The China Council for the Promotion of International Trade (CCPIT) has called on the US to respect the law of market economy and the principle of fair competition in a recent statement over Washington’s investment curbs targeting China, saying the move will jeopardize the normal business exchanges between the two countries and the security and stability of the global industrial supply chain.
US President Joe Biden signed an executive order on August 9, banning new US investment covering key technology sectors in China such as semiconductors and other microelectronics, quantum computers and certain artificial intelligence applications. Later in mid-August, the US Treasury Department provided an explanation of the specific legislative plans for the executive order and initiated a 45-day period for public comment, with the deadline for submitting comments arriving on September 28.
The China Chamber of International Commerce (CCOIC) has officially submitted comments on behalf of the Chinese business community to the US government, hoping that the US government will genuinely listen to rational voices and carefully consider the relevant rules, according to a CCPIT spokesperson through an official statement.
The US investment ban categorizes China as the only "country of concern" under this ban, designating the related industries as "specifically sensitive technological areas with significant national security implications." The regulations pertaining to restricted investment entities, restricted investment targets, and restricted transaction types are vague and overly broad, the spokesperson said.
The investment oversight applies “indiscriminately” to both civilian and military purposes, employing a one-size-fits-all approach, the spokesperson claimed, noting that this approach not only increases transaction risks and compliance costs but also introduces significant uncertainty. Furthermore, it will disrupt the industry chains that heavily rely on global division of labor and cooperation.
China is an indispensable part of the global industry chains in semiconductors, artificial intelligence, and quantum information technology. The restrictions will harm US companies in international competition, hinder technological progress, and ultimately undermine US interests, the spokesperson said.
The Chinese business community believes that open and free market access and equal and benign competition are the cornerstones of economic development. A free, fair international economic order and stable global division of labor and cooperation are in the common interest of the global business community，the trade body noted.
Win-win cooperation is the shared vision of the Chinese and American industrial sectors. The Chinese community is willing to strengthen exchanges and collaborate on development with industries from various countries, including the US, the spokesperson said.
In early August, the Chinese Foreign Ministry blasted the US' investment restrictions as "economic coercion" and "tech bullying," urging Washington to immediately withdraw its wrong decision while vowing to firmly safeguard the country's rights and interests.
China deplores and firmly rejects the US' investment restrictions targeting a number of high-tech industries in China and has lodged stern representations with the US side, the ministry said.
China's eight-day Mid-Autumn Festival and National Day holidays wrapped up on Friday, with the number of domestic trips and tourism revenue seeing robust growth and exceeding that of 2019, underscoring the robust recovery of the world's second-largest economy.
The bustling scenes seen across the country during the Golden Week holidays offered the latest sign of strong vitality in China's consumption, a major economic growth driver, and the vast potential of China's steady economic recovery, in stark contrast to the dire predictions made by Western media and politicians, analysts said.
While downward pressure remains, China's economy will continue to rebound in the rest of the year and could make a full recovery at the end of 2023, thanks to robust recovery in consumption and other areas and a range of policy measures taken to boost growth, analysts noted.
Bustling tourism
A total of 826 million domestic passenger trips were made in China during the eight-day Mid-Autumn Festival and National Day holidays, a year-on-year increase of 71.3 percent and up 4.1 percent from 2019. Holiday tourism generated 753.43 billion yuan ($104.68 billion), up 129.5 percent year-on-year and 1.5 percent increase from 2019, official data from the Ministry of Culture and Tourism showed on Friday.
Some 59.89 million trips were expected to be made on Friday during the return peak, a year-on-year increase of 58.4 percent, data from the Ministry of Transport showed on Friday. Among them, a total of 18.8 million passengers will travel via the railway with 12,571 trains to be operated, according to China Railway.
Domestic consumption experienced a strong pickup during the holidays, showing the best performance since 2019. For instance, the average daily consumption scale of service retail jumped by 153 percent compared with the same period of 2019, while the consumption scale for dine-in surged by 254 percent, according to data from China's e-commerce platform Meituan.
Multiple provincial-level regions rolled out their tourism reports for the holidays on Friday and Thursday, which returned to or even exceeded the 2019 level.
