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Earth’s magnetic field protects life on Earth from radiation, but it can move, and the magnetic poles can even flip

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Earth's magnetic field protects life on Earth from radiation, but it can move, and the magnetic poles can evenĀ flip

The Earth's magnetic field deflects particles emitted by the Sun.
Mark Garlick/Science Photo Library via Getty Images

Ofer Cohen, UMass Lowell

The Earth's magnetic field plays a big role in protecting people from hazardous radiation and geomagnetic activity that could affect satellite communication and the operation of power grids. And it moves.

Scientists have studied and tracked the motion of the magnetic poles for centuries. The historical movement of these poles indicates a change in the global geometry of the Earth's magnetic field. It may even indicate the beginning of a field reversal ā€“ a ā€œflipā€ between the north and south magnetic poles.

I'm a physicist who studies the interaction between the planets and . While the north magnetic pole moving a little bit isn't a big deal, a reversal could have a big impact on Earth's climate and our modern technology. But these reversals don't happen instantaneously. Instead, they occur over thousands of years.

A map showing the north part of Canada, with yellow dots moving southwards.
The north magnetic pole's observed locations from 1831ā€“2007 are yellow squares. Modeled pole locations from 1590ā€“2025 are circles progressing from blue to yellow.
National Centers for Environmental Information

Magnetic field generation

So how are magnetic fields like the one around Earth generated?

Magnetic fields are generated by moving electric charges. A material that enables charges to easily move in it is called a conductor. Metal is one example of a conductor ā€“ people use it to transfer electric currents from one place to the other. The electric current itself is simply negative charges called electrons moving through the metal. This current generates a magnetic field.

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Layers of conducting material can be found in the Earth's liquid iron core. Currents of charges move throughout the core, and the liquid iron is also moving and circulating in the core. These movements generate the magnetic field.

Earth's magnetic field is generated by what's called a ā€œdynamo effect.ā€

Earth isn't the only planet with a magnetic field ā€“ gas giant planets like Jupiter have a conducting metallic hydrogen layer that generates their magnetic fields.

The movement of these conducting layers inside planets results in two types of fields. Larger motions, such as large-scale rotations with the planet, to a symmetric magnetic field with a north and a south pole ā€“ similar to a toy magnet.

These conducting layers may have some local irregular motions due to local turbulence or smaller flows that do not follow the large-scale pattern. These irregularities will manifest in some small anomalies in the planet's magnetic field or places where the field deviates from being a perfect dipole field.

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These small-scale deviations in the magnetic field can actually lead to changes in the large-scale field over time and potentially even a complete reversal of the polarity of the dipole field, where the north becomes south and vice versa. The designations of ā€œnorthā€ and ā€œsouthā€ on the magnetic field refer to their opposite polarities ā€“ they're not related to geographic north and south.

A diagram showing the Earth, with two blocks on the inside, one pointing upward that says S and one pointing downward that says N, labeled South Magnetic pole and North magnetic pole, respectively. A slightly tilted line depicts the Earth's rotation axis.
Earth's magnetic field. The north and south magnetic poles mirror the geographic North and South poles.
PeterHermesFurian/iStock via Getty Images Plus

The Earth's magnetosphere, a protective bubble

The Earth's magnetic field creates a magnetic ā€œbubbleā€ called the magnetosphere above the uppermost part of the atmosphere, the ionosphere layer.

The magnetosphere plays a major role in protecting people. It shields and deflects damaging, high-energy, cosmic-ray radiation, which is created in star explosions and moves constantly through the universe. The magnetosphere also interacts with solar wind, which is a flow of magnetized gas sent out from the Sun.

The magnetosphere and ionosphere's interaction with magnetized solar wind creates what scientists call space weather. Usually, the solar wind is mild and there's little to no space weather.

However, there are times when the Sun sheds large magnetized clouds of gas called coronal mass ejections into space. If these coronal mass ejections make it to Earth, their interaction with the magnetosphere can generate geomagnetic storms. Geomagnetic storms can create auroras, which happen when a stream of energized particles hits the atmosphere and lights up.

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During space weather , there's more hazardous radiation near the Earth. This radiation can potentially harm satellites and astronauts. Space weather can also large conducting , such as major pipelines and power grids, by overloading currents in these systems.

Earth's magnetosphere protects on Earth from ejections from the Sun.

Space weather events can also disrupt satellite communication and GPS operation, which many people rely on.

