Author: The Conversation

Astronomers have long been puzzled by two strange phenomena at the heart of our galaxy. First, the gas in the central molecular zone (CMZ), a dense and chaotic region near the Milky Way’s core, appears to be ionised (meaning it is electrically charged because it has lost electrons) at a surprisingly high rate. Second, telescopes have detected a mysterious glow of gamma rays with an energy of 511 kilo-electronvolts (keV) (which corresponds to the energy of an electron at rest). Interestingly, such gamma rays are produced when an electron and its antimatter counterpart (all fundamental charged particles have antimatter versions of themselves that are…

In the 1987 classic film RoboCop, the deceased Detroit cop Alex Murphy is reborn as a cyborg. He has a robotic body and a full brain-computer interface that allows him to control his movements with his mind. He can access online information such as suspects’ faces, uses artificial intelligence (AI) to help detect threats, and his human memories have been integrated with those from a machine. It is remarkable to think that the movie’s key mechanical robotic technologies have now been accomplished by the likes of Boston Dynamics’ running, jumping Atlas and Kawasaki’s new four-legged Corleo. Similarly, we are seeing robotic exoskeletons that…

ChatGPT and other AI chatbots based on large language models are known to occasionally make things up, including scientific and legal citations. It turns out that measuring how accurate an AI model’s citations are is a good way of assessing the model’s reasoning abilities. An AI model “reasons” by breaking down a query into steps and working through them in order. Think of how you learned to solve math word problems in school. Ideally, to generate citations, an AI model would understand the key concepts in a document, generate a ranked list of relevant papers to cite, and provide convincing reasoning for…

Gravity pulls us to Earth, a lesson you learn viscerally the first time you fall. Isaac Newton described gravity as a universal attractive force, one that holds the Moon in orbit around the Earth, the planets in orbit around the Sun, and the Sun in orbit around the centre of our galaxy. In the 1990s, astronomers made the astonishing discovery that the expansion of the universe has sped up over the past 5 billion years, which implies that gravity can push as well as pull. Einstein’s theory of general relativity explains gravity as a consequence of curved space-time, where it allows for both attraction and…

Imagine a tribe of uncontacted hunter-gatherers in the deepest Amazon rainforest. Anthropologists airdrop dozens of smartphones loaded with social media apps, with solar chargers, simple instructions in their native language and Wi-Fi just within the tribe. What would happen to their culture and their mental health? Such an experiment appears fanciful, but a similar one has been unfolding in our world for about 20 years. For the first time in human evolution, everyday social interactions have changed from face-to-face to disembodied experiences, from in-person to digital and from social reality to whatever someone puts online. Social media is an evolutionary novelty,…

We are constantly fed a version of AI that looks, sounds and acts suspiciously like us. It speaks in polished sentences, mimics emotions, expresses curiosity, claims to feel compassion, even dabbles in what it calls creativity. But here’s the truth: it possesses none of those qualities. It is not human. And presenting it as if it were? That’s dangerous. Because it’s convincing. And nothing is more dangerous than a convincing illusion. In particular, general artificial intelligence — the mythical kind of AI that supposedly mirrors human thought — is still science fiction, and it might well stay that way. What we call…

The shortage of blood for medical use is a global challenge. South Africa is not exempt. Blood collection organisations such as the South African National Blood Service struggle to meet the demand for blood products because of insufficient blood donations and the scarcity of loyal blood donors. Blood collection organisations rely on the goodwill of a few individuals who voluntarily donate blood. To maintain a sustainable supply of blood, the World Health Organization (WHO) has recommended that at least 1% of a country’s population donate blood. In South Africa the donation rate is below this. There are two blood collection organisations in South Africa –…

Ideally, artificial intelligence (AI) agents aim to help humans, but what does that mean when humans want conflicting things? My colleagues and I have come up with a way to measure the alignment of the goals of a group of humans and AI agents. The alignment problem – making sure that AI systems act according to human values – has become more urgent as AI capabilities grow exponentially. However, aligning AI with humanity seems impossible in the real world because everyone has their own priorities. For example, a pedestrian might want a self-driving car to slam on the brakes if an accident seems likely,…

Three South African environmental and climate justice organisations took the South African government to court in November 2021, to challenge the authorisation of new coal-fired power as part of the country’s energy mix. Three years later, the court ruled that the government’s new coal plans were unlawful, invalid, and against the country’s constitution. Therefore, these plans cannot go ahead. Environmental law specialist Melanie Murcott researches how courts consider the risks and impacts of climate change and environmental and human rights violations in their judgments. In this article, she discusses the #CancelCoal case. Why was the #CancelCoal case brought to court? South Africa gets about 85% of…

Microsoft just celebrated its 50th anniversary. This article was written using Microsoft Word on a computer running Microsoft Windows. It is likely to be published on platforms hosted by Microsoft Azure, including LinkedIn, a Microsoft subsidiary with over one billion users. In 2024, the company generated a net profit of $88 billion from sales worth $245 billion. Its stock market value is close to $3,000 billion, making it the world’s second-most valuable company behind Apple and almost on a par with Nvidia. Cumulative profits since 2002 are approaching $640 billion. And yet, 50 years ago, Microsoft was just a tiny computer…