Category: 7. Science

Key Atlantic Ocean currents that appear to be slowing down due to climate change may be more resilient to global warming than scientists previously thought — thanks to a secret back-up system, a new study shows.

The Atlantic Meridional Overturning Circulation (AMOC) is a web of currents that loops around the Atlantic like a giant conveyor belt. Cold, salty waters sink near Greenland then travel south along the ocean floor. Eventually these waters rise to the surface again near Antarctica and return north, bringing balmier waters to the Northern Hemisphere. This system is crucial to warming Europe, in particular.

NASA has released the closest-ever photos of the sun, taken by the Parker Solar Probe at just 3.8 million miles (6.1 million kilometers) from the star’s surface. The new images reveal important features in the solar wind that will help scientists understand the origins of this mysterious space weather phenomenon and its effects on life on Earth.

The solar wind is the constant stream of charged particles — mainly protons and electrons — released by the sun’s outer atmosphere, known as the corona. This torrent of matter speeds through the solar system at more than a million miles an hour, combining with magnetic fields and material jettisoned from the sun to create auroras, strip planetary atmospheres, and generate electric currents that can interfere with power networks on Earth. Understanding and predicting this space weather is vital to protecting astronauts and spacecrafts, and minimizing the disruptions to infrastructure sometimes caused by strong solar activity.

There’s very little scientific debate about the existence of surface water on Mars in its past. The evidence at this point is overwhelming. Orbiter images clearly show river channels and deltas, and rovers have found ample minerals that only form in the presence of water. Now the scientific debate has moved on. Scientists are trying to learn the extent of Martian surface water, both on the planet’s surface and through time.

NASA’s Mars Reconnaissance Orbiter (MRO) is a prolific purveyor of images of Mars’ surface. One of its most well-known image shows Jezero Crater, the landing site of the Mars Perseverance rover. Jezero Crater is an ancient paleolake filled by an ancient river that created a delta of sediments. The orbiter also identified clays and carbonate salts, minerals that were altered by water in the planet’s past.

This image of Jezero Crater is one of the MRO’s most well-known images. It shows clear evidence of flowing water. The colours map the location of different minerals, including water-altered clays and carbonate salts. Image Credit: NASA/ JPL-Caltech/ MSSS/ JHU-APL.

There are two schools of thought around Mars’ watery past. One says that water was stable on the Martian surface for long periods of time, while the other states that the water channels were carved during geologically brief periods of time when climate shifts caused ice sheets to melt. Call the first one the ‘warm and wet’ theory and the second one the ‘cold and dry’ theory. Both theories are well developed, and make predictions about what scientists will find when they dig deeper.

Some research into Noachis Terra supports the idea that water features there were carved by ice-related processes during short-lived periods of wetness, the cold and dry theory. This 2016 paper illustrates that point of view. “Our studied valleys’ association with ice-rich material and abundant evidence for erosion caused by downslope flow of ice-rich material are consistent with a cold, wet Mars hypothesis where accumulation, flow, and melting of ice have been dominant factors in eroding crater valleys,” those researchers concluded.

Not all regions of Mars have been studied equally, and the Noachis Terra is not as well-studied as some other regions. The ‘warm and wet’ climate theory predicts that Noachis Terra would’ve had high levels of precipitation. However, there’s an overall lack of Valley Networks (VNs) in the region. Valley Networks are similar to Earth’s river drainage basins and are compelling evidence of Mars’ watery past.

This map of Mars shows important surface features, as well as all of the planet’s surface regions. Noachis Terra is a southern highland region of heavily cratered ancient terrain. Image Credit: By Jim Secosky modified NASA image. – http://planetarynames.wr.usgs.gov/images/mola_regional_boundaries.pdf, Public Domain,

New research presented at the Royal Astronomical Society’s National Astronomy Meeting presented a different sort of evidence to support the high levels of precipitation predicted in Noachis Terra by the warm and wet theory. It’s titled “The Fluvial History of Noachis Terra, Mars,” and the lead researcher is Adam Losekoot. Losekoot is a PhD student at the Open University, a public research university in the UK.

“Studying Mars, particularly an underexplored region like Noachis Terra, is really exciting because it’s an environment which has been largely unchanged for billions of years. It’s a time capsule that records fundamental geological processes in a way that just isn’t possible here on Earth,” Losekoot said in a press release.

The evidence Losekoot and his fellow researchers uncovered is in the form of Fluvial Sinuous Ridges.