Shanghai welcomed a total of 21.30 million tourists for the holidays with transactions related to tourism recording a year-on-year increase of 29.7 percent to 29.24 billion yuan, official data showed on Friday.
The Inner Mongolia Autonomous Region received a total of 14.53 million domestic tourists in the first five days of the holidays, a yearly increase of 5.38 times and 1.29 times more than the same period in 2019, thepaper.cn reported on Thursday. The region generated a total of 9.93 billion yuan in tourism revenue, a year-on-year increase of 6.31 times and 1.12 times increase compared with 2019.
Chinese tourists were able to experience the holidays in diverse forms, from touring domestic and international scenic spots and enjoying leisure time in third- and fourth-tier cities to becoming involved in emerging experiences such as cultural and tourism integration projects, night markets, and musicals, according to reports from Chinese travel agencies.
Flight bookings for top domestic destinations during the holidays surged by nearly five times compared to before the COVID-19 pandemic, with bookings for flights departing on September 29 - the first day of the holidays - hitting a record high on Chinese online travel agency platform Qunar, the company told the Global Times on Friday. Bookings for domestic hotels in popular destinations doubled compared with the pre-COVID period. The top destinations included Beijing, Chengdu, Chongqing, Shanghai and other cities.
In addition to visiting well-known cities and metropolises, some Chinese travelers also opted to enjoy the nation's rich cultural heritage and breathtaking natural scenery.
A female traveler surnamed Zhao from Southwest China's Chongqing visited the Bingling Temple Grottoes in Northwest China's Gansu Province -a world cultural heritage with a history stretching back more than 1,600 years. Zhao told the Global Times on Friday that she also encountered some foreign visitors during her visit.
Meanwhile, the ongoing 19th Asian Games in Hangzhou, East China's Zhejiang Province, sparked a consumption craze in sports and related fields throughout the holidays. The order volume for service consumption within the province exceeded 195 percent this year compared with 2019, while the dine-in order volume in Hangzhou increased by 443 percent and orders related to sports and fitness increased by 762 percent, per media reports.
At the same time, outbound tourism witnessed a strong rebound for the recently passed holidays. Orders for overseas travel on Chinese online tourism platform Ctrip.com increased by more than eight times year-on-year, according to a report sent to the Global Times on Friday. Meanwhile, bookings for international flights for the holidays on Fliggy reached a peak within the year.
The boom in tourism also spurred a consumption craze. In the first seven days of the holidays, sales of key monitored retail and dining enterprises increased by 9 percent year-on-year, while the major passenger flow in key commercial areas in 36 cities increased by 164 percent year-on-year, data from the Ministry of Commerce showed on Friday. The domestic box office also topped 2.5 billion yuan, a yearly increase of 70 percent.
Experts attributed the rebound in consumption to China's steady economic recovery and effective macroeconomic stimulus policies, showing the nation's strong resilience and huge potential in consumption, which will also play a vital role in bolstering economic growth in the fourth quarter.
Boosting GDP growth
China's economic performance outperformed 2019 in some aspects after nearly one year of post-epidemic growth, shown by the consumption rebound for the holidays and gradual recovery in trade along with other indicators, Cao Heping, an economist at Peking University, told the Global Times on Friday, expecting a full recovery by the end of 2023 or at the latest by February next year.
China's official manufacturing purchasing managers' index for September came in at 50.2, its first time in positive territory since April and after a consecutive increase over the last four months, the National Bureau of Statistics announced on September 30.
The consumption boom reflected the strong resilience and driving force of the spending power of Chinese residents, Zhang Yi, CEO of iiMedia Research Institute, told the Global Times on Friday.
Cong Yi, a professor at the Tianjin University of Finance and Economics, echoed Zhang's view and added that the targeted policy measures had further noticeable effects during the Golden Week, stressing the importance of continuing to implement the policies moving froward.
Cong told the Global Times on Friday that the consumption rebound during the holidays reflected China's huge consumption potential while also serving as a significant factor to further shore up market confidence and bolster domestic demand.
This confidence will play a vital role in promoting continuous economic growth while also elevating supply, Cong noted.