Field flips

Scientists map and track the overall shape and orientation of the Earth's magnetic field using local measurements of the field's orientation and magnitude and, more recently, models.

The location of the north magnetic pole has moved by about 600 miles (965 kilometers) since the first measurement was taken in 1831. The migration speed has increased from 10 miles per year to 34 miles per year (16 km to 54 km) in more recent years. This acceleration could indicate the beginning of a field reversal, but scientists really can't tell with less than 200 years of data.

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The Earth's magnetic field reverses on time scales that vary between 100,000 to 1,000,000 years. Scientists can tell how often the magnetic field reverses by looking at volcanic rocks in the ocean.

These rocks capture the orientation and strength of the Earth's magnetic field when they are created, so dating these rocks provides a good picture of how the Earth's field has evolved over time.

Field reversals happen fast from a geologic standpoint, though slow from a human perspective. A reversal usually takes a few thousand years, but during this time the magnetosphere's orientation may shift and expose more of the Earth to cosmic radiation. These events may change the concentration of ozone in the atmosphere.

Scientists can't tell with confidence when the next field reversal will happen, but we can keep mapping and tracking the movement of Earth's magnetic north.The Conversation

Ofer Cohen, Associate Professor of Physics and Applied Physics, UMass Lowell

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The Conversation

AI chatbots are intruding into online communities where people are trying to connect with other humans

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theconversation.com – Casey Fiesler, Associate Professor of Information Science, of Colorado Boulder – 2024-05-20 07:27:05

AI chatbots are butting into human spaces.

gmast3r/iStock via Getty Images

Casey Fiesler, University of Colorado Boulder

A parent asked a question in a private Facebook group in April 2024: Does anyone with a child who is both gifted and disabled have any experience with New York City public schools? The parent received a seemingly helpful answer that laid out some characteristics of a specific school, beginning with the context that ā€œI have a child who is also 2e,ā€ meaning twice exceptional.

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On a Facebook group for swapping unwanted items near Boston, a user looking for specific items received an offer of a ā€œgently usedā€ Canon camera and an ā€œalmost-new portable air conditioning unit that I never ended up using.ā€

Both of these responses were lies. That child does not exist and neither do the camera or air conditioner. The answers came from an artificial intelligence chatbot.

According to a Meta help page, Meta AI will respond to a post in a group if someone explicitly tags it or if someone ā€œasks a question in a post and no one responds within an hour.ā€ The feature is not yet available in all regions or for all groups, according to the page. For groups where it is available, ā€œadmins can turn it off and back on at any time.ā€

Meta AI has also been integrated into search features on Facebook and Instagram, and users cannot turn it off.

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As a researcher who studies both online communities and AI ethics, I find the idea of uninvited chatbots answering questions in Facebook groups to be dystopian for a number of reasons, starting with the fact that online communities are for people.

Human connections

In 1993, Rheingold published the book ā€œThe Virtual Community: Homesteading on the Electronic Frontierā€ about the WELL, an early and culturally significant online community. The first chapter opens with a parenting question: What to do about a ā€œblood-bloated thing sucking on our baby's scalp.ā€

Rheingold received an answer from someone with firsthand knowledge of dealing with ticks and had resolved the problem before receiving a callback from the pediatrician's office. Of this experience, he wrote, ā€œWhat amazed me wasn't just the speed with which we obtained precisely the information we needed to know, right when we needed to know it. It was also the immense inner sense of security that with discovering that real people ā€“ most of them , some of them nurses, doctors, and midwives ā€“ are available, around the clock, if you need them.ā€

This ā€œreal peopleā€ aspect of online communities continues to be critical today. Imagine why you might pose a question to a Facebook group rather than a search engine: because you want an answer from someone with real, lived experience or you want the human response that your question might elicit ā€“ sympathy, outrage, commiseration ā€“ or both.

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Decades of research suggests that the human component of online communities is what makes them so valuable for both information-seeking and social . For example, fathers who might otherwise feel uncomfortable asking for parenting advice have found a haven in private online spaces just for dads. LGBTQ+ youth often join online communities to safely find critical resources while reducing feelings of isolation. Mental health support forums provide young people with belonging and validation in addition to advice and social support.

Online communities are well-documented places of support for LGBTQ+ people.

