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Star Trek used wormholes to jump through space – what’s the science behind them?

Since Star Trek began sending its crews out to explore strange new worlds 60 years ago, the franchise has both imagined and inspired new concepts for travel across the vast distances of space.

Among the most intriguing are “wormholes”: mysterious tunnels through spacetime that connect otherwise distant places.

Star Trek always has a difficult balance to strike in making its portrayals both accessible and scientifically accurate. With wormholes, it generally favoured the former on their occasional appearances.

On screen, one end of the wormhole will often appear as a swirling vortex or tunnel. In fact, computer simulations of these theoretical space shortcuts suggest that the opening would look more like soap bubbles or crystal balls, with their surfaces showing distorted and multiplied images of whatever lies on the other side.

You could fly all around this opening and enter it from any direction, and rather than reaching the centre of the bubble, you would emerge from another similar bubble (the other end of the wormhole) somewhere totally different.

Of course, the most important question for both Starfleet captains and theoretical physicists is: should you fly into a wormhole? The job of a starship captain may be to boldly go, but as a very risk-averse physicist, I’m not so sure.

The first Star Trek wormhole

“Wormhole distortion has overloaded the main power systems!” These words, spoken by Commander Willard Decker in Star Trek: The Motion Picture (1979), marked the first appearance of a wormhole in Star Trek.

Video: SYL Ranch Darkroom.

A warp drive malfunction leads to the creation of a distorted region of spacetime that sucks in the Starship Enterprise, leading to a breakdown of the ship’s systems and a potentially deadly collision with a random asteroid.

It is a typically pioneering reference to what was, at the time, a niche research topic. John Wheeler, professor of gravitational physics at Princeton University, had first coined the term with Charles Misner in their 1957 paper Classical Physics as Geometry, which aimed to describe electric charges like electrons as the ends of tunnels in space.

The first descriptions of traversable wormholes that satisfied Einstein’s equations of general relativity – configurations of matter that balance the spacetime curvature of the tunnel – were then independently published by H.G. Ellis and K. A. Bronnikov in 1973, although they didn’t use Wheeler’s moniker.

Six years later, the first Star Trek wormhole wasn’t an accurate depiction of what scientists and science fiction enthusiasts now understand by the term. For one thing, the wormhole doesn’t appear to lead anywhere, and it dissipates once the crew regain control of the ship and drop out of warp speed.

Nevertheless, as a researcher studying black holes and the early universe, I am rather fond of this scene – in part because it is actually possible to imagine warp drives (engines that bend spacetime to move the ship at faster-than-light speeds) distorting spacetime in this way.

If you put exotic matter (one with a negative pressure) into a small region of spacetime, Einstein’s equations of general relativity tell us that region can expand exponentially fast. And if the space around it is not expanding in the same way, where can all that new space go?

The answer, at least in this hypothetical scenario, is that it must balloon out into an entirely new universe, creating a wormhole in the process – a narrow passage that links the two regions.

If you’re thinking this sounds implausible, Einstein’s theory of general relativity is actually perfectly ok with things being larger on the inside. Indeed, such scenarios may (speculatively) have arisen from rare fluctuations in the early universe.

No slow-mo

Star Trek’s first depiction of a wormhole gets one aspect precisely wrong, though. In the film, the wormhole’s “temporal distortion” makes the crew move and speak in slow motion, struggling to fire the photon torpedoes that will save them from asteroid-impact obliteration.

While the gravitational time dilation predicted by Einstein could be a feature of wormhole spacetimes, it would not be experienced as slow motion by those who fly in. For them, time would pass completely normally, with their watch ticking at one second per second.

They might, however, emerge to find that their friends had aged far more than they had. But these friends wouldn’t have experienced time in fast-forward either. Both sides think time has passed normally, they just disagree about the amount.

Again, this seems like it shouldn’t really be allowed – but the same effect is experienced by clocks on GPS satellites put into orbit around the Earth. When brought back to Earth again, they are found to have experienced more time than an equivalent clock left on the Earth’s surface, due to having spent time in a weaker gravitational field.

Next Generation wormholes

By the late 1980s, Star Trek wormholes had achieved the ultimate sign of technological maturity – somebody was trying to sell one.

This depiction, in the series Star Trek: The Next Generation (1987-94), more closely resembled the traversable wormhole framework co-developed by Kip Thorne in 1988. The US astrophysicist and future Nobel laureate had begun exploring the theoretical requirements for the existence of wormholes as portals connecting distant regions of space in the same universe.

Video: Robin Sellex.

Thorne showed that for a wormhole to be held open in a way that makes it traversable would require an exotic form of matter, violating certain energy conditions that physicists think ought to be respected at large scales.

As the Next Generation crew find out, you don’t just want to buy any old traversable wormhole – you need it to be a stable one. The original Ellis-Bronnikov wormhole uses the right kind of exotic matter as scaffolding to hold it open. But even tiny disturbances will cause it to rapidly collapse – as has been demonstrated in many numerical simulations.

