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We're within 3 years of reaching a critical climate threshold. Can we reverse course?
When you buy through links on our articles, Future and its syndication partners may earn a commission. In June, more than 60 climate scientists warned that the remaining "carbon budget" to stay below a dire warming threshold will be exhausted in as little as three years at the current rate of emissions. But if we pass that critical 1.5-degree-Celsius (2.7 degrees Fahrenheit) warming threshold, is a climate catastrophe inevitable? And can we do anything to reverse that temperature rise? Although crossing the 1.5 C threshold will lead to problems, particularly for island nations, and raise the risk of ecosystems permanently transforming, the planet won't nosedive into an apocalypse. And once we rein in emissions, there are ways to slowly bring temperatures down if we wind up crossing that 1.5 C threshold, experts told Live Science. Still, that doesn't mean we should stop trying to curb emissions now, which is cheaper, easier and more effective than reversing a temperature rise that has already happened, Michael Mann, a leading climate scientist and director of the Center for Science, Sustainability and the Media at the University of Pennsylvania, told Live Science in an email. "Every fraction of a degree of warming that we prevent makes us better off," Mann said. Delayed response A report released June 19 found that the world has only 143 billion tons (130 billion metric tons) of carbon dioxide (CO2) left to emit before we likely cross the 1.5 C target set in the Paris Agreement, which was signed by 195 countries to tackle climate change. We currently emit around 46 billion tons (42 billion metric tons) of CO2 per year, according to the World Meteorological Organization. The world is currently 1.2 C (2.2 F) warmer than the preindustrial average, with almost all of this increase in temperature due to human activities, according to the report. But our emissions may have had an even bigger warming impact that has so far been masked, because the ocean has soaked up a lot of excess heat. The ocean will release this extra heat over the next few decades via evaporation and direct heat transfer regardless of whether we curb emissions, according to the National Oceanic and Atmospheric Administration (NOAA). This means that even if carbon emissions dropped to zero today, global temperatures would continue to rise for a few decades, with experts predicting an extra 0.5 C (0.9 F) of warming from oceans alone. However, temperatures would eventually stabilize as heat radiated out to space. And over several thousand years, Earth would dial temperatures back down to preindustrial levels via natural carbon sinks, such as trees and soils absorbing CO2, according to NOAA. Why 1.5 C? Climate scientists see 1.5 C as a critical threshold: Beyond this limit, levels of warming are unsafe for people living in economically developing countries, and particularly in island nations, said Kirsten Zickfeld, a professor of climate science at Simon Fraser University in Canada. The 1.5 C limit is "an indicator of a state of the climate system where we feel we can still manage the consequences," Zickfeld told Live Science. A huge amount of additional heat could be baked into the ocean and later released if we exceed 1.5 C, which is another reason why scientists are worried about crossing this threshold. Speeding past 1.5 C also increases the risk of passing climate tipping points, which are elements of the Earth system that can quickly switch into a dramatically different state. For example, the Greenland Ice Sheet could suddenly tumble into the ocean, and the Amazon rainforest could transform into a dry savanna. Reversing temperature rise Although it's best to reduce emissions as quickly as we can, it may still be possible to reverse a temperature rise of 1.5 C or more if we pass that critical threshold. The technology needed isn't quite developed yet, so there is a lot of uncertainty about what is feasible. If we do start to bring temperatures down again, it would not undo the effects of passing climate tipping points. For example, it would not refreeze ice sheets or cause sea levels to fall after they've already risen. But it would significantly reduce risks for ecosystems that respond more quickly to temperature change, such as permafrost-covered tundras. Reversing temperature rise requires not just net zero emissions, but net negative emissions, Zickfeld said. Net zero would mean we sequester as much CO2 via natural carbon sinks and negative emissions technologies as we emit. Negative emissions would require systems that suck carbon out of the atmosphere and then bury it underground — often known as carbon capture and storage. Net zero may halt warming. But