A false-color image obtained by the James Webb Space Telescope (JWST) shows the galaxy JADES-GS-z7-01-QU, the universeÕs earliest-known “dead” galaxy, a galaxy that has stopped star formation, in this undated handout picture obtained by Reuters.
| Photo Credit: Reuters

The James Webb Space Telescope, or JWST for short, is one of the most advanced telescopes ever built. Planning for JWST began over 25 years ago, and construction efforts spanned over a decade. It was launched into space on Dec. 25, 2021, and within a month arrived at its final destination: 930,000 miles away from Earth. Its location in space allows it a relatively unobstructed view of the universe.

The telescope design was a global effort, led by NASA, and intended to push the boundaries of astronomical observation with revolutionary engineering. Its mirror is massive – about 21 feet (6.5 meters) in diameter. That’s nearly three times the size of the Hubble Space Telescope, which launched in 1990 and is still working today.

It’s a telescope’s mirror that allows it to collect light. JWST’s is so big that it can “see” the faintest and farthest galaxies and stars in the universe. Its state-of-the-art instruments can reveal information about the composition, temperature and motion of these distant cosmic objects.

As an astrophysicist, I’m continually looking back in time to see what stars, galaxies and supermassive black holes looked like when their light began its journey toward Earth, and I’m using that information to better understand their growth and evolution. For me, and for thousands of space scientists, the James Webb Space Telescope is a window to that unknown universe.

Just how far back can JWST peer into the cosmos and into the past? About 13.5 billion years.

Time travel

A telescope does not show stars, galaxies and exoplanets as they are right now. Instead, astronomers are catching a glimpse of how they were in the past. It takes time for light to travel across space and reach our telescopes. In essence, that means a look into space is also a trip back in time.

This is even true for objects that are quite close to us. The light you see from the Sun left it about 8 minutes, 20 seconds earlier. That’s how long it takes for the Sun’s light to travel to Earth.

You can easily do the math on this. All light – whether sunlight, a flashlight or a light bulb in your house – travels at 186,000 miles (almost 300,000 kilometers) per second. That’s just over 11 million miles (about 18 million kilometers) per minute. The Sun is about 93 million miles (150 million kilometers) from Earth. That comes out to about 8 minutes, 20 seconds.

But the farther away something is, the longer its light takes to reach us. That’s why the light we see from Proxima Centauri, the closest star to us aside from our Sun, is 4 years old; that is, it’s about 25 trillion miles (approximately 40 trillion kilometers) away from Earth, so that light takes just over four years to reach us. Or, as scientists like to say, four light years.

Most recently, JWST observed Earendel, one of the farthest stars ever detected. The light that JWST sees from Earendel is about 12.9 billion years old.

The James Webb Space Telescope is looking much farther back in time than previously possible with other telescopes, such as the Hubble Space Telescope. For example, although Hubble can see objects 60,000 times fainter than the human eye is able, the JWST can see objects almost nine times fainter than even Hubble can.

The Big Bang

But is it possible to see back to the beginning of time?

The Big Bang is a term used to define the beginning of our universe as we know it. Scientists believe it occurred about 13.8 billion years ago. It is the most widely accepted theory among physicists to explain the history of our universe.

The name is a bit misleading, however, because it suggests that some sort of explosion, like fireworks, created the universe. The Big Bang more closely represents the appearance of rapidly expanding space everywhere in the universe. The environment immediately after the Big Bang was similar to a cosmic fog that covered the universe, making it hard for light to travel beyond it. Eventually, galaxies, stars and planets started to grow.

That’s why this era in the universe is called the “cosmic dark ages.” As the universe continued to expand, the cosmic fog began to rise, and light was eventually able to travel freely through space. In fact, a few satellites have observed the light left by the Big Bang, about 380,000 years after it occurred. These telescopes were built to detect the splotchy leftover glow from the Big Bang, whose light can be tracked in the microwave band.

However, even 380,000 years after the Big Bang, there were no stars and galaxies. The universe was still a very dark place. The cosmic dark ages wouldn’t end until a few hundred million years later, when the first stars and galaxies began to form.

The James Webb Space Telescope was not designed to observe as far back as the Big Bang, but instead to see the period when the first objects in the universe began to form and emit light. Before this time period, there is little light for the James Webb Space Telescope to observe, given the conditions of the early universe and the lack of galaxies and stars.

Peering back to the time period close to the Big Bang is not simply a matter of having a larger mirror – astronomers have already done it using other satellites that observe microwave emission from very soon after the Big Bang. So, the James Webb Space Telescope observing the universe a few hundred million years after the Big Bang isn’t a limitation of the telescope. Rather, that’s actually the telescope’s mission. It’s a reflection of where in the universe we expect the first light from stars and galaxies to emerge.

