Astronomers and scientists, not to mention science fiction writers, have often considered whether Mars can be colonised by human beings. The nearest planet to Earth, Mars has a thin atmosphere, desolate landscape and a higher radiation exposure yet still the allure of having a colony persists.
The renowned science journal, Nature, has devised an interactive game to see how terraforming Mars might work. The game is short, easy to do and consists of interactive multi-choice questions. Access to the game can be found at this hyperlink: nature.com -terriform mars game
The Rays and Shadows is set in the immediate period before and during World War II and is based on the true life story of newspaper publisher, Jean Luchaire and his daughter, Corinne, a French film actress. Luchaire supports peace between France and Germany and becomes a collaborator with the German occupying forces and a member of the Vichy Government until 1945.
The plot: Jean Luchaire (Jean Dujardin) is a failing newspaper publisher who co-sponsors a peace movement with Germany. He befriends Francophile German citizen, Otto Abetz who secures additional finance for Luchaire's newpaper from German Government sources. When WWII breaks out, Abetz is appointed as the Nazi German Ambassador to the Vichy Government and continues supporting Luchaire. Luchaire's daugher, Corrine (Nastya Golubeva) is a rising star in French cinema but as the war looms her opportunities decline due to a diagnosis of tuberculosis and she increasingly becomes dependent on German support for her career. Both she and her father benefit not only from the German occupation of France but from a range of black market opportunities, embassy parties and access to the Nazi administration. The film portrays the seduction of collaboration, power and privilege extensively. After the war, Jean Luchaire, was placed on trial by the French and executed. His daughter Corrine was found guilty of collaboration but deemed to have committed a lower level offence and she spent her final years under the sentence of indignite nationale before dying from tuberculosis in 1950.
Nastya Golubeva in TheRays and Shadows
The film is expertly photographed with capable actors however with a screening time of over three hours, the film is too long and would have benefitted from sharper editing. Too many scenes are ancillary to the story and neither essential nor useful. Described as a 'sweeping drama', film director and screenwriter Xavier Giannoli could have wielded the red pen on the script and editing room 'scissors' before release.
Run time: 199 minutes
Rating [/10]: 6 out of 10
Recommended for cinema viewing: No. Recommended for streaming or subscription service viewing
Best described as sweet but very slow, this film by Japanese screenwriter and film director Hirokazu Kore-eda falls within the sci-fi genre covering the very topical issue of AI and robotics in a very human context.
Plot: Set in the near future, couple Otone (Haruka Ayase) and her husband Kensuke (Daigo Yamamoto) are mourning their young son who has died in mysterious circumstances. Turning to an AI/Robotics company, REbirth, they are supplied with a state-of-the-art humanoid replicantion of their lost son, Kakeru (Rimu Kuwaki). Although initially the humanoid has limited communication, over time this interaction improves despite Kensuke's dismissive references to a 'Tamagotchi' or a 'Roomba'. The couple are astonished to discover that memories of their past life with their son are surfacing from the humanoid. Memories that it should not have.
Rimu Kuwaki in Sheep in the box
The film is very slow moving with long scenes containing little activity or dialogue. It's non violent film generally and has elements of sentimentality especially when the humanoid Kakeru links up with other humanoid and human orphan children to depart for a special forest to make a home for themselves. Acting and cinematography meets the professional standard in film-making and its a pleasurable viewing experience although the film is too long at 126 minutes.
The subject of child abuse and its' impact on a family is the central focus of Gentle Monster.
Plotline: Famous concert pianist, Lucy (Lea Sedoux), her husband Philip (Laurence Rupp) and their young son move to the countryside as Philip is suffering increasingly from burnout. They settle in a country house outside of Munich into a calmer life and all seems idyllic until one morning the police arrive and seize Philip's electronic equipment and remove him for questioning. As the film progresses, Lucy questions if she knows the man she married and moment by moment comes to the realisation that Philip is guilty of trafficking child pornography for money. Lucy seeks a way forward to protect her son and herself while Philip continues to try and save the marriage. She initially supports her husband but following his confession to her and mounting evidence including that photos of their own son had been used, it becomes clear to her that the only option is to leave.
