Tag Archives: Earths

The Melting of Polar Ice Could Alter Earth’s Rotation and Timekeeping.

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Global warming is causing the Earth’s rotation to slow slightly, which could affect the way we measure time.

A study published Wednesday found that the melting of polar ice, a trend accelerated primarily by anthropogenic climate change, is causing the Earth to spin more slowly than it would otherwise.

Study author Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego, said melting polar ice changes where the Earth’s mass is concentrated. This change affects the planet’s angular velocity.

Agnew likened the dynamic to a figure skater spinning around on ice. He said, “If a skater starts spinning and lowers his arms or extends his legs, he will slow down.” However, if the skater’s arms are pulled inward, the skater will rotate faster.

So less solid ice at the poles means more mass around the equator, at the Earth’s waist.

“What melting ice does is take water that has solidified in places like Antarctica or Greenland, and when that frozen water melts, it moves that liquid to other parts of the planet. “Thomas Herring said. He was a professor of geophysics at the Massachusetts Institute of Technology but was not involved in the new research. “Water flows toward the equator.”

In other words, this study shows how human influence can successfully manipulate forces that have puzzled scholars, stargazers, and scientists for millennia: forces long thought to be constants beyond human control. It suggests that it has happened.

“It’s kind of impressive, even to me, that we were able to accomplish something that measurably changed the rotational speed of the Earth,” Agnew said. “Something unprecedented is happening.”

His research, published in the journal Nature, suggests that climate change is playing a significant enough role in the Earth’s rotation to delay the possibility of a “negative leap second.” If the polar ice hadn’t melted, clocks around the world might have needed to subtract one second by 2026 to synchronize universal time with the Earth’s rotation, which is influenced by a variety of factors.

Rather, the impact of climate change has delayed that outlook by an estimated three years. If timekeeping organizations ultimately decide to add negative leap seconds, the adjustment could disrupt computer networks.

A view of the Earth captured by a deep space climate observation satellite.NASA

The leap second adjustment is necessary because even without climate change, the Earth’s daily rotation tends to slow down over time, even though it appears constant.

Studies show that about 70 million years ago, days became even shorter, lasting about 23.5 hours. Implications of paleoceanography and paleoclimatology. This means that Cretaceous dinosaurs experienced 372 planetary days a year.

Several important factors influence a planet’s rotation, but they sometimes act in opposition.

Due in part to the moon’s gravitational pull, tidal friction in the oceans slows the Earth’s rotation. Meanwhile, since the last Ice Age, the Earth’s crust has been uplifting in some areas in response to the removal of ice sheet weight. This effect changes the distribution of mass, causing the planet to spin faster. Both of these processes are approximately constant and have predictable rates.

Yet another factor is the movement of fluids within Earth’s liquid inner core, a wild card that can either speed up or slow down Earth’s rotation, Agnew said.

Here, melted polar ice was added to the mix. As climate change intensifies, researchers expect melting ice to have an even more profound effect on the Earth’s rotation.

“As we predict, as melting accelerates over time, its contribution will become even larger,” Herring said. He added that the new study is a thorough and robust analysis that combines research from multiple scientific fields.

The need for timekeepers to adjust universal time to match the Earth’s rotation is not a new phenomenon. But historically, this involved adding leap seconds to the common standard for clocks. This is because astronomical time lags behind atomic time (measured by the vibrations of atoms in atomic clocks) due to the slowing of the Earth’s rotation.

But in recent decades, changes in the Earth’s core have caused the Earth to rotate faster than expected. This has led timekeepers, for the first time since Coordinated Universal Time was officially adopted in the 1960s, to consider whether it makes sense to subtract leap seconds to synchronize universal time with the Earth’s rotation. Ta.

The melting of polar ice counteracted that trend, avoiding any decision points regarding negative leap seconds. According to Agnew’s estimates, if the current rate of Earth’s rotation is maintained, it will likely be delayed by three years from 2026 to 2029.

Adding or subtracting leap seconds is troublesome because it can disrupt satellite, financial, and energy transmission systems that rely on very precise timing. For that purpose, Timekeepers around the world have voted to abolish leap seconds in 2022. By 2035, addition and subtraction will shift universal time from the pace of the Earth’s rotation.

