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Beyond the aurorae: How solar flares spill out across the Solar System

The Sun is extremely active right now, blasting the Earth with the biggest solar storms in 20 years. This is what it is doing to the rest of the Solar System.

If you happened to look skywards on a few nights in May 2024, there was a good chance of seeing something spectacular. For those at relatively low latitudes, there was a rare chance to see the flickering red, pink, green glow of our planet's aurorae.

A powerful solar storm had sent bursts of charged particles barrelling towards Earth and, as they bounced around in our planet's atmosphere, they unleashed spectacular displays of the Northern and Southern Lights. The dazzling displays of aurora borealis were visible far further south than they might normally be – and far further north in the case of aurora australis thanks to the power of the geomagnetic storm, the strongest in two decades.

Although some people experienced only a faint, eerie glow, others were treated to a myriad of colour as far south as London in the UK and Ohio in the US. Reports even came in from just to the north of San Francisco, California.

But while this spike in activity from the Sun left many on Earth transfixed by the light display it produced, it has also had a profound effect elsewhere in the Solar System. As most of us wondered at the colours dancing across the night's sky, astronomers have been peering far beyond to see the strange ways such intense bursts of particles affect other planets and the space between them.

"The Sun can fire material outwards in any direction like a garden sprinkler," says Jim Wild, a professor of space physics at Lancaster University in the UK. "The effects are felt throughout the Solar System."

Our Sun is currently heading towards, or has already reached, its solar maximum – the point in an 11-year cycle where it is most active. This means the Sun produces more bursts of radiation and particles from solar flares and events known as coronal mass ejections (CMEs). If these are sprayed in our direction, they can supercharge the Earth's magnetic field, causing magnificent aurorae but also posing problems for satellites and power grids.

"Things really seem to be picking up right now," says Mathew Owens, a space physicist at the University of Reading in the UK. "I think we're about at solar maximum now, so we may see more of these kinds of storms in the next couple of years."

Around the Sun, multiple spacecraft are observing this increase in activity up close. One of those, the European Space Agency's (Esa) Solar Orbiter, has been studying the Sun since 2020 on an orbit that takes it within the path of Mercury. Currently the spacecraft is "on the far side of the Sun as seen from Earth", says Daniel Müller, project scientist for the Solar Orbiter mission at Esa in the Netherlands. "So we see everything that Earth doesn't see."

The storm that hit Earth in May originated from an active region of solar flares and sunspots, bursts of plasma and twisting magnetic fields on the Sun's surface, known as its photosphere. Solar Orbiter was able to see "several of the flares from this monster active region that rotated out of Earth's view", says Müller, bright flashes of light and darkened regions called sunspots on the Sun's surface.

One of the goals of Solar Orbiter is "to connect what's happening on the Sun to what's happening in the heliosphere," says Müller. The heliosphere is a vast bubble of plasma that envelops the Sun and the planets of the Solar System as it travels through interstellar space. What Müller and his colleagues hope to learn more about is where the solar wind – the constant stream of particles spilling out from the Sun across the Solar System – "blows into the interstellar medium", he says. "So we are particularly interested in anything energetic on the Sun that we can find back in the turbulence of the solar wind."

This particular cycle, cycle 25, appears to be "significantly more active than what people predicted", says Müller, with the relative sunspot number – an index used to measure the activity across the visible surface of the Sun – eclipsing what was seen as the peak of the previous solar cycle. The National Oceanic and Atmospheric Administration (Noaa) in the US had predicted a maximum monthly average of 124 sunspots a day in May, but the actual number was 170 on average, with one day exceeding 240, according to Müller.

But the exact cause of the Sun's 11-year-long cycle and its variabilities remains a bit of a mystery.

• Alien aurora: The strange displays that light up other worlds

• Why Einstein was wrong about black holes

• The Moon is slipping away from the Earth – and our days are getting longer

The effects of these changes in solar activity, however, extend far across the Solar System. Earth is not the only planet to be hit by solar storms as they billow across interplanetary space. Mercury, the closest planet to the Sun, has a much weaker magnetic field than Earth – about 100 times less – and lacks a substantial atmosphere. But solar activity can cause the surface of the planet to glow with X-rays as solar wind rains down. Venus also lacks a substantial magnetic field, but the planet does still create auroras as the solar wind interacts with the planet's ionosphere.