By studying ancient galaxies, scientists hope to understand the unique conditions of the early universe and gain insight into the processes that helped them flourish. That includes the evolution of supermassive black holes, the life cycle of stars, and what exoplanets – worlds beyond our solar system – are made of.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

People walk on an overpass past office towers in the Lujiazui financial district of Shanghai, China October 17, 2022.
| Photo Credit: Reuters

Across the world, many cities are slowly sinking. Most are on the coast, including tropical megacities like Jakarta in Indonesia or Manila in the Philippines, or places like New Orleans, Vancouver or much of the Netherlands. Other sinking cities, like Mexico City and many of those in China, can be well inland. Yet this still remains a widely overlooked hazard.

In my three decades assessing this topic, I have reviewed evidence of subsidence in cities around the world. The problem is especially significant in Asia, where about 60% of the world’s population lives and the cities are growing rapidly. However, some cities have also shown there are things that can be done to stop subsidence.

The problem is illustrated by a recent study by researchers in China which found that more than a third of the country’s urban population – some 270 million people – live in sinking cities.

The authors analysed satellite-derived data from 2015 to 2022 across China’s 82 most important cities to produce accurate and consistent maps of vertical land movement. Consistently measuring subsidence in all these cities, with a collective population of nearly 700 million people, is a great achievement.

They found 37 of the 82 cities they looked at were sinking, and nearly 70 million people are experiencing rapid subsidence of 10mm a year or more. This may not sound much but the subsidence accumulates over time and can damage infrastructure and buildings, and make floods more dangerous.

There are a number of sinking hotspots in China mainly in the east of the country, especially near the coast. These include the inland capital Beijing and the nearby (London-sized) port city of Tianjin.

Why cities sink

The subsidence has multiple causes, both natural and human-induced. Most large changes are human-induced. For cities built on geologically young sediments such as river deltas and floodplains, the biggest cause of subsidence is people withdrawing or draining water found underground.

This groundwater is safer to drink than surface water, so as a city grows it tends to extract even more water from below. This causes the soil to consolidate and the surface above to lower.

Other causes of city sinking include mines below some cities slowly collapsing, or land reclamations which are widespread along China’s coast. The weight of the fill used to reclaim new land from the sea can cause the land to sink.

Cities often sink unevenly, and this differential subsidence is a much greater challenge than when an entire city sinks at a uniform rate. For instance traffic vibration and tunnelling is also a contributing factor in certain areas – the new study found that Beijing is sinking much faster near subways and highways, up to 45mm a year.

Subsidence is often attributed to the weight of buildings, but this is probably overstated as modern foundation design aims to minimise the effect to avoid building damage.

Coastal cities such as Tianjin are especially affected as sinking land reinforces the problem of climate change-driven sea-level rise. The sinking of sea defences is one reason why Hurricane Katrina devastated New Orleans in 2005.

China’s biggest city Shanghai has subsided up to three metres over the last 100 years. Built on already low-lying land where the Yangtze Delta meets the ocean, much of the city is barely above sea level, greatly increasing the consequences if flooding occurs.

The authors of the new study combined rates of subsidence with projected sea-level rise to estimate that the urban area in China below sea level could triple in size by 2120, affecting between 55 million and 128 million residents. This could be catastrophic without massive adaptation.

How to stop sinking

Parts of Japan’s two largest cities, Tokyo and Osaka, sank by several metres during the 20th century. However, in the 1960s and 70s both banned groundwater withdrawal and provided alternative surface water supplies. This in turn stopped or greatly reduced city subsidence – the strategy had been effective.

Shanghai in China followed a similar strategy a decade or so later. The latest study noted the city today has relatively moderate subsidence compared to the hotspot of Tianjin. The Chinese government already aspires to mitigate human-induced subsidence, and this new study shows all the cities where this needs to be considered.

But if cities are unable to stop or control sinking then they have to adapt to the reality, especially in coastal areas. In China’s low-lying coastal areas, dikes are almost universal. But a combination of sinking land and rising seas means they are already being raised.

As illustrated by the new China study, satellites are delivering unprecedented subsidence data in time and space. They provide consistent measurements across China (and potentially the world) and overcome concerns about sinking equipment which make subsidence so difficult to measure on the ground.

These satellite measurements can be repeated regularly to identify trends, and provide an important step on the road towards a solution to sinking cities. As someone who started their career when ground surveying was the norm, this is all very exciting.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Around five and half millenia ago, northern Africa went through a dramatic transformation. The Sahara desert expanded and grasslands, forests and lakes favoured by humans disappeared. Humans were forced to retreat to the mountains, the oases, and the Nile valley and delta.

As a relatively large and dispersed population was squeezed into smaller and more fertile areas, it needed to innovate new ways to produce food and organise society. Soon after, one of the world’s first great civilisations emerged – ancient Egypt.

