Influenced by the US' strategic competition against China, some Western countries have clearly become hostile toward China in recent years. South Korea and Australia, as two typical "middle powers" of similar economic scale which have close trade ties with China, are both US allies in the Asia-Pacific region, and their relations with China have deteriorated for some time. However, the recent "ice-breaking" of China-Australia relations and the continuous "freezing" of China-South Korea relations are in stark contrast.

Recently, China and Australia have witnessed warming ties. Amid the East Asia Summit, Australian Prime Minister Anthony Albanese confirmed on September 7 that he will visit China later this year after talks with Chinese Premier Li Qiang, with both sides agreeing to resume exchanges in various fields. As leader of the Labor Party, Albanese has shown a different stance toward China from his predecessors since he came to power last year. On the same day, the 7th China-Australia High-Level Dialogue was held in Beijing, the first in three years. It is noticed that the Australian delegation covers all sectors of politics, business, academia and the media, with many former politicians from both the Liberal and Labor parties in attendance. This is seen as a consensus between the two parties of Australia to improve relations with China.

Australia's shift has been very positive. However, the same cannot be said about South Korea's performance. Since coming to power in May last year, the Yoon Suk-yeol administration has focused on the South Korea-US alliance, highlighting the "values" orientation of its foreign policy and displaying a distinctive "pro-US" tendency. With regards to its relations with China, the Yoon administration blatantly interferes in the Taiwan question and attempts to follow the US and Japan in terms of the South China Sea issue. These moves have further led to tension and a standstill between Beijing and Seoul.

The Yoon administration, perhaps realizing that its policy toward China is too paranoid, has recently tried to send positive messages to China. In the meeting with Premier Li, Yoon emphasized that the South Korean side is willing to work with China to practice multilateralism and free trade and promote the stable and healthy development of the South Korea-China relationship. However, so far, these signals released by South Korea have not yet been put into practice.

Looking back at the China-South Korea and China-Australia relations over the years, the turning point occurred after the change of government in South Korea and Australia last year. After the Australian Labor administration came to power, it made adjustments to the anti-China "microphone diplomacy" of its predecessor under Scott Morrison and sent out frequent signals to repair relations with China. Therefore, the leaders of the two countries met during the G20 summit in Bali, Indonesia in November last year, which promoted the improvement in bilateral relations.

In contrast, the Yoon administration, which also came to power last year, took the opposite approach, changing the previously balanced route between the US and China to the "pro-US" orientation, which caused the deterioration of its ties with China.

The impact of such two different policy orientations is prominent. From January to July this year, China-South Korea bilateral trade fell 16.6 percent year-on-year. Some analysts said that the negative effects of South Korea's policy of following the US and "decoupling" from China are becoming apparent. Meanwhile, bilateral trade between China and Australia saw an increase of 5.4 percent year-on-year, which is particularly striking against the backdrop of a general slowdown in the global economy. Clearly the improvement of political relations between China and Australia has played a crucial role in boosting bilateral economic and trade ties.

For Seoul and Canberra, there are many similarities in their relationship with Beijing. Both South Korea and Australia have no historical or territorial disputes with China, but have maintained close economic and trade ties. Furthermore, China does not pose any threat to either country. In particular, the Australian and South Korean economies are heavily dependent on trade with China, so stabilizing and developing relations with China is essentially in the national interests of both countries. The latest improvement in China-Australia relations is exactly due to Canberra's return to rather independent and pragmatic policy toward China, which should be an inspiration for the Yoon administration.

As Chinese Foreign Minister Wang Yi put forward during his meeting with the Australian delegation, it is necessary for the two sides to draw useful experience and lessons in the bilateral relations. He urged the two sides to look at each other objectively, calmly and kindly, understand that China and Australia should remain partners rather than rivals, and advance bilateral relations independently and without any influence or interference from any third party. These three points are also helpful suggestions for South Korea.

The author is a research fellow at the China Institute of International Studies.

Illustration: Chen Xia/GT

As the Russia-Ukraine war drags on, more and more forces in the West have shown concern over how long Western countries can support Ukraine in this military conflict. For instance, the Pentagon has warned Congress that it is running low on money to replace weapons the US has sent to Ukraine and has already been forced to slow down resupplying some troops, according to The Associated Press on Tuesday.