Zhang expected the consumption momentum to become an indispensable engine for advancing the economy, as the fourth quarter is also a peak season for domestic consumption, with major consumption events like the Double 11 online shopping festival.
In response to the bearish outlook on the Chinese economy painted by some Western media outlets and politicians, experts said China's consumer market is showing strong recovery and growth signs despite downward pressure with its strong market potential, resilience and confidence.
Cong noted that China maintains its market confidence as the world's second-largest consumption market, especially amid the process of rapid structural upgrading. He also stressed the importance of stepping up efforts in sectors such as infrastructure investment and support for the private economy to ignite market dynamics.
China's economic development should be the least worrying one during the global economic recovery process, Cong said.
Tianjin University's neuroscience team has made a groundbreaking achievement by launching a high-speed brain-computer interface (BCI) with 216 targets during the 7th World Intelligence Congress 2023.
This cutting-edge device enables users to type at impressive speeds using their thoughts while wearing a compact BCI device and interacting with a virtual keyboard featuring 216 keys. The system also incorporates commonly used syllables in both Chinese and English spelling, offering seamless one-click switching between Chinese and English input methods, Global Times learned from the team.
BCI establishes a "dialogue" between the brain's electrical activity and an external device. It is categorized into invasive and noninvasive types, with the noninvasive variant, based on electroencephalography (EEG) signals, being safer, more convenient, efficient, and holding tremendous potential for commercial and industrial applications, according to the team.
The number of targets and commands is a key indicator of how well BCIs can decode the brain's intentions, Xu Minpeng, a professor from the neuroscience team at Tianjin University, told the Global Times.
Tianjin University's team has gained global prominence by developing the first high-speed BCI with over 200 targets.
At present, the team has built a domestic full-chain noninvasive BCI technology including chip, electrode, algorithm and system. Three core indicators, the EEG recognition accuracy, the number of targets and information transmission rate have reached the highest international level, according to the team.
Some towns in Yancheng, East China's Jiangsu Province, were hit by a tornado on Sunday afternoon. The tornado took two lives and injured 15 people, according to the local authorities.
The tornado hit Yancheng at around 4:15 pm Sunday, in some towns in Dafeng district, Yancheng, under the influence of strong convective weather. The tornado was identified by experts as EF2 level (medium intensity), China Central Television (CCTV) reported Sunday.
The wind speed of a EF2-level tornado is estimated at 178 to 217 km per hour and usually causes a considerable damage. Under a EF2-level tornado, whole roofs ripped off frame houses, interiors of frame homes damaged, and small, medium, and large trees uprooted. Weak structures such as barns, mobile homes, sheds, and outhouses have been completely destroyed. Cars were lifted off the ground.
According to local authorities, two deaths and 15 injuries were reported from the disaster. All of the injured have been sent to hospital for treatment and none of the injuries are life-threatening.
According to preliminary verification, 283 agricultural houses and 32 vegetable greenhouses have been damaged. The damage is being further verified, CCTV reported.
All the affected people have now been properly relocated, while post-disaster recovery and reconstruction work is being carried out in an orderly manner, according to CCTV.
The Senj Wind Farm, a project of the Belt and Road Initiative (BRI), is an example of the mutually beneficial and win-win cooperation between Croatia and China, said Luci Veljacic, manager of the Grupa Company in southern Croatia, in a recent interview with Xinhua.
"For me and my company it was a great honor to be part of the Senj Wind Farm project," Veljacic said, adding that in July 2019, the Grupa Company was offered a contract for supervision and implementation of safety and health protection, fire protection and environmental protection during construction of the Senj Wind Farm project.
Despite numerous unfavourable conditions, including the extremely complex mountainous terrains, the COVID-19 pandemic, snow, strong winds and thunderstorms during the construction process, the Senj Wind Farm, undertaken by China's Norinco International Cooperation Ltd. (Norinco International), was completed on schedule and "without any worker injuries, deaths or incidents," Veljacic noted.
"During the construction, all legal regulations of Croatia and the European Union (EU) and all safety measures were observed to the maximum," Veljacic said.
The Grupa Company is one of the more than 70 contractors from across Croatia participating in the construction, and among the daily turnover of about 300 workers during the construction, more than half of them were from Croatia, Veljacic said, adding that most Croatian workers were from the local Lika-Senj County.