if we want to reverse warming, we must remove more carbon from the atmosphere than we emit, Zickfield said. Scientists estimate that 0.1 C (0.2 F) of warming is equivalent to 243 billion tons (220 billion metric tons) of CO2, which is a "massive amount," Zickfeld said. "Let's say if we go to 1.6 C [2.9 F] and we want to drop down to 1.5 C — we need to remove around 220 billion metric tons of carbon dioxide." Currently, nature-based carbon-removal techniques, such as planting trees, sequester around 2.2 billion tons (2 billion metric tons) of CO2 each year. "So we need to scale that up by a factor of 100 to drop us down by 0.1 C" in one year, Zickfeld said. Due to competing demands for land, it is highly unlikely that we could plant enough forests or restore enough peatland to meaningfully reverse temperature change, Zickfeld said. This means we will definitely need negative emissions technologies, she said. However, most negative emissions technologies are still being tested, so it's difficult to say how effective they would be, Zickfeld said. These technologies are also extremely expensive and will likely remain so for a long time, Robin Lamboll, a climate researcher at Imperial College London and a co-author of the recent report, told Live Science in an email. "In practice we will be doing quite well if we find that the rollout of these technologies does any more than bring us to net zero," Lamboll said. There is some uncertainty about how Earth might respond to net zero, and it's possible that the planet might cool at that point. "If we cool at all, we do so very slowly. In a very optimistic case we might go down by 0.3 C [0.5 F] in 50 years," Lamboll said. RELATED STORIES —2 billion people could face chaotic and 'irreversible' shift in rainfall patterns if warming continues —Climate wars are approaching — and they will redefine global conflict —Kids born today are going to grow up in a hellscape, grim climate study finds There is no requirement under the Paris Agreement for countries to roll out negative emissions technologies. But the goal of the agreement to stay well below 2 C (3.6 F) means that governments may decide to ramp up these technologies once we pass 1.5 C, Lamboll said. Figures from the recent report indicate that at the current rate of emissions, the remaining carbon budgets to stay below 1.6 C, 1.7 C (3.1 F) and 2 C could be used up within seven, 12 and 25 years, respectively. "If we do pass 1.5 C, 1.6 C is a whole lot better than 1.7 C, and 1.7 C is a whole lot better than 1.8 C [3.2 F]," Mann said in an interview with BBC World News America in June. "At this point, the challenge is to reduce carbon emissions as quickly as we can to avert ever-worse impacts." It's worth noting that the world is making progress with emission cuts, Mann added in the interview. "Let's recognize that we're starting to turn the corner," he said. Solve the daily Crossword
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Earth's magnetic field is weakening — magnetic crystals from lost civilizations could hold the key to understanding why
When you buy through links on our articles, Future and its syndication partners may earn a commission. In 2008, Erez Ben-Yosef unearthed a piece of Iron Age "trash" and inadvertently revealed the strongest magnetic-field anomaly ever found. Ben-Yosef, an archaeologist at Tel Aviv University, had been working in southern Jordan with Ron Shaar, who was analyzing archaeological materials around the Levant. Shaar, a geologist at The Hebrew University of Jerusalem, was building a record of the area's magnetic field. The hunk of copper slag — a waste byproduct of forging metals — they found recorded an intense spike in Earth's magnetic field around 3,000 years ago. When Ben-Yosef's team first described their discovery, many geophysicists were skeptical because the magnitude of the spike was unprecedented in geologic history. "There was no model that could explain such a spike," Ben-Yosef told Live Science. Related: Major 'magnetic anomaly' discovered deep below New Zealand's Lake Rotorua So Shaar worked hard to give them more evidence. After they had analyzed and described samples from around the region for more than a decade, the anomaly was accepted by the research community and named the Levantine Iron Age Anomaly (LIAA). From about 1100 to 550 B.C., the magnetic field emanating from the Middle East fluctuated in intense surges. Shaar and Ben-Yosef were using a relatively new technique called archaeomagnetism. With this method, geophysicists can peer into the magnetic particles inside archaeological materials like metal waste, pottery and building stone to recreate Earth's magnetic past. This technique has some advantages over traditional methods of reconstructing Earth's magnetic field, particularly for studying the relatively