“Noachis Terra, in Mars’ southern highlands, is a region where ‘warm, wet’ climate models predict high rates of precipitation, but is poorly incised by VNs,” Losekoot explained. “We searched instead for Fluvial Sinuous Ridges (FSRs, aka inverted channels) here as they provide alternate evidence to VNs for stable surface water.”

FSRs are winding, elevated features left behind from Mars’ watery past. They form when water flows across the surface carrying sediment with it. The sediment deposits become harder than the rock in the surrounding terrain due to compaction and mineral precipitation. When Mars’ water disappeared, aeolian erosion ate away at the softer, surrounding rock, leaving the elevated FSRs behind.

To find the FSRs in Noachis Terra, Losekoot and his co-researchers turned to NASA’s MRO. No other mission has done more to reveal Mars’ past than the MRO. They used data from its HiRISE and other instruments, as well as data from the Mars Orbital Laser Altimeter on the Mars Global Surveyor, to identify FSRs.

Losekoot and his co-researchers found 15,000 km of FSRs in Noachis Terra. “We find FSRs to be common across Noachis Terra, with a cumulative length of more than 15,000 km. These are often isolated segments, but some systems are hundreds of km in length,” Losekoot writes.

This HiRISE image shows two branches of an FSR. The river split into two then rejoined outside of the image. The lower branch is heavily eroded and quite spread out, the upper branch is narrower but more clearly preserved. They could’ve had different exposure times or undergone different geological processes. Or they could be from different periods of water activity. There are remnants of an infilling material within the ridge and a meander where the branch turns back towards the lower trunk. The mesa in between the branches could be a crater that was filled with the same sediment as the FSR. Image Credit: HiRISE Image: ESP_085519_1585 NASA/JPL/University of Arizona. Licence type: Attribution (CC BY 4.0)

The FSRs are broadly distributed across Noachis Terra, and some are tens of meters tall. That means the water flowed for a long time.

“The broad distribution of FSRs suggests a broadly distributed source of water,” Losekoot writes. “The most likely candidate is precipitation, suggesting a benign surface environment. For FSRs to have formed mature, interconnected systems, up to tens of meters high, these conditions must also have been relatively long-lived.”

“This suggests that ~3.7 Ga, Noachis Terra experienced warm and wet conditions for a geologically relevant period,” Losekoot explained.

This HiRISE image shows narrow FSR with a pointed pinnacle ridge. The pointed could indicate that this FSR has suffered heavy erosion for a long time until only a narrow peak remained, or it may be that only a narrow part of the original river infill has been preserved. Image Credit: HiRISE Image: ESP_067439_1505 NASA/JPL/University of Arizona. Licence type: Attribution (CC BY 4.0)

The way the FSRs are distributed across Noachis Terra and their extent suggests that precipitation is responsible. They also form large, interconnected systems, which suggests the watery period was long-lived. This work supports the idea that Mars was warm and wet for a long time, rather than just for bursts of time when ice sheets melted.

This MRO CTX image gives an oblique view of part of a system of FSRs in Noachis Terra. It shows river tributaries that were probably active at the same time. The rivers meandered, and there are areas where the river banks burst and deposited fine layers of sediment. At the top of the image is a really clear example of an area where two FSRs intersect with an infilled crater. This is likely where the river flowed into the crater, filling it up and then breaching the other side to continue through the crater and down to the bottom of the image. CTX image: MurrayLab_V01_E020_N-20_Mosaic. Image Credit: NASA/JPL/MSSS/The Murray Lab. Licence type: Attribution (CC BY 4.0)

“Our work is a new piece of evidence that suggests that Mars was once a much more complex and active planet than it is now, which is such an exciting thing to be involved in,” said Losekoot.

Space is cold, and research has shown time and time again that space ice is prevalent throughout the universe. However, despite sharing a similar name to the ice we find in glaciers or even in our freezers here on Earth, new research says that frozen water found on icy planets, comets, and even in the dust that sails through space is very different from the ice you might put your soda over.

For starters, despite looking like a shapeless solid, ice is actually made up of multiple nanoscopic crystals, all of which are only a few billionths of a meter across, if that. So, what makes Earth ice and space ice so different? Well, according to researchers, Earth ice is made up of orderly lattice crystal designs. These all showcase the six-fold symmetry of snowflakes in the underlying structure.