The film is tastefully photographed and veers away from sensationalism with measured performances from the cast. The film does have some structural problems. The flashbacks used to portray images of the previous happy family life and Lucy's various concert performances are not seamless but rather muddled, distracting and seemingly dropped into the film. There are various substrata tensions with various characters alluding to other personal issues that appear unnecessary for the overall story itself.
Lea Seydoux superbly portrays a woman experiencing a range of emotions from shock, devastation, anger to optimism. Catherine Deneuve is cast as her emotionally distant mother who makes it plain that she never approved of her daughter's marriage but provides her with limited but useful support. Writer and film director Marie Kreutzer has created a powerful and morally complex film traversing a highly emotive topic.
It's difficult to find a high point aspect of this feature film other than it is just over an hour and half in duration. Viewers looking for a very funny comedy about couples relationships, sex parties, open marriages while avoiding the prodigious use of the "F"word will be disappointed by what appears on the screen.
The plot: The film is set in San Francisco in the apartment of Joe (Seth Rogan) and Angela (Olivia Wilde), best described as two tightly knit individuals with tension in their marriage. Angela invites their neighbours (Edward Norton and Penelope Cruz) from upstairs over for dinner. The neighbours are attractive, free spirited individuals who experiment with other relationships in their marriage. This makes for a tension filled evening as the couples dance around meanings and descriptions with each other.
The Invite
The scenes for the film are various rooms in the apartment where Joe and Angela live, giving rise to the impression that these performances would be better as a live stage theatre production rather than an on-camera effort. In summary, the film largely consists of Seth Rogan venting then subsiding like a volcano, Olivia Wilde trying different versions of wide incredulous eyes, Edward Norton perfecting smirking and Penelope Cruz simply trying to appear sublime and seductive around the chaos. It has the feel of an actor's workshop for experimenting with improvisation rather than a series of refined, sharp repartee responses.
Run time: 107 minutes
Rating [/10]: 5 out of 10
Recommended for cinema ticket: No. Wait for streaming or subscription services for viewing.
The Australian government has agreed to invest almost $53 million in a north Tasmanian company that will upgrade its coal-fired kiln to burn wood “waste” and used tyres for cement manufacturing.
The Federal Minister for Climate Change, Chris Bowen, says this initiative will help decarbonise the Australian economy.
However, the science is clear: burning forest biomass, or so-called forest “waste” – which could include dead trees, understorey vegetation and fallen logs – generates large amounts of carbon emissions. It will likely also accelerate poor forest health.
The empirical evidence shows burning forest biomass to make concrete is poor climate policy, poor environmental and forest policy, and a poor use of taxpayer funds.
Why is this happening?
In line with climate change treaty commitments under the Paris Agreement, governments worldwide are working to decarbonise their economies in an attempt to limit global warming.
This includes finding alternative sources of clean energy to using fossil fuel. This is especially important for carbon-intensive, high-polluting industries, such as concrete production. While about 56% of concrete emissions come from processing clinker (the base material for cement), 39% come from using fossil fuel to generate heat, and 14% from electricity.
Unfortunately, forest biomass is increasingly being promoted as an energy source to replace fossil fuels, for example in the United Kingdom and Europe. Most forest biomass used to generate energy will likely be trees. And what is often referred to as “waste” is actually a critical part of the structure and composition of natural forests. For example, understorey vegetation and logs provide habitat for a wide range of animal species. They play an essential role in nutrient cycling, such as storing substantialamounts of carbon.
Whilst forest biomass is technically a renewable resource, as trees can be regrown after logging, it is not a source of clean energy. This is because about half of tree biomass is carbon (assuming a moisture content of 45%). Therefore, burning a tonne of wood generates roughly a tonne of carbon dioxide emissions. Importantly, up to 30% of carbon dioxide emissions are still in the atmosphere after 1,000 years.
Concrete and its primary ingredient, cement, account for up to 8% of global carbon emissions. This is because high heat is required to turn limestone into ‘clinker’.chameleonseye/Getty
The time lag between release and absorption
Critically, there is a highly significant lag time, of decades to centuries, between carbon being instantaneously released from burning forest biomass and when it is removed from the atmosphere. These removals occur either by plant growth or through carbon making its way to the bottom of the ocean.