recent past. Generally, scientists study Earth's past magnetic field by looking at snapshots captured in rocks as they cooled into solids. But rock formation doesn't happen often, so for the most part, it gives scientists a glimpse of Earth's magnetic field hundreds of thousands to millions of years ago, or after relatively rare events, like volcanic eruptions. Past magnetic-field data helps us understand the "geodynamo" — the engine that generates our planet's protective magnetic field. This field is generated by liquid iron slowly moving around the planet's outer core, and this movement can also affect, and in turn be affected by, processes in the mantle, Earth's middle layer. So differences in the magnetic field hint at turmoil roiling deep below the surface in Earth's geodynamo. "We cannot directly observe what is going on in Earth's outer core," Shaar told Live Science. "The only way we can indirectly measure what is happening in the core is by looking at changes in the geomagnetic field." Knowing what the magnetic field did in the past can help us predict its future. And some studies suggest our planet's magnetic field is weakening over time. The magnetic field shields us from deadly space radiation, so its weakening could lead to a breakdown in satellite communications, and potentially increase cancer risk. As a result, predicting the magnetic field based on its past behavior has become ever more important. But observational data of the magnetic field's intensity only began in 1832, so it's difficult to make predictions about the future if we only dimly understand the forces that steered the magnetic field in the past. Archaeomagnetism has started to fill these gaps. How do we see the magnetic field from an archaeological artifact? Archaeomagnetism takes advantage of our human ancestors' harnessing of the earth around them — they started building firepits, making bricks and ceramics, and eventually, smelting metals. In each of these tasks, materials are heated to intense temperatures. At high enough temperatures, thermal energy makes the particles inside a material dance around. Then, as the material is removed from the fire and cools, the magnetically sensitive particles inside naturally orient in the direction of Earth's magnetic field, like miniature compass needles. They become "stuck" in place as the material hardens, and will retain this magnetic orientation unless the material is heated again. The settled magnetic particles in an archaeological artifact offer a unique snapshot of the magnetic field at the time the material was last hot. This snapshot is regional, spanning a radius of about 310 miles (500 kilometers) around the sample — the scale at which the magnetic field is thought to be uniform, Shaar said. When the sample is dated with radiocarbon or other techniques, scientists can begin to build a chronological record of an area's magnetic field. These artifacts are so helpful for geophysicists because Earth's magnetic field constantly drifts. For instance, in 2001, the magnetic north pole was closer to the very northern tip of Canada, but by 2007, it had moved over 200 miles (320 km) closer to the geographic north pole. That's because two large "lobes" of strong magnetism, called flux patches, in the outer core underneath Canada and Siberia act as funnels for the magnetic field, pulling it into Earth. As these lobes shift, they move magnetic north. And while most of the planet's magnetic-field lines go from north to south, about 20% diverge from these paths, swirling to form eddies called magnetic anomalies. It's these anomalies that researchers are struggling to explain, and that artifacts could reveal. A growing field Although archaeomagnetism has been around since the 1950s, magnetic-field-measuring technologies, like the magnetometer, have improved dramatically since then. Refined statistical analysis techniques also now allow much more detailed interpretation of archaeomagnetic data. To get all of the data in one place and synthesize our understanding of Earth's magnetic field, scientists have started to build a global database called Geomagia50, hosted at the University of Minnesota's (UM) Institute for Rock Magnetism. But even as the technique grows in popularity, there are many hurdles to widespread adoption. "The equipment is quite expensive," Maxwell Brown, a UM geophysicist and custodian of the Geomagia50 database, told Live Science. The most precise magnetometers can cost between $700,000 and $800,000, Brown said. "So there are only a few labs in the [United States] that have one of these." As a result, about 90% of the data in the Geomagia50 database has come from Europe, Brown said. Africa doesn't have a single magnetometer available to geophysicists for archaeomagnetic sampling, meaning our magnetic snapshot of the continent