“Since around 2000, there has been a movement to abolish leap seconds,” Agnew said.

Regardless of whether the clocks ultimately change, the idea that melting polar ice is affecting the Earth’s rotation speaks to how important an issue it has become. Studies have already shown that ice loss has significant impacts on coastal communities.

Scientists predict that sea level rise will accelerate as the climate warms, a process that will continue for hundreds of years. Last year, leading polar researchers warned in a report that parts of the major ice sheets could collapse and coastal regions should brace for several feet of sea level rise. If humans allowed global average temperatures to rise by 2 degrees Celsius, Earth could see sea levels rise by more than 40 feet.

Source: www.nbcnews.com

Research suggests that Mars enhances Earth’s deep ocean circulation

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Australian and French geoscientists have used the geological record of Earth's deep ocean to discover a link between our home planet and the orbit of Mars. They discovered a surprising 2.4 million-year cycle of increase and decrease in deep ocean currents, which they found was related to periods of increased solar energy and climate warming.

This image from Mars Express' high-resolution stereo camera shows the Martian Earth set against a dark background. The planet's disk is speckled with yellow, orange, blue, and green, giving it an overall muted shade of gray, representing the varying composition of its surface. Image credit: ESA / DLR / FU Berlin / G. Michael / CC BY-SA 3.0 IGO.

“In 1976, scientists first demonstrated and confirmed the presence of 10,000- to 100,000-year astronomical cycles in deep-sea Pleistocene sediments. Milutin Milanković's theory “Earth's climate is regulated by the periodicity of perturbations in the Earth's orbit around the Sun and Earth's axis of rotation,” said Adriana Dutkiewicz, a researcher at the University of Sydney, and colleagues.

“Apart from the well-known astronomical cycles of 19,000, 23,000, 41,000, 100,000, and 400,000 years, which vary according to the Earth's climate, the geological record includes Large-period signals with longer periods are also included.”

“These large cycles contain orbitally forced periodicities of millions or even tens of millions of years, which are similarly related to incoming solar energy and paleoclimate changes. I am.”

In a new study, the authors used deep-sea sediment records to confirm the link between sediment movement and changes in Earth's orbit.

They discovered that the strength of deep ocean currents changes over a 2.4 million year cycle.

“We were surprised to find these 2.4 million-year cycles in deep-sea sediment data,” Dr. Dutkiewicz said.

“There's only one way to explain them. They're related to the cycle of Mars-Earth interactions around the sun.”

“The gravitational fields of the planets in our solar system interfere with each other, and this interaction, called resonance, changes the planet's eccentricity, a measure of how circular a planet's orbit is.”

“For Earth, that means a 2.4-million-year period of increased solar radiation and a warming climate.”

The researchers found that warming cycles are associated with an increase in deep ocean circulation, which correlates with increased breaks in the deep ocean record.

They identified deep eddies as a key component of early ocean warming.

Although these may partially alleviate ocean stagnation, some predict that subsequent stagnation may follow. AMOC (Atlantic meridional overturning circulation) drives the Gulf Stream and maintains Europe's warm climate.

“We now know that there are at least two distinct mechanisms that contribute to the active mixing of deep water in the ocean,” Professor Müller said.

“Deep-ocean eddies, of which AMOC is one, appear to play an important role in keeping the ocean ventilated in warmer climates.”

“Of course, it doesn't have the same effect as the AMOC in terms of transporting water masses from lower to higher latitudes and vice versa.”

“These eddies are like giant whirlpools that often reach the ocean floor in deep oceans, resulting in seafloor erosion and the accumulation of large sediments called contours that resemble snowdrifts.”

“Our deep-sea data over 65 million years suggests that there is a more active deep circulation in warmer oceans,” Dr. Dutkiewicz said.

“This could prevent ocean stagnation even if the AMOC slows down or stops altogether.”

of study It was published in the magazine nature communications.