This transition from the most recent “African humid period”, which lasted from 15,000 to 5,500 years ago, to the current dry conditions in northern Africa is the clearest example of a climate tipping point in recent geological history. Climate tipping points are thresholds that, once crossed, result in dramatic climate change to a new stable climate.

Our new study published in Nature Communications reveals that before northern Africa dried out, its climate “flickered” between two stable climatic states before tipping permanently. This is the first time it’s been shown such flickering happened in Earth’s past. And it suggests that places with highly variable cycles of changing climate today may in some cases by headed for tipping points of their own.

Whether we will have any warnings of climate tipping points is one of the biggest concerns of climate scientists today. As we pass global warming of 1.5˚C, the most likely tipping points involve the collapse of ice sheets in Greenland or Antarctica, tropical coral reefs dying off, or abrupt thawing of Arctic permafrost.

Some say that there will be warning signs of these major climate shifts. However, these depend very much on the actual type of tipping point, and the interpretation of these signals is therefore difficult. One of the big questions is whether tipping points will be characterised by flickering or whether the climate will initially appear to become more stable before tipping over in one go.

620,000 years of environmental history

To investigate further, we gathered an international team of scientists and went to the basin of Chew Bahir in southern Ethiopia. There was an extensive lake here during the last African humid period, and deposits of sediment, several kilometres deep, underneath the lake bed record the history of climate-driven lake level fluctuations very precisely.

Today, the lake has largely disappeared and the deposits can be drilled relatively cheaply without the need for a drill rig on a floating platform or on a drillship. We drilled 280 metres below the dry lake bed – almost as deep as the Eiffel Tower is tall – and extracted hundreds of tubes of mud around 10 centimetres in diameter.

By putting these tubes together in order they form a so-called sediment core. That core contains vital chemical and biological information which records the past 620,000 years of eastern African climate and environmental history.

We now know that at the end of the African humid period there was around 1,000 years in which the climate alternated regularly between being intensely dry and wet.

In total, we observed at least 14 dry phases, each of which lasted between 20 and 80 years and recurred at intervals of about 160 years. Later there were seven wet phases, of a similar duration and frequency. Finally, around 5,500 years ago a dry climate prevailed for good.

Climate flickering

These high-frequency, extreme wet-dry fluctuations represent a pronounced climate flickering. Such flickering can be simulated in climate model computer programs and also happened in earlier climate transitions at Chew Bahir.

We see the same types of flickering during a previous change from humid to dry climate around 379,000 years ago in the same sediment core. It looks like a perfect copy of the transition at the end of the African humid period.

This is important because this transition was natural, as it occurred long before humans had any influence on the environment. Knowing such a change can occur naturally counters the argument made by some academics that the introduction of livestock and new agricultural techniques may have accelerated the end of the last African humid period.

Conversely, humans in the region were undoubtedly affected by the climate tipping. The flickering would have had a dramatic impact, easily noticed by a single human, compared to the slow climate transition spanning tens of generations.

It could perhaps explain why the archaeological findings in the region are so different, even contradictory, at times of the transition. People retreated during the dry phases and then some came back during the wet phases. Ultimately, humans retreated to the places that were consistently wet like the Nile valley.

Confirmation of climate flickering as precursors to a major climate tipping is important because it may also provide insights into possible early warning signals for large climate changes in future.

It seems that highly variable climate conditions such as rapid wet–dry cycles may warn of a significant shift in the climate system. Identifying these precursors now may provide the warning we need that future warming will take us across one of more of the sixteen identified critical climate tipping points.

This is particularly important for regions such as eastern Africa whose nearly 500 million people are already highly vulnerable to climate change induced impacts such as drought.

Martin H. Trauth, Professor, University of Potsdam; Asfawossen Asrat, Professor, Addis Ababa University, and Mark Maslin, Professor of Natural Sciences, UCL

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A critical NASA mission in the search for life beyond Earth, Mars Sample Return, is in trouble. Its budget has ballooned from US$5 billion to over $11 billion, and the sample return date may slip from the end of this decade to 2040.

The mission would be the first to try to return rock samples from Mars to Earth so scientists can analyze them for signs of past life.

NASA Administrator Bill Nelson said during a press conference on April 15, 2024, that the mission as currently conceived is too expensive and too slow. NASA gave private companies a month to submit proposals for bringing the samples back in a quicker and more affordable way.

As an astronomer who studies cosmology and has written a book about early missions to Mars, I’ve been watching the sample return saga play out. Mars is the nearest and best place to search for life beyond Earth, and if this ambitious NASA mission unraveled, scientists would lose their chance to learn much more about the red planet.