is largely blank. Additionally, there are no current avenues for the average archaeologist to send their artifacts to be sampled, Ben-Yosef added. Anyone without a magnetometer has to set up an official partnership with someone who does have one. Even if the equipment is available, sampling takes time and expertise, Shaar said. Measuring the direction of the field can sometimes be relatively simple, but understanding the intensity of the field takes much more work. The sample must be heated and reheated 20 separate times, gradually replacing the original magnetization and destroying the sample. "It sounds like it's an easy thing: We put it in a magnetometer or instrument, and we get the results. No. For each artifact, we spend two months working in the lab, making experiments and then getting the results. It's a complicated, experimental procedure," Shaar explained. This lack of global data limits our understanding of what the magnetic field has been up to in recent history. "We clearly have a very strong bias [toward Europe] in the data distribution," Monika Korte, a geophysicist and magnetic modeler at Germany's GFZ Helmholtz Centre for Geosciences, told Live Science. "Where we have sparse data we have just a very blurred picture, a very rough idea of what's going on." Geographic diversity is important, as samples taken from one area can indicate the magnetic field only in that area. For instance, other data similar to the Levantine Iron Age Anomaly's intense spikes of magnetic strength have been spotted in places like China and Korea around the Iron Age as well, but there's not enough evidence to confirm these as bona fide anomalies or to say whether they are related to the Levantine Iron Age Anomaly, Korte said. Why should we learn more about historic anomalies? The discovery of the Levantine Iron Age Anomaly redefined our previous understanding of the potential strength of the field, Shaar said. Understanding how much the magnetic field can change may seem like a purely abstract endeavor, but these ancient fluctuations may have implications for modern times. Another important anomaly is the South Atlantic Anomaly (SAA), a region of weakened magnetic field that spans central South America in a strip that ends near southern Africa. It likely first emerged 11 million years ago, caused by the slight difference in location of the magnetic axis and the rotational axis at Earth's core. As the magnetic field is slightly off-center to the rotational axis, the field dips in strength over the South Atlantic, though the field's interaction with the churning mantle may also contribute to the anomaly. The South Atlantic Anomaly still exists today, and has disrupted communications from satellites and the International Space Station, as the weak magnetic field in the region lets through more radiation from solar wind. Studying the SAA throughout its history has helped scientists understand how our magnetic field changes over time, and how such anomalies alter the likelihood of a magnetic field reversal, when Earth's north and south poles flip. But although scientists have a reasonable understanding of the South Atlantic Anomaly, its weakened magnetic field is very different from the strong spikes of the Levantine Iron Age Anomaly, which has baffled geophysicists. And though researchers haven't pinpointed the exact extent of the anomaly, its seemingly small scale of around 1,000 miles (1,609 km) across, combined with the extremely high spikes in the magnetic field, isn't easily explained. Some geomagnetists had suggested that the Levantine Iron Age Anomaly developed due to a narrow flux patch that developed on the outer core under the equator before it drifted north towards the Levant, potentially contributing to other spikes of intensity recorded in China. The inverse of the large lobes that funnel the magnetic field into the planet at the North Pole, this 'positive' flux patch would have pushed the field out in a powerful burst. Others believed the single flux patch didn't travel, instead multiple grew under the Levant, erupted, and decayed in place. Still, no theories can explain why the flux patch developed in the first place. With the most up-to-date archaeomagnetic data, geomagnetist Pablo Rivera at the Complutense University of Madrid published a paper in January that simulated both the Levantine Iron Age Anomaly and the South Atlantic Anomaly. By modeling their movement over time, his work suggested that both anomalies may have been influenced by a superplume underneath Africa — a massive blob of hot rock on the barrier between the core and the mantle that may disrupt the flow of the geodynamo below it. However, much is still unknown. "So far, there is not a single simulation that really describes all the [magnetic] features that we see well," Korte told Live