UPDATE 19:30 UTC (20:30) CET

We have confirmation of the atmospheric reentry of ERS-2 at 17:17 UTC (18:17 CET) +/- 1 minute over the North Pacific Ocean between Alaska and Hawaii.

Coordinates: https://t.co/BNX4K1YxW2

— ESA Operations (@esaoperations) February 21, 2024

ERS-2 meets end over Pacific Ocean

The European Space Agency reports its dead ERS-2 satellite has fallen from the sky. It dropped into the atmosphere about 90 minutes after the estimated time of re-entry somewhere over the Pacific Ocean. ESA marked the time of re-entry as 11:17 a.m. Central Standard Time (17:17 UTC). Consequently, the falling satellite appears not to have caused any property damage, ESA said.

UPDATE 17:35 UTC (18:35 CET)

We have now reached the end of the final reentry window. We have received no new observations of ERS-2. This may mean that the satellite has already reentered, but we are waiting for information from our partners before we can confirm. Stay tuned.

— ESA Operations (@esaoperations) February 21, 2024

Dead satellite reentry window is over

A European Space Agency satellite – ERS-2 – was to reenter today (February 21, 2024). The uncontrolled or “natural” reentry window was centered at 9:41 a.m. central (15:41 UTC). Ultimately, the reentry window passed with no confirmation of the satellite’s reentry.

Accordingly, ESA said in a blog post updating reentry data:

The vast majority of the satellite will burn up, and any pieces that survive will be spread out somewhat randomly over a ground track on average hundreds of kilometers long and a few tens of kilometers wide (which is why the associated risks are very, very low).

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Not a threat to humans

During a press conference on February 13, ESA said:

We estimate that the largest fragment of the satellite that could reach the ground is 115 pounds (52 kg).

But in addition, it also said:

The odds of a piece of satellite falling on someone’s head is estimated at one in a billion.

So, when you consider that 71% of Earth’s surface is water, odds are likely that the dead satellite made a big splash somewhere.

Satellite photo captured on descent

The Australian satellite imaging company HEO Robotics captured images of the doomed ERS-2 European Space Agency satellite. The pictures show a blurry satellite looking very much, in fact, like a TIE fighter from “Star Wars.” ESA said in a press release issued Monday, February 19, 2024:

The U.K. Space Agency recently worked with HEO to capture these images of ERS-2 during its descent. Using cameras on other satellites to image objects reentering the atmosphere is a relatively new approach.

In the future, these images may be used alongside data from ground-based sensors to refine reentry predictions.

What was ERS-2?

ERS-2 was ESA’s second European Remote Sensing satellite. Launched on April 21, 1995, the satellite had a 16-year career observing Earth until ESA retired it in 2011. Later, in July and August of that year, the space agency directed the satellite in 66 maneuvers to assist with deorbit. The maneuvers used up the satellite’s fuel in order to decrease its orbit and lessen its chance of hitting operational satellites. Additionally, lowering the satellite’s orbit also ensured that the satellite would reenter within the next 15 years, instead of 100 to 200 years. Also, by September 2011, all the fuel from ERS-2 was drained. After that, the spacecraft was inoperable.

Over the satellite’s lifetime, ERS-2 collected data on polar ice, changing land surfaces, sea-level rise, warming oceans and atmospheric chemistry. It was also pressed into service during natural disasters in remote regions. ESA said ERS-2:

… returned a wealth of information that revolutionized our perspective of our planet and understanding of climate change. As well as leaving a remarkable legacy of data that still continue to advance science, this outstanding mission set the stage for many of today’s satellites and ESA’s position at the forefront of Earth observation.

Dead satellite stats

ERS-2 weighed approximately 5,057 pounds (2294 kg). ESA said that:

On average, an object of similar mass reenters Earth’s atmosphere every week or two.

Previously, the space agency had said the satellite would begin to break up when it reached about 50 miles (80 km) above the ground. Indeed, most of the fragments would burn up completely in Earth’s atmosphere. As a result, the risk to humans was minute. According to ESA:

The annual risk of an individual human being injured by space debris is under 1 in 100 billion.

And, what does the burning spacecraft do to our atmosphere? ESA said:

… the short-term impact on the atmosphere due to the burn up of a single spacecraft is modest.

But, as ESA also said, an object this size reenters every week or two. And in October 2023, a team of scientists released a study that said:

… about 10% of the aerosol particles in the stratosphere contain aluminum and other metals that originated from the “burn-up” of satellites and rocket stages during reentry. Although direct health or environmental impacts at ground level are unlikely, these measurements have broad implications for the stratosphere and higher altitudes. With many more launches planned in the coming decades, metals from spacecraft reentry could induce changes in the stratospheric aerosol layer.

Just in from our colleagues at @esa's Earth Observation centre outside Rome: footage of the ERS-2 satellite passing over the area yesterday???

In the video you can see the fly-by in real speed and slowed down to a quarter of that speed (the satellite was in and out of the frame… pic.twitter.com/1fLqb4r2CC

— ESA Earth Observation (@ESA_EO) February 21, 2024

Bottom line: A dead satellite – ESA’s ERS-2 satellite – re-entered Earth’s atmosphere today. The entry was uncontrolled or “natural,” ESA said.

Via ESA

The post Dead satellite enters atmosphere over Pacific Ocean first appeared on EarthSky.

Whales aren’t fish!

Because they have fins and flippers, you might think whales are big fish, but they’re actually mammals, just like us. And that means that they’re warm-blooded, they breathe air and that baby whales need their mothers’ milk to survive. And they even have hair! Before they’re born, a layer of fuzz covers whales. It’s called lanugo, and some even keep hair as adults. Sound familiar?

So, if they’re more akin to humans than fish, why do they live in the ocean? Around 50 million years ago, the ancestors of whales lived on the land. We know this by looking at whale skeletons. They don’t have legs, but they do have tiny hip bones left over from their prehistoric relatives. Evolution changed them, and these animals that used to hunt on land started hunting in water. Over time, they changed and adapted to an aquatic lifestyle.