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A. Dutkiewicz other. 2024. Deep-sea hibernation records reveal orbital pacing with an orbital eccentricity of 2.4 million grand cycles. Nat Commune 15th, 1998. doi: 10.1038/s41467-024-46171-5

Source: www.sci.news

The gravitational force of Mars could potentially disturb Earth’s oceans

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The planets are doing a gravitational dance around the sun

Shutterstock/Johan Swanepoel

Mars’ gravitational pull could be strong enough to shake up Earth’s oceans and shift sediment as part of a 2.4 million-year climate cycle, researchers claim.

It has long been recognized that wobbles in Earth’s orbit around the sun affect Earth’s climate, and these Milankovitch cycles operate at intervals measured in thousands of years. Now, Adriana Dutkiewicz and his colleagues at the University of Sydney say they have discovered a 2.4-million-year “great cycle” that is driven by Mars and has dramatically affected the flow of Earth’s oceans for at least 40 million years. It is believed that it has been given.

Evidence for this cycle comes from approximately 300 deep-sea drill cores, revealing unexpected fluctuations in marine sediment deposition. During periods of stable ocean currents, oceanographers expect sediment to be deposited in stable layers, but when abnormal currents or eddies occur, sediment can be deposited elsewhere.

The researchers say the gaps or hiatus in the sediment record coincide with the period when Mars’ gravity exerts its greatest force on Earth, exerting subtle effects on the stability of Earth’s orbit. This changes solar radiation levels and climate, manifesting as stronger currents and eddies in the ocean.

team members Dietmar MullerResearchers, also from the University of Sydney, acknowledged that the great distance between Earth and Mars makes it unlikely that there is any significant gravitational force at work. “But there is so much feedback that even the slightest change can be amplified,” he says. “Mars’ influence on Earth’s climate is similar to the butterfly effect.”

benjamin mills Researchers from the University of Leeds in the UK say the drill core provides further evidence of the existence of “megacycles” in global environmental change.

“Many of us have seen these multimillion-year cycles in various geological, geochemical, and biological records, such as during the famous Cambrian explosion of animal life,” he said. says. “This paper helps solidify these ideas as an important part of environmental change.”

but matthew england A professor at the University of New South Wales in Sydney welcomed the study and said he believed it would improve our understanding of climate cycles on a geological scale, but said he was not convinced by the paper’s conclusions.

“I’m skeptical about the Mars connection, given that Mars’ gravitational pull on Earth is very weak, only about a millionth of the Sun’s gravitational pull,” he says. “Even Jupiter has a stronger gravitational field than Earth.”

The UK also points out that even if there is an impact from Mars, it will be negligible compared to human-induced climate change. “By comparison, greenhouse gas forcing is like a sledgehammer and has no effect on our current climate, where melting ice sheets are reducing ocean circulation.”

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Source: www.newscientist.com

Study suggests Mimas, one of Saturn’s moons, could be responsible for forming Earth’s oceans beneath its icy shell

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From a detailed analysis of Mimas’s orbital motion based on data from NASA’s Cassini mission, planetary researchers from the Sorbonne, the University of Nantes, Queen Mary University of London, Franche-Comte University, and Jinan University have discovered that the heavily cratered They showed that some ice shells hide recently formed ice shells. (less than 2-3 million years ago) global ocean 20-30 km deep.

The surface of Mimas, like the surfaces of other major Saturn moons that do not have atmospheres, is not pure ice but contains some black impurities. Relatively dark markings appear along the lower part of the walls of the 130km-wide Herschel Crater (the crater's central peak is about the same height as Mount Everest); the impact may have all but destroyed the Moon. there is). some small craters. Scientists interpret the darkening as evidence that the impurities have gradually become concentrated as icy material evaporates in areas where they are slowly sliding down the crater walls. Image credit: NASA / JPL / Space Science Institute.

There is growing evidence that some moons may have oceans beneath their surfaces, but such watery worlds are difficult to detect.

Mimas — Saturn's innermost and smallest (radius = 198.2 km, or 123 miles) regular moon — is an unlikely candidate due to the different nature of its surface compared to other icy moons such as Enceladus .

This theory has been challenged by Sorbonne University researcher Valerie Rainey and others who are evaluating Cassini's observations of small satellites.