In addition to similar findings in my own lab related to LGBTQ+ participants in online communities, as well as Black Twitter, two more recent studies, not yet peer-reviewed, have emphasized the importance of the human aspects of information-seeking in online communities.

One, led by PhD student Blakeley Payne, focuses on fat people's experiences online. Many of our participants found a lifeline in access to an audience and community with similar experiences as they sought and shared information about topics such as navigating hostile healthcare systems, finding clothing and dealing with cultural biases and stereotypes.

Another, led by Ph.D student Faye Kollig, found that people who share content online about their chronic illnesses are motivated by the sense of community that comes with shared experiences, as well as the humanizing aspects of connecting with others to both seek and support and information.

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Faux people

The most important of these online spaces as described by our participants could be drastically undermined by responses coming from chatbots instead of people.

As a type 1 diabetic, I follow a number of related Facebook groups that are frequented by many parents newly navigating the challenges of caring for a young child with diabetes. Questions are frequent: ā€œWhat does this mean?ā€ ā€œHow should I handle this?ā€ ā€œWhat are your experiences with this?ā€ Answers come from firsthand experience, but they also typically come with compassion: ā€œThis is hard.ā€ ā€œYou're doing your best.ā€ And of course: ā€œWe've all been there.ā€

A response from a chatbot claiming to speak from the lived experience of caring for a diabetic child, offering empathy, would not only be inappropriate, but it would be borderline cruel.

However, it makes complete sense that these are the types of responses that a chatbot would offer. Large language models, simplistically, function more similarly to autocomplete than they do to search engines. For a model trained on the millions and millions of posts and comments in Facebook groups, the ā€œautocompleteā€ answer to a question in a support community is definitely one that invokes personal experience and offers empathy ā€“ just as the ā€œautocompleteā€ answer in a Buy Nothing Facebook group might be to offer someone a gently used camera.

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Meta has rolled out an AI assistant across its social and messaging apps.

Keeping chatbots in their lanes

This isn't to suggest that chatbots aren't useful for anything ā€“ they may even be quite useful in some online communities, in some contexts. The problem is that in the midst of the current generative AI rush, there is a tendency to think that chatbots can and should do everything.

There are plenty of downsides to using large language models as information retrieval systems, and these downsides point to inappropriate contexts for their use. One downside is when incorrect information could be dangerous: an eating disorder helpline or legal advice for small businesses, for example.

Research is pointing to important considerations in how and when to design and deploy chatbots. For example, one recently published paper at a large human-computer interaction conference found that though LGBTQ+ individuals lacking social support were sometimes turning to chatbots for help with mental health needs, those chatbots frequently fell short in grasping the nuance of LGBTQ+-specific challenges.

Another found that though a group of autistic participants found value in interacting with a chatbot for social communication advice, that chatbot was also dispensing questionable advice. And yet another found that though a chatbot was helpful as a preconsultation tool in a health context, sometimes found expressions of empathy to be insincere or offensive.

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Responsible AI and deployment means not only auditing for issues such as bias and misinformation, but also taking the time to understand in which contexts AI is appropriate and desirable for the humans who will be interacting with them. Right now, many companies are wielding generative AI as a hammer, and as a result, everything looks like a nail.

Many contexts, such as online support communities, are best left to humans.The Conversation

Casey Fiesler, Associate Professor of Information Science, University of Colorado Boulder

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

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The Conversation

Is hard water bad for you? 2 water quality engineers explain the potential benefits and pitfalls that come with having hard water

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theconversation.com – Sarah Blank, Master's Student in Civil Engineering, Iowa University – 2024-05-20 07:26:46

Do you know how hard your is?

Tatiana Maksimova/Moment via Getty Images

Sarah Blank, Iowa State University and Timothy Ellis, Iowa State University

When you turn on your faucet to get a glass of water or wash your face, you're probably not thinking about what's in your water ā€“ besides water. Depending on where you live and whether you have a water-softening system, your water might contain dissolved minerals such as calcium and magnesium. And these minerals can play a role in whether certain pollutants such as stay out of your water.

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The more dissolved minerals, the ā€œharderā€ your water. But is hard water actually good or bad for you?

As engineering researchers who study water quality, we have seen the effects ā€“ both good and bad ā€“ that soft and hard water can have on everything from plumbing systems to the human body.

What is hard water?

Hard water is water that contains dissolved minerals such as calcium, magnesium, iron and manganese. Soft water contains lower concentrations of these minerals.