The habitability of Mars

The first NASA missions to reach the surface of Mars in 1976 revealed the planet as a frigid desert, uninhabitable without a thick atmosphere to shield life from the Sun’s ultraviolet radiation. But studies conducted over the past decade suggest that the planet may have been much warmer and wetter several billion years ago.

The Curiosity and Perseverance rovers have each shown that the planet’s early environment was suitable for microbial life.

They found the chemical building blocks of life and signs of surface water in the distant past. Curiosity, which landed on Mars in 2012, is still active; its twin, Perseverance, which landed on Mars in 2021, will play a crucial role in the sample return mission.

Why astronomers want Mars samples

The first time NASA looked for life in a Mars rock was in 1996. Scientists claimed they had discovered microscopic fossils of bacteria in the Martian meteorite ALH84001. This meteorite is a piece of Mars that landed in Antarctica 13,000 years ago and was recovered in 1984. Scientists disagreed over whether the meteorite really had ever harbored biology, and today most scientists agree that there’s not enough evidence to say that the rock contains fossils.

Several hundred Martian meteorites have been found on Earth in the past 40 years. They’re free samples that fell to Earth, so while it might seem intuitive to study them, scientists can’t tell where on Mars these meteorites originated. Also, they were blasted off the planet’s surface by impacts, and those violent events could have easily destroyed or altered subtle evidence of life in the rock.

There’s no substitute for bringing back samples from a region known to have been hospitable to life in the past. As a result, the agency is facing a price tag of $700 million per ounce, making these samples the most expensive material ever gathered.

A compelling and complex mission

Bringing Mars rocks back to Earth is the most challenging mission NASA has ever attempted, and the first stage has already started.

Perseverance has collected over two dozen rock and soil samples, depositing them on the floor of the Jezero Crater, a region that was probably once flooded with water and could have harbored life. The rover inserts the samples in containers the size of test tubes. Once the rover fills all the sample tubes, it will gather them and bring them to the spot where NASA’s Sample Retrieval Lander will land. The Sample Retrieval Lander includes a rocket to get the samples into orbit around Mars.

The European Space Agency has designed an Earth Return Orbiter, which will rendezvous with the rocket in orbit and capture the basketball-sized sample container. The samples will then be automatically sealed into a biocontainment system and transferred to an Earth entry capsule, which is part of the Earth Return Orbiter. After the long trip home, the entry capsule will parachute to the Earth’s surface.

The complex choreography of this mission, which involves a rover, a lander, a rocket, an orbiter and the coordination of two space agencies, is unprecedented. It’s the culprit behind the ballooning budget and the lengthy timeline.

Sample return breaks the bank

Mars Sample Return has blown a hole in NASA’s budget, which threatens other missions that need funding.

The NASA center behind the mission, the Jet Propulsion Laboratory, just laid off over 500 employees. It’s likely that Mars Sample Return’s budget partly caused the layoffs, but they also came down to the Jet Propulsion Laboratory having an overfull plate of planetary missions and suffering budget cuts.

Within the past year, an independent review board report and a report from the NASA Office of Inspector General raised deep concerns about the viability of the sample return mission. These reports described the mission’s design as overly complex and noted issues such as inflation, supply chain problems and unrealistic costs and schedule estimates.

NASA is also feeling the heat from Congress. For fiscal year 2024, the Senate Appropriations Committee cut NASA’s planetary science budget by over half a billion dollars. If NASA can’t keep a lid on the costs, the mission might even get canceled.

Thinking out of the box

Faced with these challenges, NASA has put out a call for innovative designs from private industry, with a goal of shrinking the mission’s cost and complexity. Proposals are due by May 17, which is an extremely tight timeline for such a challenging design effort. And it’ll be hard for private companies to improve on the plan that experts at the Jet Propulsion Laboratory had over a decade to put together.

An important potential player in this situation is the commercial space company SpaceX. NASA is already partnering with SpaceX on America’s return to the Moon. For the Artemis III mission, SpaceX will attempt to land humans on the Moon for the first time in more than 50 years.

However, the massive Starship rocket that SpaceX will use for Artemis has had only three test flights and needs a lot more development before NASA will trust it with a human cargo.

In principle, a Starship rocket could bring back a large payload of Mars rocks in a single two-year mission and at far lower cost. But Starship comes with great risks and uncertainties. It’s not clear whether that rocket could return the samples that Perseverance has already gathered.

Starship uses a launchpad, and it would need to be refueled for a return journey. But there’s no launchpad or fueling station at the Jezero Crater. Starship is designed to carry people, but if astronauts go to Mars to collect the samples, SpaceX will need a Starship rocket that’s even bigger than the one it has tested so far.

Sending astronauts also carries extra risk and cost, and a strategy of using people might end up more complicated than NASA’s current plan.

With all these pressures and constraints, NASA has chosen to see whether the private sector can come up with a winning solution. We’ll know the answer next month.

