How well have you been following events in physics? There are 20 questions in total: blue is your current question and white means unanswered, with green and red being right and wrong.
16–20 Top quark – congratulations, you’ve hit Einstein level
11–15 Strong force – good but not quite Nobel standard
WIRED spoke with DeepMind’s Pushmeet Kohli about the recent past—and promising future—of the Nobel Prize-winning research project that changed biology and chemistry forever.
This episode of the Physics World Weekly podcast features Pat Hanrahan, who studied nuclear engineering and biophysics before becoming a founding employee of Pixar Animation Studios. As well as winning three Academy Awards for his work on computer animation, Hanrahan won the Association for Computing Machinery’s A.M. Turing Award for his contributions to 3D computer graphics, or CGI.
Earlier this year, Hanrahan spoke to Physics World’s Margaret Harris at the Heidelberg Laureate Forum in Germany. He explains how he was introduced to computer graphics by his need to visualize the results of computer simulations of nervous systems. That initial interest led him to Pixar and his development of physically-based rendering, which uses the principles of physics to create realistic images.
Hanrahan explains that light interacts with different materials in very different ways, making detailed animations very challenging. Indeed, he says that creating realistic looking skin is particularly difficult – comparing it to the quest for a grand unified theory in physics.
He also talks about how having a background in physics has helped his career – citing his physicist’s knack for creating good models and then using them to solve problems.
Merge Labs, a brain-computer interface startup that seeks to read brain activity using ultrasound, is being spun out of Forest Neurotech, a Los Angeles nonprofit.
Polling shows that nearly half of Americans now believe aliens have visited this planet—and that the number who aren't sure has dropped by two-thirds. The reasons why, experts say, are complicated.
As the world looks to incorporate more renewables into energy grids, centuries-old systems that can balance supply and demand are being reappraised and innovated upon.
Science Corporation, founded by Neuralink’s first president, Max Hodak, has unveiled a prototype machine to extend the life of organs for longer periods.
Yale epidemiologist Harvey Risch, who has entertained a connection between Covid vaccines and “turbo cancer” and promoted ivermectin, says he'll chair the President's Cancer Panel.
If a major disaster like Fukushima or Chornobyl ever happens again, the world would know almost straight away, thanks to an array of government and DIY radiation-monitoring programs running globally.
A destructive storm in 2020 prematurely shut down Iowa’s only nuclear plant. With Google’s plans to reopen it to power nearby data centers, will extreme weather threaten the reactor’s safety?
More molecules and compounds vital to the origin of life have been detected in asteroid samples delivered to Earth by NASA’s OSIRIS-REx mission. The discovery strengthens the case that not only did life’s building blocks originate in space, but that the ingredients of RNA, and perhaps RNA itself, were brought to our planet by asteroids.
Two new papers in Nature Geoscience and Nature Astronomy describe the discovery of the sugars ribose and glucose in the 120 g of samples returned from the near-Earth asteroid 101955 Bennu, as well as an unusual carbonaceous “gum” that holds important compounds for life. The findings complement the earlier discovery of amino acids and the nucleobases of RNA and DNA in the Bennu samples.
A third new paper, in Nature Astronomy, addresses the abundance of pre-solar grains, which is dust that originated from before the birth of our Solar System, such as dust from supernovae. Scientists led by Ann Nguyen of NASA’s Johnson Space Center found six times more dust direct from supernova explosions than is found, on average, in meteorites and other sampled asteroids. This could suggest differences in the concentration of different pre-solar dust grains in the disc of gas and dust that formed the Solar System.
Space gum
It’s the discovery of organic materials useful for life that steals the headlines, though. For example, the discovery of the space gum, which is essentially a hodgepodge chain of polymers, represents something never found in space before.
Scott Sandford of NASA’s Ames Research Center, co-lead author of the Nature Astronomy paper describing the gum discovery, tells Physics World: “The material we see in our samples is a bit of a molecular jumble. It’s carbonaceous, but much richer in nitrogen and, to a lesser extent, oxygen, than most of the organic compounds found in extraterrestrial materials.”
Sandford refers to the material as gum because of its pliability, bending and dimpling when pressure is applied, rather like chewing gum. And while much of its chemical functionality is replicated in similar materials on our planet, “I doubt it matches exactly with anything seen on Earth,” he says.
Initially, Sandford found the gum using an infrared microscope, nicknaming the dust grains containing the gum “Lasagna” and “Neapolitan” because the grains are layered. To extract them from the rock in the sample, Sandford went to Zack Gainsforth of the University of California, Berkeley, who specializes in analysing and extracting materials from samples like this.
Platinum scaffolding
Having welded a tungsten needle to the Neapolitan sample in order to lift it, the pair quickly realised that the grain was very delicate.
“When we tried to lift the sample it began to deform,” Gainsforth says. “Scott and I practically jumped out of our chairs and brainstormed what to do. After some discussion, we decided that we should add straps to give it enough mechanical rigidity to survive the lift.”