These stunning creatures live in every ocean on the planet. You can find them in temperate oceans and tropical waters around the equator, as well as in the frigid Arctic and Antarctic oceans. Some whale species live in seas, including the North Sea and the Mediterranean.

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There are 2 types of whales

Over millions of years, the water – which gives more support to their humongous bodies than air does – has allowed them to grow into 92 different species of all shapes and sizes.

All whales are cetaceans, but there are two major types. One is the toothed whale (77 species) and the other one is the baleen whale (15 species). And, as you probably guessed, their differences can be found in their mouths. Some whales have teeth, while others have hairy structures called baleens.

Baleen whales

The giant brushes in baleen whales’ mouths act like a big sieve, filtering food out of the water. A favorite meal for baleen whales is one of the smallest animals in the ocean, a little crustacean called krill. These tiny creatures only grow to around 0.4 or 0.8 inches (1 or 2 centimeters) long. So obviously, whales need to eat a lot of them. In fact, they eat about 40 million krill a day! To give you an idea of how much that is, put five cows together, and you got it.

Some whales use bubble netting to feed. How clever! They cooperatively blow bubbles that encircle their prey. The prey won’t cross through the bubbles, trapping them, and making it easy for the whales to eat them.

When whales sense food ahead, they open their mouths, with some species stretching open to almost 90 degrees! And when they close their mouths, their giant tongues squeeze the water out through the baleen filters, leaving delicious food, such as plankton, inside.

Whales get iron from krill in the deep ocean. Then the krill waste (whale poop) floats to the surface and serves as a fertilizer for shallow ecosystems. This helps sequester 200,000 tons of carbon from the atmosphere every year by fertilizing photosynthetic plankton.

Toothed whales

The toothed whale family includes the sperm whale, the all-white beluga whale and the narwhal with its incredible unicorn-like tusk. Toothed whales also eat fish, squid and crustaceans, but some, like the orcas (killer whales), hunt other mammals such as seals. They have even learned to launch themselves onto beaches to catch seals in the shallows. They may be one of the biggest predators in the ocean. But don’t worry, they don’t attack humans.

Whales breathe through their blowholes

Over the years, cetacean nostrils migrated back from snouts to the top of their heads. Baleen whales have two holes, while toothed whales have one. The purpose of having blowholes on top of their heads is for the convenience of not having to lift their entire head out of the water to take a breath. In fact, whales can’t breathe through their mouths.

Whales’ breathing is very efficient. And they have conscious control over their breathing and heart rate. They can regulate their oxygen levels, which is particularly important for deep-diving species. Once underwater, they can slow down their heart rate and shunt the oxygenated blood to needed areas, like their brain, heart and muscles. How long whales can hold their breath underwater depends on the species.

These gigantic animals expel air, not water, from their blowholes. When a whale goes back to the surface after an impressive breath hold, what you hear or see is them breathing out before they inhale and dive back underwater. As moist warm air from the whale’s lungs meets cold air outside, the moisture condenses into a cloud, like seeing your breath on a cold day. This cloud also includes mucus and droplets of seawater that were covering the blowhole when the whale exhaled. And you can even see whales producing rainbows.

The misconception that water comes out of a whale’s blowhole can be harmful. Dan Jarvis of the British Divers Marine Life Rescue describes instances of people finding a stranded whale and “pouring water directly into the blowhole thinking it’s a fish and it needs to be filled up with water.” Sadly, they have unintentionally killed the animal as a result.

Other parts of their anatomy

Because whales descended from animals with limbs, their backbones don’t naturally bend side to side, but rather up and down. That’s why their tail fins are horizontal, instead of vertical like fish. Even though they no longer have hind limbs, their hips aren’t completely gone in some species.

Whales don’t have external ears, and their ear canals are no longer open to the outside, but ear wax still builds up inside! When a whale dies, scientists can use this ear wax to study its diet and its hormone levels every year the whale was alive, like we do with tree rings! A Q-tip, anybody?

And even when whales die, they serve a purpose. When their heavy carcasses fall to the deep ocean, they can form mini ecosystems called whale falls, which sustain countless deep-sea species for decades.

Breaking records

There are many more incredible facts about these creatures. They’re the biggest living animals on Earth. The blue whale holds that record, weighing up to 400,000 pounds (182,000 kg or approximately 33 elephants) and reaching up to 98 feet (30 m) in length. But they smash other records, too.

The Cuvier’s beaked whale can hold its breath for two hours, the longest for any mammal. It’s also been tracked 10,000 feet (3,000 meters) below the surface. Check out this animation that shows how deep the ocean really is.

A bowhead whale is also the longest-lived mammal; it lives in northern Canada and has a natural life span of 268 years! So, it can be even older than the founding of the United States.

The sperm whale has the largest brain in the animal kingdom; it’s six times the size of a human’s. They are thought to be one of the most intelligent animals on Earth.

Humpback whales in the Southern Hemisphere live off their fat reserves for 5 1/2 to 7 1/2 months each year, as they migrate from their tropical breeding grounds to the Antarctic.

Whales and echolocation

Toothed whales like the sperm whales can communicate, navigate and hunt by using echolocation. These whales produce clicks in the nasal passages. Then they cross the melon (a spot in the forehead), and then the lower jaw picks up the returning echoes and delivers those vibrations back to the inner ear.

A beluga’s melon is generally more flexible compared to other whale species, and it can change in shape when the whale is producing sounds.

See an image of the process, here.

Did you know? Bats use echolocation, too.

Big brains, big voices

Baleen whales like humpbacks don’t use echolocation, but they are famous for their songs. And not any song; they’re very complex with short phrases combined into themes that can last for half an hour or more. They’re talented musicians.

Whale calls are the loudest of any creature on the planet and can be heard underwater for hundreds of miles/ kilometers.

We still don’t know how whales produce their sounds, but scientists think they use a big sac under their vocal cords to squeeze air into the larynx. And they also have huge lungs to hold the air and keep singing for a long, long time.