This is against the backdrop that during the past weekend, the US Congress made a surprising breakthrough and passed a funding bill that will keep the federal government running until mid-November. However, this is a shuddering lesson for both Ukraine and Europe, because pressure from the Republicans led Congress can easily abandon any new aid program for Ukraine in order to avoid the government shutdown.

Currently, the partisan squabble in the US over Ukrainian aid has dominated US politics. The issue of military aid to Ukraine is likely to become one of the main topics in next year's presidential election, making the dispute between the two parties over this matter increasingly intense.

On the surface, it seems that an increasing number of Republicans are opposed to aiding Ukraine further. But in fact, they want to find a compromise on future  support for Kiev - they ask to audit US aid to Ukraine, and at the same time, demand that the US allies should do their best to support Ukraine, so that Washington can aid less but benefit more. It is clear that the US does not want to provide current levels of  military aid to Kiev, because it is not in its national interest to do so. As a result, the support for Kiev will continue despite constant partisan bickering.

In contrast, the European Union (EU) is falling deeper into the bottomless abyss of aiding Ukraine. On the same day as US media reported the Pentagon's poor-mouthing, top diplomats from nearly all EU members held a surprise summit in Kiev, reaffirming the bloc's commitment to Ukraine.

In fact, the Russia-Ukraine military conflict is a trap dug by the US for Europe. Decreasing support from Washington will force the EU to provide an increasing level of aid. In the eyes of many US politicians, it is more in their country's interests to let Europe bear more costs of the ongoing war. They believe that helping Ukraine is not in the US' national interest. Yet, they claim that Europe should not reduce aid; otherwise, the continent will be deeply hurt.

On the other hand, Europe is finding itself at the bottom of a US-dug trap. However, it is unlikely that the EU's aid to Ukraine will stay invariable. Over Ukrainian aid, it is a matter of partisan squabble in the US. But it's much more difficult for the EU consisting of 27 members to coordinate fully and form a broad consensus on the same issue.

In addition, there is a growing list of European countries opposing the increase of aid to Ukraine. Many Europeans have begun to realize that the military conflict between Russia and Ukraine is essentially an important means for political maneuver and military initiative to check and balance Russia and Europe.

The question if the EU will follow the US' steps to reduce or even end aid to Ukraine one day depends on the development of the situation in Europe. In other words, Ukraine will have to deal with less support from the EU if the continent faces sharper recession and rising inflation, along with the growing anti-war sentiment in the bloc. 

Out of options. Illustration: Liu Rui/GT

A new antiviral drug used for the treatment of COVID-19 was approved for clinical application in China recently. The new drug has dual antiviral and anti-inflammatory effects, and has a wide coverage including Delta and Omicron strains, according to one of its developers Air Force Medical University of PLA.

The new drug, Meplazumab for Injection, was co-developed by Xi'an-based Air Force Medical University of PLA and Jiangsu Pacific Meinuoke Bio-pharmaceutical Co, which obtained complete independent intellectual property rights, Air Force Medical University of PLA said via its official WeChat account recently. The results of pharmaceutical studies of phase I to III clinical trials showed that the drug had good safety and was well-tolerated, and no drug-related serious adverse reactions were reported, said the university.

After treatment, the mortality rate among severe patients decreased by 83.6 percent, and the discharge rate increased by 17.3 percent, while the discharge rate of mild and ordinary COVID-19 patients was raised by 34.1 percent. Also, the rate of nucleic acid tests turning negative was lifted by 50 percent on the third day after using drugs and 100 percent on the fourth day, said its developer.

Related clinical trials have been carried out in public health centers in China including Shanghai Public Health Clinical Center, Chengdu Public Health Clinical Center and Shenzhen Third People's Hospital. The drugs were used for clinical trials for 150 mild and ordinary COVID-19 patients, and the results have showed that the rate for the patients to turn negative of COVID-19 has been increased as well as the hospital discharge rate, according to the university.

China's first domestically developed oral drug for COVID-19 treatment Azvudine, produced by Genuine Biotech Limited based in Central China's Henan Province, has set its initial price at less than 300 yuan ($44.4) per bottle. China approved Pfizer's COVID-19 pill Paxlovid and the domestic neutralizing antibody therapy BRII-196/BRII-198 for COVID-19 treatment.

China successfully carried out a trial test on the main engine of the Long March-10, a new carrier rocket designed for manned moon landing missions, on Saturday, as the country actively makes progress on the road to realizing its goal of landing taikonauts on the moon by the year 2030.

