño is considered the “warm phase” because that is when the waters of the tropical Pacific Ocean are warmer than average. One reason for the warmer than normal water is due to weaker easterly trade winds, or winds that flow east to west. Weaker trade winds mean the deeper, cold ocean water doesn’t as easily reach the water’s surface, keeping the water warmer.
But the weaker surface winds can also allow the surface layer of the water to propagate back eastward, creating a Kelvin wave. Because this surface layer of the ocean water is warmer than average, it can continue to warm the ocean water. And that includes the temperature of the water off the North American coastline as it moves up.
Kelvin waves can bring warmer waters and higher water levels on the North American West Coast. Image via Yajun Dong/ Pexels.
Strengthening El Niño
El Niño in the Pacific this year is strong. The latest update from NOAA’s Climate Prediction Center says that this current El Niño has a 75% chance of being historically strong, topping the strength of previous El Niño events since 1950, when reliable records began.
This means the likelihood of more significant impacts due to El Niño are much higher. For decades, NOAA scientists have been studying the impact of El Niño on high tide flooding, which is when water covers roads and lower lying areas due to high tide and higher sea levels. They have noticed an increase in high tide flooding during El Niño years.
With sea levels already rising over the decades, Kelvin waves could see coastal communities — especially along the western coast of North America — dealing with more flooding through the fall and winter.
Bottom line: As El Niño continues to strengthen, it could cause Kelvin waves to move east and eventually trigger coastal flooding in the North American west.
A viewing platform at Massai Point in Chiricahua National Monument. Image via Lucy Whitt. Used with permission.