The Whale-SETI team has been studying humpback whale communication systems in an effort to develop what SETI researchers call “intelligence filters” in the search for extraterrestrial intelligence.

Threatened

It’s estimated that there were over 225,000 Antarctic blue whales before their exploitation in the 1800s-1900s. Today, there are between 10,000 to 25,000 left in the world.

Despite all the amazing abilities whales have, for many years they’ve been heavily hunted by people, and some species remain close to extinction even today. But thanks to a global hunting ban in the 1960s, in the last few years the number of blue and humpback whales is finally starting to increase.

We hope to see these majestic creatures in the wild for many more years to come.

Thank you to the amazing photographers from Pexels and Unsplash.

Bottom line: Whales are not just the biggest animals on the planet, they have smashed other records, too. And they way they communicate and eat … Wow!

Read more the ocean sunfish, an odd, gentle giant, too.

The post Whales are the biggest living animals: Lifeform of the week first appeared on EarthSky.

Spring 2024 is is going to be the season of the cicada

• Researchers predict the emergence of trillions of cicadas across the eastern U.S. this spring.
• Cicadas follow 13- and 17-year cycles. This rare double cicada mega-brood emergence happens only once every 221 years.
• Cicadas are harmless to humans. Though sometimes confused with locusts, their potential harm to plants isn’t too serious. No need to break out the insecticides. On the other hand, cicadas can be loud. Their buzzing reaches up to 106.7 decibels.

Researchers at the University of Connecticut are predicting the emergence of trillions of cicadas – the red-eyed, chirping, winged insects – across the United States this spring. But don’t worry. They won’t all be coming out at once or in the same region.

Cicadas – members of the order Hemiptera along with stink bugs, bed bugs and aphids – spend as long as 17 years underground before emerging as adults. This year, the bugs will dig their way to freedom across 1.5 million acres throughout the Eastern U.S., an area roughly the same size as the state of Delaware.

The UConn researchers describe it this way:

If we accept an estimate of a million cicadas per acre and if the total combined area of a periodical cicada emergence is roughly the size of Delaware, then more than a trillion cicadas will be involved. For 2024, since cicadas will emerge from Maryland to Oklahoma, Illinois to Alabama, clearly, trillions of adult cicadas will be present – but not all in the same place at the same time.

Some cicadas will emerge as early as March, but the big coming-out will be in April and May, depending on the weather.

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Rare double cicada mega-brood emergence

CicadaSafari.org says 2024 will be a banner year for cicadas, as two of the biggest broods will emerge at the same time in bordering areas of the Midwest:

The 17-year Brood XIII will emerge in Northern Illinois, while the 13-year Brood XIX will emerge in parts of Southeastern United States. It is not common to have a dual emergence between Broods XIII and XIX. They occur once every 221 years, and the last time these two broods emerged together was in 1803.

In 1803, Thomas Jefferson was President of the United States, and Lewis and Clark started their exploration of the Louisiana Purchase.

The areas where Brood XIII and Brood XIX occur mostly don’t overlap, according to the cicada experts at UConn. However, there could be small areas where both broods are active:

The greatest likelihood of contact between these broods is around Springfield, Illinois. … While there may be scattered woods in which both broods are present, there will be no broad overlap, and it will be impossible, in 2024, to identify any areas of overlap, large or small.

CicadaSafari.org offers tips on where to see cicadas, all kinds of cicada facts and figures, and has a cicada tracking app so amateur entomologists can get in on the cicada action.

Cicadas are subterranean math wizards

A common misconception is cicadas are a kind of locust or grasshopper. They aren’t. With their large red eyes and long body, cicadas do resemble locusts but instead are “true insects” of the order Hemiptera.

Cicadas appear on every continent but Antarctica. There are 190 varieties of cicada in North America, and about 3,400 varieties recorded worldwide so far. Some kinds of cicadas appear every year, while the periodic cicadas appear on 13- and 17-year cycles.

As fryrsquared explains via TikTok, 13 and 17 are prime numbers that can’t be factored. This means Brood XIII with its 17-year cycle and Brood XIX with its 13-year cycle can only emerge together every 221 years.

@fryrsquared The big news story of 2024 that literally no one is talking about ? #2024 #math #maths #circada ? original sound – fryrsquared

Don’t spray the cicadas!

Cicadas are loud but basically harmless to humans and the environment, so there’s no need to break out the insecticide. When they emerge, the only thing they’re interested in is mating and laying eggs, says UConn:

Cicadas do not possess special defensive mechanisms — they do not sting or bite. The ovipositor is used only for laying eggs and the mouthparts are used only for feeding on twigs; thus, periodical cicadas can hurt you only if they mistake you for a tree branch!

Cicadas will fly off when they feel threatened, and the males will make their iconic buzz. That buzz – produced when males flex drum-like organs called tymbals – is loud, reaching up to 106.7 decibels, about the same as a chain saw.

The male cicadas sing during the day to attract females. Dog-day (annual) cicadas tend to sing more in late afternoon and evening. Each cicada species has its own distinctive sound to avoid attracting the wrong cicada. Typically, periodical cicada emergences consist of three species, that can be distinguished by the male songs as well as by slight differences in their appearance. The nymphs of these cicadas feed on the roots of trees and shrubs.

Insects are disappearing

Leaving all insects alone is probably a good idea these days. According to a peer-reviewed study by German biologists published in 2017, the biomass of winged insects has declined by 76% since 1990. The researchers warn this decline in insect populations could have devastating effects across the entire global environment:

For example, 80% of wild plants are estimated to depend on insects for pollination, while 60% of birds rely on insects as a food source. The ecosystem services provided by wild insects have been estimated at $57 billion annually in the USA. Clearly, preserving insect abundance and diversity should constitute a prime conservation priority.

If you take any photos of the cicadas emerging this spring, send them to us!

Bottom line: Trillions of harmless cicadas will emerge in the Eastern U.S. this spring. The song of the cicadas may be loud, but the insects are basically harmless.

Read more: Insects have declined worldwide since 1925

The post Cicadas by the TRILLIONS emerging this spring! first appeared on EarthSky.