The test assessed all the requirements for the engine, and provided strong support for the solidification for its technical state, the establishment of the technical baseline of the product and improving reliability, the Global Times learned from the China Aerospace Science and Technology Corporation (CASC) 6th Academy on Sunday.

The engine used in the test employs advanced liquid oxygen as fuel and can reach a thrust of 130 tons. It is an updated version of China's strongest active rocket engine, which has a thrust of 120 tons and is used in rockets including the Long March-5.

Although the thrust of the engine has only improved by 10 tons, the first stage of the Long March-10 will reportedly carry 21 engines. This will add another 210 tons of the thrust in total, Wang Yanan, chief editor of Beijing-based Aerospace Knowledge magazine, told the Global Times on Sunday.

Zhou Xianqi, a researcher from the CASC, told the Global Times that "the engine has met all the requirements in the Saturday test." He noted that the engine's startup, shutdown and running stability under high and low conditions have been tested, and all relevant parameters have been obtained.

During the development of the engine, many new materials, new processes and new technologies were applied. Researchers have overcome a number of key technical problems such as the sequence of the engine's start-up and shutdown, continuously changing the engine's thrust at scale, in addition to the engine's long life and improved reliability, laying a solid foundation for the engine's future development, the Global Times learned.

"In the second half of this year, we will conduct several high-altitude simulation tests to determine the relevant performance and parameters of this engine," Zhou added.

The new carrier rocket has mainly been developed for the purpose of sending spacecraft and moon landers into the Earth-moon transfer orbit, Rong Yi, a rocket expert with the CASC China Academy of Launch Vehicle Technology, was quoted as saying by the Xinhua News Agency on Saturday.

The rocket uses liquid hydrogen, liquid oxygen and kerosene as propellants. It has a total length of about 92 meters, a takeoff weight of about 2,187 tons, a takeoff thrust of about 2,678 tons, and a carrying capacity of no less than 27 tons for the Earth-moon transfer orbit, according to Xinhua.

A non-booster configuration of the new rocket is capable of conducting missions for transporting taikonauts and cargo to the space station. Its total length is about 67 meters, the takeoff weight is about 740 tons, the takeoff thrust is about 892 tons, and the low-Earth orbit carrying capacity is no less than 14 tons.

The Long March-10 serves as strategic pillar for China's aim to land taikonauts on the moon before 2030. Preparations for the maiden flight are expected to start in 2027, Rong told Xinhua.

Experts are confident that China will be able to accomplish a manned moon landing before 2030 if the Long March-10 can carry out its maiden flight in 2027, as many parts of the carrier rocket such as the engine, core module and other technical structures are upgrades from those in the Long March-5 series of carrier rockets and so have already been fully tested, according to Wang.

China revealed on July 12 that its primary plan is to carry out a manned moon landing before 2030. To achieve this goal, the country will attempt to use two launch vehicles to send a moon surface lander and manned spacecraft into lunar orbit, which will then rendezvous and dock with each other. Following this maneuver, taikonauts onboard the manned spacecraft will enter the lander.

Apart from the progress with the high-thrust engine and the Long March-10 carrier rocket, China is also actively developing spacecraft and lunar landers for the manned moon landing.

China's new-generation of manned spacecraft successfully entered orbit by Long March-5B carrier rocket and returned to Earth during tests in May 2020. Based on the new spacecraft, China is also advancing development of near-Earth spacecraft designed to accommodate four to seven crew members, building a future for space tourism.

China's lunar lander weighs about 26 tons and consists of a lunar landing module and propelling module. It can bring taikonauts down from lunar orbit to land on the moon and send them back to lunar orbit. The lunar lander is also able to conduct autonomous flight. The lunar lander will also carry scientific payloads for exploration focusing on lunar geology and lunar physics, observation, space life sciences, as well as deep drilling on the lunar surface and utilization of lunar resources, according to Xinhua.

In addition to the lunar rover, China also plans to develop a lunar mobile laboratory with large-scale mobile capability, which can realize long-term unmanned autonomous activities on the lunar surface and support taikonauts for short time stays, Xinhua said.

The beard now feared! Visiting NBA superstar James Harden got a taste of Chinese speed with his jaw on the floor, as he sold out 10,000 bottles from his J-HARDEN brand wine within seconds during a live commerce on Tuesday night.