The lag time between burning forest biomass and tree regrowth is important because the increase in atmospheric carbon dioxide concentrations causes even more climate change. This is one of the key reasons why widespread burning of forest biomass in some European countries threatens their ability to meet Paris Agreement greenhouse gas reduction targets.
Furthermore, forest biomass has a far lower calorific content relative to coal. This means large quantities of forest material has to be burned to generate an equivalent amount of energy. This high demand for wood for biomass energy can contribute significantly to poor forest health.
Notably, Australia, along with many other governments, has committed to ending deforestation and degradation by 2030. This recognises the importance of forest carbon sequestration and storage in meeting climate targets and achieving the Paris Agreement goals.
Not an isolated example
The Tasmanian plan, that would see Cement Australia burn forest “waste” to generate energy, is far from an isolated case. There are well-developed plans for Verdant Earth Industries to reopen the former coal-fired Redbank Power Station in the Hunter Valley, in New South Wales, and generate energy by burning hundreds of thousands of tonnes of “wood waste” annually.
Much of this “waste” will likely be trees from forest and woodland regrowth, which are fundamental to the integrity of those ecosystems. This regrowth also provides habitat for a vast array of species, including a range of threatened species.
Biomass burning is frequently supported by native forest logging advocates because of structural issues in the industry. These issues include attempts to extract some financial return from an industry that is largely unprofitable. The native forest sector produces primarily low-value, high-volume commodities such as [woodchips and paper pulp], whereas plantation forest sector dominates high-value sawn wood products.
Similarly, state government forestry agencies have been unable to get market certification for wood products such as woodchips and pulpwood from bodies such as the Forest Stewardship Council. This is partly because the areas logged to produce wood products are often are home to a diverse range of plants and animals that may be threatened by logging.
Decarbonisation matters
We fully acknowledge the efforts being made to explore how emissions-intensive industries can be decarbonised, such as reducing the clinker content in cement.
However, Australian governments must stop using taxpayer money to subsidise projects that entail large-scale burning of forest and woodland biomass for industrial energy.
Alternative forms of energy, including concentrated solar power, will be important in this regard. Unlike forest biomass burning, these are both renewable and clean sources of energy.
The return to Germany in 1949 of Nobel Prize winning writer, Thomas Mann is the subject of this first rate directed, acted and photographed film by acclaimed Polish director Pawel Pawlikowski.
The Plot: Mann (Hanns Zischler) had left Germany in 1933 following Hitler's rise to power and his first visit to his homeland, since the end of WWII, accompanied by his daughter Erika (Sandra Huller), is to receive the Goethe Prize. Photographed in black and white, the film conveys the images of a Germany in ruins with shortages of most consumer items and limited public services. Welcomed warmly by the Mayor of Frankfurt, Mann must contend with threats labelling him as a 'traitor' and 'communist scum' from the wider community. In various social cocktail parties, Mann's former colleagues are at pains to mitigate or deny their cooperation with the former Nazi regime. He will have none of it. Mann also receives an invitation to visit Weimar in the Soviet occupation zone where he is also to receive another Goethe award. His road trip in his black Buick through the zones and finally to Weimar provides a contrast between the US and Soviet occupations. A personal family loss adds to the pressure of this trip.
Sandra Huller and Hanns Zischler in Fatherland
A film with a profound story of family, loss and guilt in a time of extreme turmoil.
Winner of the Grand Prix at the Cannes Film Festival 2026
Winner of the Jury Prize at the Sydney Film Festival 2026
Best described as a complex, urgent and ultimately provocative film by the master Russian film director, Andrey Zvyagintsev, Minotaur confronts both personal crises and societal ones simultaneously. Set in Russia in 2022, the backdrop of the Russia-Ukraine war is an ever constant in this thriller.
Plotline: A successful businessman, Gleb (Dmitriy Mazurov) is living in an idyllic, expensive waterfront home with his wife Galina (Iris Lebedeva) and their young son. The usual stresses of life appear to the same as for most normal families. But these are not normal times. Gleb's staff are resigning and disappearing and he is under pressure to assist with filling recruitment quotas for the Russian Army. News reports show Russian citizens heading for the borders with other countries and Gleb finds he is facing another distraction as he fears his wife is having an affair. After hiring a private detective, his worst fears are confirmed and a suspect lover is identified. He now must face two challenges of trying to protect his staff from being drafted and dealing with his wife's lover. Fateful decisions are made to resolve both matters.