Happy Valentine’s Day! We’re sharing the love by celebrating some of the many heart-shaped objects you can find from way out in the depths of space to closer to our neighborhood in the solar system to right here on Earth.

2024 lunar calendars on sale now. Makes a great gift! Check it out here.

Heart shapes in space

Finding love on Earth

Bottom line: The shape of hearts is ubiquitous in the universe, as we can see in these photos from small petals on Earth to galaxies in the distant universe.

The post We heart the Earth and sky! PHOTOS first appeared on EarthSky.

Exquisite crystalline snowflakes capture the imagination. But what is the science behind their formation, and is it true there are no two snowflakes alike?

First of all, the temperature and humidity of the atmosphere determine the shapes of snowflakes. And snowflakes form in the atmosphere when cold water droplets freeze onto dust particles. Finally, depending on the temperature and humidity of the air where the snowflakes form, the resulting ice crystals will grow into a myriad of different shapes.

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Wilson Bentley

Wilson Bentley (1865–1931) from Jericho, Vermont, was the first person to capture photographs of snowflakes through a microscope attached to a camera. His collection of over 5,000 images – no two alike – introduced many people to the astounding diversity of snow crystals.

Classification systems

In 1951, scientists from an organization now called the International Association of Cryospheric Sciences (IACS) devised a classification system that characterized snowflakes into 10 basic shapes. Kenneth Libbrecht, professor of physics at the California Institute of Technology, in his guide to snowflakes at SnowCrystals.com, provides this chart of 35 types of snow crystals. They range from ice fragments to rods to the much more complex fern-like dendritic flakes we are all familiar with.

How snowflakes form from water vapor

Libbrecht has made extensive observations of how water molecules get incorporated into snow crystals. In his research, he observed that the most intricate snowflake patterns form when there is moisture in the air. Snowflakes produced in drier conditions tend to have simpler shapes.

According to Libbrecht’s research, temperature also has a large effect on the formation of snowflakes. Snowflakes formed in temperatures below -7.6 degrees Fahrenheit (-22 degrees C) consist primarily of simple crystal plates and columns. Meanwhile, snowflakes with extensive branching patterns are formed in warmer temperatures.

Visit Libbrecht’s website SnowCrystals.com for a wealth of information about snowflakes, including short videos of lab-grown snowflakes forming.

A gallery of snowflakes by Wilson Bentley

Bottom line: Temperature and humidity influence snowflake shape. The most intricate snowflake patterns form during warm and wet conditions.

Read more from NOAA

The post How snowflakes get their distinct and various shapes first appeared on EarthSky.

ChatGPT and Kelly Kizer Whitt created a 3-point summary for the longer article below:

• A strong El Niño pattern contributed to extreme weather events in 2023.
• El Niño is beginning to weaken and should dissipate by late spring 2024, potentially transitioning to neutral conditions and possibly to La Niña by fall.
• El Niño tends to reduce Atlantic hurricane storms. Whether the 2024 season will be active remains to be seen.

Written for The Conversation by Paul Roundy, University at Albany, State University of New York

El Niño dominated 2023. What’s coming for 2024?

Wild weather has been roiling North America for the past few months, thanks in part to a strong El Niño that sent temperatures surging in 2023. The climate phenomenon fed atmospheric rivers drenching the West Coast and contributed to summer’s extreme heat in the South and Midwest and fall’s wet storms across the East.

That strong El Niño is now starting to weaken and will likely be gone by late spring 2024.

So, what does that mean for the months ahead … and for the 2024 hurricane season?

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What is El Niño?

Let’s start with a quick look at what an El Niño is.

El Niño and its opposite, La Niña, are climate patterns that influence weather around the world. El Niño tends to raise global temperatures, as we saw in 2023, while La Niña events tend to be slightly cooler. The two result in global temperatures fluctuating above and below the warming trend set by climate change.

El Niño starts as warm water builds up along the equator in the eastern tropical Pacific Ocean, off South America.

Typically, tropical Pacific winds blow from the east, exposing cold water along the equator and building up warm water in the western Pacific. Every three to seven years or so, however, these winds relax or turn to blow from the west. When that happens, warm water rushes to the east. The warmer-than-normal water drives more rainfall and alters winds around the world. This is El Niño.

The water stays warm for several months until, ultimately, it cools or the return of trade winds drives it away from the equator.

When the eastern Pacific region along the equator becomes abnormally cold, La Niña has emerged, and global weather patterns change again.

What to expect in 2024

While the 2023-24 El Niño event likely peaked in December, it is still strong.

For the rest of winter, forecasts suggest that strong El Niño conditions will likely continue to favor unusual warmth in Canada and the northern United States. Additionally, the southern states could see occasional stormy conditions.

El Niño is likely to end in late spring or early summer, shifting briefly to neutral. There’s a good chance we will see La Niña conditions this fall. But forecasting when that happens and what comes next is harder.

How an El Niño ends

While it’s easy to tell when an El Niño event reaches its peak, predicting when one will end depends on how the wind blows. And everyday weather affects the winds.

The warm area of surface water that defines El Niño typically becomes more shallow toward spring. In mid-May 1998, at the end of an even stronger El Niño event, there was a time when people fishing in the warm surface water in the eastern tropical Pacific could have touched the cold water layer a few feet below by just jumping in. At that point, it took only a moderate breeze to pull the cold water to the surface, ending the El Niño event.

But exactly when a strong El Niño event reverses varies. A big 1983 El Niño didn’t end until July. And the El Niño in 1987 retreated into the central Pacific but did not fully reverse until December.

As of early February 2024, strong westerly winds were driving warm water from west to east across the equatorial Pacific.

These winds tend to make El Niño last a little longer. However, they’re also likely to drive what little warm water remains along the equator out of the tropics, up and down the coasts of the Americas. The more warm water that is expelled, the greater the chances of full reversal to La Niña conditions in the fall.

Summer and the hurricane risk

Among the more important El Niño effects is its tendency to reduce Atlantic hurricane activity.