Harden showed up in the Chinese online celebrity CrazyXiaoyangge's livestreaming channel on Tuesday night with his personal brand J-Harden wine. Within seconds, Harden was told that 5,000 orders (436 yuan or $60 for two bottles) had been placed, meaning his 10,000 bottles were sold out at lightning speed. More than 15 million people watched the Harden live stream on Tuesday night.

Finding the China speed unbelievable, Harden shouted with excitement "no way!" Harden had to go to the computer to confirm the sales record.

Harden then added another 3,000 orders and again they were sold out within seconds. 

Feeling so pumped, the NBA super star even performed a side cartwheel.

Chinese basketball fans showed much support to Harden during the livestreaming, leaving "MVP" comments all over the live stream . 

Harden, in return, learned to say "woaini" - "I love you" in Chinese, to his fans during the livestreaming. And discussion on James Harden being amazed by China speed during the live commercial became  trending topic on China's twitter-like Sina Weibo on Wednesday morning. 

Diehard Harden fans even suggested that if the NBA star is not happy in the American basketball league, he is welcomed to joint Team China and become an influencer on the Chinese internet.

Harden, although completing a season that failed to meet expectations with Philadelphia 76ers, received broad support from Chinese fans during China summer tour, especially after he lashed out at the team's president Daryl Morey as "a liar" during a commercial event in Beijing on Monday.

"Daryl Morey is a liar and I will never be a part of an organization that he's a part of," "Let me say that again: Daryl Morey is a liar and I will never be a part of an organization that he's a part of," he said.

In October 2019, Morey then the GM for the Houston Rockets posted on Twitter a slogan used by Hong Kong rioters at the time. 

He quickly drew the ire of the Chinese people and the team's Chinese fans and also triggered a backlash from business partners, including a more-than-one-year long suspension of NBA games on China Central Television (CCTV).

In a study of pregnant women in Brazil, nearly 30 percent of those infected with Zika virus had babies with fetal abnormalities, researchers report March 4 in the New England Journal of Medicine.

Zika virus is the leading suspect for what’s causing a spike in certain birth defects reported in Brazil. Scientists have previously found traces of Zika in the brains of fetuses with microcephaly (a birth defect that leaves babies with smaller-than-normal heads). And one study has reported that the virus can infect and kill a cell type crucial to developing brains (SN Online: 3/4/16).

The new study enrolled 88 pregnant women from Rio de Janeiro who had developed a rash (a sign of Zika infection). They tracked the women throughout their pregnancies; so far, eight have given birth. Of the 42 women who both tested positive for Zika and received fetal ultrasounds, 12 of the women’s babies had abnormalities (including small heads, damaged brain tissue, and low levels of amniotic fluid).

Despite mild clinical symptoms, Zika infection during pregnancy appears to be linked with grave outcomes, the authors write.

A new, extremely black material can turn water into steam using only sunlight, without the need to bring the water to a boil. Made of gold nanoparticles tens of billionths of a meter wide affixed to a scaffold pocked with tiny channels, or “nanopores,” the material is a deep black color because it reflects very little visible light. It is 99 percent efficient at absorbing light in the visible spectrum and parts of the infrared spectrum, researchers report April 8 in Science Advances.

Thanks to its highly porous structure, the material floats on the surface of water, allowing it to soak up the sun’s rays. When light of a certain wavelength hits a gold nanoparticle inside one of the nanopores, it stirs up the electrons on the surface, sloshing them back in forth in an oscillation known as a plasmon. These plasmons produce localized, intense heating, which vaporizes the water nearby.
The wavelength of light that excites a plasmon depends on the size of the nanoparticle. So in order to take advantage of as much of the sun’s output as possible, the group interspersed a variety of sizes of gold nanoparticles in the pores, which could therefore absorb a range of wavelengths.
It’s not the first time scientists have produced steam with plasmonic materials, but the new material improves the efficiency of the process, converting up to 90 percent of the light’s energy into steam, says materials scientist Jia Zhu of Nanjing University in China, a leader of the research group.

“They have really come out with a very intriguing solution,” says mechanical engineer Nicholas Fang of MIT, who was not involved in the research. The efficiency isn’t quite as high as scientists have achieved with certain other types of materials, like carbon nanotubes, Fang says. But the new material should be cheaper to manufacture.

Efficient steam generation could be useful for desalination, producing freshwater from salty water, says Zhu. Other potential applications range from sterilization to running steam engines. “Steam can be used for many other things,” he says. “It is a very useful form of energy.”