But we’ve long believed that space ice has a different structure. Instead, because of the near-vacuum conditions of space, the water frozen there likely lacked the energy needed to form these orderly lattices. Scientists believed they were most likely made up of random arrangements of crystals. But new research is challenging this perspective.

Instead of being made up entirely of random crystallized structures, the researchers found that in order for the ice they made in their tests to truly resemble that of space ice, they had to give it some structure — roughly 20% of the overall structure. But what is even more intriguing is that when warmed slightly, they found that the crystals retain the structure seen in their original designs.

This suggests that the ice holds onto some of its memory of the past, which could help greatly in future studies of frozen water in space. It could also fundamentally change our understanding of how life came to Earth, something that researchers have long theorized happened as amino acids hitched rides in the frozen water of comets.

But if space ice retains some of the structure of its original design, then the empty places for those acids to grow and live would be even more scarce than they was previously thought to be. Of course, the study is far from definitive, and further research will need to be done to confirm these findings. For now, though, they raise some interesting questions about what we think we know about how the universe and space ice actually works.

A groundbreaking study in the journal Science, has unveiled how deep ocean currents—known as global overturning circulation—play a pivotal role in shaping the diversity and function of microbial life across the South Pacific Ocean. 

This research, led by scientists from J. Craig Venter Institute (JCVI), UC San Diego’s Scripps Institution of Oceanography, and University of California Berkeley offers the most detailed genetic map to date of how microbial communities are structured by the physical movement of ocean water.

Winds and storms only reach to about 500 meters (1,640 feet), about an eighth of the total ocean depth of 4,000 meters (13,125 feet), said study lead author Bethany Kolody, a graduate of Scripps Oceanography who is currently a postdoctoral researcher at Cal. Beyond 500 meters below the surface, currents are driven by differences in water temperature and salinity, which affects its density, forming the global overturning circulation. This circulation acts like a conveyor belt, transporting water—and the microbes within it—across vast distances and depths.

“Until now, it was unclear whether these water masses also served as distinct microbial ecosystems,” said Kolody. “We can now answer that question with a resounding, ‘yes.’”

The research team collected over 300 water samples along a transect from Easter Island in the South Pacific Ocean to Antarctica, spanning the full depth of the ocean. Using advanced metagenomic and metabarcoding techniques, they reconstructed the genomes for more than 300 microbes and identified tens of thousands of additional microbial species using a molecular fingerprinting technique that looks at highly conserved genes—the 16S rRNA gene for prokaryotes (which includes both bacteria and archaea) and the 18S rRNA gene for eukaryotes.

Their findings revealed a striking pattern: microbial diversity increases sharply some 300 meters (1,000 feet) below the ocean surface in a zone they call the “prokaryotic phylocline.” This layer, akin to the pycnocline (a zone of rapid density change), marks a transition from low-diversity surface waters to the rich microbial communities of the deep ocean.

The study, released July 10, identified six distinct microbial “cohorts,” three of which correspond to depths and the other three aligning with major water masses: Antarctic Bottom Water, Upper Circumpolar Deep Water , and ancient Pacific Deep Water. Each cohort harbors unique microbial species and functional genes, shaped by the temperature, pressure, nutrient levels, and age of the water.

For example, the Antarctic Bottom Water cohort includes microbes adapted to cold, high-pressure environments, with genes that help maintain membrane fluidity and resist oxidative stress. In contrast, the ancient water cohort—found in slow circulating water that has not seen the surface in 1,000 or more years—hosts microbes with genes enabling life in low oxygen environments and the breakdown of complex, low-energy carbon compounds.

Beyond taxonomy, the researchers also mapped the functional potential of microbial communities. They identified ten “functional zones” based on the presence of key metabolic genes. These zones correspond to oceanographic features such as upwelling regions, nutrient gradients, and oxygen minimum zones.

Surface zones were rich in genes for light harvesting, iron acquisition, and photoprotection—traits essential for life in the sunlit upper ocean. Deeper zones featured genes for breaking down complex organic molecules, surviving low oxygen, and enduring environmental stress.

Microbes are the engines of the ocean’s carbon cycle. They convert carbon dioxide into organic compounds (carbon fixing), recycle nutrients, and help trap carbon in the deep sea (carbon sequestration). Understanding how their communities are structured by ocean circulation is crucial for predicting how climate change might alter these processes.

“The study provides a baseline for how microbial ecosystems are organized under current ocean conditions,” said Andrew Allen, senior author of the study and a microbial oceanographer at JCVI and Scripps Oceanography. “As climate change impacts global overturning circulation, the distribution and function of these microbial communities could shift, with unknown consequences for global carbon cycling.”