Moreover, participation in the project has made many Croatian companies gain extensive professional experience, which will certainly make them more competitive in the EU market, not just in Croatia, Veljacic said.
Veljacic hailed the "exceptional" cooperation with the Chinese side during the construction process.
"We had an exceptional cooperation, both professional and friendly, with all Chinese companies and workers at the Senj Wind Farm project," Veljacic said, noting that in spite of the language barrier, "we successfully communicated, negotiated, solved daily problems and performed work safely."
In addition, "We also found time to socialize during the project, getting to know the cultures of the two countries ... we talked about history, music, education, customs and the like," Veljacic added.
Veljacic was deeply impressed by the hard work and expertise of the Chinese workers during the construction process.
"During this project, Chinese workers performed the most demanding work and showed exceptional expertise, professionalism, endurance and technological progress," she said, adding that she and her company colleagues also received a lot of help from Chinese engineers who "were always ready to help with their professional knowledge and experience."
The Senj Wind Farm, located on the Adriatic coast of western Croatia and inaugurated in December 2021, produces about 530 million kilowatt-hours (kWh) of green electricity each year and reduces Croatia's carbon dioxide emissions by about 460,000 tonnes per year.
In the eyes of Veljacic, the Senj Wind Farm is a project valuable and important not only for the Lika-Senj County but also for the whole Croatia, as it can significantly contribute to the total annual production of electricity from clean and renewable sources, reduce electricity imports and further promote low-carbon development.
"With this project, Norinco International has become one of the largest investors in green energy and the green economy in Croatia ... The example of the Senj Wind Farm project, the joint successful cooperation of Chinese and Croatian workers and companies will certainly be further developed," Veljacic said.
Most people don’t live close to a coral reef. If we want to visit one, we have to travel far, to the tropical waters that are home to these beautiful and diverse ecosystems. But, it turns out, most coral reefs aren’t that far from people. And it’s those really accessible reefs that we should be worrying about, a new study argues.
Eva Maire of the University of Montpellier in France and colleagues started by breaking up all of the world’s coral reefs into 1-kilometer-square cells. They then calculated how much travel time sat between each of those cells and the nearest human settlement, doing their best to account for whether a person would have to use a boat, a road or a meager track to reach the reef. Fifty-eight percent of the cells are less than 30 minutes from people, the group reports February 15 in Ecology Letters. Most of those reefs can be found in the Caribbean, the Coral Triangle off Southeast Asia, the Western Indian Ocean and around islands in the Pacific. Others, such as those in the Coral Sea or the northwest Hawaiian Islands, are largely inaccessible, requiring 12 hours or more to reach — too far for a quick fishing jaunt.
Being close to people means that a reef and its resources can be more easily accessed and exploited. Proximity to a market — a source of income for fishermen with easy access to a rich catch — may make that even easier. The researchers found that a quarter of the reefs were within four hours of a major market, and nearly a third were more than 12 hours away. And how close a reef sat to a market appears to matter when it comes to the amount of fish swimming on the reef — those that are closer have lower amounts of fish, the team calculated.
Then the group looked at the pattern of protection for reefs. Many reefs are in marine protected areas that have been set up to limit exploitation. But the reefs most likely to be in a protected area are those that are far from people. An isolated coral reef is more than twice as likely to be protected than average.
The pattern is easy to explain. To set up a protected area, a government has to get everyone who is using that swath of ocean — for fishing, recreation, tourism or anything else — on board with the restrictions that will be placed on usage. And it’s a lot easier to do that with remote patches that not many people are using.
The problem with this, Maire and her colleagues note, is that it means that we may be protecting areas of the ocean that don’t really need protection. And it’s possible that the global goal of protecting 10 percent of the ocean by 2020 “can be met without actually reducing human impacts on the seascape,” they write.
There needs to be more work analyzing the pattern of marine protected areas before any such conclusion can be drawn. And there’s also something to be said for protecting coral reefs now, before they’re totally exploited. Corals already face an uphill battle for survival, given the threats of climate change and ocean acidification. Setting some reefs aside before fishermen and others can do damage doesn’t seem like a bad idea.