A spinning version of the Ellis-Bronnikov wormhole appears potentially more robust, but its so-called “nonlinear stability” is yet to be established. Flying a starship through one of these would be a useful, if rather risky, test.

The space between what is mathematically possible and physically realistic has always been a key part of the magic of Star Trek, inspiring several generations of scientists to explore strange new spacetimes. But if a soap-bubble wormhole ever appears in front of my spacecraft, I would always let Starfleet go first.

The Conversation

Katy Clough receives funding from the Science and Technology Facilities Council (STFC) and the Simons Foundation. She will be speaking at the Star Trek Lates event at the Science Museum in London on Tuesday, September 8.

Autonomous weapons can select targets without human help – now is the time for binding rules

One-way military drones already have the capability to select their targets. Anelo/Shutterstock

Government experts are meeting in Geneva, Switzerland, to work towards a possible negotiating mandate on autonomous weapons systems (AWS). These are military systems that can select and engage targets without human intervention.

This major international gathering follows a recent call by the UN and the International Committee of the Red Cross (ICRC) for urgent controls on these weapons, sometimes dubbed “killer robots” in descriptions by the media.

Recent events in Ukraine have further consolidated concerns that a slide towards weapons with full autonomy (and without meaningful human control) is well underway. According to the New York Times, a Russian drone attacked a petrol station in Zaporizhzhia on July 6, killing three civilians. What marked it out was the drone’s use of AI to decide where and when to strike.

The drone aircraft had been programmed to fly towards the petrol station. But on its approach, an AI system autonomously chose the precise target – probably propane tanks – based on its ability to recognise them.

On August 25, Mirjana Spoljaric, the president of the ICRC, and António Guterres, the secretary-general of the United Nations, issued their joint appeal to the international community to agree on legally binding rules regulating the development and use of AWS.

New technologies are making it cheaper and easier for nations to put together these weapons. Thus, the UN and ICRC appeal for binding rules could not be more urgent. The international community is ideally placed to start negotiations soon, building on many years of diplomatic talks.

For the past decade, governments have debated how AWS challenge existing international law and what should be done under the auspices of the convention on certain conventional weapons, a UN arms control framework. Since 2017, the group of governmental experts (GGE) on lethal autonomous weapons systems (LAWS) – which is part of the convention on certain conventional weapons – has convened typically twice a year.

The experts are meeting again this week in Geneva. The aim is to agree a governance framework and language for a rolling text that could be the foundation for negotiations. This text provides a baseline for continued discussions in November.

While this process has been rife with political disagreements, most experts agree on the need to retain some level of meaningful human control over the use of autonomous systems.

Ground robot
The Ukraine war has seen the increasing use of armed ground robots on the frontline. Anton_AV / Shutterstock

Moral significance

This demonstrates a shared sense by states participating in the process that human judgment is pivotal for the laws governing warfare. It also shows that the moral significance of warfare underlines the importance of human responsibility.

Human judgment is also embedded in international humanitarian law. Targeting processes require context-specific judgments about the targets themselves, potential harm to civilians from striking the target and other precautions. These tasks cannot be delegated to machines.

AI-enabled systems show how technology already shapes human perceptions of targets and risk. With autonomous weapons, the system shifts from influencing human judgement to exercising the targeting function itself.

Any AI system is only as good as the data it has been trained on, or that it works with. For armed conflicts, this data is difficult to come by and is almost always insufficient for dynamic and variable human contexts. This means many systems are likely to be technically inadequate.

The problem becomes quite visible with rules around assessing proportionality, for example, which is a context specific judgement about anticipated civilian harm versus military advantage.

Militaries may try to quantify targeting decisions in a way that creates the appearance of precision. However, the underlying legal judgment remains qualitative regardless. Technical accuracy, therefore, is not the same as lawfulness or moral consideration.

Only humans can understand the significance of respecting the inherent rights and dignity of other humans. Decisions to end human life must therefore be made qualitatively, by humans, in order to be morally and legally justifiable. Without this provision, and clear guidelines around it, we argue that governments risk running into a legal vacuum and a steep moral abyss.

AWS, especially those that prioritise speed and scale of action though AI, carry a significant risk of enabling an uncontrolled and rapid escalation. Escalation from crisis to war, or from conflict to a higher level of violence, could come about by erroneous indications of attack or by a simple sensor or computer error.

Unpredictable systems could give leaders false impressions of the capabilities of those systems. This could lead to overconfidence or encourage preemptive attacks.

Inevitable outcome?

One argument raised by academic researchers in the context of AWS is that they become necessary because they are inevitable. The risk is that more countries opt for full autonomy as components become cheaper and readily available, exacerbating an arms race.

However, an adversary’s conduct does not release a state from its own obligations under international humanitarian law. Following those rules is also part of what makes military force legitimate, including through civilian protection, precautions and accountability. We might turn the argument around and say: legally binding rules become inevitable, because they are absolutely necessary.