Previous research suggests two possibilities inside Mimas. It is either an elongated rocky core or a global ocean.

A new study reveals that the small moon's rotational motion and orbit change due to internal influences.

For the solid-state model to apply, the rock core must be elongated and approximately pancake-shaped, which is inconsistent with observations.

Rather, measurements of Mimas' position suggest that the evolution of its orbit is better explained as influenced by an internal ocean.

The researchers calculate that the ocean lies beneath an ice shell about 20 to 30 kilometers deep.

Their simulations suggest that it appeared between 25 and 2 million years ago.

Therefore, signs of such an underground ocean would not have had time to leave traces on the surface.

This result suggests that recent processes on Mimas may have been common during the early stages of the formation of other ice worlds.

“Mimas was a small moon with a cratered surface and no sign of an ocean hidden beneath,” said co-author Nick Cooper, a researcher at Queen Mary University of London. the doctor said.

“With this discovery, Mimas joins an exclusive club of moons with inland oceans, including Enceladus and Europa, but with a unique difference: its oceans are surprisingly young.”

of study Published in today's magazine Nature.

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V. Rainey other. 2024. A recently formed ocean within Saturn's moon Mimas. Nature 626, 280-282; doi: 10.1038/s41586-023-06975-9

Source: www.sci.news

The Formation and Potential Destruction of the Himalayas by Earth’s Tectonic Plates

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Deep underground in the heart of Asia, two giant plates are colliding with each other. Violent, slow-motion collisions between the geological plates are continuously shaping the towering Himalayas. However, newly discovered research suggests that this ongoing tectonic collision is also dividing Tibet in half.

A group of Chinese and American scientists conducted a study of underground seismic waves from earthquakes in and around Tibet and analyzed the geochemical composition of gases in surface hot springs. They found evidence that the Indian plate may be behaving unexpectedly as it collides with the Eurasian plate.

This research, which has not yet undergone peer review, was presented at the American Geophysical Union’s annual meeting in December. The scientists theorize that as the Indian plate continues its thrust beneath the Eurasian plate, it may be splitting apart beneath Tibet, separating the eastern and western halves of the slab. This fissure could have significant implications for the stability of the region, increasing the risk of earthquakes and other hazards.

The findings of the study provide an interesting and plausible explanation for the dynamic activity in this region, according to Barbara Romanowitz, a professor at the University of California, Berkeley. She also suggests that this potential split in the Indian plate may create a zone of weakness that could lead to large earthquakes.

The study proposes that the lithospheric mantle, one of the hard parts of the Earth’s crust, are sloughing off, leaving the crust behind, causing controversy within the scientific community as to how the collision of the Indian and Eurasian plates would occur or what it would mean for the Earth.

The region where this collision is occurring is unique and serves as a natural laboratory for scientists to understand the process of continental collision in real time. It is compared to a game of hide-and-seek, providing a brief snapshot of a particular process of continental collision.

Source: www.nbcnews.com

The reason behind the burning up of Hayabusa’s lunar lander in Earth’s atmosphere.

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Launch of the Peregrine Lunar Module on a Vulcan rocket on January 8th

APFootage / Alamy Stock Photo

The mission of the Hayabusa lander is over. The American company that built Astrobotic, a lunar lander whose plans failed, was unable to complete its trip to the moon due to a fuel leak, so it was brought back and burned in Earth's atmosphere.

What was wrong with the Hayabusa lander?

Just seven hours after launching on a Vulcan rocket on January 8, engineers noticed that Peregrine wasn't facing the right direction and its solar panels weren't charging the batteries that power its electronics. Shortly afterward, it was discovered that fuel was leaking from the aircraft. It was eventually determined that the oxidizer tank had ruptured, probably due to a stuck valve, and that the leak had generated a small amount of thrust, causing the probe to change direction. By the time everything was figured out, Peregrine had already lost too much fuel to reach the moon, let alone perform the maneuvers needed to land gently on the moon.

The peregrine falcon was in space for days, but what was it doing all that time?