Resistance may soon be futile. With machine implants worthy of a Star Trek villain, a new breed of beetle takes walking instructions from its human overlords.
Hirotaka Sato and his colleagues at Nanyang Technological University in Singapore inserted electrodes into flower beetles (Mecynorrhina torquata) to stimulate specific leg muscle groups. By altering the order of electrical zap sequences, the team was able to control a beetle’s gait. Changing the duration of the electrical signals also altered the insects’ speed and step length, Sato and colleagues report March 30 in the Journal of the Royal Society Interface.
Scientists have already made cyborg insects that can fly, scuttle, and crawl, but controlling things like speed could allow biobots to do more complex tasks. Cyborg beetles and other insects provide a more energy efficient and easier-to-assemble alternative to plain old robots and double as a means to study insect locomotion, the researchers argue.
Dome effect dōm ih-fekt n. Airborne black carbon, also called soot, can cause the dome effect by warming the atmosphere’s top layer and blocking sunlight that would otherwise warm the surface air. The reduced temperature difference between the two layers lowers the boundary between them. This effect traps pollution around major cities, worsening air quality, new research suggests.
Researchers observed the dome effect around several of China’s megacities in December 2013. The compressed near-surface layer of the atmosphere led to thick hazes of pollution, the researchers report online March 16 in Geophysical Research Letters. Reducing local black carbon emissions from industry, biofuel burning, diesel vehicles and coal burning would quickly improve air quality around many megacities, the researchers propose.
Raging wildfires could burn away efforts to reduce Arctic-damaging soot emissions. Soot produced by burning fossil fuels and plants, also called black carbon, can cause respiratory diseases and greenhouse warming, and can accelerate the melting of ice.
Rising temperatures and changing weather patterns will shift where and how fiercely wildfires burn and spew soot, new simulations show. Outside of the tropics, fire seasons will last on average one to three months longer during the 2090s than they do currently, researchers report online April 8 in the Journal of Geophysical Research: Atmospheres. Soot emissions from wildfires will as much as double in regions that border the Arctic and counteract projected reductions in soot from human activities, the researchers predict. “Humankind would do well to proactively develop adequate land and fire management strategies to have at least some control on future wildfire emissions,” says study coauthor Andreas Veira, an earth system scientist at the Max Planck Institute for Meteorology in Hamburg.
Predicting the future of fires is difficult because many factors — from weather to vegetation — influence wildfires. Veira and colleagues strung together three different computer simulations that projected the impact of climate change on wildfires (SN Online: 7/15/15). The first predicted future changes in global vegetation, which fed into the second, a wildfire simulation called SPITFIRE. Finally, the researchers plugged their predicted fires into a climate simulation.
If carbon emissions aren’t cut, overall soot emissions from wildfires will stay fairly steady but shift in location. Outside of the tropics, wildfire soot emissions will increase 49 percent by the end of the century as fire seasons get longer, the researchers predict. In the tropics, changing land usage and fewer human-caused ignitions due to urbanization will help decrease emissions there by 37 percent.
A northward shift in wildfires will push more soot emissions toward the Arctic, the researchers warn. Fallen soot darkens ice and snow, accelerating melting (SN: 10/5/13, p. 26). A 2009 study estimated that soot was responsible for more than a third of Arctic warming between 1976 and 2007. The new simulations show that about 53 percent more soot will fall on the Arctic at the end of the century, even if humans cut their own soot emissions in half.
Many factors that could influence future wildfires remain uncertain, says atmospheric scientist Shane Murphy of the University of Wyoming in Laramie. “We shouldn’t take the absolute numbers to mean too much, just to inform us that there’s the potential for severe consequences.”
In a 1967 episode of Star Trek, Captain Kirk and crew investigated the mysterious murders of miners on the planet Janus VI. The killer, it turned out, was a rock monster called the Horta. But the Enterprise’s sensors hadn’t registered any signs of life in the creature. The Horta was a silicon-based life-form, rather than carbon-based like living things on Earth.