Dmitriy Mazurov in Minotaur
With well paced scenes, selected locations and meaningful dialogue matched with precision atmospheric cinematography, Minotaur is a taunt thriller.
The plotline: In February 1977, failed property developer Tony Kiritsis (Bill Skarsgard) ties a shotgun trigger to the neck of mortgage broker Richard Hall (Dacre Montgomery) and abducts him. Holding Hall as a hostage in his own crumbling apartment, Kiritsis claims to the police and increasing media circus that he has been betrayed in a land deal with Hall's father. Seeking financial compensation and a public apology Kiritsis portrays himself as the little guy whose dream has been stolen by morally corrupt elites. The actions of Hall's father (Al Pacino) to his son's abduction only reinforces that perception. The film essentially follows the abduction seige before finally a negotiated hostage release occurs and Kiritsis is arrested.
The film is well-paced, capably acted drama in a period setting from over 49 years ago. Van Sant is a long-term experienced director with a formidable list of film credits particularly in social commentary/issues stories.
Dacre Montgomery and Bill Skarsgard in Dead Man's Wire
Run time: 105 minutes
Rating [/10]: 7 out of 10
Recommended for cinema viewing: No. Streaming or subscription viewing.
Whales and dolphins inhabit some of the largest and seemingly most pristine environments on Earth, from tropical coastlines to Antarctic waters. Yet even they cannot escape PFAS – persistent “forever chemicals” that leak from our homes, factories and waterways into the sea.
Forever chemicals are the secret ingredients in our non-stick pans, waterproof jackets and stain-resistant carpets. These chemicals belong to a group of more than 1,400 compounds known as PFAS (per- and polyfluoroalkyl substances). They enter the environment through manufacturing waste, industrial runoff, wastewater treatment plants and firefighting foams. But once these chemicals escape our homes and factories, they become almost impossible to get rid of. Washed into waterways, they make their way to the sea.
Small organisms absorb them from the water, fish eat those organisms and larger predators eat the fish. At each step, the chemical load increases. As top predators, whales and dolphins can end up with very high levels in their bodies. Not even deep-diving species living and feeding far from humans are safe.
In our new research, we found PFAS concentrations in cetaceans have increased globally since 2000. Animals in the Pacific Ocean were the most contaminated, with humpback dolphins showing the highest PFAS concentrations.
These mammals are sentinels of ocean health. They sit high in the food web, live for many years and are exposed to pollution across large areas of the ocean. When whales and dolphins show signs of chemical exposure, it tells us something is wrong in the wider marine ecosystem.
Forever chemicals move through the food web and end up in the bodies of high-level predators such as dolphins.Dmitry Miroshnikov/Getty
Why are we worried about forever chemicals?
Many of these chemicals have been in use for decades. Their sheer durability and ability to resist heat, oil and water make them very useful.
Scientists have grown increasingly concerned about them because they persist for decades and build up over time in our own bodies, as well as in wildlife and the broader environment.
The key concern is what these chemicals may be doing to the animals that accumulate them.
Research in humans and laboratory animals links PFAS to immune suppression, hormonal changes, reproductive problems and developmental effects. But we don’t yet have enough research to understand how different PFAS compounds and levels of exposure affect health.
Understanding these impacts in whales and dolphins is harder still. Marine mammals are long-lived, highly mobile and exposed to many human-made problems at once, from climate change to noise pollution to other contaminants.
Even so, there are warning signs. Some dolphin studies have reported changes in immune-related markers associated with PFAS exposure.
How do you test a whale for forever chemicals?
For humans, testing PFAS levels is usually done with a blood test. It is not as simple for whales and dolphins.
It is extremely difficult to take blood samples from large marine mammals in the wild. Scientists often rely on tissue samples from dead animals, particularly from the liver and kidney where many PFAS compounds tend to accumulate. These samples are analysed in specialised laboratories capable of detecting tiny concentrations of individual PFAS compounds.
This way, scientists have been measuring PFAS in whales and dolphins for decades. Each study added another piece to the puzzle, showing these chemicals were present in different species, populations and oceans.
Our study took a step back and looked at the global picture.
