On October 3, the US House of Representatives voted to oust Speaker Kevin McCarthy, making him the first Speaker of the House in US history to be voted out, and also the one with the shortest tenure. What's crucial is that it marks the deepening division within the Republican Party and the further polarization between the two major political parties in the US.
The state of the US politics is essentially fragmented, with significant changes in the core voter demographics of both parties and the emergence of prominent extremist forces. Within the Republican Party, extreme factions like the Freedom Caucus have gained prominence since the era of Donald Trump. This political fragmentation has led to confusion and internal strife within both parties, as explained by Diao Daming, a professor at the Renmin University of China in Beijing. According to Diao, this event is a result of political decline and the failure of governance. Instead of addressing critical issues such as the debt ceiling and government shutdown, both parties prioritized maximizing their internal interests.
Following this turmoil, the space for compromise between the two parties is expected to shrink further. This phenomenon is driven by both technical and strategic reasons, said Yang Xiyu, a senior research fellow at the China Institute of International Studies. Faced with the budget dispute between the two parties, McCarthy made a compromise that did not sit well with the hardliners within his party. His removal essentially prevents future Speakers of the House, who are also leaders of the Republican Party, from following in McCarthy's footsteps.
From a strategic perspective, the divisions between the two parties extend beyond specific budgetary issues to affect US' national development. The different budget proposals put forward by the Democratic and Republican parties reflect their distinct visions for the country. With the turmoil within the Republican Party, it has become increasingly difficult for both parties to reach compromises.
Yang pointed out that this upheaval is not merely about reaching or failing to reach compromises; it fundamentally reflects a disconnect between the current design of the US democratic system and the rapidly changing society. This shift in leadership within the US House of Representatives was triggered by the budget issue, but it is also rooted in the profound divisions between the two parties regarding the direction of the nation. However, the functioning of this political system is becoming increasingly incompatible with the deeply divided American society.
Presently, the US is in a state of political extremism, with both major parties becoming more polarized. As political figures navigate the pressures of Washington, they must continuously rally their constituents. Consequently, voters from both parties are becoming more polarized, further exacerbating the division.
The US had long presented itself as a "beacon of democracy." However, with its domestic political turmoil, this myth has been shattered. This has led to increasing contradictions between the two major driving forces of US foreign policy—American interests and American values. The failure of the American democratic system domestically has raised questions about American values on the international stage. While the US has sought to incorporate these values into its foreign policy and promote them globally, it has also sparked growing conflicts. As a result, the US' international influence has declined, eroding international confidence in the so-called American values.
While EU's trade chief Valdis Dombrovskis urges China to do more to help "reduce the perception of risk," there are multiple signs that bilateral economic ties are embarking on fast-track development. Obviously, the European business community hopes EU's priority is to promote cooperation, rather than "de-risk" its relationship with China.
Amid global uncertainty, European and Chinese senior officials held high-level economic and trade talks on Monday. Despite some disagreements which are continually hyped up by some EU politicians, the high-level trade talks serve as a good opportunity for China and the EU to enhance communication and understanding.
Ahead of the dialogue, some statistics showed German companies continue to invest heavily in China despite calls from a number of German politicians to reduce their exposure in China. Investment in China as a share of Germany's overall investments increased to 16.4 percent in the first half of this year from 11.6 percent in 2022 and 5.1 percent in 2019, Reuters reported on Wednesday, citing data from the German Economic Institute, a private economic research institute in Germany.
Germany has been Europe's economic engine for decades. However, persistent inflation has pushed the German economy into a technical recession with data showing that the economy contracted in the first quarter of 2023. Overall, German direct investment outflows dropped sharply, to 63 billion euros ($67 billion) in the first half of 2023 from 104 billion euros in the first half of 2022.
At a time when Europe's largest economy is battling recession, the Chinese economy offers opportunities for German enterprises. That's why in spite of the so-called decoupling or de-risking rhetoric made by some Western officials, European investments continue to pour into China.