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The more gender equal a society is, the more similar men and women will be, adopting more similar interests, personality traits and behavioural patterns. Or so many people seem to believe.

Statements like this might sound like truisms, but science shows reality may be more complicated.

Several studies have found that some psychological sex differences, such as those in personality, are larger in more gender-equal countries. The same goes for countries that are more educated, prosperous and otherwise have better living conditions. This has become known as the gender-equality paradox.

Until recently, it was unclear how widespread this pattern might be. My team, which included research assistant Kare Hedebrant, tried to address that in a recently published study, where we investigated which psychological sex differences are associated with living conditions and, if so, how.

The study covered a range of themes, from personality and cognitive functions to sexting and circadian rhythm. Our study focused on mostly western countries but used some data from other countries such as India and Kenya.

We reviewed 54 articles that analyse the relationship between magnitudes of psychological sex differences and country-level indicators of living conditions. We also used data from 27 meta-analyses (reviews of previous research) of psychological sex differences and conducted new analyses to determine associations between sex differences and national economy, education, health, gender equality and more.

Sex differences

Each study used data from at least five countries, usually spanning several decades.

We grouped the many psychological dimensions covered by these studies into six categories: personal characteristics, cognition, interpersonal relations, emotion, academic preferences (such as a pull towards science, technology, engineering and maths) and morals and values.

Our findings paint a complex picture, showing that variation in psychological sex difference did not follow a uniform pattern. In countries with better living conditions, males and females are more alike in some regards and more different in others.

For example, differences in personality characteristics were frequently found to be larger in countries with better living conditions. This includes traits such as extroversion, agreeableness and altruism, which research seems to show are more strongly associated with women. The same was true for sex differences in some dimensions of emotion, specifically negative emotions in which females tend to score higher, such as shame.

There were also exceptions to the gender-equality paradox. Sex differences in sexual behaviour, like engaging in casual sex, were consistently found to be smaller in countries with better living conditions. This is probably because women in these countries, where there are more permissive norms, have better access to contraceptives.

A complicated phenomenon

For cognitive functions, sex differences were sometimes larger, sometimes smaller in countries with better living conditions. Interestingly, the sex differences were larger in cognitive domains where women have strengths.

For instance, episodic memory (memory for experienced events) and verbal ability, where females typically do better than males, saw larger sex differences as living conditions improved. Females got better at episodic memory when they had better living conditions. By contrast, sex differences in semantic memory (memory for facts) and mathematical ability, where males tend to do better, decreased when living conditions improved.

This suggests that, when it comes to cognitive abilities, females benefit more than males from improvements in living conditions. The performance gap increases in domains where females have an advantage and closes in domains where males are ahead.

Not all psychological sex differences were associated with living conditions in the same way. So, can we say that there is a gender-equality paradox? Yes, to some extent, since more sex differences grew, rather than decreased, in countries with better living conditions.

In most cases, however, psychological sex difference magnitudes were not significantly associated with living conditions. This suggests that, in general, psychological sex differences are not greatly affected by living conditions but seem instead quite stable. For instance, research often finds females get higher grades at school across different subjects. It’s also common for researcher to find males have greater interest in maths. But neither seems to be affected by living conditions.

Even in cases where the magnitude of sex differences did vary in relation to living conditions, the pattern of male and female advantages usually remained the same. So, for example, though the female advantage over males in episodic memory ability is greater in some countries than others, females outperform males in almost all countries.

In summary, we found little support for the idea that psychological sex differences will vanish as societies develop. Policymakers probably cannot rely on that if they hope to achieve equal distributions of men and women in different professions. Instead, it appears that the dominant feature of psychological sex differences is their robustness in the face of social change.

Image for Representation
| Photo Credit: Getty Images/iStockphoto

Imagine the tap of a card that bought you a cup of coffee this morning also let a hacker halfway across the world access your bank account and buy themselves whatever they liked. Now imagine it wasn’t a one-off glitch, but it happened all the time: imagine the locks that secure our electronic data suddenly stopped working.

This is not a science fiction scenario. It may well become a reality when sufficiently powerful quantum computers come online. These devices will use the strange properties of the quantum world to untangle secrets that would take ordinary computers more than a lifetime to decipher.

We don’t know when this will happen. However, many people and organisations are already concerned about so-called “harvest now, decrypt later” attacks, in which cybercriminals or other adversaries steal encrypted data now and store it away for the day when they can decrypt it with a quantum computer.

As the advent of quantum computers grows closer, cryptographers are trying to devise new mathematical schemes to secure data against their hypothetical attacks. The mathematics involved is highly complex – but the survival of our digital world may depend on it.

‘Quantum-proof’ encryption

The task of cracking much current online security boils down to the mathematical problem of finding two numbers that, when multiplied together, produce a third number. You can think of this third number as a key that unlocks the secret information. As this number gets bigger, the amount of time it takes an ordinary computer to solve the problem becomes longer than our lifetimes.