Science. Many archaeomagnetic data points from around the globe suggest there may be more intensity spikes that could help resolve the mystery and create a unifying theory to explain the SAA, the LIAA and other spikes. But there currently isn't enough data to describe them accurately, or even begin to understand their causes. "We don't really understand what causes these anomalies, but we hope to learn more about how the geodynamo operates and what kinds of changes we also can expect for the future magnetic field," Korte said. This certainty is needed now more than ever, as more of our communications take to the skies. More than 13,500 satellites currently orbit Earth — a dramatic increase from only around 3,000 in 2020. The Government Accountability Agency estimates that another 54,000 satellites will launch by 2030. These satellites monitor weather patterns, send phone and TV signals, and create GPS. Satellites are generally protected from space radiation by Earth's magnetic field. But in places where the field is weaker, such as above the South Atlantic Anomaly, satellites have more memory problems as radiation bombards onboard computers and corrupts data. Filling out the picture Despite the expense and technical challenges of archaeomagnetism, there are many initiatives to expand the amount of data. In the U.S., the Institute for Rock Magnetism is expanding its archaeomagnetism program to begin building a more thorough history of the magnetic field in the Midwest, hoping to build their own localized dating system using archaeomagnetism, similar to the record Shaar and his collaborators have built in the Levant. RELATED STORIES —Weird dent in Earth's magnetic field is messing with auroras in the Southern Hemisphere —Earth's magnetic field formed before the planet's core, study suggests —Why do magnets have north and south poles? Interest in archaeomagnetism is also growing around the globe. The first archaeomagnetism data from Cambodia was published in 2021, and the first regional model of the magnetic field of Africa for the recent past was published in 2022. As the field of archaeomagnetism grows, scientists can start building a better understanding of how features like superplumes affect the magnetic field. The past 50 or so years of data has captured "only a really tiny snapshot in time," Shaar said, and "maybe there are more [anomalies] to find." Solve the daily Crossword
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2 days ago
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Rare snowfall in Atacama Desert forces the world's most powerful radio telescope into 'survival mode'
When you buy through links on our articles, Future and its syndication partners may earn a commission. A rare snowfall in the driest place on Earth has halted operations of one of the world's premier telescope arrays, and climate change may mean the observatory will face more extreme weather events like this in the future. The snow has blanketed part of the Atacama Desert, which gets less than an inch of rainfall per year and is home to home the Atacama Large Millimeter/submillimeter Array (ALMA), a large network of radio telescopes in northern Chile. The snowfall occurred over ALMA's Operations Support Facility, located at an altitude of 9,500 feet (2,900 meters) and about 1,050 miles (1,700 kilometers) north of Santiago. Scientific operations have been suspended since Thursday (June 26). "There hasn't been a record of snowfall at the base camp for over 10 years. It doesn't snow every day at ALMA!" ALMA representatives told Live Science via WhatsApp. ALMA's radio telescope array is perched high on the Chajnantor Plateau — a desert plain at 16,800 feet (5,104 m) in Chile's Antofagasta region — typically sees three snowfalls a year. The high plateau shared by Chile, Bolivia and Peru typically experiences snowstorms during two seasons: in February, during the "Altiplanic Winter," driven by moist air masses from the Amazon; and from June to July, during the Southern Hemisphere's winter, said Raúl Cordero, a climatologist at the University of Santiago. "In winter, some storms are fueled by moisture from the Pacific, which can extend precipitation even to the Atacama Desert's coastal areas," Cordero told Live Science. At elevations above 16,400 feet (5,000 m), annual snowfall ranges from 8 to 31 inches (20 to 80 centimeters). However, snowfall at 3,000 meters (9,840 feet), where ALMA's base camp is located, "is much less frequent," Cordero noted. This week's snowfall was triggered by unusual atmospheric instability affecting northern Chile. The Chilean Meteorological Directorate issued a snow and wind alert due to the passage of a "cold core" through the region, said meteorologist Elio Brufort. "We issued a wind alert for the Antofagasta region and areas further north, with