El Niño’s Pacific Ocean heat affects upper level winds that blow across the Gulf of Mexico and the tropical Atlantic Ocean. That increases wind shear – the change in wind speed and direction with height – which can tear hurricanes apart.

The 2024 hurricane season likely won’t have El Niño around to help weaken storms. But that doesn’t necessarily mean an active season.

During the 2023 Atlantic hurricane season, El Niño’s effect on the winds was more than offset by abnormally warm Atlantic waters, which fuel hurricanes. The season ended with more storms than average.

The strange El Niño of 2023-24

Although the 2023-24 El Niño event wasn’t the strongest in recent decades, many aspects of it have been unusual.

It followed three years of La Niña conditions, which is unusually long. It also emerged quickly, from March to May 2023. The combination led to weather extremes unseen since perhaps the 1870s.

La Niña cools the tropics but stores warm water in the western Pacific. It also warms the middle latitude oceans by weakening the winds and allowing more sunshine through. After three years of La Niña, the rapid emergence of El Niño helped make the Earth’s surface warmer than in any recent year.

Paul Roundy, Professor of Atmospheric and Environmental Sciences, University at Albany, State University of New York

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: El Niño helped contribute to extreme weather and warm temperatures in 2023. Now that it is weakening, what changes may be in store for 2024?

Read more: Tropical volcanoes trigger El Niños, says study

The post El Niño is weakening. What will happen next? first appeared on EarthSky.

• Earth is witnessing a rise in the intensity of hurricanes, attributed to the warming of both the air and oceans.
• Researchers propose for a new hurricane category, Category 6, to accommodate the observed increase in hurricane strength.
• They suggest classifying hurricanes with sustained wind speeds of 192 mph (309 kph) or more under this new category. The current highest category of hurricanes begins at sustained wind speeds of 157 mph (253 kph).

Hurricanes are getting stronger. That’s because the warmth of the air and the oceans drives hurricanes, and both Earth’s air and Earth’s oceans are getting warmer. So we’re already seeing mega-hurricanes like Hurricane Patricia of 2015, the most powerful tropical storm on record worldwide, in terms of wind speed. And now some researchers are now calling for a new category to be added to the currently used hurricane scale. Currently, that scale ranks hurricanes from 1 to 5. Michael Wehner of the Lawrence Berkeley National Laboratory in California and James Kossin of the University of Wisconsin-Madison proposed on February 5, 2024, that we add a new Category 6 for hurricanes.

Hurricanes must have sustained wind speeds greater than 157 mph (253 kph) to be ranked as Category 5. Wehner and Kossin propose sustained winds of 192 mph (309 kph) or more for Category 6 hurricanes.

The researchers published their peer-reviewed findings in the Proceedings of the National Academy of Sciences on the same day.

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Intensity of hurricanes increasing

As the oceans and atmosphere continue to warm, mega-hurricanes are becoming stronger. While the number of hurricanes is remaining about the same, the strength of them is increasing. Indeed, as Milan noted in The Guardian, the intensity of hurricanes has notably increased during the four-decade period of satellite records.

More often now, hurricanes are reaching the level of unprecedented sustained winds, pushing the limits of Category 5 (157 mph/253 kph or more). Wehner and Kossin say that such atypical strong hurricanes – with winds of 192 mph (309 kph) or more – should be re-categorized as Category 6 on the Saffir-Simpson Hurricane Wind Scale. Oliver Milman wrote about the proposed change for The Guardian on February 5, 2024. Wehner told him:

[A sustained wind speed of] 192 mph is probably faster than most Ferraris. It’s hard to even imagine. Being caught in that sort of hurricane would be bad. Very bad.

The paper stated:

Global warming leads to more intense tropical cyclones (TCs). Three separate lines of evidence from both observations and models suggest that the open endedness of the 5th category of the Saffir–Simpson hurricane wind scale becomes increasingly problematic for conveying wind risk in a warming world. We investigate considering the extension to a 6th category of the Saffir–Simpson hurricane wind scale to communicate that climate change has caused the winds of the most intense TCs to become significantly higher.

Only a matter of time until more extreme hurricanes in Atlantic Ocean

Category 5 hurricanes are bad enough. Hurricane Katrina in 2005 and Hurricane Maria in 2017 are two examples of how powerful they can be. But hurricane winds reaching 192 mph or more is a new extreme. So far, that has been mostly limited to storms in the Pacific Ocean, for example, Typhoon Haiyan in the Philippines in 2013, which killed over 6,000 people and Hurricane Patricia near Mexico in 2015. In fact, Maria’s winds reached a top speed of an incredible 215 mph.

But overall, such mega-hurricanes are already starting to become more frequent. When the research team performed a historical data analysis of hurricanes from 1980 to 2021, they found five that would have been classified as Category 6, if it existed on the scale now. All of them occurred within a nine-year period.

It may only be a matter of time until hurricanes in the Atlantic Ocean reach the same levels. As Wehner noted in The Guardian:

There haven’t been any in the Atlantic or the Gulf of Mexico yet but they have conditions conducive to a Category 6, it’s just luck that there hasn’t been one yet. I hope it won’t happen, but it’s just a roll of the dice. We know that these storms have already gotten more intense, and will continue to do so.

He also said:

Even under the relatively low global warming targets of the Paris Agreement, which seeks to limit global warming to just 1.5 degrees Celsius above preindustrial temperatures by the end of this century, the increased chances of Category 6 storms are substantial in these simulations.

Greater awareness of climate change

The researchers said that having a new Category 6 would help to make people more aware of how climate change is affecting hurricanes and other storms. Wehner said:

Our motivation is to reconsider how the open-endedness of the Saffir-Simpson Scale can lead to underestimation of risk, and, in particular, how this underestimation becomes increasingly problematic in a warming world.

He also noted in The Guardian:

Our main purpose is to raise awareness that climate change is affecting the most intense storms.