Future quantum computers, however, should be able to crack these codes much more quickly. So the race is on to find new encryption algorithms that can stand up to a quantum attack.

The US National Institute of Standards and Technology has been calling for proposed “quantum-proof” encryption algorithms for years, but so far few have withstood scrutiny. (One proposed algorithm, called Supersingular Isogeny Key Encapsulation, was dramatically broken in 2022 with the aid of Australian mathematical software called Magma, developed at the University of Sydney.)

The race has been hotting up this year. In February, Apple updated the security system for the iMessage platform to protect data that may be harvested for a post-quantum future.

Two weeks ago, scientists in China announced they had installed a new “encryption shield” to protect the Origin Wukong quantum computer from quantum attacks.

Around the same time, cryptographer Yilei Chen announced he had found a way quantum computers could attack an important class of algorithms based on the mathematics of lattices, which were considered some of the hardest to break. Lattice-based methods are part of Apple’s new iMessage security, as well as two of the three frontrunners for a standard post-quantum encryption algorithm.

What is a lattice-based algorithm?

A lattice is an arrangement of points in a repeating structure, like the corners of tiles in a bathroom or the atoms in a diamond crystal. The tiles are two dimensional and the atoms in diamond are three dimensional, but mathematically we can make lattices with many more dimensions.

Most lattice-based cryptography is based on a seemingly simple question: if you hide a secret point in such a lattice, how long will it take someone else to find the secret location starting from some other point? This game of hide and seek can underpin many ways to make data more secure.

A variant of the lattice problem called “learning with errors” is considered to be too hard to break even on a quantum computer. As the size of the lattice grows, the amount of time it takes to solve is believed to increase exponentially, even for a quantum computer.

The lattice problem – like the problem of finding the factors of a large number on which so much current encryption depends – is closely related to a deep open problem in mathematics called the “hidden subgroup problem”.

Yilei Chen’s approach suggested quantum computers may be able to solve lattice-based problems more quickly under certain conditions. Experts scrambled to check his results – and rapidly found an error. After the error was discovered, Chen published an updated version of his paper describing the flaw.

Despite this discovery, Chen’s paper has made many cryptographers less confident in the security of lattice-based methods. Some are still assessing whether Chen’s ideas can be extended to new pathways for attacking these methods.

More mathematics required

Chen’s paper set off a storm in the small community of cryptographers who are equipped to understand it. However, it received almost no attention in the wider world – perhaps because so few people understand this kind of work or its implications.

Last year, when the Australian government published a national quantum strategy to make the country “a leader of the global quantum industry” where “quantum technologies are integral to a prosperous, fair and inclusive Australia”, there was an important omission: it didn’t mention mathematics at all.

Australia does have many leading experts in quantum computing and quantum information science. However, making the most of quantum computers – and defending against them – will require deep mathematical training to produce new knowledge and research.

A: Shivering (physical thermogenesis) occurs when the tension of the skeletal muscles rises beyond a critical level or when the body temperature falls below the critical level of 37.1 degrees C.

Shivering is actually an involuntary contraction of muscles to maintain body temperature during fever and in cool environments. It involves oscillating skeletal-muscle contractions that occur at 10-20 per second. The movement is at first irregular, then assumes quick involuntary movements during which small groups of muscles contract asynchronously. Due to the asynchronous movement, they do not move the parts associated with them in a coordinated manner.

The posterior hypothalamus region in the brain harbours the primary motor centre responsible for shivering. When the body temperature falls below 37.1 degrees C, the skin sends cold signals to the spinal cord. These are picked by the hypothalamus, which takes advantage of the fact that increased skeletal-muscle activity generates heat. Acting through descending pathways that terminate on the motor neurons controlling the body’s skeletal muscles, the hypothalamus gradually increases skeletal-muscle tone (constant level of tension within muscles).

Thus shivering begins throughout the body when the tension of the skeletal muscles rises beyond the critical level, producing heat and increasing the temperature of the body within a matter of seconds. Studies reveal that shivering may produce as much as 42.5 cal/hr, almost seven times greater than man’s normal resting metabolism at room temperature. In a resting person, most body heat is produced by the thoracic and abdominal organs due to ongoing metabolic activities.

Generally, shivering is seen only in birds and mammals.

Over the last 25 years, the ozone hole which forming over Antarctica each spring has started to shrink.

But over the last four years, even as the hole has shrunk it has persisted for an unusually long time. Our new research found that instead of closing up during November it has stayed open well into December. This is early summer – the crucial period of new plant growth in coastal Antarctica and the peak breeding season for penguins and seals.