Still, it didn’t take long to determine that the Horta was alive. The first clue was that it skittered about. Spock closed the case with a mind meld, learning that the creature was the last of its kind, protecting its throng of eggs. But recognizing life on different worlds isn’t likely to be this simple, especially if the recipe for life elsewhere doesn’t use familiar ingredients. There may even be things alive on Earth that have been overlooked because they don’t fit standard definitions of life, some scientists suspect. Astrobiologists need some ground rules — with some built-in wiggle room — for when they can confidently declare, “It’s alive!” Among the researchers working out those rules is theoretical physicist Christoph Adami, who watches his own version of silicon-based life grow inside a computer at Michigan State University in East Lansing. “It’s easy when it’s easy,” Adami says. “If you find something walking around and waving at you, it won’t be that hard to figure out that you’ve found life.” But chances are, the first aliens that humans encounter won’t be little green men. They will probably be tiny microbes of one color or another — or perhaps no color at all.
By definition Trying to figure out how to recognize those alien microbes, especially if they are very strange, has led scientists to propose some basic criteria for distinguishing living from nonliving things. Many researchers insist that features such as active metabolism, reproduction and Darwinian evolution are de rigueur for any life, including extraterrestrials. Others add the requirement that life must have cells big enough to contain protein-building machines called ribosomes.
But such definitions can be overly restrictive. A list of specific criteria for life may give scientists tunnel vision, blinding them to the diversity of living things in the universe, especially in extreme environments, says philosopher of science Carol Cleland of the University of Colorado Boulder. Narrow definitions will “act as blinkers if you run into a form of life that’s very different.”
Some scientists, for instance, say viruses aren’t alive because they rely on their host cells to reproduce. But Adami disagrees. “There’s no doubt in my mind that biochemical viruses are alive,” he says. “They don’t carry with them everything they need to survive, but neither do we.” What’s important, Adami says, is that viruses transmit genetic information from one generation to another. Life, he says, is information that replicates. Darwinian evolution should be off the table, too, Cleland says. Humans probably won’t be able to tell at a quick glance whether something is evolving, anyway. “Evolvability is hard to detect,” she says, “because you’ve got a snapshot and you don’t have time to hang around and watch it evolve.”
Cell size restrictions may also squeeze minuscule microbes out of consideration as aliens. But a cell too tiny to contain ribosomes may still be big enough if it uses RNA instead of proteins to carry out biochemical reactions, says Steven Benner, an astrobiologist at the Foundation for Applied Molecular Evolution in Alachua, Fla. Cells are thought necessary because they separate one organism from another. But layers of clay could provide the needed separation, Adami suggests. Cleland postulates that life could even exist as networks of chemical reactions that don’t require separation at all.
Such fantastical thinking can loosen the grip of rigid criteria limiting scientists’ ability to recognize alien life when they see it. But they will still need to figure out where to look. Up close and personal With the discovery in recent years of more than a thousand exoplanets far beyond the solar system, the odds favoring the existence of extraterrestrial life in the cosmos are better than ever. But even the most powerful telescopes can’t detect microscopic organisms directly. Chances of finding microbial life are much higher if scientists can reach out and touch it, which means looking within our solar system, says mineralogist Robert Hazen, of the Carnegie Institution for Science in Washington, D.C.
“You really need a rover down on its hands and knees analyzing chemicals,” Hazen says. Rovers are sampling rocks on Mars (SN: 5/2/15, p. 24) and the Cassini probe has bathed in geysers spewing from Saturn’s icy moon Enceladus (SN: 10/17/15, p. 8). Those mechanical explorers and others in the works may send back signs of life.
But those signs are probably going to be subtle, indirect “biomarkers.” It may be surprisingly difficult to tell whether those biomarkers are from animals, vegetables, microbes or minerals, especially at a distance.
“We really need to have life be as obvious as possible,” says astrobiologist Victoria Meadows, who heads the NASA Astrobiology Institute’s Virtual Planetary Laboratory at the University of Washington in Seattle. By obvious, she partly means Earth-like and partly means that no chemical or geologic process could have produced a similar signature. Some scientists say life is an “I’ll know it when I see it” phenomenon, says Kathie Thomas-Keprta, a planetary geologist. But life may also be in the eye of the beholder, as Thomas-Keprta knows all too well from studying a Martian meteorite. She was part of a team at the NASA Johnson Space Center in Houston that studied a meteorite designated ALH84001 (discovered in Antarctica’s Allan Hills ice field in 1984).