By pairing genomic data with physical and chemical measurements, scientists can build a global, species-resolved atlas of ocean life—essential for understanding and protecting the planet’s largest ecosystem.

“This study is a reminder that life in ocean ecosystems is, in part, governed by fundamental patterns and processes that are unknown to us,” said Allen. “Seeing and understanding them requires that we examine them more sensitively, carefully, and thoroughly. The breakthroughs reported in this study are the result of a truly interdisciplinary effort involving physical oceanographers, biological oceanographers, and genome biologists all working very closely together. Agencies, such as the National Science Foundation, that support basic interdisciplinary ecological research in life and earth sciences, continue to be essential to our ability to understand factors that control the distribution, diversity, metabolism, and evolution of organisms in nature.”

The authors advocate for incorporating molecular sampling into global ocean monitoring programs like GO-SHIP. 

Besides Andrew Allen, Scripps Oceanography researchers affiliated with the study include  Zoltán Füssy, Sarah Purkey and Eric Allen. 

The complete study, “Overturning circulation structures the microbial functional seascape of the South Pacific,” is published in the journal Science. This research was supported by the National Science Foundation, the Simons Foundation, the National Institutes of Health, the Emerson Collective, the Gordon and Betty Moore Foundation, and the Chan Zuckerberg Initiative.

Adapted from JCVI

 

A new device combining ultrasound and advanced imaging to provide crucial information for the safe delivery of drugs into the brain has been developed by University of Queensland researchers.

Dr. Pranesh Padmanabhan from UQ’s School of Biomedical Sciences and Queensland Brain Institute said the device allows real-time observation of individual cells after ultrasound treatment, which is an emerging technology for the delivery of drugs past the blood-brain barrier.

The information learned about how treated cells respond and change could ultimately benefit the treatment of neurodegenerative brain disorders such as Alzheimer’s and Parkinson’s disease.

The blood-brain barrier prevents most drug uptake into the brain.

Insights from this device will help inform ultrasound treatment protocols and establish a balance where uptake of drugs into the brain is effective, yet still safe.”

Dr. Pranesh Padmanabhan from UQ’s School of Biomedical Sciences and Queensland Brain Institute 

The custom-built device will examine sonoporation-based drug delivery.

Sonoporation is an emerging strategy involving ultrasound-based treatment combined with injected ‘microbubbles’.

In this process, sound waves interact with the microbubbles causing them to vibrate and exert force on the blood-brain barrier to create a tiny pore at the cell surface.

Dr. Padmanabhan said the device, developed over 5 years, will allow researchers to identify and map changes in treated cells and observe how they respond and recover.

“This device will enable scientists to understand how ultrasound-based treatments work at the single-molecule and single-cell levels,” he said.

“It has the potential to improve treatment of neurodegenerative diseases, where drugs target specific areas of the brain.

“The goal is really to improve the rate of uptake of drugs into the brain, as currently only about 1-2 per cent of small molecule drugs actually reach it.

“The results could also help inform treatment in other medical fields where sonoporation shows great promise, including cardiology and oncology.”

The research is published in Journal of Controlled Release.

A comet is hurtling into our solar system from interstellar space at about 152,000 miles per hour. The comet, named 3I/ATLAS, was discovered by the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope in Rio Hurtado, Chile, on July 1. When the object was first spotted, it was assumed to be one of the many usual denizens of our solar system. But just a few hours later, astronomers realized that the U.S. National Science Foundation (NSF)-funded Zwicky Transient Facility (ZTF) had previously observed the body on June 28 and 29. Those “pre-discovery” observations refined the comet’s orbit, sparking excitement throughout the astronomical community.

“The extremely hyperbolic, or open, orbit could only be explained by this being an interstellar visitor,” says George Helou, a co-investigator of ZTF and a research professor of physics at Caltech.

Comet 3I/ATLAS is the third known interstellar object discovered to date; the other two are asteroid ‘Oumuamua and comet 2I/Borisov, discovered in 2017 by the University of Hawai’i’s Pan-STARRS1 survey and in 2019 by amateur astronomer Gennadiy Borisov, respectively.