At Mars, the effect of solar activity is more obvious. Here, a Nasa spacecraft called Maven (Mars Atmosphere and Volatile Evolution) has been studying the planet's atmosphere from orbit since 2014. "We were on the declining side of solar cycle 24 [then]," says Shannon Curry, a planetary scientist at the University of Colorado, Boulder in the US and the lead on the mission. "We are now coming up on the peak of cycle 25, and this latest series of active regions has produced the strongest activity Maven has ever seen."

Between 14 and 20 May the spacecraft detected exceptionally powerful solar activity reaching Mars, including an X8.7 – solar flares are ranked B, C, M, and X in order from weakest to strongest. Results from the event have yet to be studied, but Curry noted that a previous X8.2 flare had resulted in "a dozen papers" published in scientific journals. Another flare on 20 May, later estimated to be an even bigger X12, hurled X-rays and gamma rays towards Mars before a subsequent coronal mass ejection launched a barrage of charged particles in the same direction.

Images beamed back from Nasa's Curiosity Rover on Mars revealed just now much energy struck the Martian surface. Streaks and dots caused by charged particles hitting the camera's sensors caused the images to "dance with snow", according to a press release from Nasa. Maven, meanwhile, captured glowing aurora as the particles hit the Mars' atmosphere, engulfing the entire planet in an ultraviolet glow.

The flares can cause the temperature of the Martian atmosphere to "dramatically increase," says Curry. "It can even double in the upper atmosphere. The atmosphere itself inflates. The entire atmosphere expands dozens of kilometres – exciting for scientists but detrimental for spacecraft, because when the atmosphere expands there's more drag on the spacecraft."

The expanding atmosphere can also cause degradation of the solar panels on spacecraft orbiting Mars from the increase in radiation. "The last two flares caused more degradation than what a third of a year would typically do," says Curry.

Mars, while it has lost most of its magnetic field, still has "crustal remnant magnetic fields, little bubbles all over the southern hemisphere", says Curry. During a solar event, charged particles can light those up and excite particles. "The entire day side lights up in what we call a diffuse aurora," says Curry. "The entire sky glows. This would most likely be visible to astronauts on the surface."

By the time solar storms reach further out into the solar system, they tend to have dissipated but can still have an impact on the planets they encounter. Jupiter, Saturn, Uranus, and Neptune all have aurorae that are in part driven by charged particles from the Sun interacting with their magnetic fields.

But one of the key effects of solar activity on interplanetary space that astronomers are eager to study is something called "slow solar wind", a more sluggish, but denser stream of charged particles and plasma from the Sun. Steph Yardley, a solar astronomer at Northumbria University in the UK, says solar wind is "generally classed about 500km/s (310 miles/s)", but slow wind falls below this. It also has a lower temperature and tends to be more volatile.

Recent work by Yardley and her colleagues, using data from Solar Orbiter, suggests that the Sun's atmosphere, its corona, plays a role in the speed of the solar wind. Regions where the magnetic field lines, the direction of the field and charged particles are "open" – stretching out into space without looping back – provide a highway for solar wind to reach high speeds. Closed loops over some active regions – where the magnetic field lines have no beginning and end – can occasionally snap, producing slow solar wind. The variability in the slow solar wind seems to be driven by the unpredictable flow of plasma inside the Sun, which makes the magnetic field particularly chaotic.

The X-class flares and coronal mass ejections seen in May transformed the interplanetary medium as they flung out material across the solar system. Solar Orbiter detected a huge spike in ions moving at thousands of kilometres per second immediately after the 20 May flare. Computers on board other spacecraft – the BepiColombo probe, which is currently on a seven-year journey to Mercury, and Mars Express, in orbit around the Red Planet – both saw a dramatic increase in the number of memory errors caused by the high energy solar particles hitting the memory cells.

The day after the coronal mass ejection, magnetometers on board the Solar Orbiter also saw large swings in the magnetic field around the spacecraft as a huge bubble of plasma made up of charged particles thrown out from by the event washed past it at 1,400km/s (870 miles/s).

Increased solar activity is a boon for scientists. "If you track the number of papers produced by solar physicists, you can almost see an 11-year cycle in there," says Owens. "We are all more scientifically productive when there's a lot of activity to study."