In 1996, a team led by Thomas-Keprta’s late colleague David McKay claimed that carbonate globules embedded in the meteorite resembled microscopic life on Earth. The researchers found large organic molecules with the carbonate, indicating that they formed at the same time. Thomas-Keprta also identified tiny magnetite crystals overlapping the globules that closely resemble crystals formed by “magnetotactic” bacteria on Earth. Such bacteria use chains of the crystals as a compass to guide them as they swim in search of nutrients. The researchers believed that they were looking at fossils of ancient Martians.
Other researchers disagreed. The globules and crystals could have formed by chemical or geologic processes, not biology, critics said. Since then, the claim of fossilized Martian life has been widely dismissed.
Surely, recognizing something that is still alive, rather than dead and turned to rock, would be much simpler. But don’t bet on it, Cleland says. There may even be strange forms of life on Earth — a shadow biosphere — that people have overlooked.
Desert varnish One bit of evidence for shadow terrestrials is “desert varnish,” the dark stains on the sunny sides of rocks in arid areas. Odd, communal life-forms could be sucking energy from the rocks and building the varnish’s hard outer crust, Cleland suggests. Some scientists, for instance, think manganese-oxidizing bacteria or fungi might be responsible for concentrating iron and manganese oxides to create the stains. Unknown microbes may cement the metals with clay and silicate particles to produce the varnish’s shellac. Scientists have tried and failed to re-create desert varnish in the lab using fungi and bacteria. Critics say that varnishes form too slowly — over thousands of years — to be a microbial process and that oxidizing manganese doesn’t generate enough energy to live on. Desert varnish is most likely a product of physical chemistry, they say.
But that criticism shows bias, Cleland responds. “We have an assumption that life on Earth has a pace,” she says. Shadow life may grow far more leisurely, making it hard for scientists to classify it as alive.
One way to determine whether the varnish has a biological or geologic origin is to measure isotope ratios, Cleland says. Isotopes are forms of elements with differing numbers of neutrons in the nuclei of their atoms. Lighter isotopes, with fewer neutrons, are favored by some biochemical reactions.
“Life is lazy,” says Cleland. “It doesn’t want to haul around an extra neutron.” Concentrations of lighter isotopes could signal the handiwork of living organisms, she notes.
Mineral distortions To find life, and classify it correctly, look for the odd thing out, suggests Hazen, who is looking for messages in minerals. Minerals on Earth are unevenly distributed, he and colleagues have determined. There are 4,933 recognized minerals on the planet. Hazen and colleagues mapped the locations of 4,831 of them and found that 22 percent exist in only one location (SN Online: 12/8/14). Close to 12 percent occur in only two places, the researchers reported last year in The Canadian Mineralogist.
One reason for the skewed distribution is that evolving life has used local resources and concentrated them into new minerals. Take for example hazenite, named for Hazen. The phosphate mineral is produced only by microbes living in California’s Mono Lake. Actions of other species in other places on Earth have combined with the planet’s geology to make Earth’s mineralogy unique, Hazen wrote with colleagues last year in Earth and Planetary Science Letters.
Finding similarly distorted distributions of minerals on other planets or moons could indicate that life exists, or once existed, there. Hazen has advised NASA on how rovers might identify mineral clues to life on Mars. But determining whether something is unusual might not be as easy as it sounds. Scientists don’t yet know enough about the environment of Mars, Benner says. “Every rover has given us surprises.” He’d like to see a manned fact-finding mission, which he says might lead to a better understanding of the Red Planet and speed up the search for life there.
Mars was once wet (SN Online: 10/8/15) and still has occasional running water (SN: 10/31/15, p. 17). That and other mounting evidence that the Red Planet was once capable of supporting life led Benner to hypothesize in 2013 that Mars may have seeded life on Earth. Whether that hypothesis holds may depend on finding Martians, but Benner doesn’t seem worried.