ZTF is a robotic survey camera based at Caltech’s Palomar Observatory near San Diego. It scans the whole night sky every three nights, detecting anything that moves or changes in brightness in the night sky. In addition to discovering and classifying more than 10,000 supernovae, among other interesting cosmic specimens, it regularly spots near-Earth asteroids and comets. For instance, back in 2020, it discovered the closest known asteroid to fly by Earth as well as the first asteroid known to orbit entirely within the orbit of Venus.

In the early morning on July 1, the ATLAS team detected a seemingly slow-moving object in the constellation of Sagittarius and reported its new discovery to the International Astronomical Union Minor Planet Center, a hub for tracking small bodies. A few hours later, Quanzhi Ye of the University of Maryland and member of the ZTF collaboration, was busy going about his usual job of logging ZTF observations of comets and asteroids. He has a computer program that checks for new candidate small-body discoveries and then scans ZTF data to see if the camera imaged the objects. Ye then submitted the ZTF data to the Minor Planet Center.

Included in his batch of data on this day were ZTF measurements taken of comet 3I/ATLAS on June 28 and 29. But at that point, neither he nor anybody else had realized the comet was interstellar in origin, so Ye went back to his other duties.

Everything changed a few hours after that when an email from Robert Seaman, an engineer at the Catalina Sky Survey of the University of Arizona went out to astronomers indicating that ZTF’s pre-discovery images had led to an update of 3I/ATLAS’s orbit that suggested possible interstellar origins. The orbital arc—the portion of the comet’s orbit recorded by observers—had changed from covering a period of three hours to three days.

“The new three-day arc suggested a strongly hyperbolic orbit, which means the comet is just passing through our solar system and will not come back. This prompted speculation on community mailing lists that the object might be interstellar,” says Ye, who stayed up that night until 2 a.m. July 2 double checking the ZTF data, including additional pre-discovery images dating back to May 22.

“I was trembling because I didn’t want to make a mistake that prompted speculation of the body being interstellar. There were a lot of intense email exchanges. We were all very excited.”

The object 3I/ATLAS poses no threat to Earth and is currently about 4.5 astronomical units (about 416 million miles) from the Sun. 3I/ATLAS will reach its closest approach to the Sun around October 30, at a distance of 1.4 astronomical units (about 130 million miles), just inside the orbit of Mars.

As to why astronomers are discovering more interstellar objects than ever before, Helou says “there are a lot of ground-based large-format cameras on telescopes that are surveying the sky now—including ZTF, which is designed to find moving objects across the whole sky.”

Caltech’s ZTF is funded by the NSF and an international collaboration of partners. Additional support comes from the Heising-Simons Foundation and from Caltech. ZTF data are processed and archived by IPAC, an astronomy center at Caltech. NASA supports ZTF’s search for near-Earth objects through the Near-Earth Object Observations program.

When the average person looks around the universe, they don’t stop and think, “Wow, there is just too much gold.” That is, however, what many astronomers and other scientists think.

Not because the amount of gold (and other heavy elements) is causing any type of problem (the opposite, in fact) but because based on what they know of how gold is created, there shouldn’t be so much of it in the universe.

For some time now, scientists have been trying to figure out exactly how and why there is so much of it out there, but one group might have found an answer. At least a partial one.

First, let’s look at why it is believed that there is more gold than there should be. At the big bang and for some time after it, various elements were created. Light elements like hydrogen and helium were formed relatively easily as the universe cooled. Atomic nuclei were able to capture electrons, which created vast amounts of these very common elements.

Heavier elements are more difficult to make since they require far more protons and neutrons to come together. The creation of all of the elements up to iron (which has 26 protons, about 30 neutrons, and 26 electrons) can be explained either from the natural cooling of the universe or the forging of these elements via nuclear fusion within stars. The extraordinary temperature and pressure creates elements like iron without much trouble.

A team of researchers set out to understand how these heavier elements, including gold, were created in the quantities that are observed in the universe. In a paper published in The Astrophysical Journal Letters, the researchers explain how it is understood that some of these elements are made:

“Roughly half of the elements in our universe heavier than iron are synthesized through the rapid neutron capture process (r-process). Despite this recognition, identifying the astrophysical sites that give rise to the necessary conditions for an r-process has remained challenging.”

Some of the events in the universe that have the necessary conditions to go through the r-process include things like when neutron stars merge, the proto-neutron star winds during a supernovae, and the outflows of black hole accretion disks.

These don’t happen frequently enough, or early enough in the evolution of the universe, to account for the amount of these heavy elements. When trying to understand this issue, the researchers looked at data from both NASA and ESA telescopes that was gathered back in 2004 for other types of research.