Hardness is measured in terms of calcium carbonate, CaCOā‚ƒ, which is used as a reference point for comparing different minerals.

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The amount of these minerals in a 's water supply varies by region. It depends on both where the water is coming from and how the water is treated.

Communities that source their water from wells rather than surface water such as lakes, streams, rivers and reservoirs often start with hard water pretreatment. As groundwater moves through the soil to a well, it picks up minerals. At the same time, where the types of rock and sediment are more prone to dissolving in water may have harder water.

A map showing water hardness across the U.S., with the hardest water in the Midwest, West and Southwest.

Streamflow water hardness across the U.S., where purple and blue indicate softer water and white and red indicate harder water. This map was updated in 2005 by the U.S. EPA.

U.S. Geological Survey

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Effects on water lines and distribution

Water that's too hard or too soft could damage pipes and lead to health and aesthetic concerns.

Since hard water has a higher mineral concentration, minerals can build up in pipes, which to clogged pipes in homes and public water systems. Hardness also creates more deposits at higher temperatures, so hot water heaters are prone to mineral buildup. In areas with hard water, water heaters have a shorter span.

A pipe with gray material around the inside.

A pipe that has a thick layer of mineral deposits inside of it.

Mevedech/Wikimedia Commons

But hard water can help, too. While minerals from hard water can clog pipes, a thin layer of mineral deposition in water lines can protect you from ingesting toxins that could seep in from the pipe itself. Water without any minerals can play a role in pipe corrosion, because without a thin, protective layer of minerals, the water may start to eat away at the pipes, releasing metals from the pipes into the water. Drinking this water might mean ingesting metals such as lead, copper and iron.

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While water that is too soft or too hard can have different effects on water lines, there is more chemistry than just hardness that plays a role in pipe corrosion and clogging. So, there's no specific hardness level that is a cause for concern. Water treatment plants take the appropriate measures to adjust for different hardness levels.

A large tank of water, with fences around the top.

Drinking water normally undergoes treatment at a plant before it makes its way to your home.

Florida Water Daily, CC BY

Effects on skin and hair

Whether you use hard or soft water to wash up can also have noticeable effects on your skin and hair.

Hard water is more likely to leave your skin dry. The minerals in hard water strip moisture from skin and create deposits that clog pores.

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Hard water can also strip the hair of moisture, leaving it dry and coarse. Dry hair is more prone to frizz, tangles and breakage. Mineral deposits can also build up on the hair and scalp, clogging your hair follicles and leading to dandruff and slowed hair growth.

Many households have their own water-softening systems. A water-softening system may help hair and skin dryness and buildup. But many of these systems trap and replace calcium and magnesium with sodium, a mineral that does not contribute to water hardness, to lower overall hardness. Increasing the water's sodium content may be a concern for anyone on a low-sodium diet.

Overall health benefits

Other than aesthetic and water heater concerns, drinking hard water is actually good for you and doesn't come with any serious adverse side effects.

For example, the extra magnesium and calcium you consume in hard water may a gentle solution to digestive issues and constipation.

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Also, researchers have found positive correlations between the hardness of drinking water and bone health. Since calcium is an essential mineral in bones, individuals in areas with drinking water that has more calcium may have higher bone mineral density and may be less prone to osteoporosis.

Researchers have also found that drinking hard water has been associated with a decrease in cardiovascular disease-related mortality. Magnesium helps regulate your cardiac muscles, while calcium keeps the sodium-potassium balance in your cardiac muscles in check, which they need to function.

Whether you have hard or soft water, don't worry too much. Water treatment plants take appropriate measures to ensure safe water for the communities they support.

To learn more about the water hardness in your area, you can contact your local water treatment plant about its specific water treatment . Private well owners can contact their state to find out the testing recommendations for their area.The Conversation

Sarah Blank, Master's Student in Civil Engineering, Iowa State University and Timothy Ellis, Associate Professor of Civil, Construction and Environmental Engineering, Iowa State University

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Black holes are mysterious, yet also deceptively simple āˆ’ a new space mission may help physicists answer hairy questions about these astronomical objects

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theconversation.com – Gaurav Khanna, Professor of Physics, of Rhode Island – 2024-05-15 07:16:18

An illustration of a supermassive black hole.