gusts reaching 80 to 100 km/h [50-62 mph]," Brufort said to the local press. The phenomenon was accompanied by heavy rainfall that occurred farther north, causing a stream to swell and damage several properties. Schools were ordered to close, and power outages and landslides were reported. So far, no casualties have been reported. A weather event of this magnitude has not been seen in nearly a decade. Extreme conditions paralyze ALMA As of Friday, ALMA reported to Live Science that the snowstorm remained active over the Chajnantor Plateau, so scientific operations continued to be suspended to protect the antennas from extreme weather conditions. Early Thursday morning, the observatory activated its "survival mode" safety protocol: In addition to the snowfall, temperatures had plummeted to 10 degrees Fahrenheit (minus 12 degrees Celsius) — with a wind chill of minus 18 F (minus 28 C) — making work at the high-altitude camp extremely difficult. As part of this protocol, all of ALMA's large antennae have been reoriented downwind, helping to minimize potential damage from snow buildup or strong gusts. "Once the storm passes, snow-clearing teams are immediately activated to visually inspect each antenna before resuming observations," ALMA representatives said. "This has to happen fast, as some of the best observing conditions occur just after a snowfall: the cold helps lower air humidity, which is what most interferes with our measurements." ALMA, which consists of 66 high-precision antennae spread across the Chajnantor Plateau, is an international collaboration that forms the most powerful radio telescope on the planet — and one designed to handle extreme weather events like this. The fact that the snow halted operations raises questions about the array's operations as the climate warms. The Atacama Desert typically receives only 0.04 to 0.6 inch (1 to 15 millimeters)of precipitation per year, and many areas can go years without recording any measurable rain or snow. Could events like this become more frequent? "That's a good question," Cordero replied. While it's still too early to link lower-altitude snowfalls in the desert directly to climate change, "climate models predict a potential increase in precipitation even in this hyper-arid region," he concluded. "We still can't say with certainty whether that increase is already underway." This article was originally published in Live Science. You can read the original article here.
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3 days ago
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Why are so many men color-blind?
When you buy through links on our articles, Future and its syndication partners may earn a commission. An estimated 300 million people worldwide are color-blind. This typically means they can't distinguish certain shades of color, they struggle to tell how bright colors are or, more rarely, they can't see any colors at all. Color blindness doesn't affect males and females equally, though. According to Cleveland Clinic, the condition affects about 1 in 12 males, compared with 1 in 200 females. So why are so many more males color-blind than females? The answer comes down to the genetics governing the function of the human eye. People see colors using specialized cells in the backs of their eyeballs called cones. There are three types of cone cells, and each is tuned to be most sensitive to certain wavelengths of light. "There are three types of cones that see color: red, green and blue," Dr. Usiwoma Abugo, a clinical spokesperson for the American Academy of Ophthalmology, told Live Science in an email. "When one or more of these color cone cells are absent or not working properly, color blindness happens." The most common form of color blindness is red-green color blindness. This happens when people are born without the type of cones that are attuned to red and/or green light, or when those cones are in short supply or are inadvertently tuned to the wrong wavelength of light. If a person has problems with the blue-sensitive cones in their eyes, they will be blue-yellow color-blind, although this form of color blindness is less common than red-green. And if every type of cone is missing or substantially impaired, it can cause total color blindness, also called "complete color vision deficiency." But this form of color blindness is extremely rare, affecting fewer than 1 in 30,000 individuals. Related: New cells discovered in eye could help restore vision, scientists say Color blindness affects males more often than females because it's typically caused by a recessive genetic trait linked to the X chromosome. Recessive traits typically aren't expressed unless a person inherits two dysfunctional copies of a gene, meaning one copy from each parent. As such, a person with one functional copy of a