As the Sun continues into solar maximum, the Solar System will see more and more activity streaming from its surface. Yet while all the planets witness at least some of the activity, our planet bears the brunt more than most. "Earth is slightly unique in that space weather can have interesting effects on human technologies," says Wild. "There's an extra dimension here on Earth."

Perhaps one day those anthropogenic effects might be felt elsewhere, too. "If you're going to fly to Mars and you have a six-month flight through the interplanetary environment, you're going to potentially suck up a lot of space weather events," says Wild. "How you protect your astronauts is an interplanetary issue that we need to get our heads around."

"Pictures on the wall were falling," New Yorkers rattled by earthquake
An earthquake jolted New York City on Friday morning, followed by more than 10 aftershocks which shook New Jersey, sending tremors as far as Philadelphia to Boston and jolting buildings in Manhattan and throughout its five boroughs. The preliminary quake, measuring 4.8 magnitude, centered around Lebanon, New Jersey, approximately 60 kilometers from New York City, with a depth of about 5 kilometers. Following the earthquake, New York City mayor Eric Adams stated at a press conference that no injuries had been reported, but they would continue to monitor and inspect critical infrastructure. The densely populated New York City was caught off guard by the unusual event. Broadcaster CBS reported that New York had not experienced an earthquake of this magnitude since 1884. Residents in Brooklyn expressed their shock when experiencing tremors which shook the city. "At first, I thought it was just construction next door, but then I noticed the pictures on the wall had fallen," Jennifer Wu, a resident in New York, told the Global Times on Saturday. Video footage circulating online showed the Statue of Liberty and the New York City skyline trembling as the earthquake struck. An angle from directly above Lady Liberty caught Ellis Island shaking during the incident. "It is fine," New York's famous Empire State Building posted on social platform X after the earthquake. The United Nations headquarters located in New York was hosting a Security Council meeting on the Israeli-Palestinian issue, and diplomats present in the meeting felt the tremors, local media reported. According to the Weather Channel, residents in Baltimore, Philadelphia, New Jersey, Connecticut, Boston and other areas of the Northeast seaboard also reported shaking. Tremors lasting for several seconds were felt over 200 miles away near the Massachusetts-New Hampshire border. The New York mayor told the press that New Yorkers should go about their normal day, while the governor Kathy Hochul emphasized the seriousness of the situation. She initiated assessments for damage across the state and had discussions with New Jersey Governor Phil Murphy. The quake caused flight delays throughout the New York area, with temporary control measures put in place across New York's John F. Kennedy International Airport, Newark Liberty International Airport in Newark, New Jersey, and Baltimore-Washington's Thurgood Marshall International Airport, checking for damage to runways. Operations resumed around Friday noon, ABC reported.
It may be getting harder to leave your smart wearable for the sake of your health
The world's first portable electrocardiograph was an 85-pound backpack, and now a 10-gram patch attached to your chest can transmit electrocardiograms uninterrupted for two weeks. The Apple Watch, which is worn by an estimated 100 million people, can send a text message to alert people when their heartbeat is irregular. Wearable sensors on the arms, wrists and fingers can now report arrhythmias, blood sugar levels, blood oxygen and other health indicators. Medical journals have also proposed a more ambitious vision - wearable devices can monitor patients with chronic diseases, eliminating the need for frequent hospital visits. They can spot potential health problems before a stroke or diabetes develops. The forces of health technology and wearables are converging. Tech giants like Apple (AAPL) and Alphabet's (GOOGL) Google are adding health features to their products. Medical technologists like electrocardiogram patch maker iRhythm Technologies or blood sugar monitor makers DexCom (DXCM) and Abbott Laboratories (ABT) are taking their devices beyond the clinic. "In the sensor world, people started on the consumer side and wanted to get into health care," said Kevin Sayer, chief executive of Decon Medical. "In health care, we're trying to be more consumer oriented, and I think all of those things are sort of colliding." Early bets favored the tech giants, with every health-related announcement from Apple, Google or Samsung Electronics hitting medical tech stocks. But changing doctors' practices will also require sustained investment in clinical trials. Big tech companies have cut back on investments in health care. Now it seems that medical technologists will be at the vanguard of the digital health revolution - with smartwatches and smart rings bringing them more customers who need to be diagnosed. Blake Goodner, co-founder of Bridger Management, a hedge fund focused on health care, said: "A group of medtech companies focused on digital health are maturing and reaching a scale where they can not only be profitable but also make investments to compete with larger tech companies." Tech giants aren't getting out of the health business. Apple's smartwatch has an electronic heart rate sensor that generates a single-point electrocardiogram, a wrist temperature sensor, and an accelerometer that can detect violent falls. Hundreds of millions of people are wearing smartwatches with health features from Apple or its rivals Samsung and Garmin.