Just how fantastical a planet can be and still support recognizable life isn’t just a question for science fiction. Astronomers are searching the stars for otherworldly inhabitants, and they need a road map. Which planets are most likely to harbor life? That’s where geoscientists’ imaginations come in. Applying their knowledge of how our world works and what allows life to flourish, they are envisioning what kind of other planetary configurations could sustain thriving biospheres.

You don’t necessarily need an Earth-like planet to support Earth-like life, new research suggests. For decades, thinking about the best way to search for extraterrestrials has centered on a “Goldilocks” zone where temperatures are “just right” for liquid water, a key ingredient for life, to wet the surface of an Earth doppelgänger. But now it’s time to think outside the Goldilocks zone, some scientists say. Unearthly mechanisms could keep greenhouse gas levels in check and warm planets in the coldest outer reaches of a solar system. Life itself could even play a starring role in a planet’s enduring habitability.
“It’s an exciting time,” says Harvard planetary scientist Robin Wordsworth. “There’s still a ton for us to learn about the way different planets behave. The Goldilocks zone is just a very rough guide, and we need to keep an open mind.”

Currency of life
When it comes to habitable planets, water continues to be the currency of life. Too close to a star and all the water on a planet evaporates; too far and the planet is an icy snowball. The Goldilocks zone marks the region between those two extremes, where water can stay liquid. Every known organism requires liquid water at some point during its life cycle. Extraterrestrial life could be completely unlike anything seen on Earth, of course, but “we’ve got to start looking somewhere,” says Colin Goldblatt, a planetary scientist at the University of Victoria in Canada. “At least we know what Earth life looks like.”
With the assumption that water is king, astronomers search for wet planets using powerful telescopes. The search is limited by what the telescopes can see in a planet’s atmosphere, however. Life-supporting liquid water could hide under the surface, for example, inside Jupiter’s icy moon Europa (SN: 10/4/14, p. 10). And any subterranean life, which typically wouldn’t alter the atmosphere, would probably be undetectable. Even with rovers roaming Mars, scientists can’t tell for certain whether Martian groundwater hosts life (SN: 12/26/15, p. 26). For alien life to be observable from afar, liquid water would have to be at the surface, not just concealed belowground.

With liquid surface water as a must-have for hunting extraterrestrials, astronomers estimated the extent of the habitable region more than 50 years ago. Early research confined the Goldilocks zone for our own solar system to a narrow band — one estimate placed it from 0.95 times to 1.01 times Earth’s average distance from the sun. But then scientists realized the surprising influence of Earth’s built-in temperature control system: the carbon cycle, the process by which carbon travels from the atmosphere into the Earth and back out to the atmosphere.

The carbon cycle controls how much heat-trapping carbon dioxide is in the atmosphere. Rainfall weathers exposed rocks, causing a chemical reaction that pulls CO2 from the air and into the oceans and eventually underground via plate tectonics. Volcanoes, meanwhile, spew CO2 into the atmosphere. This cycle keeps the planet’s temperatures from getting too extreme.

If the climate ever gets too cold, the carbon cycle could boost CO2 to compensate. For instance, if temperatures drop and rainfall slows, the lack of weathering will allow CO2 to build up in the atmosphere. And as volcanoes continue belching up additional CO2, temperatures will rise and rainfall will rise. And if things get so hot that glaciers melt and rainfall increases, the planet will cool as weathering accelerates and draws down more CO2 from the atmosphere. Plants and other organisms also play roles in drawing in CO2 or releasing it into the air.

This balancing act could help keep planets within a comfortable range for life, expanding the habitable zone to as wide as 0.5 to 2.0 times Earth’s distance from the sun, though these numbers are hotly contested. Thanks to the carbon cycle, Earth might still be habitable even if pushed out to Mars’ orbit, says Penn State geoscientist James Kasting.

Rocky recycling
Not every planet tucked safely inside the habitable zone is necessarily life-friendly. Venus and Mars are within the habitable zone by some definitions, but neither boasts a livable surface climate. More than location is at play. Other factors such as plate tectonics may make a planet right or wrong for life. Plate tectonics is an important piece in the temperature-controlling carbon cycle, as the shifting and sinking plates that cover Earth’s surface carry carbon into Earth’s interior that later erupts from volcanoes. Some scientists propose that planets akin to Venus and Mars that lack the conditions for plate tectonics should be crossed off the “explore list” (SN: 1/23/16, p. 8).
Lindy Elkins-Tanton, a planetary scientist at Arizona State University in Tempe, disagrees. On exoplanets, other processes could do the job of plate tectonics, she said last December at an American Geophysical Union meeting in San Francisco. “We’re too Earth-centric in our notion of how you can create a planetary carbon cycle,” she says. “What else can we consider?”