We compiled PFAS data from cetaceans worldwide, focusing on liver samples because they are the most commonly available tissue type, allowing us to compare studies across species and regions.
What did we find?
We found PFAS contamination differed substantially across species, location, sex, age and time.
Infographic showing the main findings of the study.CC BY
The highest concentrations tended to be found in coastal dolphins and porpoises, suggesting animals living near urban and industrial areas face greater exposure.
Cetaceans in the Pacific had higher levels than other oceans. This is likely due to high industrial activity and the extent of historical PFAS production in coastal regions.
Female whales and dolphins can transfer forever chemicals during pregnancy and nursing. This means their calves can be exposed to concerning levels of PFAS at a very early age.
Males often end up with higher levels than females overall, as they cannot transfer these chemicals to their young.
There are some large gaps in the global dataset we collated, which means we don’t fully know the extent of PFAS contamination in cetaceans off India, Indonesia and parts of Africa.
Female whales and dolphins can transfer forever chemicals to their calves.Kerstin Meyer/Getty
What should we do?
While important questions remain about the effects of forever chemicals on whales and dolphins, the widespread contamination we observed is a real concern. We need to continue monitoring while strengthening regulations and working to reduce PFAS flows into the environment.
History shows global action on harmful chemicals works. After it became clear Earth’s protective ozone layer was being eaten away, nations agreed to phase out the chemicals responsible. The ozone layer is now recovering.
The European Union moved to ban some PFAS compounds 20 years ago. Our study found lower levels of some legacy PFAS compounds in the Mediterranean Sea, a pattern that may reflect the effects of regulation. This is positive, but not sufficient given overall PFAS levels in whales and dolphins have increased globally over time. The EU is now moving to better regulate this class of forever chemicals.
Forever chemicals are one of the defining pollution challenges of our time. The more we understand how these chemicals accumulate in whales and dolphins, the better equipped we will be to reduce future contamination and protect marine ecosystems.
What ends up in the ocean does not simply disappear. And neither do PFAS.
This article is based on collaborative research that also included Lavinia Stokes (University of Wollongong), Jesuina de Araujo (National Measurement Institute) and Gavin Stevenson (National Measurement Institute).
Australian documentary film director, Christopher Nelius has created an entertaining, uplifting and quirky film with 'Whistle'. The documentary follows the preparation and staging of the world's greatest whistling competition held in Hollywood, Los Angeles, USA and includes interviews with key competitors in their own home countries in the UK, US, Spain and Japan. Whistling diva and producer of the competition, Carole Anne Kaufman is on a mission to elevate both whistling as an artform and the standing of this competition and the film captures her efforts from start to finish. It's an eccentric cast of characters altogether.
This is a professionally produced documentary with excellent editing, pacing and dramatic effects as the competition proceeds, without being overly sentimental. The film leaves the viewer with admiration for musical expertise and dedication of the competitors and the devoted commitment of the event organiser and her volunteers.
For documentary film lovers, this film is a must-see.
Researchers at the University of Cambridge have developed what they describe as a fundamentally new type of vaccine using artificial intelligence (AI). The vaccine’s key component was designed entirely by AI and has now been tested in people for the first time.
The goal is ambitious: a single vaccine that works not just against all known human coronavirus variants, but against related bat viruses that could jump from animals to humans and cause future pandemics.
Traditional vaccines train our immune system to recognise one specific virus. The problem is that viruses mutate. When they change enough, the vaccine stops working, which is why we need a new flu shot every year and why COVID vaccines have been updated repeatedly since 2021.
AI offers a way around this. By analysing genetic data from thousands of related viruses, it can identify the parts that stay the same across different strains and that are unlikely to change over time. Target those stable features, and you have a vaccine that should work against the whole family, not just the strain you started with.
This is exactly what the Cambridge team did. They used AI to scan viruses from the sarbecovirus family, which includes the viruses that cause both SARS and COVID, as well as a range of animal coronaviruses – looking for shared features that evolution has left largely untouched. Those features became the basis of the vaccine.
DNA vaccines
While many people are familiar with the mRNA shots used during the pandemic, this new vaccine uses DNA. DNA vaccines are generally more stable than mRNA vaccines, making them easier to store and transport. A significant advantage in lower-income countries where “cold-chain” infrastructure is limited.