Insurers fret over militant attacks, AI hacks at Paris Olympics
LONDON, July 5 (Reuters) - Insurers are nervous that militant attacks or AI-generated fake images could derail the Paris Olympics, risking event cancellations and millions of dollars in claims. Insurers faced losses after the 2020 Tokyo Olympics were postponed for a year due to the COVID-19 pandemic. Since then, wars in Ukraine and Gaza and a spate of elections this year, including in France, have driven up fears of politically-motivated violence at high-profile global events. The Olympics take place in Paris from July 26-Aug 11 and the Paralympics from Aug 28-Sept 8. German insurer Allianz (ALVG.DE), opens new tab is insurance partner for the Games. Other insurers, such as the Lloyd's of London (SOLYD.UL) market, are also providing cover. "We are all aware of the geopolitical situation the world is in," said Eike Buergel, head of Allianz's Olympic and Paralympic programme. "We are convinced that the IOC (International Olympic Committee), Paris 2024 and the national organising committees, together with the French authorities, are taking the right measures when it comes to challenges on the ground."
Rotten eggs chemical detected on Jupiter-like alien planet
WASHINGTON, July 8 (Reuters) - The planet known as HD 189733b, discovered in 2005, already had a reputation as a rather extreme place, a scorching hot gas giant a bit larger than Jupiter that is a striking cobalt blue color and has molten glass rain that blows sideways in its fierce atmospheric winds. So how can you top that? Add hydrogen sulfide, the chemical compound behind the stench of rotten eggs. Researchers said on Monday new data from the James Webb Space Telescope is giving a fuller picture of HD 189733b, already among the most thoroughly studied exoplanets, as planets beyond our solar system are called. A trace amount of hydrogen sulfide was detected in its atmosphere, a first for any exoplanet. "Yes, the stinky smell would certainly add to its already infamous reputation. This is not a planet we humans want to visit, but a valuable target for furthering our understanding of planetary science," said astrophysicist Guangwei Fu of Johns Hopkins University in Baltimore, lead author of the study published in the journal Nature, opens new tab. It is a type called a "hot Jupiter" - gas giants similar to the largest planet in our solar system, only much hotter owing to their close proximity to their host stars. This planet orbits 170 times closer to its host star than Jupiter does to the sun. It completes one orbit every two days as opposed to the 12 years Jupiter takes for one orbit of the sun. In fact, its orbit is 13 times nearer to its host star than our innermost planet Mercury is to the sun, leaving the temperature on the side of the planet facing the star at about 1,700 degrees Fahrenheit (930 degrees Celsius). "They are quite rare," Fu said of hot Jupiters. "About less than one in 100 star systems have them." This planet is located 64 light-years from Earth, considered in our neighborhood within the Milky Way galaxy, in the constellation Vulpecula. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). "The close distance makes it bright and easy for detailed studies. For example, the hydrogen sulfide detection reported here would be much more challenging to make on other faraway planets," Fu said. The star it orbits is smaller and cooler than the sun, and only about a third as luminous. That star is part of a binary system, meaning it is gravitationally bound to another star. Webb, which became operational in 2022, observes a wider wavelength range than earlier space telescopes, allowing for more thorough examinations of exoplanet atmospheres.
Beyond the aurorae: How solar flares spill out across the Solar System