It is worth noting that there is a trend that the more open China becomes, the more vigilant the EU has become against China. It is true that economic and trade disputes exist in China-EU relations. The European Commission launched an investigation on September 13 into whether to impose additional tariffs to protect EU producers against cheaper Chinese electric vehicle (EV) imports it says are benefiting from the so-called state subsidies. Trade protectionism could be a double-edged sword for bilateral relations, as China is now an important overseas market for European enterprises.
Dombrovskis said in a speech he delivered at Tsinghua University in Beijing on Monday that Europe's economic ties with China are deep, but China "could do a lot to help reduce our perception of risk," according to a Reuters report. The report said the EU has long complained about "a lack of level playing field in China" and "the politicization of the business environment," which is mainly a Western narrative to sow discord and to pressure China to give foreign investors supernational treatment.
As a matter of fact, Europe is the party that adopts protectionist measures to disrupt economic and trade cooperation. China welcomes investment from European countries, but the ball is in the European's court to break down barriers over mutually-beneficial economic cooperation. The best way to help reduce European perception of risk is to put geopolitical thinking aside, stop adopting protectionist measures, fully consider the feelings of European companies, and resolve each other's concerns through dialogue and consultation.
Monday's dialogue, the first in-person meeting post-pandemic, has drawn wide attention. It's impossible to solve each and every problem overnight, especially amid the "decoupling" calls and the instigations by the US, but achievements will add up through frank dialogues and communications, pushing forward China-EU economic ties.
Monday's trade talks won't become the endpoint for both sides to seek common ground and solutions to resolve differences and problems. Future efforts should be made and the European side should take more responsibility, as it is the party bowing to trade protectionism. Whether it can "reduce the perception of risk" depends on Europe's attitude toward trade protectionism.
Airbus is playing a role of "catalyst" in Chinese market for the development of sustainable aviation fuel (SAF) industry, propelling sustainable energy transition in civilian aviation sector to realize decarbonization targets, an executive from Airbus said in Beijing on Tuesday.
Airbus is working on a number of levers, so the first one is technology and fleet renewal. The company is also working actively on improving the efficiency of operations. And the third and very big one is the energy transition of which SAF is a key topic, Julie-Kitcher, Executive Vice President of Airbus said.
The comments are made as more Chinese airlines vowing to promote use of sustainable aviation fuel. In October of last year, Airbus said its Tianjin plant delivered an A320neo to China Eastern Airlines that used five percent SAF as the fuel during its delivery flight.
SAF is a sustainable aviation fuel made from feedstock ranging from used fat, oil and grease to municipal and forestry waste. Compared to fossil jet fuel, SAF has been demonstrated to result in an up to 80 percent reduction in CO2 emissions. Therefore, it is considered as a key enabler to contribute to the de-carbonization of aviation sector. And so when talking about SAF, there's a huge capability in China with feedstock in abundance, technology and innovation and in fact, China has been supporting certification since 2008 in different ways. All the airlines have expressed interest in environmental matters on sustainability, SAF in particular, Kitcher said.
And Airbus is working with China National Aviation Fuel Group Corporation to develop the SAF industry or act as a catalyst in China, she added.
In July of last year, the Airbus Lifecycle Services Center project broke ground in Chengdu, Southwest China's Sichuan Province. The project is Airbus' first aircraft lifecycle service project outside Europe. The company said the project has moved from the planning stage to construction and the aim is for it to enter into service by the end of 2023.
Airbus is spending around 2 billion euros per annum on R&D, which is mainly targeting sustainable aviation. All partners and players will need to make significant investments for their respective licenses to continue to operate. Aircraft manufacturer need to really look at the overall lifecycle of the aircraft, so it's from design, supply chain, the operations, the maintenance, and the end of life recycling, Kitcher said.
To show the conviction in terms of the necessity to decarbonize the sector, Kitcher said that they're working on different levels for the industry, including the technology starting with fleet renewal and enhancing and improving the efficiency of air traffic management operations.
She also said to enhance the energy transition, which means to increase the adoption of SAF, Airbus targets to certify all its aircraft with 100 percent SAF capability by the end of this decade, adding that the company is also developing hydrogen technologies for future use.
Airbus is aiming to reach a global 10 percent target by 2030, which is around 34 million tons of SAF by 2030.Actual demand for probably around 20 million tons are committed. So "we still have progress to make, but we're confident that collectively we can get there", she said.