What they found was information that suggested that magnetars may be responsible for somewhere between 1 and 10% of all of the heavy element creation in our galaxy. A magnetar is a specific type of neutron star that has a very strong magnetic field. The team had a hypothesis that if the magnetars were creating these heavier elements, they would be able to identify it in the light coming from the stars.

To prove their theory, they looked back at the data gathered during a 2004 giant flare that took place on a distant magnetar. What they saw matched with their predictions very closely. The team wrote:

“The finding that magnetars produce heavy elements, as just the second directly confirmed r-process source after neutron star mergers, has implications for the chemical evolution of the galaxy. In particular, giant flares offer a confirmed source that promptly tracks star formation.”

This is good evidence that this is indeed where at least least some of the heavier elements came from, helping to balance the scales between what is observed and what is expected. Additional data will be needed to get a better understanding of just how much of a given heavy element might be created in this type of environment.

Fortunately, NASA is set to launch the Compton Spectrometer and Imager (COSI) in 2027. This will be able to gather the specific type of data needed to test their theory further.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.

One of the earliest known human burials — that of a young child — could have been a cross between modern humans and Neanderthals, a new study suggests.

Researchers analyzed a skull that was found at a 140,000-year-old burial site and concluded that the child it belonged to had both modern human (Homo sapiens) and Neanderthal characteristics. However, the child’s precise ancestry is still uncertain.

• Not all days are created equal. Some days are actually a millisecond shorter than other days.
• Since 2020, Earth has notched up unprecedentedly short days midway through the year. It happens again in 2025 around July 9, July 10, July 22 and August 5.
• So why has Earth accelerated? Many factors affect Earth’s spin. But as of now, no one knows for sure.

TimeandDate published this original post on June 16, 2025. Edits by EarthSky.

Earth does not quite spin at a constant rate

Our planet is an almost-but-not-quite-perfect timekeeper. On average, from the point of view of the sun, Earth completes one full rotation on its axis in exactly 86,400 seconds, give or take a millisecond or so.

So, 86,400 seconds is another way of saying 24 hours. A millisecond (ms) is 0.001 seconds. That’s considerably less than a blink of an eye, which lasts around 100 milliseconds.

The only way to measure these tiny day-to-day variations in Earth’s spin speed is with atomic clocks. The first practical atomic clocks began their timekeeping in the 1950s. The number of milliseconds above or below 86,400 seconds is what we call the length of day.

Earth speeds up

Until 2020, the shortest length of day that atomic clocks ever recorded was -1.05 ms. This means Earth completed one rotation with respect to the sun in 1.05 milliseconds less than 86,400 seconds.

Since then, however, Earth has managed to shatter this old record every year by around half a millisecond. The shortest day of all was -1.66 ms on July 5, 2024. Earth should get close to this again in 2025 around July 9, July 10, July 22 and August 5. The newest estimates from July 10 confirm these as the shortest days of 2025. Also, the latest figures suggest the shortest day of the year overall may in fact turn out to be July 10. But this still needs to be confirmed.

Why multiple possible dates?

The orbit of the moon affects the short-term variations in the length of day. Our planet spins more quickly when the moon’s position is far to the north or south of Earth’s equator.

The moon will be around its maximum distance from Earth’s equator on these dates. Input the date into TimeandDate’s Moon Light World Map. This will show you the moon’s position – indicated by the moon symbol – at the time and date you choose.

Why is all this happening?

Why has Earth accelerated, and when will it slow down again? These are difficult questions. Long-term variations in Earth’s spin speed are affected by a long list of factors that includes the complex motion of Earth’s core, oceans and atmosphere. Leonid Zotov, a leading authority on Earth rotation at Moscow State University, said:

Nobody expected this. The cause of this acceleration is not explained.

Most scientists believe it is something inside the Earth. Ocean and atmospheric models don’t explain this huge acceleration.

Early last year, there were indications Earth might be slowing down, and Dr. Zotov predicted that Earth would decelerate. Zotov said at the time:

But the future will show if that’s right.

That prediction turned out to be premature. Yet Dr. Zotov is striking a similar note in 2025:

I think we have reached the minimum. Sooner or later, Earth will decelerate.

Bottom line: The shortest days on Earth for 2025 will be in July and August. But why is Earth spinning faster? It’s a bit of a mystery.

Via TimeandDate

Read more: Why don’t we feel Earth’s spin?