Governments and advocacy groups have worked hard over the past decade to put together a lucid proposal for the regulation of AWS. Some efforts are intended to prohibit those systems that target humans directly, or that are unpredictable and therefore cannot be meaningfully controlled by a human. All other AWS must be strictly regulated.

There are signs of political momentum. In November 2025, 156 states voted in favour of a UN General Assembly resolution that “draws attention to the serious challenges and concerns” that autonomous weapons raise. A legally binding instrument is possible, even if some states resist it.

The time is now. Clear, binding rules would help ensure that increasingly autonomous warfare does not make violence easier to unleash and harder to control.

The Conversation

Elke Schwarz is Vice-Chair for the International Committee for Robot Arms Control.

Jessica Dorsey is affiliated with Airwars as a member of the Executive Board and a member of the Advisory Board of the Atlantische Commissie.

We can’t quit smartphones, but we can manage digital junk food better

Amy, a 27-year-old software developer, has struggled with disordered eating since she was a teenager. “But after learning to code, I got much better,” she said in a research interview. “I often code for ten or more hours without stopping.” Her psychiatrist, however, worried that Amy has replaced one compulsive behaviour with another.

“Digital addiction” is often used to describe our relationship with smartphones, social media and other digital technologies. This way of thinking suggests that people get “hooked” on digital activity because their body becomes “addicted” to dopamine. It borrows from models of substance addiction: the focus is on the physical need to keep using a substance because the body has adapted to it, despite harmful consequences. The implied solution is straightforward: abstinence, which translates into practices like digital detox.

But Amy’s story, which forms part of our ongoing research, points to a more complicated reality of our relationship with digital technology. Coding consumed much of her time and attention, yet it also helped her earn an income and build a professional identity. Like many forms of digital engagement, it was not just a distraction but a way of navigating life.

As research shows, for many people digital technologies are not only a source of entertainment but key components of their education, work and social mobility. Unlike in the case of addictive substances, opting out of digital life is easier said than done when schools, banks and public services increasingly require it.

How people relate to digital technology isn’t just about them as individuals. It’s shaped by their personal vulnerabilities, but also by digital environments intentionally built to hook us, and by the wider social conditions people live in.

So comparing smartphones to substances like alcohol, tobacco or drugs can be misleading. It overlooks the fact that digital devices have become a kind of essential infrastructure for daily life. Given how we have built our lives around them, these technologies are now very difficult to live without.

How, then, do we develop a sustainable relationship with technologies such as smartphones that are both indispensable and potentially harmful?

The sugar model

Amy’s story with disordered eating may be useful here. Recovery from an eating disorder isn’t about eliminating food altogether, but about learning to live with it.

In the same way that we cannot remove food from our lives, it is also difficult to remove digital technologies from our everyday. So the challenge becomes developing ways of living with them.

Take, for example, sugar. In many countries, foods high in sugar are subject to a wide range of public health measures. Think national food safety standards, public health interventions, school nutrition policies, limits on advertising. So it’s not about focusing on one thing only. Rather, it’s the interaction between all of these interventions that shapes patterns of consumption and impacts wellbeing.

When using a smartphone, it can be easy for hours of time to seemingly disappear. SWEETLOUISE/PIXABAY, CC BY

A similar approach is needed for digital technologies. At the level of state and industry governance, this includes regulation of platform and design – particularly when it is aimed at capturing and holding users’ attention.

Just as food labels describe ingredients, nutrition and additives, digital products could disclose what data they collect, what algorithms they run on and what psychological techniques keep their users engaged.

The UK’s decision to ban social media for under 16s while continuing to expand digital literacy and coding education reflects an important point: not all digital technologies are the same.

“Digital use” cannot be treated as a single category to be either embraced or banned. Like sugar, the question is not whether children should have it at all, but what kinds, in what quantities, and in what conditions.

Beyond counting calories and screen hours

Just as sharing a meal with family affects people differently from eating alone, playing games with friends is not the same as scrolling endlessly through social media. Both count as screen time, but they create very different social and emotional experiences.

Reflecting on our own digital habits remains important. But tracking screen time is like counting calories: it tells us how much, but not necessarily why. We have to ask ourselves what role digital technologies play in our lives.

Are they helping us work, connect, rest, escape, cope, feel less or more alone? Without this kind of reflection, self-tracking risks turning a complex social issue into a matter of individual self-control.

Understanding digital technologies through the lens of food rather than addiction shifts the emphasis in important ways. Both are domains where necessity, pleasure, risk and social obligation are intertwined, which is why abstinence may not be an adequate, long-term response.

Instead of treating excessive technology use as a matter of personal discipline, approaching them like some foods locates it within broader systems of design, industry governance, state policy and social practices. The challenge then is to integrate these different levels to make life with digital technologies sustainable.

The Conversation

Tanja Ahlin receives funding from the Dutch Research Council (NWO), Grant number VI.Veni.241S.150, https://doi.org/10.61686/EWUXQ23921

Xin Zhan receives funding from the University of Cambridge.

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