They also noted how the Saffir-Simpson hurricane scale has been good for measuring severe rainfall and coastal flooding, but needs improvement regarding actual wind speeds. The researchers don’t want to change the scale itself as such, but rather to adapt it to a changing climate. Kossin said:

Our results are not meant to propose changes to this scale, but rather to raise awareness that the wind-hazard risk from storms presently designated as Category 5 has increased and will continue to increase under climate change.

Other climate change-related modifications

If ever enacted, this wouldn’t be the first climate change-related modification made. In Australia, the Bureau of Meteorology added the color purple to its weather maps. This is to indicate areas and incidents of intense heat, another factor becoming more common. In late January, the Coral Reef Watch program in the U.S. added three new alert categories. The additional categories measure the increasing heat stress being experienced by coral reefs.

Bottom line: Hurricanes are becoming stronger due to climate change. And 2 researchers in the U.S. say we need a new Category 6 to classify mega-hurricanes.

Source: The growing inadequacy of an open-ended Saffir–Simpson hurricane wind scale in a warming world

Via Lawrence Berkeley National Laboratory

Via The Guardian

Read more: Global warming is making hurricanes stronger

Read more: Hurricanes heat the ocean, even far from the storm

The post Stronger hurricanes require new Category 6, researchers say first appeared on EarthSky.

Asteroid that hit Germany was a rare type

Astronomers discovered a new asteroid last January 21, 2024, just hours before it struck Earth’s atmosphere above Germany. As it fell, producing a fireball, the little asteroid dropped meteorites – or fragments of itself – onto the countryside below. Meteorite hunters west of Berlin got to work and soon discovered asteroid fragments, which they then sent to labs for scientific analysis On February 5, 2024, the SETI Institute said the rock from space was a rare type: an aubrite. They said the fragments might have originated on Mercury.

The SETI Institute scientists said aubrites are tricky to find. Most meteorites that hit Earth have a thin black outer crust, resulting from their fiery passage through Earth’s atmosphere. But aubrites have a mostly translucent, glassy crust.

Peter Jenniskens of the SETI Institute traveled to Germany to help hunt for the meteorites. He said in a statement:

They were devilishly difficult to find because, from a distance, they look like other rocks on Earth. Close up, not so much … We only spotted the meteorites after a Polish team of meteorite hunters had identified the first find and could show us what to look for.

It was Jenniskens’ 4th trip to the site of an asteroid impact where remnant meteorites were indeed found on the ground. The previous three were in Sudan in 2008, Botswana in 2018, and France in 2023.

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An official classification

Scientists at the Natural History Museum of Berlin examined one of the meteorites with an electron beam microprobe, which is a non-destructive tool that determines the chemical composition of small volumes of solid materials. They found the mineralogy and chemical composition was that of an aubrite. Then, they submitted their result to the International Nomenclature Commission of the Meteoritical Society on February 2, 2024. The society examined the meteorite and confirmed their classification.

Aubrites are named for a village in France: Aubrés. On September 14, 1836, a meteorite fell in this location and showed evidence of a violent origin. These magnesium-rich, igneous rocks might have originated on Mercury.

Ansgar Greshake, scientific head of the Natural History Museum of Berlin’s meteorite collection, said:

So far, there is only material from eleven other observed falls of this type in meteorite collections worldwide.

Christopher Hamann of the Natural History Museum of Berlin further described rare aubrites:

Aubrites do not look like what people generally imagine meteorites to look like. Aubrites look more like a gray granite and consist mainly of the magnesium silicates enstatite and forsterite. It contains hardly any iron and the glassy crust, which is usually a good way to recognize meteorites, looks completely different than that of most other meteorites. Aubrites are therefore difficult to detect in the field.

The recovery of the meteorites

Meteorite hunters were on high alert on January 21, when reports first came in that an asteroid was going to impact Earth’s atmosphere above Germany. Observers in the area watched a bright burst of light as the asteroid exploded. Though small, the asteroid was large enough to survive in the form of small fragments that showered the countryside west of Berlin. And on January 26, 2024, the Natural History Museum of Berlin said that searchers found suspected fragments the size of a walnut.

Other meteorite hunters have also been sharing their finds on social media.

Via Carlos Augusto Di Pietro

The first meteorites from the asteroid 2024 BX1 (the Berlin fireball) that entered our atmosphere on January 20 were found. Fragments were located by Micha? Nebelski, Kryspin Kmieciak and Kazimierz Magneto pic.twitter.com/cuo2pIx3W5

— Space Initiatives (@AsteroidEnergy) January 25, 2024

Ein Meteoritensucher im Havelland …

Video: Zsolt Kereszty #2024BX1 #Sar2736 pic.twitter.com/G2HXnDYY9t

— Weltraum-Nerd (@NicosPanoptikum) January 25, 2024

Nachdem Erfolg der polnischen Gruppe, haben sich zwei Ungarn 10 Stunden ins Auto gesetzt, um ins Havelland zu fahren. Und nach nur 58 Minuten im Suchgebiet waren sie erfolgreich.#2024BX1 #Sar2736 @AsteroidEnergy pic.twitter.com/84JFRYdpcr

— Weltraum-Nerd (@NicosPanoptikum) January 26, 2024

Da ist er, der vierte Fund des Havelland-Meteoriten. Glückwunsch ans @mfnberlin! #2024BX1 #Sar2736 https://t.co/juuMgokJMh

— Weltraum-Nerd (@NicosPanoptikum) January 26, 2024

Asteroid impact predicted beforehand

In the late-night hours of January 21, 2024 – 90 minutes before impact over European skies – NASA said a small asteroid would hit Earth’s atmosphere. And hit it did. The space rock struck on schedule above an area west of Berlin, Germany. The asteroid was only about 1 meter (3 feet) in diameter. It posed no danger to people on the ground.

Soon after, footage of the fireball in the skies over Germany started coming in on social media.

Asteroid hunter Krisztián Sárneczky of Budapest, Hungary, discovered the asteroid only shortly before impact. Sárneczky has become famous for last-minute discoveries such as this one, including the discoveries of an asteroid that fell over France in 2023 and another that hit over the Arctic Ocean in 2022. This is only the 8th asteroid detected before impact.