That’s a worry. When the ozone hole forms, more ultraviolet rays get through the atmosphere. And while penguins and seals have protective covering, their young may be more vulnerable.

Why does ozone matter?

Over the past half century, we damaged the earth’s protective ozone layer by using chlorofluorocarbons (CFCs) and related chemicals. Thanks to coordinated global action these chemicals are now banned.

Because CFCs have long lifetimes, it will be decades before they are completely removed from the atmosphere. As a result, we still see the ozone hole forming each year.

The lion’s share of ozone damage happens over Antarctica. When the hole forms, the UV index doubles, reaching extreme levels. We might expect to see UV days over 14 in summers in Australia or California, but not in polar regions.

Luckily, on land most species are dormant and protected under snow when the ozone hole opens in early spring (September to November). Marine life is protected by sea ice cover and Antarctica’s moss forests are under snow. These protective icy covers have helped to protect most life in Antarctica from ozone depletion – until now.

Unusually long-lived ozone holes

A series of unusual events between 2020 and 2023 saw the ozone hole persist into December. The record-breaking 2019–2020 Australian bushfires, the huge underwater volcanic eruption off Tonga, and three consecutive years of La Niña. Volcanoes and bushfires can inject ash and smoke into the stratosphere. Chemical reactions occurring on the surface of these tiny particulates can destroy ozone.

These longer-lasting ozone holes coincided with significant loss of sea ice, which meant many animals and plants would have had fewer places to hide.

What does stronger UV radiation do to ecosystems?

If ozone holes last longer, summer-breeding animals around Antarctica’s vast coastline will be exposed to high levels of reflected UV radiation. More UV can get through, and ice and snow is highly reflective, bouncing these rays around.

In humans, high UV exposure increases our risk of skin cancer and cataracts. But we don’t have fur or feathers. While penguins and seals have skin protection, their eyes aren’t protected.

Is it doing damage? We don’t know for sure. Very few studies report on what UV radiation does to animals in Antarctica. Most are done in zoos, where researchers study what happens when animals are kept under artificial light.

Even so, it is a concern. More UV radiation in early summer could be particularly damaging to young animals, such as penguin chicks and seal pups who hatch or are born in late spring.

As plants such as Antarctic hairgrass, Deschampsia antarctica, the cushion plant, Colobanthus quitensis and lots of mosses emerge from under snow in late spring, they will be exposed to maximum UV levels.

Antarctic mosses actually produce their own sunscreen to protect themselves from UV radiation, but this comes at the cost of reduced growth.

Trillions of tiny phytoplankton live under the sea ice. These microscopic floating algae also make sunscreen compounds, called microsporine amino acids.

What about marine creatures? Krill will dive deeper into the water column if the UV radiation is too high, while fish eggs usually have melanin, the same protective compound as humans, though not all fish life stages are as well protected.

Four of the past five years have seen sea ice extent reduce, a direct consequence of climate change.

Less sea ice means more UV light can penetrate the ocean, where it makes it harder for Antarctic phytoplankton and krill to survive. Much relies on these tiny creatures, who form the base of the food web. If they find it harder to survive, hunger will ripple up the food chain. Antarctica’s waters are also getting warmer and more acidic due to climate change.

An uncertain outlook for Antarctica

We should, by rights, be celebrating the success of banning CFCS – a rare example of fixing an environmental problem. But that might be premature. Climate change may be delaying the recovery of our ozone layer by, for example, making bushfires more common and more severe.

Ozone could also suffer from geoengineering proposals such as spraying sulphates into the atmosphere to reflect sunlight, as well as more frequent rocket launches.

If the recent trend continues, and the ozone hole lingers into the summer, we can expect to see more damage done to plants and animals – compounded by other threats.

We don’t know if the longer-lasting ozone hole will continue. But we do know climate change is causing the atmosphere to behave in unprecedented ways. To keep ozone recovery on track, we need to take immediate action to reduce the carbon we emit into the atmosphere.

Argentine palaeontologist Sebastian Rozadilla holds a fossil of the Chakisaurus nekul, an newly-discovered herbivorous dinosaur that lived about 90 million years ago in the Patagonia region, at the Buenos Aires’ Natural Science museum, in Buenos Aires, Argentina April 24, 2024.
| Photo Credit: Reuters

Palaeontologists from Argentina announced the discovery of a new medium-sized herbivorous dinosaur, which was a fast runner and lived about 90 million years ago in the Late Cretaceous period in present day Patagonia.

The animal, named Chakisaurus nekul, was found in the Pueblo Blanco Natural Reserve, in the southern province of Río Negro, an area rich in fossils where many mammals, turtles, and fish have been found along with other species of dinosaur.

It is estimated that the largest Chakisaurus reached 2.5 or 3 meters long and was 70 centimeters high (8 to 10 feet long and 27 inches high).

