Siobhan Roberts writes: Lunchtime in the cafeteria at the Institute for Advanced Study in Princeton, N.J. — sometimes called the Institute for Advanced Dining — is a heady scene, and Freeman Dyson, who died last week at 96, was a regular fixture, arriving with reading material tucked under his arm. One day about 10 years ago, Dr. Dyson put down his tray of food at the physics table and joined the conversation. Nima Arkani-Hamed, a professor in the institute’s School…
David J. Eicher writes: Decades of astrophysical research beginning in the late 19th century established the universe as we see it, culminating with the Big Bang theory. We now know the universe is about 13.8 billion years old and at least 150 billion trillion miles across. But in recent years, astronomers have begun to address a staggering possibility — the universe we can observe, and in which we live, may be one of many that makes up the cosmos. The…
Ethan Siegel writes: If you were to go as far out into space as you can imagine, what would you encounter? Would there be a limit to how far you could go, or could you travel a limitless distance? Would you eventually return to your starting point, or would you continue to traverse space that you had never encountered before? In other words, does the Universe have an edge, and if so, where is it? Believe it or not, there…
Is there anybody out there? Greg Rakozy/Unsplash, CC BY-SA By Robin Smith, Sheffield Hallam University In 1900, so the story goes, prominent physicist Lord Kelvin addressed the British Association for the Advancement of Science with these words: “There is nothing new to be discovered in physics now.” How wrong he was. The following century completely turned physics on its head. A huge number of theoretical and experimental discoveries have transformed our understanding of the universe, and our place within it….
Gearoid Hayes/Flickr, CC BY-SA By Alessandro Fedrizzi, Heriot-Watt University and Massimiliano Proietti, Heriot-Watt University Alternative facts are spreading like a virus across society. Now it seems they have even infected science – at least the quantum realm. This may seem counter intuitive. The scientific method is after all founded on the reliable notions of observation, measurement and repeatability. A fact, as established by a measurement, should be objective, such that all observers can agree with it. But in a paper…
Paul Sutter writes: Astronomers around the world are in a bit of a tizzy because they can’t seem to agree about how fast the universe is expanding. Ever since our universe emerged from an explosion of a tiny speck of infinite density and gravity, it has been ballooning, and not at a steady rate, either — the expansion of the universe keeps getting faster. But how quickly it’s expanding has been up for a dizzying debate. Measurements of this expansion…
Adam Frank writes: Materialism holds the high ground these days in debates over that most ultimate of scientific questions: the nature of consciousness. When tackling the problem of mind and brain, many prominent researchers advocate for a universe fully reducible to matter. ‘Of course you are nothing but the activity of your neurons,’ they proclaim. That position seems reasonable and sober in light of neuroscience’s advances, with brilliant images of brains lighting up like Christmas trees while test subjects eat…
Jess Romeo writes: During a 2015 conference on theoretical cosmology at Princeton University, Roger Penrose, a pioneer in the field of mathematical physics, was asked to speak on a panel about the origin of the universe. For decades, the leading theory had been that, during roughly the first trillionth of a trillionth of a nanosecond following the Big Bang, there was a single period of extremely rapid expansion, known as inflation, that formed the universe we observe today. When it…
Anthony Aguirre writes: One afternoon some years ago, I was walking through the snow thinking about other universes. More specifically, I was turning over in my mind the fact that the hospitality provided by our universe depends on many extremely special things. For example, if the electric repulsion between protons in the nuclei of atoms were just a bit stronger, then those atoms, and hence chemistry, and hence life itself, could not apparently exist. And there are many other such…
Natalie Wolchover writes: In 1981, many of the world’s leading cosmologists gathered at the Pontifical Academy of Sciences, a vestige of the coupled lineages of science and theology located in an elegant villa in the gardens of the Vatican. Stephen Hawking chose the august setting to present what he would later regard as his most important idea: a proposal about how the universe could have arisen from nothing. Before Hawking’s talk, all cosmological origin stories, scientific or theological, had invited…
Joshua Sokol writes: Recently at the Laboratory for Laser Energetics in Brighton, New York, one of the world’s most powerful lasers blasted a droplet of water, creating a shock wave that raised the water’s pressure to millions of atmospheres and its temperature to thousands of degrees. X-rays that beamed through the droplet in the same fraction of a second offered humanity’s first glimpse of water under those extreme conditions. The X-rays revealed that the water inside the shock wave didn’t…
NASA reports: Astronomers using NASA’s Hubble Space Telescope say they have crossed an important threshold in revealing a discrepancy between the two key techniques for measuring the universe’s expansion rate. The recent study strengthens the case that new theories may be needed to explain the forces that have shaped the cosmos. A brief recap: The universe is getting bigger every second. The space between galaxies is stretching, like dough rising in the oven. But how fast is the universe expanding?…
Rebecca Holmes writes: I spent a lot of time in the dark in graduate school. Not just because I was learning the field of quantum optics – where we usually deal with one particle of light or photon at a time – but because my research used my own eyes as a measurement tool. I was studying how humans perceive the smallest amounts of light, and I was the first test subject every time. I conducted these experiments in a…
Alan Lightman writes: Planets, stars, life, even the direction of time all depend on disorder. And we human beings as well. Especially if, along with disorder, we group together such concepts as randomness, novelty, spontaneity, free will and unpredictability. We might put all of these ideas in the same psychic basket. Within the oppositional category of order, we can gather together notions such as systems, law, reason, rationality, pattern, predictability. While the different clusters of concepts are not mirror images…
MIT Technology Review reports: Back in 1961, the Nobel Prize–winning physicist Eugene Wigner outlined a thought experiment that demonstrated one of the lesser-known paradoxes of quantum mechanics. The experiment shows how the strange nature of the universe allows two observers—say, Wigner and Wigner’s friend—to experience different realities. Since then, physicists have used the “Wigner’s Friend” thought experiment to explore the nature of measurement and to argue over whether objective facts can exist. That’s important because scientists carry out experiments to…
Ian Sample writes: All the brain cells of life on Earth still cannot explain life on Earth. Its most intelligent species has uncovered the building blocks of matter, read countless genomes and watched spacetime quiver as black holes collide. It understands much of how living creatures work, but not how they came to be. There is no agreement, even, on what life is. The conundrum of life is so fundamental that to solve it would rank among the most important…