Here's the full video of the asteroid #Sar2736, a ~1 m object that broke up some 50 m west of #Belin, #Germany, and probably dropped some meteorites on the ground. Video credit: https://t.co/72o6ZzPNz8 pic.twitter.com/PA73dkqid1

— Denis Vida (@meteordoc) January 21, 2024

A small asteroid hit Earth overnight, lighting up skies over Germany.

The discovery images of the imminent impactor #2024BX1 (aka #Sar2736 ) with the 60-cm Schmidt Telescope at #Piszkéstet? Mountain Station, part of Konkoly Observatory (#konkolyobs) in #Hungary. pic.twitter.com/qMcXerhvL4

— Krisztián Sárneczky (@sarneczky) January 21, 2024

The small asteroid received the preliminary designation Sar2736. Then the International Astronomical Union’s Minor Planet Center gave it a formal label of 2024 BX1.

Videos of the asteroid impact

As it blazed through Earth’s atmosphere, the small asteroid appeared as a fireball, that is, a very bright meteor or shooting star.

Visual, video and photograph records of Sar2736 atmospheric entry are of primary importance: if you saw or recorded the fireball, please fill in a fireball report form: https://t.co/Ez7rkd3pHC
Thanks in advance!

Image credit: Fripon-Germany pic.twitter.com/a7MDop00Cn

— IMO Meteor Org. (@IMOmeteors) January 21, 2024

Prague's view of #Sar2736: a minor planet entering Earth's atmosphere on Jan 21, 2024, at 00:32 UT. pic.twitter.com/KXDnBvzmGX

— Hanjie Tan (@HonkitTan) January 21, 2024

??über Berlin.? pic.twitter.com/AYROUbTpSy

— FloBerlin (@BerlinFlo5) January 21, 2024

Another *incredible* shot of the small asteroid burning up above Germany just moments ago—wow. pic.twitter.com/OGl0GuWGe6

— Dr Robin George Andrews ??? (@SquigglyVolcano) January 21, 2024

News of the imminent impact

Social media lit up with reports of the impending impact.

Heads Up: A tiny asteroid will disintegrate as a harmless fireball west of Berlin near Nennhausen shortly at 1:32am CET. Overseers will see it if it’s clear!

— NASA Asteroid Watch (@AsteroidWatch) January 21, 2024

The latest nominal impact location is ~50 km west of Berlin between 00:30 – 00:35 UTC (01:30 – 01:35 CET).

— Denis Vida (@meteordoc) January 20, 2024

(2/n)
– After capturing the fireball, take a long-exposure picture of stars after recording the fireball.
– Record the accurate time of the recording. Visit https://t.co/ZnxfG2GKex and take a picture of the website.

— Denis Vida (@meteordoc) January 20, 2024

Bottom line: Scientists analyzing the meteorites left behind by the asteroid that hit Germany said they are a rare type known as an aubrite.

Via SETI Institute

The post Asteroid that exploded in German skies is rare aubrite first appeared on EarthSky.

‘High’ flood risk in Southern California

The state of California is bracing for an onslaught of rain, strong winds and snow at higher elevations, as another atmospheric river slams the state. The San Francisco Bay Area is expecting high winds, while Southern California is bracing for the threat of widespread, dangerous flooding. The storm came ashore Saturday night, with highest rainfall amounts expected today (February 4, 2024) and Monday. Some areas could see close to a foot of rain.

Officials have issued an evacuation warning for part of Santa Barbara County.

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?? EVACUATION WARNINGS have been issued for parts of Santa Barbara County. These EVACUATION WARNINGS are due to an incoming storm arriving Saturday, February 3 through Tuesday, February 5.
? Info: https://t.co/iGQy84pGay pic.twitter.com/rDZTAwboVI

— SBCountyOEM (@SBCountyOEM) February 2, 2024

California has had a lower-than-average snowpack this season. It’s been too warm to snow, but this coming week the state will make up a little of the deficit at higher altitudes with the incoming storm. Mountainous area could see up to 6 feet of snow by Thursday, February 7.

California and the Pacific Northwest have already seen a lot of rain over the past week, as a previous atmospheric river hit the West Coast.

What is an atmospheric river?

An atmospheric river is a long, narrow band of water vapor in the lowest part of the atmosphere. It’s like a river in the sky that releases precipitation when it hits the coast and mountains. When it encounters these landforms, the atmospheric river gets pushed upward, causing the water vapor to condense (change from a gas to a liquid) and fall to the ground. According to the USGS:

Up to 50% of California’s annual precipitation can come from atmospheric rivers.

Back-to-back atmospheric rivers make for a high flood risk. As The Conversation explained:

The first heavy downpours saturate the ground. As consecutive storms arrive, their precipitation falls on soil that can’t absorb more water. That contributes to more runoff. Rivers and streams fill up.

A historic nine consecutive atmospheric rivers hit California last winter, helping refill the reservoirs in the state. But they also brought flooding and mudslides.

The next atmospheric river takes shape in the eastern Pacific Ocean.

Heavy precipitation is expected in parts of California as soon as late Saturday night. pic.twitter.com/TebSJhNQ5B

— CIRA (@CIRA_CSU) February 2, 2024

Warnings from the NWS

Here are the latest Key Messages for the impending Atmospheric River set to deliver copious amounts of rain & snow to California & parts of Nevada through Tuesday. A High Risk has been issued for Sunday across portions of the Transverse Ranges in Southern California. #CAwx #NVwx pic.twitter.com/smXRh5YW1K

— NWS Weather Prediction Center (@NWSWPC) February 3, 2024

Powerful storm will bring widespread damaging winds to SW Calif, especially SLO/Santa Barbara counties with gusts 50-70 mph, except isold gusts 80 mph in mtns/coastal foothills tonight-Sun night. Expect extensive downed trees/powerlines+power outages #SLOWeather #cawx pic.twitter.com/IoLFLZp6Fl

— NWS Los Angeles (@NWSLosAngeles) February 4, 2024

And up in the Bay Area:

? Rapid rises in main stem rivers are expected with this system with some rivers now anticipated to reach flood stage as early as tomorrow morning. Please be sure to stay informed and weather aware tomorrow. #CAwx pic.twitter.com/EKhzZmdY3R

— NWS Bay Area ? (@NWSBayArea) February 4, 2024

Bottom line: An atmospheric river is poised to hit California, bringing rain, wind and heavy snowfall at high altitudes. The National Weather Service warns people to make preparations.

