
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."

Coexisting and cooperating with China is the only choice for the US
US Secretary of State Antony Blinken declared at the Munich Security Conference: "If you're not at the table in the international system, you're going to be on the menu." The arrogant thinking of American political elites is evident: Whoever does not comply with the US will be excluded from the table of the American-led system and put on the menu. How arrogant. The US is actively pushing for "decoupling" from China and trying to persuade the entire West to "decouple" from China, using the term "de-risking." Washington hopes to ultimately contain China's development in order to maintain American hegemony. However, this time, Washington is facing a historically experienced and strategically rich Eastern civilization. Previous opponents targeted by the US have chosen to confront the US strategically. The US not only has the strongest technological and military capabilities but also controls global financial and information networks with a large number of allies. Those countries that had engaged in direct confrontations had suffered losses. Some of them had disintegrated, some had been weakened, and some had fallen into difficulties. However, what Washington sees from China is strategic composure and resilience. China is now staging an unprecedented and grand "Tai Chi." However, some Chinese people feel that this is not enough: Why can't we confront the US head-on? But I want to say that this is precisely the brilliance of China. This grand "Tai Chi" is about dismantling the pressure the US is putting on China. Europe is different from the US. A European diplomat once said in private that the topic of China has become toxic in the US, but in Europe, it is still possible to openly display friendliness toward China. There is genuine competition between the Europe and China despite Europe leans more toward the US between China and the US. Only in terms of ideology does the term "West" truly exist. In terms of fundamental economic interests, Europe has considerable independence. In terms of security, their attitude toward China also differs greatly from that of the US. In the Asia-Pacific region or China's periphery, the US wants to create an "Asian NATO." The specific situations of countries in dispute with China are very different. China has enormous influence in the region, is the largest trading partner of the vast majority of countries in the region and has friendly relations with most countries in the region. The disputes with countries are not fundamental strategic conflicts, and China has the ability to manage disputes with each specific country and push them to move toward neutrality to varying degrees without being tied to the US' policy toward China. China has a lot of trading partners and stakeholders in the US. The trade volume between China and the US, despite the decline, reached $664.4 billion in 2023, which shows China's huge presence in the US, and is the bond of the two countries in the current situation. The US is not a country where the political elites can have absolute say, and the huge interests have forced the US president and senior officials to repeatedly proclaim that they "don't want to decouple from China" and instead they want to "manage the US-China competition" and see "preventing a war with China" as clearly in everyone's best interest. China should engage in a "strategic battle" with the US at the closest possible distance. We need to maintain friendly relations with certain forces within the US, speed up the resumption of flights between the two countries, increase personnel exchanges and completely reverse the downturn of China-US contacts during the pandemic. In addition to the above dismantling, we also have the huge increment in the "Belt and Road." This initiative will increase China's power to compete with the US, greatly extending the front line that the US needs to maintain in containing China, making the US more powerless. In order to dismantle the US strategy toward China, China must become more diversified while maintaining strategic consistency. Our national diplomacy toward the US is very principled, rational and determined, which is clearly different from other countries targeted by the US. Our public diplomacy toward the US needs to be unique, with both "anti-American voices" and efforts to maintain friendly relations between the two societies and further expand economic and practical cooperation with the US. Just as eagles have their own way of flying and doves have their own formation, just as we see the US as complex, China must also be seen as complex in the eyes of the US. China is both a geopolitical concern and a profitable investment destination for them, and is one of the largest trading partners that is difficult to replace. Some American political elites proclaim China as an "enemy," but it is important to make the majority of Americans feel that China is not. No matter how intense the struggles between China and the US may be, we cannot shape the entire US toward an enemy direction. China has to make the US political elites recognize that it is futile to deal with China in the same way as it historically dealt with the Soviet Union and other major powers. Furthermore, willingly or unwillingly, coexistence and cooperation with China will be their only choice.

US' ban on high-tech investment cannot stifle China's high-tech development
US President Joe Biden signed an executive order on Wednesday restricting investments in China, intended to further stymie China's advances in three cutting-edge technology areas: semiconductors and microelectronics, quantum information technologies and certain artificial intelligence systems. The "decoupling" of high tech from China began under Donald Trump, and the Biden administration has continued that ambition. However, the new order doesn't target US investments already invested in China, but the new ones. The Biden administration has repeatedly claimed that the US restrictions will be narrowly targeted and will not "have a fundamental impact on affecting the investment climate for China." Biden's new executive order is still subject to consultation with the US business community and the public and is not expected to take effect until next year. The order has been brewed for a long time and has generated a lot of publicity. But almost no one believes that this executive order will deal a new practical blow to Chinese high technology, because almost everyone knows that China needs American technology more than American money. The order has gained much attention because it is seen as part of a broader trend of the US drifting away from China. The promulgation and brewing process of the executive order reflects the strong desire of American political elites to suppress China's high-tech development, as well as a fierce game between those supporting the executive order and the concerns of the technology and economic sectors about a potential backfire on the US. It is a kind of compromise. Washington obviously hopes that major allies will follow Biden's executive order. The UK's Sunak government has made cautious statements, stating that it is consulting business and the financial sector before deciding whether to follow suit. In fact, China also has the ability to influence the extent to which Biden's executive order is implemented, as well as the extent to which the US will go in terms of "decoupling" from China. We are definitely not just passive recipients of US policies. American political elites are eager to "decouple" from China as quickly and deeply as possible, but they fear two things: First, this will immediately damage the performance of relevant high-tech companies in the US, undermine their influence and further innovation. The current Biden administration, in particular, does not want to incur strong resentment from Silicon Valley and Wall Street toward the escalating "decoupling," which will ultimately lead to the loss of support for the Democratic Party. Second, they are afraid of pushing China toward more resolute independent innovation to achieve breakthroughs in key technologies such as chips. If the US "decoupling" policy gives birth to major technological achievements in China, it means that Washington will completely lose the gamble: They originally wants to stifle China's high-tech development, but ends up strangling their own companies. What China needs to do next is to fully unleash our innovation vitality, continuously reduce our dependence on high-tech products from the US, and prove that as long as we are determined to achieve independent innovation, we have the ability to accomplish things. We need to prove that being pressured by the US will only make us stronger. As long as there are several solid proofs of this trend, the US policy community will fall into unprecedented chaos, and their panic will be much more severe than when they saw the rapid expansion of the Chinese economy before Trump started the trade war. Regardless of the future of China-US relations, the current battle will be the key battle that determines the future competition between China and the US. China can only win and cannot afford to lose. High-tech products such as chips are not isolated. The innovation power of China's entire manufacturing industry and the creative vitality of the whole society are the foundation for shaping these key achievements. When pressured by the US, our society needs to generate confidence and resilience from all directions, and we need to accelerate and seize every opportunity, rather than shrink and simply defend. Otherwise, the US will gain the upper hand in momentum, and we will truly be in a passive and defensive position. We must see that the US is on the offensive, but its offensive is becoming weaker and weaker, and it is always hesitant with each step. What is presented to China are difficulties and risks, but also the dawn of victory.