Studies of Chakisaurus yielded new findings indicating that it was a fast runner and had its tail curved unusually downward.

“This new species, Chakisaurus nekul, was a bipedal herbivore that among its most important characteristics had a tail that, unlike other dinosaurs, which was horizontal, had a downward curvature,” said Rodrigo Álvarez, author of the study.

“It is something super new for these animals. In addition, it is known that it was a good runner, which was something it needed because it lived with a large number of predators and its only defense was to be faster than them.”

The dinosaur’s name derives from Chaki, which is a word from the Aonikenk language, of the indigenous Tehuelche people, which means “old guanaco”, a reference to a medium-sized herbivore mammal found in the region. Nekul means “fast” or “agile” in the Mapudungún language, of the local Mapuche people.

“He had very strong hind limbs and a tail with an anatomy that allowed him to maneuver it to the sides and so be able to balance during races,” Sebastián Rozadilla, co-author of the publication, explained to Reuters.

A team of Argentine paleontologists with the support of the National Geographic Society, made the discovery initially in 2018, but recently unveiled their finding in the journal Cretaceous Research.

Flowering plants – from corn, wheat, rice and potatoes to maple, oak, apple and cherry trees as well as roses, tulips, daisies and dandelions and even the corpse flower and voodoo lily – are cornerstones of Earth’s ecosystems and essential for humankind.
| Photo Credit: Reuters

Flowering plants – from corn, wheat, rice and potatoes to maple, oak, apple and cherry trees as well as roses, tulips, daisies and dandelions and even the corpse flower and voodoo lily – are cornerstones of Earth’s ecosystems and essential for humankind.

New research based on genome data for 9,506 species, as well as an examination of 200 fossils, provides the deepest understanding to date of the evolutionary history of flowering plants, called angiosperms – the largest and most diverse plant group. It details how angiosperms appeared and became dominant during the age of dinosaurs and how they have changed over time.

The scientists devised a new tree of life for angiosperms, covering 15 times more types of flowering plants – nearly 60% of them – than the nearest comparable study.

“It is a massive leap forward in our understanding of plant evolution,” said botanist William Baker of the Royal Botanic Gardens, Kew (RBG Kew) in London, senior author of the research published on Wednesday in the journal Nature.

Angiosperms, plants that produce flowers and generate their seeds in fruits, encompass about 330,000 species and comprise about 80% of the world’s plants. They include, among others, all the major food crops, grasses, most broad-leaved trees and most aquatic plants. Their closest relatives are the gymnosperms, a group that preceded them on Earth and includes conifers and some others, with a bit more than 1,000 species.

The study identified two pulses of diversification among angiosperms. The first one occurred around 150-140 million years ago at the dawn of their existence during the Mesozoic era, with 80% of major angiosperm lineages arising during that time. The next one happened about 100 million years later during the Cenozoic era, after the demise of the dinosaurs and the rise of mammals, amid decreasing global temperatures.

“Angiosperms have many structural adaptations that confer advantages over gymnosperms, but chief among these are those contributing to reproductive success,” Baker said.

Gymnosperms and angiosperms both have seeds, but the flowering plants have enclosed seeds that protect them from dehydration and enable them to prosper in a wider range of environments, from tropics to deserts to Antarctica.

They also evolved the flower, a structure that allowed them to form relationships with animal pollinators, especially insects, while gymnosperms usually rely upon the wind for pollination. Angiosperms evolved a high diversity of fruit types, permitting effective seed dispersal.

“With these innovations, angiosperms have become invincible,” Baker said.

Charles Darwin, the 19th century British naturalist and architect of evolutionary theory, was astonished by how flowering plants exploded onto the scene in the Mesozoic fossil record.

In an 1879 letter to Joseph Hooker, RBG Kew’s then-director, Darwin wrote that “the rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery.”

“Remarkably,” Baker said, “we have been able to use the ‘molecular fossil record,’ the accumulated change in DNA over time, to see real evidence of that explosion happening at the dawn of the angiosperms.”

Flowering plants provide the majority of calories consumed by humans – grains, fruits and vegetables – including indirectly as feed for livestock. They also have enthralled people with their beauty – fields of sunflowers, bouquets of roses, bunches of calla lilies – and their pleasant fragrance.

“They are sources of many of our medicines and hold potential solutions to global challenges, such as climate change, biodiversity loss, human health, food security and renewable energy,” Baker said.

The study could help scientists better understand disease and pest resistance in angiosperms and navigate potential new medicinal uses – for example, to combat malaria.

“Combining the tree of life with extinction risk assessments for each lineage allow us to prioritize lineages for conservation based on their uniqueness,” RBG Kew botanist and study lead author Alexandre Zuntini said. “This is extremely important for mankind, as these lineages may hold chemical compounds or even genes that can be useful for survival of our species.”