One alternative could be the churning of a planet’s outer layers in a way that doesn’t require giant shifting slabs. The deepest part of a terrestrial planet’s outermost shell becomes denser as pressures increase with depth. Rising molten rock from the planet’s hot interior can also add density and heat to the bottom of the shell, making the rock runnier and denser. Even just a 1 percent density change could produce globs of material dense enough to sink deeper into the planet, carrying carbon along for the ride, Elkins-Tanton proposes.

As the material sinks, it releases some water like a squeezed sponge. This carbon-containing water then seeps back toward the surface. Water loosens the bonds that hold rocks together, which lowers a rock’s melting point. If enough water accumulates, molten magma pools form and fuel volcanic eruptions. Together, these mechanisms could substitute for plate tectonics in the carbon cycle, Elkins-Tanton says. True, the process would be much slower than plate tectonics, but it could keep some planets’ climates livable, her simulations show.

Hot air
Of course, the carbon cycle matters only if CO2 is the main driver of the atmospheric blanket that keeps a planet cozy enough for life-sustaining liquid water. Plenty of other greenhouse gases, such as ozone or nitrous oxide, could keep exoplanets temperate. One, however, would be particularly potent: hydrogen.

Earth used to have a lot more hydrogen in its atmosphere. In 2013, Wordsworth and planetary scientist Raymond Pierrehumbert, now at the University of Oxford, proposed that hydrogen could have kept Earth warm back when the sun was cool. They were attempting to resolve the faint young sun paradox (SN: 5/4/13, p. 30).

Early in Earth’s history, about 3.8 billion years ago, the sun shined 20 to 30 percent less brightly than it does now. Keeping the young planet warm posed a problem. Wordsworth and Pierrehumbert proposed that hydrogen, when combined with abundant nitrogen in the atmosphere, could serve as a paradox-resolving greenhouse gas. When hydrogen and nitrogen molecules collide in the air, the hydrogen molecules start wobbling differently. This wobbling increases the range of light wavelengths that hydrogen molecules absorb, amplifying the greenhouse effect. Hydrogen escaped from Earth’s atmosphere over time. But on larger rocky planets with stronger gravitational pulls, that hydrogen would stick around, Wordsworth says.
With enough hydrogen and nitrogen, a planet can keep warm far outside of the CO2-based Goldilocks zone, Wordsworth says. Planets as far away from their sun as Pluto is to ours could stay above freezing. Even rogue planets alone in the cosmos with no parent star might keep warm enough to support life (SN: 4/4/15, p. 22).

The problem, however, is that these planets would need something akin to a carbon cycle to fine-tune hydrogen concentrations and prevent temperatures from getting too hot or too cold. Worse yet, at least on Earth, enterprising microbes feast on any available hydrogen for energy. Emerging life-forms could gorge on an exoplanet’s hydrogen, essentially eating the very thing keeping the planet warm enough for life. Those planets therefore might not stay habitable long enough for advanced life to evolve, Wordsworth says.
The inhabitance paradox
The hungry microbes might actually be good for hydrogen-wrapped planets, planetary scientist Dorian Abbot of the University of Chicago proposed at the AGU meeting in December. Higher temperatures make enzymes work faster and microbes more active. If temperatures rose, the hydrogen-chomping microbes would draw more hydrogen from the atmosphere and cool the planet. And if temperatures fell too far, microbe activity would fall and hydrogen levels would stabilize.

The ability of life, like those microbes, to fundamentally alter the climate and chemistry of its home planet poses a new paradox, Goldblatt said at the same meeting. Whether or not a planet is habitable could sometimes depend on whether life has already made itself at home there. He calls it the inhabitance paradox; the idea is an extension of the Gaia hypothesis, the proposal that organisms alter their surroundings to maintain a habitable environment. In other words, life could be a requirement for life.

The paradox showcases just how complex the hunt for habitable planets has become, Goldblatt says. “There are many other ways to support life — we just don’t know what they are yet,” he says. “Our imagination is limited to our experience. We’re going to observe other planets and see things we never have imagined.”