They can also be administered without needles. A high-pressure stream of liquid delivers the vaccine through the skin, making administration less painful and easier to scale up during an outbreak.
DNA and RNA viruses explained.
Could it protect against future pandemics?
These practical advantages matter most if the vaccine itself can do something no existing jab can: protect against viruses we haven’t encountered yet.
Broad-spectrum vaccines could change the way the world responds to emerging infectious diseases. By offering much wider protection than traditional vaccines, they could provide rapid immunity against new and emerging viral threats. This would equip public health officials with tools to stop future outbreaks in their tracks before they have a chance to turn into global pandemics.
They could also transform our approach to more familiar diseases. Influenza is a prime target because it exists in many different strains and evolves so rapidly. Scientists have to predict which strains will dominate each flu season, and they guess wrong, vaccine effectiveness can suffer. A universal flu vaccine that targets features shared across multiple strains could eventually end the annual race to keep up with the virus.
And the Ebola virus shows why this matters right now. The recent outbreak in the Democratic Republic of the Congo and Uganda is driven by the Bundibugyo strain, which bypasses existing vaccines. While researchers rush to create a new vaccine specifically for this strain, local communities remain at high risk. A broad-spectrum vaccine designed to cover an entire virus family could transform that picture.
What the trial found
This is the first human trial of an AI-designed vaccine. The results showed that this DNA vaccine was able to stimulate the immune system to produce antibodies that can recognise different types of sarbecoviruses. The technology was found to be safe and well tolerated.
This is an exciting advance because it demonstrates how AI has the potential to design variant-proof vaccines against future pandemic threats. The needle-free delivery system could also make the vaccine easier to administer and distribute worldwide.
However, there is more work to do. Although the results in this study are encouraging, the immune responses following vaccination were modest. It was also uncertain how long the protection lasts and whether further boosters will be required. Larger trials are also needed to determine whether the vaccine can prevent or reduce virus infections in the real world.
A universal vaccine remains a few years away. And any new vaccine must still pass larger trials to prove it is safe, effective and provides lasting protection. But this study shows the goal is getting closer – and AI may help us get there faster.
Part 8 of this series on AI explored the impact of the new technology on the retail sector. This posting will further consider AI's effect on specific retail functions.
Marketing and advertsiing in retail
AI has most impact with -
Performance marketing: Google and Meta's advertising platforms are increasingly self-optimising with informed automation. The previous large teams of digital marketing specialists who managed bid strategies, audience targetting and creative testing are shrinking. The platforms can carry out the operations that previously employees would carry out.
Personalised communications: AI can and does generate individualised email, push notifications and SMS content at scale replacing or reducing human campaign teams.
Market research and consumer insight: AI can synthesise customer data, social media listening, consumjer feedback and sales patterns into insight reports thus reducing analyst headcount.
Fashion retail specifically
Fashion sits at the intersection between the retails and creative indsutries making it doubly exposed -
Trend forecasting: traditionally carried out by high-cost specialist agencies and in-house teams, AI can now analyse social media, runway coverage and sales data to predict trends with considerable accuracy.
Design assistance: Ai tools can and do generate design concepts, colourway combinations and print patterns. This places junior design assistant roles under pressure in a very cost conscious industry.
Fit and sizing: AI fit technology reduces return rates thus threatening the customer service infrastructure built around managing returns.
Wholesale and buying: the buyer role which requires relationship-building with suppliers and market intuition is more protected from AI encroachment. The analytical support underneath these roles is much less so.
At this stage AI appplication in fashion is more of an augmenting role rather than displacement of jobs but increasingly this may change.
Aliens might exist. But there are three reasons why they’re not visiting us
Steven Spielberg’s new film, Disclosure Day, explores the idea of extraterrestrial life.
UniversalCarol Oliver, UNSW Sydney
The United States government’s recent release of hundreds of previously classified Unidentified Anomalous Phenomena (UAPs) cases spanning the 1940s to the present, along with the new Steven Spielberg movie, Disclosure Day, about extraterrestrial life, has fuelled the idea that aliens are visiting Earth.
In fact, polls in Australia, the US and elsewhere indicate around a third of the public believes aliens are here.
