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Scientists are tracking a large gas planet experiencing quite a quandary as it orbits extremely close to a young star – a predicament never previously observed. This exoplanet, as planets beyond our solar system are called, orbits its star so tightly that it appears to trigger flares from the stellar surface – larger than any observed from the sun – reaching several million miles (km) into space that over time may strip much of this unlucky world’s atmosphere. The phenomenon appears to be caused by the planet’s interaction with the star’s magnetic field, according to the researchers. And this star is a kind known to flare, especially when young. “A young star of this type is an angry beast, especially if you’re sitting as close up as this planet does,” said Netherlands Institute for Radio Astronomy astrophysicist Ekaterina Ilin, lead author of the study published in the journal Nature. The star, called HIP 67522, is slightly more massive than the sun and is located about 407 light-years from Earth in the constellation Centaurus. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). This star and planet, as well as a second smaller gas planet also detected in this planetary system, are practically newborns. Whereas the sun and our solar system’s planets are roughly 4.5 billion years old, this star is about 17 million years old, with its planets slightly younger. The planet, named HIP 67522 b, has a diameter almost the size of Jupiter, our solar system’s largest planet, but with only 5% of Jupiter’s mass. That makes it one of the puffiest exoplanets known, with a consistency reminiscent of cotton candy (candy floss). It orbits five times closer to its star than our solar system’s innermost planet Mercury orbits the sun, needing only seven days to complete an orbit. A flare is an intense eruption of electromagnetic radiation emanating from the outermost part of a star’s atmosphere, called the corona. So how does HIP 67522 b elicit huge flares from the star? As it orbits, it apparently interacts with the star’s magnetic field – either through its own magnetic field or perhaps through the presence of conducting material such as iron in the planet’s composition. “We don’t know for sure what the mechanism is. We think it is plausible that the planet moves within the star’s magnetic field and whips up a wave that travels along magnetic field lines to the star. When the wave reaches the stellar corona, it triggers flares in large magnetic field loops that store energy, which is released by the wave,” Ilin said. “As it moves through the field like a boat on a lake, it creates waves in its wake,” Ilin added. “The flares these waves trigger when they crash into the star are a new phenomenon. This is important because it had never been observed before, especially at the intensity detected.” The researchers believe it is a specific type of wave called an Alfvén wave, named for 20th century Swedish physicist and Nobel Prize laureate Hannes Alfvén, that propagates due to the interaction of magnetic fields. The flares may heat up and inflate the planet’s atmosphere, which is dominated by hydrogen and helium. Being lashed by these flares could blast away lighter elements from the atmosphere and reduce the planet’s mass over perhaps hundreds of millions of years. “At that time, it will have lost most if not all the light elements, and become what’s called a sub-Neptune – a gas planet smaller than Neptune,” Ilin said, referring to the smallest of our solar system’s gas planets. The researchers used observations by two space telescopes: NASA’s TESS, short for Transiting Exoplanet Survey Satellite, and the European Space Agency’s CHEOPS, short for CHaracterising ExOPlanet Satellite. The plight of HIP 67522 b illustrates the many circumstances under which exoplanets exist. “It is certainly no sheltered youth for this planet. But I am not sad about it. I enjoy diversity in all things nature, and what this planet will eventually become – perhaps a sub-Neptune rich in heavy elements that did not evaporate – is no less fascinating than what we observe today.” Will Dunham, Reuters
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Several leading medical organizations on Monday filed a suit against the U.S. Department of Health and Human Services and its Secretary Robert F. Kennedy Jr., arguing that current policies on the COVID-19 vaccine pose an imminent threat to public health. The plaintiffs, including the American Academy of Pediatrics, American College of Physicians, American Public Health Association and Infectious Diseases Society of America, have asked the court to vacate Kennedy’s recent directive removing the COVID-19 vaccine from the Centers for Disease Control and Prevention’s childhood and pregnantwomen immunization schedules. Representatives for HHS did not immediately respond to a request for comment. Kennedy, a long-time vaccine skeptic whose department oversees the CDC, has been remaking the U.S. health system to align with President Donald Trump’s goal of dramatically shrinking the federal government. He signed a directive in May delisting the COVID-19 vaccine for healthy children and healthy pregnant women. The complainants alleged that such “baseless and uninformed policy” decisions place critical populations at “grave and immediate risk” of preventable illness, long-term harm, or death. Mrinalika Roy, Reuters
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Submerged in about 40 meters (44 yards) of water off Scotland’s coast, a turbine has been spinning for more than six years to harness the power of ocean tides for electricity a durability mark that demonstrates the technology’s commercial viability. Keeping a large, or grid-scale, turbine in place in the harsh sea environment that long is a record that helps pave the way for bigger tidal energy farms and makes it far more appealing to investors, according to the trade association Ocean Energy Europe. Tidal energy projects would be prohibitively expensive if the turbines had to be taken out of the water for maintenance every couple of years. Tidal energy technologies are still in the early days of their commercial development, but their potential for generating clean energy is big. According to the National Renewable Energy Laboratory, marine energy, a term researchers use to refer to power generated from tides, currents, waves or temperature changes, is the worlds largest untapped renewable energy resource. The MeyGen tidal energy project off the coast of Scotland has four turbines producing 1.5 megawatts each, enough electricity collectively to power up to 7,000 homes annually. On Thursday, the Swedish company SKF announced that its bearings and seals on one of the turbines had passed the 6 1/2-year mark without needing unplanned or disruptive maintenance. It has been working closely with the industry for a decade on design and testing. Achieving six years in the water with constant operations is a very significant milestone that bodes well for the future of tidal energy, said Rémi Gruet, CEO of Ocean Energy Europe. Scotland and the United Kingdom are global leaders in tidal energy. The MeyGen site, operated by SAE Renewables, has been sending electricity to the grid for about eight years. There are very few tidal energy projects generating electricity continuously. Most have been tests and demonstrations, said Andrea Copping, an expert in marine renewable energy development. Copping said there are still large hurdles to overcome before tidal energy can be adopted more widely, such as dealing with regulatory issues, potential environmental effects and conflicts with other ocean users. Still, the Scotland project seems to have addressed the question of whether the turbines can last in seawater, added Copping, a distinguished faculty fellow in the School of Marine and Environmental Affairs at the University of Washington. I think they have checked the boxes, she said. Because skeptics, and that includes investors of course and governments, said, How on Earth are you going to operate these things especially for any length of time in this very tough environment? And thats what I think they proved. It’s very hard to take what is essentially a wind turbine normally found on land and put it under water, said Fraser Johnson, operations and maintenance manager at MeyGen. The record-setting turbine should keep going for at least another year before it needs to come out of the water for maintenance, he added. The four turbines are in the Inner Sound of the Pentland Firth, a narrow channel between the Scottish mainland and Stroma Island known for strong tidal currents. Tidal energy systems need strong currents to make electricity efficiently. MeyGen plans to add 20 turbines in 2030 to produce more electricity, after needed upgrades to the electricity grid are finished. The site could eventually hold as many as 130 turbines that are more powerful than those at the site today. The MeyGen site is in the open water, while another type of tidal project involves creating a dam-like structure called a barrage across tidal waters. With four turbines, MeyGen is considered the largest tidal energy project of its kind worldwide, said Johnson. It’s a title we wish we didn’t have. We want more, we want others, he said. Unfortunately others are having difficulty achieving what MeyGen has achieved. But working with SKF moving forward, we’ll push the industry forward. ___ The Associated Press climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find APs standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org. Jennifer McDermott, Associated Press
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