Travel heat continued to spread nationwide. The number of railway trips made by Chinese passengers is expected to hit 16.40 million on Monday, the fourth day of eight-day-long National Day holiday and the Mid-Autumn Festival.
On October 1, the national railway transported 16.29 million passengers, China Railway, the national railway operator, said on Monday. On October 2, it is estimated that the national railway will transport 16.40 million passengers, with 11,274 passenger trains in operation, including 906 additional trains.
The Yangtze River Delta region is expected to transfer 3.5 million passenger trips, which is about 28 percent more than the same period in 2019, according to media reports.
The 2023 Golden Week started from September 29 to October 6. The 8-day holiday is the longest public holiday of the year.
The Ministry of Culture and Tourism estimated there will be 896 million domestic tourists traveling during the Golden Week holiday, an increase of 86 percent compared to last year. Domestic tourism revenue is expected to reach 782.5 billion yuan ($107.2 billion), up by 138 percent on a yearly basis.
The popularity of scenic spots, urban leisure, rural tourism, and visiting relatives and friends has increased significantly, the ministry said.
Localities on Monday started to release travel statistics for the first three days.
Beijing's major scenic spots received 6.825 million tourists during the first three days of the holiday, up by 60.6 percent year-on-year. Tourism revenue reached 4.19 trillion yuan, an increase of 25.2 percent year-on-year.
A netizen posted a photo of the Badaling Great Wall in Beijing, saying that it is not exhausting at all climbing the Great Wall, when you only take two steps in three minutes.
Hangzhou, East China's Zhejiang Province, which is hosting the 19th Asian Games, has welcomed a record number of tourists during the holiday. During the first three days, the city welcomed a total of 4.7 million tourists.
Tickets of many popular scenic spots were sold out, with some sold out even before the holiday started.
Tickets for Mount Taishan in East China's Shandong Province were all sold out until Wednesday. Tickets can be booked 14 days in advance. The current daily limit is 80,000 tourists.
A netizen posted a photo of crowds queuing at the entrance of Mount Taishan at 4:30 in the morning, attempting to avoid huge tourist flows.
Mount Huangshan in East China's Anhui Province said in an announcement on Sunday that tickets for Monday have been sold out and advised tourists who failed to buy a ticket to avoid the site. Huangshan welcomed 29,753 tourists alone on Sunday.
A number of museums also announced that they have reached their daily limits.
Sichuan Museum in Chengdu, Southwest China's Sichuan Province, said its reservations have reached daily limit of 10,000 visitors until Wednesday.
The Emperor Qinshihuang's Mausoleum Site Museum in Northwest China's Shaanxi Province was also fully booked until Wednesday, with only few tickets left for Thursday and Friday.
A netizen who visited the museum joked: "Even the terracotta warriors would not have room to stand, if they were not put inside the protection window."
China's Tiangong space station launched the second Tiangong painting exhibition on Saturday, representing a special gift sent by the Shenzhou-15 mission astronauts at the Chinese space station to teenagers across the country during the Chinese New Year's Eve.
With the theme of “Painting a beautiful China, talking about good life,” this year’s exhibition displays 40 paintings from teenagers from 17 provinces, municipalities and autonomous regions as well as the Hong Kong and Macao special administrative regions.
In August 2022, Chinese astronauts Chen Dong, Liu Yang and Cai Xuzhe, who are members of the Shenzhou-14 crew, called on teenagers to send in works for the painting exhibition to be held at China’s space station. The activity received enthusiastic response from schools, parents and teenagers across the country, and more than 3,000 paintings were received from teenagers aged 5 to 18.
On November 29, 2022, the 40 outstanding works that were selected through expert review and online voting were taken with the Shenzhou-15 manned spaceship to enter the Chinese space station.
The works on display at the Chinese space station will return to the ground with the Shenzhou spacecraft later. The organizer will choose the time to hold a ground painting exhibition and invite award-winning teenagers and outstanding instructor representatives to watch the on-site rocket launch and conduct exchanges with astronauts.