However, while what we know about the universe suggests aliens may exist, there are three compelling reasons why they probably aren’t visiting us.
Space is big – very big
To begin with, space is vast – beyond our imagination.
Proxima Centauri, the nearest star to our Sun, is about 40 trillion kilometres away, 268,000 times farther than the Sun is from Earth. That’s 4.3 light years as astronomers measure it. A light year is the distance light travels in one year at 300,000km per second.
We can only travel across space at a fraction of the speed of light with current technology. Even our fastest spacecraft, the Parker Solar Probe, travels at a top speed of roughly 191 kilometres per second – 0.064% the speed of light.
At that speed, it would take about 6,650 years to reach Proxima Centauri, and that’s just in our local stellar neighbourhood. So interstellar travel within human lifespans would require much higher velocities.
Let’s assume we did have the means to travel close to the speed of light. That introduces the first problem with travelling at that velocity. Albert Einstein demonstrated that time is relative; the rate of time flow is not the same everywhere in the universe. The faster a spaceship travels from Earth, the slower time will pass for its passengers. This is called time dilation.
For example, when NASA astronaut Scott Kelly arrived back on Earth from a year on the International Space Station, he was milliseconds younger than his identical twin because time moves more slowly for objects in motion, and the International Space Station travels at roughly 28,150 kilometres per hour.
This difference was negligible for the Kelly twins. But for any aliens cartwheeling through our skies, it would be significantly more because of the journey to Earth and back from a distant star system at a necessarily higher speed. They would go home to a planet much older than the one they left – perhaps by a century or more. They would be time exiles.
A photograph from the Apollo 17 mission in December 1972.NASA
Unimaginably high energy requirements
Then there’s the unimaginably high energy requirement for interstellar travel.
The mass of the spaceship increases with velocity, so an increasing amount of energy is required to accelerate it.
At the speed of light, the ship becomes infinitely massive, requiring an infinite amount of energy. This is clearly impossible.
Another significant issue is that space is a vacuum – but not completely. There are just enough particles to worry about. They can potentially cause fatal radiation for passengers and the instruments of a high velocity spacecraft, or destroy it. Sparsely spread hydrogen atoms turn into intense radiation at near light speed, and the heat that is generated would ablate and eventually destroy the hull.
Faster-than-light travel, according to physicist Miguel Alcubierre, is possible, but it comes with its own set of issues and a currently impossible energy requirement.
That raises the question of why spend all this energy to travel to Earth? Anything we have, an advanced civilisation (as they would have to be to get here) would be able to make on their planet.
A unique biosphere
Yet another issue is our biosphere, unique to Earth as far as scientists know.
Life and the planet co-evolved. Complex life would not exist on Earth if cyanobacteria, a type of single-celled microbe, had not pumped oxygen into our mostly nitrogen atmosphere 2.4 billion years ago.
It’s therefore not toxic for us, but oxygen is reactive and could be highly corrosive for aliens. And while they could wear protective suits like humans do when going to inhospitable environments, reports of visiting aliens do not include any descriptions of spacesuits.
So, are aliens out there?
If aliens are not here, are they out there?
It’s an interesting question, scientifically and philosophically. Scientists do not have enough information yet, but they are working on the question.
About 6,200 exoplanets have been found in more than 4,700 solar systems, though none are like Earth or our Solar System.
Most stars could have at least one planet, and there are more than 100 billion stars in our galaxy alone. The number of planets is therefore astronomical, and some may be habitable.
Closer to home, there are worlds with potential for microbial life either past or present – Mars, Europa (a moon of Jupiter), and Enceladus and Titan (moons of Saturn). If we discover life began twice in our Solar System, that will increase the odds of life elsewhere.
Since 1960, we’ve had the capability to look for intelligence elsewhere, piggybacking on normal radio astronomy. The biggest search for alien life projects are carried out by the SETI Institute in California and the Breakthrough Listen project based at Oxford University in the United Kingdom.
Nothing has been found across all the searches made. Finding intelligence in our time frame – about a hundred years – in the 13.8-billion-year history of the universe is challenging.
However, as a 1959 Nature paper noted, while it’s difficult to estimate the chance of success, if we don’t search, the chance drops to zero.