Astrobotic's engineers were able to correct Peregrine's orientation, and once the solar panels were oriented in the correct direction, the battery was charged. This will allow Peregrine operators to perform a quick test ignition of the main engine and power on the onboard spacecraft, allowing them to better understand the spacecraft's operation in space and determine what went wrong. Helpful. They also remotely switched on some scientific instruments and made measurements of radiation in interplanetary space that could provide useful scientific insights. By operating the spacecraft for several days, Astrobotic will also be able to decide whether to extend its mission in space by changing from its planned moon landing, or continue on its way back to Earth. I was given time to do it.

Why did it have to be brought back to Earth rather than left in space?

Although the peregrine falcon could have survived a little longer in Earth orbit, there were some risks to leaving it there. Eventually, the spacecraft will run out of fuel completely and become essentially a cannonball flying uncontrollably around the Earth. This type of space debris can cause significant damage to operating satellites.a statement The Astrobotic article says: “Ultimately, we have to balance the risk of a damaged spacecraft causing problems with our own desire to extend Peregrine's life, operate the payload, and learn more about the spacecraft. .”

Wouldn't it be dangerous to bring it back to Earth?

It's actually much safer to return the spacecraft to Earth. Satellites are regularly deorbited in this way, usually burning up in the incredible heat they experience as they plummet through the atmosphere. The falcon was also carefully targeted towards the Pacific Ocean just east of Australia to minimize the risk of any surviving debris hitting populated areas.

What about the other things Peregrine was carrying?

In addition to scientific instruments, the spacecraft also carried two controversial payloads sent into space by a company called Celestis, which provides what is called a “commemorative spaceflight.” These two vessels of hers contained cremated human remains. Star Trek Creator Gene Roddenberry and actors James Doohan and Nichelle Nichols. It is unclear whether the capsule survived Earth's atmosphere and ended up in the ocean.

Why do missions to the moon continue to fail?

Indeed, this is the third mission to land on the moon that has failed in the last year, but that's only partially due to the difficulty of sending a probe into space and making a soft landing hundreds of thousands of kilometers away. Lunar landing attempts have also increased significantly, many using new equipment and protocols that have not yet been tested. While there are understandably some growing pains, more moon landings are planned in the future, and Astrobotic executives are already discussing plans to try again.

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Source: www.newscientist.com

Hayabusa lunar lander meets fiery fate as it re-enters Earth’s atmosphere

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After more than a week in space, the doomed lunar lander met a violent end Thursday as it burned up in Earth’s atmosphere, ending its mission.

A private spacecraft named Peregrine was designed to travel to the moon and settle on its surface. However, shortly after launching into orbit on January 8, the lander suffered a severe propellant leak, forcing operators to abort the entire mission.

Astrobotic Technology, the Pittsburgh-based company that developed the lander, said Thursday that the limp spacecraft safely burned up in Earth’s atmosphere in a remote stretch of the South Pacific Ocean at about 4:04 p.m. ET. announced.

in Updates posted on XThe company confirmed it had lost contact with the spacecraft just before 4 p.m. ET, suggesting the lander had re-entered the atmosphere, but officials said they were “waiting for independent confirmation from a government agency.” ” he added.

An early failure left the Peregrine lander with no means of reaching the moon. Astrobotic’s team fought for nine days to save the spacecraft and its onboard equipment and extend the remainder of the mission.

Engineers were able to stabilize the spacecraft, but Astrobotic said last week it would not be possible to attempt a controlled landing on the moon.

“We applaud @Astrobotic’s perseverance,” NASA announced Tuesday. Statement posted on X.

The Peregrine mission attracted attention because it was the first American lunar lander launched into space in more than 50 years. If successful, Peregrine would also have become the first commercially developed spacecraft to land on the moon.

Besides NASA, the former Soviet Union, China, and India are the only countries to have successfully made a controlled landing, or “soft landing,” on the moon’s surface. Japan aims to join that elite club on Friday when it attempts to land its Smart Lander for Lunar Exploration (SLIM).

Peregrine’s mission is part of NASA’s Commercial Lunar Module Services Program, which was established to encourage private companies to develop new lunar landers and ultimately help NASA bring cargo and scientific equipment to the lunar surface. You can now hire this lander for transport.