cone-cell gene will usually have normal color vision. Most males carry one X and one Y chromosome in each cell; they inherit their single X chromosome from their mother and their Y from their father. The genes responsible for the light-sensitive proteins that constitute cone cells are located solely on the X chromosome, though, so that means males get one only copy of each gene — and just one chance for each to work properly. Thus, if that lone copy has a mutation, they'll likely be color-blind. Females, on the other hand, typically have two X chromosomes in each cell — one from each parent. So even if one X chromosome carries a faulty version of a cone-cell gene, the other often carries a working copy that can compensate. As a result, females are much less likely to develop color blindness, although they can still carry and pass on the faulty genes that underpin the condition. RELATED STORIES —Scientists hijacked the human eye to get it to see a brand-new color. It's called 'olo.' —'Super-vision' contact lenses let wearers see in the dark — even with their eyes closed —What animal has the best eyesight? "Women can experience color blindness, but it's quite rare and is usually caused by something other than genetics," Abugo said. Conditions such as inflammation of the optic nerve, cataracts and glaucoma can cause color blindness later in life, for example. For now, there aren't any widely available cures for color blindness, but some researchers are investigating experimental gene therapies that could give people with visual deficits tied to their genetics the chance to see the world in full color. In these animal experiments and early trials with humans, scientists use a harmless virus to deliver functional cone genes into the eyes. These therapies have so far been used to restore full color vision in animal models with the same genetic mutations that color-blind people have, and now, they're now being investigated in humans. This article is for informational purposes only and is not meant to offer medical advice.
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6 days ago
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This Stunning Meteor Shower Will Illuminate the Sky With Up to 100 Shooting Stars Per Hour
The Perseid meteor shower, caused by debris from Comet Swift-Tuttle, is currently active and will peak on August 12, offering up to 100 meteors per hour. Due to the full moon occurring just days before the peak, moonlight may hinder visibility of fainter meteors, making July 18 to 28 a better viewing window despite fewer meteors. Best viewed in the Northern Hemisphere, the Perseids are visible to the naked eye from dark locations during the pre-dawn hours, with meteors appearing to originate from the Perseus Fourth of July fireworks displays may be long gone, but nature is planning its own sparkling spectacular soon—the annual Perseid meteor shower. It's active right now and will last through late August, according to When viewing a meteor shower, you are seeing pieces of comet debris that heat up and burn as they enter the Earth's atmosphere, resulting in bright bursts of light streaking across the sky. According to NASA, the Perseids occur when Earth passes through the debris left behind by Comet Swift-Tuttle. The Perseid meteor shower is predicted to peak on August 12, when Earth travels through the densest and dustiest part of the comet debris. Per NASA, stargazers can typically see an average of 50 to 100 meteors per hour during this time. These meteors travel at an average of 37 miles per second, making it one of the best meteor showers of the year. Unfortunately, this year's peak takes place just three days after a full moon, so the moonlight may make it difficult to spot fainter meteors, with only the very brightest shooting stars visible. Because of this, you may want to observe the shower from July 18 to 28, when moonlight is at a minimum, suggests Live Science. The rate of shooting stars will be much lower, though. The Perseids are best viewed in the Northern Hemisphere during the pre-dawn hours, though it is possible to see them as early as 10 p.m. To see the light show, head out around 11 p.m. local time (or in the pre-dawn hours of August 11 and 12) to the darkest location you can find. You won't need a telescope or binoculars to see the celestial display, as it's visible to the naked eye. According to NASA, the Perseids' radiant (where the shooting stars appear to originate from) is in the Perseus constellation in the northeastern sky. Meteor showers are named after the constellation from which they appear to emanate. Though Perseus isn't the easiest to find, it follows the brighter, more prominent constellation Cassiopeia, which is known for its "W" or "M" shape that's formed by five stars. Read the original article on Martha Stewart