The Tiangong painting exhibition has been held for two consecutive sessions so far, with the first held on January 1, 2022.
2022 marked the 30th anniversary of the establishment and implementation of China’s manned spaceflight project and the year when the Chinese space station was fully completed. According to the schedule, there will also be more follow-up offline activities aimed at encouraging teenagers’ interests and enthusiasm in manned spaceflight this year.
China launched its largest solid propellant rocket Lijian-1 on Wednesday, successfully sending 26 satellites into preset orbit and setting the country's new record for launching multiple satellites in one go. The satellites will mainly provide commercial remote sensing information services.
The Wednesday launch marks the second flight of Lijian-1, indicating the maturity of the solid propellant rocket's technology and the continuous improvement of its reliability, which can further boost the commercialization of China's launch vehicles.
In an exclusive interview with the Global Times, chief engineer assistant on Lijian-1 Shi Xiaoning said he was quite confident about the rocket as its reliability has been verified. But he was still concerned about the separation of satellites from the rocket.
"This time, there were more satellites to send and we not only needed to ensure that each of them could be successfully separated, but also ensure the accuracy of the satellite's orbit insertion, which was quite challenging," Shi said. "Therefore, we closely monitored data for each satellite separation, but in the end we accurately delivered each satellite to the designated orbit."
Lijian-1 made its maiden flight on July 27, 2022, successfully sending six satellites into their preset orbits. According to its developer, the Chinese Academy of Sciences (CAS), the 2.65-meter-diameter and 30-meter-long new rocket is the largest of its kind in China.
It has achieved breakthroughs in six key technologies and utilized 13 domestic technologies for the first time, enriching China's spectrum of solid carrier rocket launch capabilities and making significant contributions to the technological transformation of China's carrier rocket industry.
Lijian-1 is a four-stage launch vehicle weighing 135 tons at launch with a thrust of 200 tons. It is capable of sending payloads of 1,500 kilograms into 500-kilometer Sun-synchronous orbits (SSO). Prior to that, the capacity of Chinese commercial space rockets in SSO was below 1,000 kilograms.
For the next step, the rocket developer Guangzhou Zhongke Aerospace Exploration Technology Co (CAS Space) will continue to enrich the spectrum of China's solid propellant launch vehicles. In addition to building a sea launch platform for Lijian-1, a new solid rocket with a diameter of 3.5 meters is also under development, the Global Times has learned.
Tianjin Customs recently seized 92 globes that mistakenly labeled China's Taiwan region alongside the name of countries, violating the one-China principle, according to China's General Administration of Customs (GAC) on Thursday.
The globes were discovered by on-site customs officers at North China's Tianjin's Xingang Customs, during the inspection of a declared imported shipment of globes in the import freight channel, according to the GAC.
The globes have been seized according to law and will be further processed.
The GAC said that maps are the main representation of the national territory. A correct national map is a symbol of national sovereignty and territorial integrity.
All printed matter and publications that do not comply with China's regulations on the content representation of open map are strictly prohibited from printing or importing/exporting, according to the GAC.
Additionally, relevant map or map product production and import-export enterprises should strictly comply with laws and regulations and carry out map business activities in accordance with the law.
China's Ministry of Natural Resources (MNR) issued the open map content representation specification in February, requiring open maps or the content representation of map graphics products, should comply with the specification. Detailed requirements have been specified to regulate the depiction of maps concerning China's Taiwan region, the South China Sea, and the Diaoyu Islands, among other areas.
Japanese great tits (Parus minor) communicate using at least 10 different notes on their own and in combination. Researchers played different calls for Japanese great tits in a forest in Nagano, Japan, to see how the birds responded — an indication of what the call might mean. The birds responded differently to individual notes than they did when played the same note in combination with other notes. And, when researchers reversed the note order, the birds didn’t respond the same way. By itself, a note means one thing to great tits, but in combination, it means something different, the team argues March 8 in Nature Communications. Similarly, among humans, the order of words in a sentence, its compositional syntax, matters.