Another Houston-based company, Intuitive Machines, plans to launch its own commercially developed lander next month as part of the same NASA effort.

The Commercial Lunar Payload Services Program is part of the agency’s Artemis program, with the goal of returning astronauts to the Moon over the next few years, eventually establishing regular flights to the Moon, and building a lunar base camp. It is said that NASA recently announced the postponement of two upcoming Artemis missions, pushing back a lunar circumnavigation flight that was scheduled to launch later this year to 2025 and pushing back Artemis’s first landing attempt to next year.

Source: www.nbcnews.com

For the First Time, NASA Unveils World Map of Earth’s Surface Minerals

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NASA’s EMIT has produced the first global map of hematite, goethite, and kaolinite in the dry regions of Earth using data from the year ending November 2023. The mission collected billions of data measurements of three different minerals along with seven minerals that could impact climate when released into the air. The mission, EMIT, aims to provide a detailed map of the mineral composition of Earth’s dust source regions, which can help scientists model the impact of fine particles on climate change.

EMIT launched to the International Space Station in 2022, will be launched by NASA’s Jet Propulsion Laboratory and surveys the Earth’s surface from approximately 250 miles in the air. The mission captures high-resolution images to create detailed maps of surface composition and is capable of detecting plumes of methane and carbon dioxide emitted by various human activities. EMIT’s data will be used to improve climate models and study the effects of dust on global ecosystems, including its impact on phytoplankton blooms and the transport of essential nutrients over long distances.

In addition to tracking the 10 major minerals as part of its primary mission, EMIT’s data also tracks other minerals, vegetation types, snow and ice, and even humans at or near the surface. The instrument was selected from NASA’s Earth Venture Instrument-4 public offering and is managed by the California Institute of Technology in Pasadena, California. The data collected by EMIT is publicly available for use by other researchers and the public at the NASA Land Processes Distributed Active Archive Center.

Source: scitechdaily.com

Strange Alien Planet Indicates Earth’s Survival After Sun’s Demise

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Mark Garlick/Science Photo Library

When I found out the date of the end of the Earth, everything seemed so simple. Five billion years from now, the solar system will have changed dramatically. Instead of the gentle presence we are accustomed to, the sun will become a behemoth, hundreds of times larger than it is today. In the process, it will wipe out the rocky inner planets, including our own.

Or will it be? We recently witnessed the death stages of another star for the first time. And miraculously, it seems some planets will be able to survive this apocalyptic era. Observations like these call into question the story of how the Earth will die, and give us hope that somehow the Earth may outlast the Sun. Even if it doesn’t, all is not lost. The study also provides clues as to where humans might best seek refuge.

How does the sun die?

The sun is powered by nuclear fusion. In nuclear fusion, hydrogen atoms fuse into helium, releasing a huge amount of energy in the process. However, the fate of our star is determined by one fact. This means that the supply of hydrogen is limited. As this energy begins to deplete, in about another 5 billion years, the Sun’s internal structure will change and it will expand to about 200 times its current size. It will change from the current yellow dwarf to a red giant. After another billion years, the star shrinks and expands again, before disappearing and becoming a stellar corpse called a white dwarf.

As it grows…

Source: www.newscientist.com

Decoding Earth’s magnetosphere: A simplified understanding

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Earth’s magnetosphere, essential for protecting us from solar radiation, is in sharp contrast to Mars, which has lost its protective field. Studying this shield, especially through NASA missions such as the Magnetospheric Multiscale Mission, is important for understanding space weather and its effects on Earth.

What is Earth’s magnetosphere?

Enveloping our planet and protecting us from the wrath of the sun is a giant magnetic bubble called the magnetosphere. It deflects most of the solar material that rushes toward us from our star at more than 1 million miles per hour. Without the magnetosphere, the relentless activity of these solar particles could strip Earth of the protective layer that protects us from the sun’s ultraviolet rays. It is clear that this magnetic bubble was the key to the development of Earth into a habitable planet.

