Blurs

You are reading these words. You can hear sounds around you. You can remember yesterday. You can imagine tomorrow. You can feel pain, recognise a face and wonder what it means to be alive. All of this feels completely ordinary. But scientifically, it is extraordinary. Somehow, electrical and chemical activity inside roughly three pounds of biological tissue is associated with the experience of being you. We know an enormous amount about the brain. We can observe neurons firing. We can map brain regions. We can measure electrical activity and watch networks communicate. We can even manipulate brain activity and change perception, memory and behaviour. And yet one enormous question remains: Why is there an experience at all? The brain clearly matters Before going further, there is an important distinction. There is overwhelming evidence that consciousness is intimately connected to the brain. Damage particular brain systems and consciousness can be profoundly altered. Anaesthesia can rev...

We tend to picture the universe as something that simply keeps going. Stars stretch into galaxies. Galaxies form enormous clusters. Beyond those clusters are more galaxies, more empty space, more darkness. And beyond that? We instinctively imagine… more. But there is a problem with that picture. When cosmologists talk about the universe being infinite, they are not necessarily saying they have established that it literally extends forever. They are describing one possible geometry of the universe — one that fits remarkably well with what we currently observe. So here's a strange question: What if the universe isn't infinite? And if it isn't, does that mean there must be an edge? And if there were an edge, what could possibly be beyond it? The universe doesn't necessarily need an edge Our everyday experience makes the idea of a finite universe difficult to comprehend. A football has a surface with a finite area. Walk far enough across it and, eventually, you come back to...

The first crewed mission to Mars is often imagined as the beginning of humanity's journey to another world.  But getting astronauts there is only half the problem. Can we actually bring them home? Mars has fascinated humanity for centuries. From the canals imagined by nineteenth-century astronomers to today's robotic explorers, the Red Planet has gradually changed from a distant point of light into a destination. But there is a question that receives surprisingly less attention than the journey there: If humans eventually land on Mars, will they actually be able to come back? A mission to Mars is not simply a longer version of a trip to the Moon. The distances are enormous, launch windows are limited, communication is delayed and returning a crew safely requires spacecraft, fuel, power and life-support systems to work hundreds of millions of kilometres from Earth. And unlike the Apollo missions, astronauts travelling to Mars could be away from Earth for years. Mars Is a Long Wa...

For a few milliseconds, somewhere in the distant universe, something releases an extraordinary burst of radio energy. Then it disappears. There may be no visible explosion. No obvious warning. No gradual build-up. Just a brief pulse of radio waves travelling across intergalactic space before arriving at Earth. Astronomers call these phenomena Fast Radio Bursts, or FRBs. They are among the most mysterious signals ever detected from the cosmos. And although scientists increasingly suspect that extreme objects such as magnetars are responsible for at least some of them, the complete picture remains unresolved. So what exactly are these strange signals? And could any of them really be evidence of an extraterrestrial civilisation? A Flash Lasting Milliseconds The first recognised FRB was detected in 2007. It appeared in archived data from the Parkes radio telescope in Australia. The signal lasted only milliseconds, yet it appeared to have travelled an enormous distance. That was the beginni...

Earth has a magnetic field that stretches far into space, protecting the planet from much of the charged radiation streaming from the Sun. Most people know the basic explanation: movement of molten, electrically conductive material in Earth's outer core generates the geodynamo responsible for the main magnetic field. But Earth's magnetism is considerably more complicated than that. The field measured at Earth's surface is actually a combination of several magnetic sources. One comes from deep within the planet. Another comes from magnetised rocks in the crust. Others are generated by electrical currents in the ionosphere and magnetosphere. And there is a particularly intriguing component that sometimes gets described as Earth's "second magnetic field." It isn't a second planet-sized dynamo hidden inside Earth. But it reveals just how dynamic our magnetic environment really is. The Main Magnetic Field Earth's dominant magnetic field is generated in the ...