Some primates combine calls to convey different messages, but individual notes don’t carry unique meaning in these species. Great tits are the first nonhuman species shown to use compositional syntax, the researchers write. In this recording, researchers played three types of calls for Japanese great tits: First, a call with three notes — A, B, and C — which signals danger; second, a one-note call (D), which attracts mates; and finally, a combination call, ABC-D, which causes the birds to scan the skies for predators and fly to the source of the sound. Researchers played an ABC-D call for great tits, and then reversed an ABC-D call. Birds responded differently in each case.
Despite massive public health campaigns, the rise in worldwide obesity rates continues to hurtle along like a freight train on greased tracks.
In 2014, more than 640 million men and women were obese (measured as a body mass index of 30 or higher). That’s up from 105 million in 1975, researchers estimate in the April 2 Lancet. The researchers analyzed four decades of height and weight data for more than 19 million adults, and then calculated global rates based on population data. On average, people worldwide are gaining about 1.5 kilograms per decade — roughly the weight of a half-gallon of ice cream. But the road isn’t entirely rocky. During the same time period, average life expectancy also jumped: from less than 59 years to more than 71 years, George Davey Smith points out in a comment accompanying the new study. Smith, an epidemiologist at the University of Bristol in England, boils the data down to a single, seemingly paradoxical sentence: “The world is at once fatter and healthier.”
For beings that are supposedly alien to human culture, extraterrestrials are pretty darn common. You can find them in all sorts of cultural contexts, from comic books, sci-fi novels and conspiracy theories to Hollywood films and old television reruns. There’s Superman and Doctor Who, E.T. and Mindy’s friend Mork, Mr. Spock, Alf, Kang and Kodos and My Favorite Martian. Of course, there’s just one hitch: They’re all fictional. So far, real aliens from other worlds have refused to show their faces on the real-world Earth — or even telephone, text or tweet. As the Italian physicist Enrico Fermi so quotably inquired during a discussion about aliens more than six decades ago, “Where is everybody?” Scientific inquiry into the existence of extraterrestrial intelligence still often begins by pondering Fermi’s paradox: The universe is vast and old, so advanced civilizations should have matured enough by now to send emissaries to Earth. Yet none have. Fermi suspected that it wasn’t feasible or that aliens didn’t think visiting Earth was worth the trouble. Others concluded that they simply don’t exist. Recent investigations indicate that harsh environments may snuff out nascent life long before it evolves the intelligence necessary for sending messages or traveling through space. In any event, Fermi’s question did not launch humankind’s concern with visitors from other planets. Imagining other worlds, and the possibility of intelligent life-forms inhabiting them, did not originate with modern science or in speculative fiction. In the ancient world, philosophers argued about the possibility of multiple universes; in the Middle Ages the question of the “plurality of worlds” and possible inhabitants occupied the deepest of thinkers, spawning intricate and controversial philosophical, theological and astronomical debate. Far from being a merely modern preoccupation, life beyond Earth has long been a burning issue animating the human race’s desire to understand itself, and its place in the cosmos.
Other worlds, illogical From ancient times Earth’s place was widely regarded to be the center of everything. As articulated by the Greek philosopher Aristotle, the Earth was the innermost sphere in a universe, or world, surrounded by various other spheres containing the moon, sun, planets and stars. Those heavenly spheres, crystalline and transparent, rotated about the Earthly core comprising four elements: fire, air, water and earth. Those elements layered themselves on the basis of their essence, or “nature” — earth’s natural place was at the middle of the cosmos, which was why solid matter fell to the ground, seeking the inaccessible center far below.
On the basis of this principle, Aristotle deduced the impossibility of other worlds. If some other world existed, its matter (its “earth”) would seek both the center of its world and of our world as well. Such opposite imperatives posed a logical contradiction (which Aristotle, having more or less invented logic, regarded as a directly personal insult). He also applied further reasoning to point out that there is no space (no void) outside the known world for any other world to occupy. So, Aristotle concluded, two worlds cannot both exist.
Some Greeks (notably those advocating the existence of atoms) believed otherwise. But Aristotle’s view prevailed. By the 13th century, once Aristotle’s writings had been rediscovered in medieval Europe, most scholars defended his position. But then religion leveled the philosophical playing field. Fans of other worlds got a chance to make their case.