The magnetosphere envelops our planet and protects us from the brunt of the sun, and is key to Earth’s development into a habitable planet. credit: NASA

Earth vs. Mars: The role of the magnetosphere

compare with earth Mars – A planet that lost its magnetosphere about 4.2 billion years ago. It is thought that solar winds stripped away most of Mars’ atmosphere, probably after the Red Planet’s magnetic field disappeared. As a result, Mars is the desolate, barren world we see today through the “eyes” of NASA’s orbiters and probes. In contrast, Earth’s magnetosphere appears to continue to protect the atmosphere.

“If we didn’t have the magnetic field, we might be left with a completely different atmosphere, devoid of life as we know it,” said Eftihir Zesta of NASA’s Goddard Space Flight Center’s Geospace Physics Laboratory. states.

The magnetosphere is the result of the Earth’s internal magnetic field, generated by the rotation and convection of electrically conductive material within its central core. This magnetic field spreads out into space and acts as a shield against the solar wind, forming the magnetosphere.

Understanding and researching the magnetosphere

Understanding the magnetosphere is a key element in helping scientists predict space weather that could one day impact technology on Earth. Extreme space weather events can disrupt communication networks. GPS Navigation and power grids.

The magnetosphere is a permeable shield. The solar wind periodically connects to the magnetosphere and forces its reconfiguration. This can cause cracks and allow energy to flow into our safe haven. These cracks open and close many times a day, sometimes even an hour. Most of them are small and short-lived. Others are vast and persistent. When the sun’s magnetic field connects with the Earth’s magnetic field, fireworks begin.

“Earth’s magnetosphere absorbs incoming energy from the solar wind and releases it in bursts in the form of magnetic storms and substorms,” ​​Zesta said.

Illustration of four MMS spacecraft in orbit in the Earth’s magnetic field. Credit: NASA

Magnetic Reconnection and MMS Mission

How does this happen? Magnetic field lines converge and rearrange, resulting in magnetic energy and charged particles flying around at breakneck speeds. Scientists have been trying to understand why this crossing of magnetic field lines, called magnetic reconnection, causes such violent explosions and opens cracks in the magnetosphere.

NASA’s Magnetospheric Multiscale Mission (MMS) launched in March 2015 to make the first observations of the electronic physics of magnetic reconnection. Four of her MMS spacecraft, packed with high-energy particle detectors and magnetic sensors, flew close to the region on the surface of Earth’s magnetosphere where magnetic reconnection occurs. Since then, MMS has conducted similar searches in the magnetotail.

MMS complements the missions of NASA and partner agencies such as THEMIS, Cluster, and Geotail, and will provide important new details for ongoing studies of Earth’s magnetosphere. The data obtained from these surveys not only helps us understand the fundamental physics of the universe, but also helps improve space weather forecasting.

Source: scitechdaily.com

The real cause of the degradation of Earth’s most magnificent creature

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New study shows that humans, not climate, caused decline of megafauna 50,000 years ago

New research from Aarhus University confirms that it was humans, not climate, that caused the dramatic decline in large mammal populations over the past 50,000 years. Scientists have long debated whether humans or climate were to blame, but new DNA analysis of 139 extant large mammal species shows that climate cannot explain the decline.

About 100,000 years ago, the first modern humans migrated from Africa, settling in every type of terrain and hunting large animals using clever techniques and weapons. Unfortunately, this led to the extinction of many large mammals during the era of human colonization, and new research reveals that the surviving large mammals also experienced a dramatic decline.

According to Jens Christian Svenning, professor and director of the Danish National Research Foundation’s Center for New Biosphere Ecodynamics at Aarhus University, the populations of nearly all 139 species of large mammals declined about 50,000 years ago. DNA analysis shows that the decline is related to human dispersal rather than climate change.

This study used DNA analysis to map the long-term history of 139 large mammal species that have survived without extinction for the past 50,000 years, and scientists were able to estimate the population size of each species over time. The results are conclusive that human dispersal is the most likely cause of the decline in large mammal populations.

The study also showed that woolly mammoths are a poor example for climate-based models of extinction, as the vast majority of megafauna species that went extinct lived in temperate and tropical regions, not mammoth grasslands. Despite ongoing debate, the evidence strongly points to human activity rather than climate change as the main cause of the dramatic decline in large mammal populations.

Source: scitechdaily.com