The Sydney Film Festival (SFF) is currently running until 14 June 2026 with up to 18 separate screen venues in operation. With a mix of all genres of film and including major releases from the international film festivals, this blog will provide a series of film reviews from the SFF over coming days.
Cities around the world are planting more trees to cope with rising urban heat. But our research shows trees alone are often not enough. In some cases, the wrong kind of greening can even make streets feel less comfortable on a hot day.
We compared field measurements from Melbourne, Munich and Hong Kong to test how different kinds of urban planting changed the heat people experience outdoors.
The results showed layered vegetation – where trees are combined with shrubs and ground cover – often cooled cities more effectively than trees alone. We also found local climate and street design strongly shaped whether greening worked well.
These findings matter because urban greening is no longer just about aesthetics. As cities spend billions adapting to extreme heat, planting design may matter as much as planting quantity.
Cities are getting hotter
Cities trap heat. Roads, buildings and asphalt absorb solar energy during the day and slowly release it back into the air, especially at night.
This “urban heat island” effect, combined with climate change, is making heatwaves more intense and more dangerous in our cities.
Trees are one of the most popular responses because they provide shade and reduce the amount of heat absorbed by surrounding surfaces. But outdoor comfort depends on more than air temperature alone.
People experience heat through sunlight, reflected heat, humidity and airflow. A shaded street can still feel uncomfortable if humidity is high or if wind cannot move through the space.
That is why a “one-size fits all” greening strategy can fail. A planting design that works well in Melbourne may behave very differently in Hong Kong or Munich.
What we found
To better understand how urban vegetation affects heat stress, we did field measurements in three cities with different climates: temperate Melbourne, cooler Munich and humid subtropical Hong Kong.
Rather than relying only on computer models, we measured real conditions in streets and green spaces during summer.
We compared open urban spaces (with no plantings), sites with trees only, and layered planting (which means trees, shrubs and ground cover together).
Importantly, we did not just measure air temperature. We also measured “mean radiant temperature”, which captures the heat radiating from roads, walls and other surfaces onto the human body.
In Melbourne, street trees reduced radiant heat absorbed by pedestrians by more than 18°C, compared with open streets. Even where air temperatures changed only slightly, shaded streets felt substantially cooler.
Munich showed the strongest benefits from layered planting. There, streets and green spaces containing trees, shrubs and ground cover reduced afternoon heat stress by almost 8°C compared with more open spaces.
Hong Kong also benefited from vegetation, especially through shade created by overlapping tree canopies. But the results there were more mixed because the humid climate changed how cooling worked (more on that later).
Across all three cities, one finding stood out: vegetation structure matters.
Combining trees with shrubs and ground cover often performed better than trees alone, but the benefits depended on how the planting interacted with the local environment.
Why some greening can fail
The study showed that more vegetation is not automatically better.
In Hong Kong, dense vegetation sometimes increased humidity enough to reduce some of the cooling benefit. Plants release water vapour into the air through transpiration, which can help to cool dry climates. But in already humid cities, extra moisture can make outdoor spaces feel sticky and uncomfortable because sweat evaporates less efficiently.
In some Munich streets, dense vegetation reduced airflow through narrow urban corridors, trapping warm air and slowing the movement of vehicle pollution away from pedestrians.
These findings highlight why cities cannot rely on generic canopy targets copied from elsewhere. Climate, street width and airflow all shape whether vegetation improves comfort or creates unintended side effects.
Designing cooler cities
The solution is not to stop planting trees. It is to design urban greening more carefully.
Cities need planting strategies tailored to local conditions rather than universal greening formulas. In parks and open green spaces, layered vegetation can provide strong cooling while also supporting biodiversity. In dense streets, planners may need to balance shade with ventilation.
The findings also suggest cities should move beyond measuring success through tree numbers alone. The arrangement, density and type of vegetation matter just as much as canopy cover.
Designing for local conditions
Our research shows urban vegetation can reduce heat stress, but the benefits depend on how and where cities plant it.
Melbourne demonstrated the strong cooling effect of street trees on radiant heat, Munich showed the added value of layered vegetation, and Hong Kong revealed how dense planting can sometimes backfire in humid conditions.
Cities need climate-smart green spaces designed for local conditions, airflow and human comfort to remain liveable as temperatures rise.