In 1277, the bishop of Paris, Étienne Tempier, banned scholars from teaching 219 principles, manny associated with Aristotle’s philosophy. Among the prohibited teachings on the list was item 34: that God could not create as many worlds as he wanted to. Since the penalty for violating this decree was excommunication, Parisian scholars suddenly discovered rationales allowing multiple worlds, empowering God to defy Aristotle’s logic. And since Paris was the intellectual capital of the European world, scholars elsewhere followed the Parisian lead. While several philosophers asserted that God could make many worlds, most intimated that he probably wouldn’t have bothered. Hardly anyone addressed the likelihood of alien life, although both Jean Buridan in Paris and William of Ockham in Oxford did consider the possibility. “God could produce an infinite [number of] individuals of the same kind as those that now exist,” wrote Ockham, “but He is not limited to producing them in this world.” Populated worlds showed up more prominently in writings by the renegade thinkers Nicholas of Cusa (1401–1464) and Giordano Bruno (1548–1600). They argued not only for the existence of other worlds, but also for worlds inhabited by beings just like, or maybe better than, Earth’s humans.
“In every region inhabitants of diverse nobility of nature proceed from God,” wrote Nicholas, who argued that space had no center, and therefore the Earth could not be central or privileged with respect to life. Bruno, an Italian friar, asserted that God’s perfection demanded an infinity of worlds, and beings. “Infinite perfection is far better presented in innumerable individuals than in those which are numbered and finite,” Bruno averred.
Burned at the stake for heretical beliefs (though not, as often stated, for his belief in other worlds), Bruno did not live to see the triumph of Copernicanism during the 17th century. Copernicus had placed the sun at the hub of a planetary system, making the Earth just one planet of several. So the existence of “other worlds” eventually became no longer speculation, but astronomical fact, inviting the notion of otherworldly populations, as the prominent Dutch scientist Christiaan Huygens pointed out in the late 1600s. “A man that is of Copernicus’ opinion, that this Earth of ours is a planet … like the rest of the planets, cannot but sometimes think that it’s not improbable that the rest of the planets have … their inhabitants too,” Huygens wrote in his New Conjectures Concerning the Planetary Worlds, Their Inhabitants and Productions.
A few years earlier, French science popularizer Bernard le Bovier de Fontenelle had surveyed the prospects for life in the solar system in his Conversations on the Plurality of Worlds, an imaginary dialog between a philosopher and an uneducated but intelligent woman known as the Marquise.
“It would be very strange that the Earth was as populated as it is, and the other planets weren’t at all,” the philosopher told the Marquise. Although he didn’t think people could live on the sun (if there were any, they’d be blinded by its brightness), he sided with those who envisioned inhabitants on other planets and even the moon.
“Just as there have been and still are a prodigious number of men foolish enough to worship the Moon, there are people on the Moon who worship the Earth,” he wrote.
From early modern times onward, discussion of aliens was not confined to science and philosophy. They also appeared in various works of fiction, providing plot devices that remain popular to the present day. Often authors used aliens as stand-ins for evil (or occasionally benevolent) humans to comment on current events. Modern science fiction about aliens frequently portrays them in the role of tyrants or monsters or victims, with parallels to real life (think Flash Gordon’s nemesis Ming the Merciless, a 1930s dictator, or the extraterrestrials of the 1980s film and TV show Alien Nation — immigrants encountering bigotry and discrimination). When humans look for aliens, it seems, they often imagine themselves.
Serious science While aliens thrived in fiction, though, serious scientific belief in extraterrestrials — at least nearby — diminished in the early 20th century, following late 19th century exuberance about possible life on Mars. Supposedly a network of lines interpreted as canals signified the presence of a sophisticated Martian civilization; its debunking (plus further knowledge about planetary environments) led to general agreement that finding intelligent life elsewhere in the solar system was not an intelligent bet. On the other hand, the universe had grown incredibly vaster than the early Copernicans had imagined. The sun had become just one of billions of stars in the Milky Way galaxy, which in turn was only one of billions of other similar galaxies, or “island universes.” Within a cosmos so expansive, alien enthusiasts concluded, the existence of other life somewhere seemed inevitable. In 1961, astronomer Frank Drake developed an equation to gauge the likelihood of extraterrestrial life’s existence; by the 1990s he estimated that 10,000 planets possessed advanced civilizations in the Milky Way alone, even before anybody really knew for sure that planets outside the solar system actually existed.