The post Atmospheric river puts California at risk for floods first appeared on EarthSky.

By Samuel Fabian, Imperial College London; Jamie Theobald, Florida International University, and Yash Sondhi, University of Florida

It’s an observation as old as humans gathering around campfires: Light at night can draw an erratically circling crowd of insects. In art, music and literature, this spectacle is an enduring metaphor for dangerous but irresistible attractions. And watching their frenetic movements really gives the sense that something is wrong … that instead of finding food and evading predators, these nocturnal pilots are trapped by a light.

Sadly, centuries of witnessing what happens have produced little certainty about why it happens. How does a simple light change fast, precise navigators into helpless, flittering captives? We are researchers examining flight, vision and evolution, and we have used high-speed tracking techniques in newly published research to provide an answer.

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Moths to a flame?

Many old explanations for this hypnotic behavior have not fully panned out. An early notion was that the insects might be attracted to the heat of a flame. This was interesting, as some insects really are pyrophilic: They are attracted to fire and have evolved to take advantage of conditions in recently burned areas. But most insects around a light are not in this category, and cool lights attract them quite well.

Another thought was that insects were just directly attracted to light, a response called phototaxis. Many insects move toward light, perhaps as a way to escape dark or entrapping surroundings. But if this were the explanation for the clusters around a light, you might expect them to bump straight into the source. This theory does little to explain the wild circling behavior.

Celestial navigation?

Still another idea was that insects might mistake a nearby light for the moon, as they attempted to use celestial navigation. Many insects reference the moon to keep their course at night.

This strategy relies on how objects at great distance seem to hover in place as you move along a straight path. A steady moon indicates that you have not made any unintentional turns, as you might if you were buffeted by a gust of wind. Nearer objects, however, don’t appear to follow you in the sky but drift behind as you move past.

The celestial navigation theory held that insects worked to keep this light source steady, turning sharply in a failed attempt to fly straight. An elegant idea, but this model predicts that many flights will spiral inward to a collision, which doesn’t usually match the orbits we see. So what’s really going on?

Insects turn their backs to the light

To examine this question in detail, we and our colleagues captured high-speed videos of insects around different light sources to precisely determine flight paths and body postures, both in the lab at Imperial College London and at two field sites in Costa Rica, CIEE and the Estación Biológica. We found that their flight patterns weren’t a close match for any existing model.

Rather, a broad swath of insects consistently pointed their backs toward the lights. This is a known behavior called the dorsal light response. In nature, assuming that more light comes down from the sky than up from the ground, this response helps keep insects in the proper orientation to fly.

But pointing their backs toward nearby artificial lights alters their flight paths. Just as airplanes bank to turn, sometimes rolling until the ground seems nearly straight out your window, banking insects turn as well. When their backs orient to a nearby light, the resulting bank loops them around the light, circling but rarely colliding.

These orbiting paths were only one of the behaviors we observed. When insects flew directly under a light, they often arched upward as it passed behind them, keeping their backs to the bulb until, eventually flying straight up, they stalled and fell out of the air. And even more compelling, when flying directly over a light, insects tended to flip upside down, again turning their backs to the light but then abruptly crashing.

Why have a dorsal light response?

Although light at night can harm other animals – for example, by diverting migrating birds into urban areas – larger animals don’t seem to lose their vertical orientation. So why do insects, the oldest and most species-rich group of flyers, rely on a response that leaves them so vulnerable?

It may have to do with their small size. Larger animals can sense gravity directly with sensory organs pulled by its acceleration, or any acceleration. Humans, for example, use the vestibular system of our inner ear, which regulates our sense of balance and usually gives us a good sense of which way is down.

But insects have only small sensory structures. And especially as they perform rapid flight maneuvers, acceleration offers only a poor indication of which way is down. Instead, they seem to bet on the brightness of the sky.

Before modern lighting, the sky was usually brighter than the ground, day or night, so it provided a fairly reliable cue for a small active flyer hoping to keep a steady orientation. The artificial lights that sabotage this ability, by cueing insects to fly in circles, are relatively recent.

The growing problem of nighttime lighting

As new technology spreads, lights that pervade the night are proliferating faster then ever. With the introduction of cheap, bright, broad-spectrum LEDs, many areas, such as large cities, never see a dark night.

Insects aren’t the only creatures affected. Light pollution disrupts circadian rhythms and physiological processes in other animals, plants and humans, often with serious health consequences.

But insects trapped around a light seem to get the worst of it. Unable to secure food, easily spotted by predators and prone to exhaustion, many die before the morning comes.

How to help insects

In principle, light pollution is one of the easiest things to fix, often by just flipping a switch. Restricting outdoor lighting to useful, targeted warm light, no brighter than necessary, and for no longer than necessary, can greatly improve the health of nocturnal ecosystems. And the same practices that are good for insects help restore views of the night sky: Over 1/3 of the world population lives in areas where the Milky Way is never visible.

Although insects circling around a light are a fascinating spectacle, it is certainly better for the insects and the benefits they provide to humans when we leave the night unlit and let them go about the activities they so masterfully perform under the night sky.

Samuel Fabian, Postdoctoral Research Associate in Bioengineering, Imperial College London; Jamie Theobald, Associate Professor of Biological Sciences, Florida International University, and Yash Sondhi, Postdoctoral Research Associate in Entomology, McGuire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of Florida

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Insects get confused by artificial lighting, thinking it’s the sky, and exhaust themselves flying around the light source.

Read more: Insects have declined worldwide since 1925

The post Light pollution causes insects to lose track of the sky first appeared on EarthSky.