The Sun is extremely active right now, blasting the Earth with the biggest solar storms in 20 years. This is what it is doing to the rest of the Solar System. If you happened to look skywards on a few nights in May 2024, there was a good chance of seeing something spectacular. For those at relatively low latitudes, there was a rare chance to see the flickering red, pink, green glow of our planet's aurorae. A powerful solar storm had sent bursts of charged particles barrelling towards Earth and, as they bounced around in our planet's atmosphere, they unleashed spectacular displays of the Northern and Southern Lights. The dazzling displays of aurora borealis were visible far further south than they might normally be – and far further north in the case of aurora australis thanks to the power of the geomagnetic storm, the strongest in two decades. Although some people experienced only a faint, eerie glow, others were treated to a myriad of colour as far south as London in the UK and Ohio in the US. Reports even came in from just to the north of San Francisco, California. But while this spike in activity from the Sun left many on Earth transfixed by the light display it produced, it has also had a profound effect elsewhere in the Solar System. As most of us wondered at the colours dancing across the night's sky, astronomers have been peering far beyond to see the strange ways such intense bursts of particles affect other planets and the space between them. "The Sun can fire material outwards in any direction like a garden sprinkler," says Jim Wild, a professor of space physics at Lancaster University in the UK. "The effects are felt throughout the Solar System." Our Sun is currently heading towards, or has already reached, its solar maximum – the point in an 11-year cycle where it is most active. This means the Sun produces more bursts of radiation and particles from solar flares and events known as coronal mass ejections (CMEs). If these are sprayed in our direction, they can supercharge the Earth's magnetic field, causing magnificent aurorae but also posing problems for satellites and power grids. "Things really seem to be picking up right now," says Mathew Owens, a space physicist at the University of Reading in the UK. "I think we're about at solar maximum now, so we may see more of these kinds of storms in the next couple of years." Around the Sun, multiple spacecraft are observing this increase in activity up close. One of those, the European Space Agency's (Esa) Solar Orbiter, has been studying the Sun since 2020 on an orbit that takes it within the path of Mercury. Currently the spacecraft is "on the far side of the Sun as seen from Earth", says Daniel Müller, project scientist for the Solar Orbiter mission at Esa in the Netherlands. "So we see everything that Earth doesn't see." The storm that hit Earth in May originated from an active region of solar flares and sunspots, bursts of plasma and twisting magnetic fields on the Sun's surface, known as its photosphere. Solar Orbiter was able to see "several of the flares from this monster active region that rotated out of Earth's view", says Müller, bright flashes of light and darkened regions called sunspots on the Sun's surface. One of the goals of Solar Orbiter is "to connect what's happening on the Sun to what's happening in the heliosphere," says Müller. The heliosphere is a vast bubble of plasma that envelops the Sun and the planets of the Solar System as it travels through interstellar space. What Müller and his colleagues hope to learn more about is where the solar wind – the constant stream of particles spilling out from the Sun across the Solar System – "blows into the interstellar medium", he says. "So we are particularly interested in anything energetic on the Sun that we can find back in the turbulence of the solar wind." This particular cycle, cycle 25, appears to be "significantly more active than what people predicted", says Müller, with the relative sunspot number – an index used to measure the activity across the visible surface of the Sun – eclipsing what was seen as the peak of the previous solar cycle. The National Oceanic and Atmospheric Administration (Noaa) in the US had predicted a maximum monthly average of 124 sunspots a day in May, but the actual number was 170 on average, with one day exceeding 240, according to Müller. But the exact cause of the Sun's 11-year-long cycle and its variabilities remains a bit of a mystery. • Alien aurora: The strange displays that light up other worlds • Why Einstein was wrong about black holes • The Moon is slipping away from the Earth – and our days are getting longer The effects of these changes in solar activity, however, extend far across the Solar System. Earth is not the only planet to be hit by solar storms as they billow across interplanetary space. Mercury, the closest planet to the Sun, has a much weaker magnetic field than Earth – about 100 times less – and lacks a substantial atmosphere. But solar activity can cause the surface of the planet to glow with X-rays as solar wind rains down. Venus also lacks a substantial magnetic field, but the planet does still create auroras as the solar wind interacts with the planet's ionosphere. At Mars, the effect of solar activity is more obvious. Here, a Nasa spacecraft called Maven (Mars Atmosphere and Volatile Evolution) has been studying the planet's atmosphere from orbit since 2014. "We were on the declining side of solar cycle 24 [then]," says Shannon Curry, a planetary scientist at the University of Colorado, Boulder in the US and the lead on the mission. "We are now coming up on the peak of cycle 25, and this latest series of active regions has produced the strongest activity Maven has ever seen." Between 14 and 20 May the spacecraft detected exceptionally powerful solar activity