But now everybody does. In the space of the last two decades, conclusive evidence of exoplanets, now numbering in the thousands, has reconfigured the debate and sharpened Fermi’s original paradox. No one any longer doubts that planets are plentiful. But still there’s been not a peep from anyone living on them, despite years of aiming radio telescopes at the heavens in hope of detecting a signal in the static of interstellar space.
Maybe such signals are just too rare or too weak for human instruments to detect. Or possibly some cosmic conspiracy is at work to prevent civilizations from communicating — or arising in the first place. Or perhaps civilizations that do arise are eradicated before they have a chance to communicate.
Or maybe the alien invasion has merely been delayed. Fermi’s paradox implicitly assumes that other civilizations have been around long enough to develop galactic transportation systems. After all, the universe, born in the Big Bang 13.8 billion years ago, is three times as old as the Earth. So most analyses assume that alien civilizations had a head start and would be advanced enough by now to go wherever they wanted to. But a new paper suggests that livable galactic neighborhoods may have developed only relatively recently. In a young, smaller and more crowded universe, cataclysmic explosions known as gamma-ray bursts may have effectively sterilized otherwise habitable planets, Tsvi Piran and collaborators suggest in a paper published in February in Physical Review Letters.
A planet near the core of a galaxy would be especially susceptible to gamma-ray catastrophes. And in a young universe, planets closer to the galactic edge (like Earth) would also be in danger from gamma-ray bursts in neighboring satellite galaxies. Only as the expansion of the universe began to accelerate — not so long before the birth of the Earth — would galaxies grow far enough apart to provide safety zones for life.
“The accelerated expansion induced by a cosmological constant slows the growth of cosmic structures, and increases the mean inter-galaxy separation,” Piran and colleagues write. “This reduces the number of nearby satellites likely to host catastrophic” gamma-ray bursts. So most alien civilizations would have begun to flourish not much before Earth’s did; those aliens may now be wondering why nobody has visited them.
Still, the radio silence from the sky makes some scientists wonder whether today’s optimism about ET’s existence will go the way of the Martian canal society. From one sobering perspective, aliens aren’t sending messages because few planets remain habitable long enough for life to develop an intelligent civilization. One study questions, for instance, how likely it is that life, once initiated on any planet, would shape its environment sufficiently well to provide for lasting bio-security.
In fact, that study finds, a wet, rocky planet just the right distance from a star — in the Goldilocks zone — might not remain habitable for long. Atmospheric and geochemical processes would typically drive either rapid warming (producing an uninhabitable planet like Venus) or quick cooling, freezing water and leaving the planet too cold and dry for life to survive, Aditya Chopra and Charles Lineweaver conclude in a recent issue of Astrobiology. Only if life itself alters these processes can it maintain a long-term home suitable for developing intelligence.
“Feedback between life and environment may play the dominant role in maintaining the habitability of the few rocky planets in which life has been able to evolve,” wrote Chopra and Lineweaver, both of the Australian National University in Canberra.
Yet even given such analyses — based on a vastly deeper grasp on astronomy and cosmology than medieval scholars possessed — whether real aliens exist remains one of those questions that science cannot now answer. It’s much like other profound questions also explored in medieval times: What is the universe made of? Is it eternal? Today’s scientists may be closer (or not) to answering those questions than were their medieval counterparts. Nevertheless the answers are not yet in hand.
Maybe we’ll just have to pose those questions to the aliens, if they exist, and are ever willing to communicate. And if those aliens do arrive, and provide the answers, humankind may well discover how medieval its understanding of the cosmos still is. Or perhaps the aliens will be equally clueless about nature’s deepest mysteries. As Fontenelle’s philosopher told the Marquise: “There’s no indication that we’re the only foolish species in the universe. Ignorance is quite naturally a widespread thing.”