NASA/JPL

Gaurav Khanna, University of Rhode Island

Physicists consider black holes one of the most mysterious objects that exist. Ironically, they're also considered one of the simplest. For years, physicists like me have been looking to prove that black holes are more complex than they seem. And a newly approved European space mission called LISA will us with this hunt.

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Research from the 1970s suggests that you can comprehensively describe a black hole using only three physical attributes ā€“ their mass, charge and spin. All the other properties of these massive dying , like their detailed composition, density and temperature profiles, disappear as they transform into a black hole. That is how simple they are.

The idea that black holes have only three attributes is called the ā€œno-hairā€ theorem, implying that they don't have any ā€œhairyā€ details that make them complicated.

Black holes are massive, mysterious astronomical objects.

Hairy black holes?

For decades, researchers in the astrophysics community have exploited loopholes or work-arounds within the no-hair theorem's assumptions to up with potential hairy black hole scenarios. A hairy black hole has a physical property that scientists can measure ā€“ in principle ā€“ that's beyond its mass, charge or spin. This property has to be a permanent part of its structure.

About a decade ago, Stefanos Aretakis, a physicist currently at the University of Toronto, showed mathematically that a black hole containing the maximum charge it could hold ā€“ called an extremal charged black hole ā€“ would develop ā€œhairā€ at its horizon. A black hole's horizon is the boundary where anything that crosses it, even light, can't escape.

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Aretakis' analysis was more of a thought experiment using a highly simplified physical scenario, so it's not something scientists expect to observe astrophysically. But supercharged black holes might not be the only kind that could have hair.

Since astrophysical objects such as stars and planets are known to spin, scientists expect that black holes would spin as well, based on how they form. Astronomical evidence has shown that black holes do have spin, though researchers don't know what the typical spin value is for an astrophysical black hole.

Using computer simulations, my team has recently discovered similar types of hair in black holes that are spinning at the maximum rate. This hair has to do with the rate of change, or the gradient, of -time's curvature at the horizon. We also discovered that a black hole wouldn't actually have to be maximally spinning to have hair, which is significant because these maximally spinning black holes probably don't form in nature.

Detecting and measuring hair

My team wanted to develop a way to potentially measure this hair ā€“ a new fixed property that might characterize a black hole beyond its mass, spin and charge. We started looking into how such a new property might a signature on a gravitational wave emitted from a fast-spinning black hole.

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A gravitational wave is a tiny disturbance in space-time typically caused by violent astrophysical in the universe. The collisions of compact astrophysical objects such as black holes and neutron stars emit strong gravitational waves. An international network of gravitational observatories, the Laser Interferometer Gravitational-wave Observatory in the United States, routinely detects these waves.

Our recent studies suggest that one can measure these hairy attributes from gravitational wave data for fast-spinning black holes. Looking at the gravitational wave data offers an for a signature of sorts that could indicate whether the black hole has this type of hair.

Our ongoing studies and recent progress made by Som Bishoyi, a student on the team, are based on a blend of theoretical and computational models of fast-spinning black holes. Our findings have not been tested in the field yet or observed in real black holes out in space. But we hope that will soon change.

LISA gets a go-ahead

In January 2024, the European Space Agency formally adopted the space-based Laser Interferometer Space Antenna, or LISA, mission. LISA will look for gravitational waves, and the data from the mission could help my team with our hairy black hole questions.

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Three spacecrafts spaced apart sending light beams towards each other while orbiting the Sun

The LISA spacecrafts observing gravitational waves from a distant source while orbiting the Sun.

Simon Barke/Univ. Florida, CC BY

Formal adoption means that the has the go-ahead to move to the construction phase, with a planned 2035 launch. LISA consists of three spacecrafts configured in a perfect equilateral triangle that will trail behind the Earth around the Sun. The spacecrafts will each be 1.6 million miles (2.5 million kilometers) apart, and they will exchange laser beams to measure the distance between each other down to about a billionth of an inch.

LISA will detect gravitational waves from supermassive black holes that are millions or even billions of times more massive than our Sun. It will build a map of the space-time around rotating black holes, which will help physicists understand how gravity works in the close vicinity of black holes to an unprecedented level of accuracy. Physicists hope that LISA will also be able to measure any hairy attributes that black holes might have.

With LIGO making new observations every day and LISA to offer a glimpse into the space-time around black holes, now is one of the most exciting times to be a black hole physicist.The Conversation

Gaurav Khanna, Professor of Physics, University of Rhode Island

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