“I think I would be surprised now if they don’t find life on Mars,” he says. Once the announcement is made, researchers will begin fighting over whether the Martians are real, he predicts. “It will be a good-natured fight because everybody wants to find life, but everybody is aware of the pitfalls of experiments conducted at a 100-million-mile distance by robots.”
Manned missions could easily reach Mars to confirm a find, says Dirk Schulze-Makuch, an astrobiologist at Washington State University in Pullman. “If you have a human with a microscope and the microbe is wiggling and waving back, that’s really hard to refute,” he jokes.
But humans and even probes may have a harder time spotting life on more distant or exotic locales, such as the moons of Jupiter and Saturn. Europa, Enceladus and Titan are frigid places barely kissed by the sun’s energetic rays, but that doesn’t mean they are devoid of life, Schulze-Makuch says. ET hunters are particularly attracted to Europa and Enceladus because liquid oceans slosh beneath their icy crusts. Liquid water is thought to be necessary for many of the chemical reactions that could support life, so it’s one of the primary things astronomers look for.
Going for the less obvious But water is actually a terrible solvent for forming complex molecules on which life could be based, Schulze-Makuch says. Instead, he thinks, really alien aliens might have spawned at hot spots deep in the hydrocarbon lakes of Saturn’s biggest moon, Titan. There, “you could make something very intriguing. Whether you can get all the way to life, we don’t know,” he says. If he sent a probe to that moon, he would first look for large macro-molecules similar to the DNA, RNA and proteins that Earth life uses, but with a Titanic twist.
He has been studying a natural asphalt lake in Trinidad to learn more about what life in Titan’s lakes might be like. Last July in the journal Life, he and colleagues laid out the physical, chemical and physiological limits that life on Titan would bump up against.
Perhaps the biggest challenge for Titanic life is the extreme cold, says chemical engineer Paulette Clancy of Cornell University. Frosty Titan is so cold that methane — a gas on balmy Earth — is a viscous, almost-freezing liquid, and water “would be like a rock,” she says. Under those conditions, organisms with Earth-like chemistry wouldn’t stand a chance. For one thing, the membranes that hold in a cell’s guts on Earth wouldn’t work on Titan. Membranes are made of twin sheets of chainlike molecules each with an oxygen-containing head and a long tail of fatty acids. “On Titan,” says Clancy, “long chains would be a disadvantage because they would be frozen in place,” making membranes brittle. Plus, Titan has no free oxygen to form the molecules’ traditional heads.
But Clancy and her Cornell colleagues, chemical engineer James Stevenson and astronomer Jonathan Lunine, simulated experiments under Titan-like conditions. (Molecules that would be stable on Titan would fall apart on Earth, so the researchers had to do computer experiments instead of synthesizing the molecules in a lab.) Short-tailed acrylonitrile molecules with nitrogen-containing heads could spontaneously create stable bubbles called azotosomes, the researchers reported last year in Science Advances. The bubbles are similar to cell membranes.
“Azo” is a prefix that denotes a particular configuration of nitrogen atoms in a molecule. It’s also Greek for “without life.” The word’s meaning “would be ironic if life on Titan were based … on nitrogen,” Clancy says.
Like desert varnish, life on Titan may have unfamiliar pacing that could prevent Earthlings from determining whether azotosomes or other membranous bubbles found in that moon’s methane oceans actually harbor life. With little solar radiation to stimulate evolution and frigid temperatures to slow chemical reactions, life on Titan may be really poky, Schulze-Makuch says. He imagines that Titanic life-spans may stretch to millions of years, with organisms reproducing or even breathing only once every thousand years. Scientists may need to measure metabolic reactions instead of generation times to determine whether something is living on Saturn’s frigid satellite.
Clancy hopes to explore what types of metabolism Titan’s chemistry might allow. Neptune’s icy moon Triton, which is covered in a thin veneer of nitrogen and methane and has nitrogen-spewing geysers, may also be a candidate for new and exciting biochemistry, she says.
With so many options out there, Clancy predicts that there are several planets or moons with life on them. “That we have the lock on the way life decided to develop, I think, is unlikely.”
Many other researchers are also optimistic that life is out there to find. “I think life is a cosmic imperative,” Hazen says. Someday, astrobiologists may come face-to-face with ET. Maybe they will even recognize it when they see it.