reaching Mars, including an X8.7 – solar flares are ranked B, C, M, and X in order from weakest to strongest. Results from the event have yet to be studied, but Curry noted that a previous X8.2 flare had resulted in "a dozen papers" published in scientific journals. Another flare on 20 May, later estimated to be an even bigger X12, hurled X-rays and gamma rays towards Mars before a subsequent coronal mass ejection launched a barrage of charged particles in the same direction. Images beamed back from Nasa's Curiosity Rover on Mars revealed just now much energy struck the Martian surface. Streaks and dots caused by charged particles hitting the camera's sensors caused the images to "dance with snow", according to a press release from Nasa. Maven, meanwhile, captured glowing aurora as the particles hit the Mars' atmosphere, engulfing the entire planet in an ultraviolet glow. The flares can cause the temperature of the Martian atmosphere to "dramatically increase," says Curry. "It can even double in the upper atmosphere. The atmosphere itself inflates. The entire atmosphere expands dozens of kilometres – exciting for scientists but detrimental for spacecraft, because when the atmosphere expands there's more drag on the spacecraft." The expanding atmosphere can also cause degradation of the solar panels on spacecraft orbiting Mars from the increase in radiation. "The last two flares caused more degradation than what a third of a year would typically do," says Curry. Mars, while it has lost most of its magnetic field, still has "crustal remnant magnetic fields, little bubbles all over the southern hemisphere", says Curry. During a solar event, charged particles can light those up and excite particles. "The entire day side lights up in what we call a diffuse aurora," says Curry. "The entire sky glows. This would most likely be visible to astronauts on the surface." By the time solar storms reach further out into the solar system, they tend to have dissipated but can still have an impact on the planets they encounter. Jupiter, Saturn, Uranus, and Neptune all have aurorae that are in part driven by charged particles from the Sun interacting with their magnetic fields. But one of the key effects of solar activity on interplanetary space that astronomers are eager to study is something called "slow solar wind", a more sluggish, but denser stream of charged particles and plasma from the Sun. Steph Yardley, a solar astronomer at Northumbria University in the UK, says solar wind is "generally classed about 500km/s (310 miles/s)", but slow wind falls below this. It also has a lower temperature and tends to be more volatile. Recent work by Yardley and her colleagues, using data from Solar Orbiter, suggests that the Sun's atmosphere, its corona, plays a role in the speed of the solar wind. Regions where the magnetic field lines, the direction of the field and charged particles are "open" – stretching out into space without looping back – provide a highway for solar wind to reach high speeds. Closed loops over some active regions – where the magnetic field lines have no beginning and end – can occasionally snap, producing slow solar wind. The variability in the slow solar wind seems to be driven by the unpredictable flow of plasma inside the Sun, which makes the magnetic field particularly chaotic. The X-class flares and coronal mass ejections seen in May transformed the interplanetary medium as they flung out material across the solar system. Solar Orbiter detected a huge spike in ions moving at thousands of kilometres per second immediately after the 20 May flare. Computers on board other spacecraft – the BepiColombo probe, which is currently on a seven-year journey to Mercury, and Mars Express, in orbit around the Red Planet – both saw a dramatic increase in the number of memory errors caused by the high energy solar particles hitting the memory cells. The day after the coronal mass ejection, magnetometers on board the Solar Orbiter also saw large swings in the magnetic field around the spacecraft as a huge bubble of plasma made up of charged particles thrown out from by the event washed past it at 1,400km/s (870 miles/s). Increased solar activity is a boon for scientists. "If you track the number of papers produced by solar physicists, you can almost see an 11-year cycle in there," says Owens. "We are all more scientifically productive when there's a lot of activity to study." As the Sun continues into solar maximum, the Solar System will see more and more activity streaming from its surface. Yet while all the planets witness at least some of the activity, our planet bears the brunt more than most. "Earth is slightly unique in that space weather can have interesting effects on human technologies," says Wild. "There's an extra dimension here on Earth." Perhaps one day those anthropogenic effects might be felt elsewhere, too. "If you're going to fly to Mars and you have a six-month flight through the interplanetary environment, you're going to potentially suck up a lot of space weather events," says Wild. "How you protect your astronauts is an interplanetary issue that we need to get our heads around."