Fragile sample A microscopic particle of asteroid Bennu is manipulated under a transmission electron microscope. To move the 30 µm fragment for further analysis, the researchers reinforced it with thin platinum strips (the L shape on the surface). (Courtesy: NASA/University of California, Berkeley)
By straps, Gainsforth is referring to micro-scale platinum scaffolding applied to the grain to reinforce its structure while they cut it away with an ion beam. Platinum is often used as a radiation shield to protect samples from an ion beam, “but how we used it was anything but standard,” says Gainsforth. “Scott and I made an on-the-fly decision to reinforce the samples based on how they were reacting to our machinations.”
With the sample extracted and reinforced, they used the ion beam cutter to shave it down until it was a thousand times thinner than a human hair, at which point it could be studied by electron microscopy and X-ray spectrometry. “It was a joy to watch Zack ‘micro-manipulate’ [the sample],” says Sandford.
The nitrogen in the gum was found to be in nitrogen heterocycles, which are the building blocks of nucleobases in DNA and RNA. This brings us to the other new discovery, reported in Nature Geoscience, of the sugars ribose and glucose in the Bennu samples, by a team led by Yoshihiro Furukawa of Tohoku University in Japan.
The ingredients of RNA
Glucose is the primary source of energy for life, while ribose is a key component of the sugar-phosphate backbone that connects the information-carrying nucleobases in RNA molecules. Furthermore, the discovery of ribose now means that everything required to assemble RNA molecules is present in the Bennu sample.
Notable by its absence, however, was deoxyribose, which is ribose minus one oxygen atom. Deoxyribose in DNA performs the same job as ribose in RNA, and Furukawa believes that its absence supports a popular hypothesis about the origin of life on Earth called RNA world. This describes how the first life could have used RNA instead of DNA to carry genetic information, catalyse biochemical reactions and self-replicate.
Intriguingly, the presence of all RNA’s ingredients on Bennu raises the possibility that RNA could have formed in space before being brought to Earth.
“Formation of RNA from its building blocks requires a dehydration reaction, which we can expect to have occurred both in ancient Bennu and on primordial Earth,” Furukawa tells Physics World.
However, RNA would be very hard to detect because of its expected low abundance in the samples, making identifying it very difficult. So until there’s information to the contrary, “the present finding means that the ingredients of RNA were delivered from space to the Earth,” says Furukawa.
Nevertheless, these discoveries are major milestones in the quest of astrobiologists and space chemists to understand the origin of life on Earth. Thanks to Bennu and the asteroid 162173 Ryugu, from which a sample was returned by the Japanese Aerospace Exploration Agency (JAXA) mission Hayabusa2, scientists are increasingly confident that the building blocks of life on Earth came from space.
At an FDA discussion of testosterone replacement therapy, a top official called for special health centers to address a “men’s health crisis.” Others called to ease men’s access to hormones.
With support from Microsoft, Stripe, and Shopify, Running Tide billed itself as on the cutting edge of carbon removal. In the end, it resorted to dumping thousands of tons of wood chips in the sea.
As a physicist in industry, I spend my days developing new types of photovoltaic (PV) panels. But I’m also keen to do something for the transition to green energy outside work, which is why I recently installed two PV panels on the balcony of my flat in Munich. Fitting them was great fun – and I can now enjoy sunny days even more knowing that each panel is generating electricity.
However, the panels, which each have a peak power of 440 W, don’t cover all my electricity needs, which prompted me to take an interest in a plan to build six wind turbines in a forest near me on the outskirts of Munich. Curious about the project, I particularly wanted to find out when the turbines will start generating electricity for the grid. So when I heard that a weekend cycle tour of the site was being organized to showcase it to local residents, I grabbed my bike and joined in.
As we cycle, I discover that the project – located in Forstenrieder Park – is the joint effort of four local councils and two “citizen-energy” groups, who’ve worked together for the last five years to plan and start building the six turbines. Each tower will be 166 m high and the rotor blades will be 80 m long, with the plan being for them to start operating in 2027.
I’ve never thought of Munich as a particularly windy city, but at the height at which the blades operate, there’s always a steady, reliable flow of wind
I’ve never thought of Munich as a particularly windy city. But tour leader Dieter Maier, who’s a climate adviser to Neuried council, explains that at the height at which the blades operate, there’s always a steady, reliable flow of wind. In fact, each turbine has a designed power output of 6.5 MW and will deliver a total of 10 GWh in energy over the course of a year.
Practical questions
Cycling around, I’m excited to think that a single turbine could end up providing the entire electricity demand for Neuried. But installing wind turbines involves much more than just the technicalities of generating electricity. How do you connect the turbines to the grid? How do you ensure planes don’t fly into the turbines? What about wildlife conservation and biodiversity?
At one point of our tour, we cycle round a 90-degree bend in the forest and I wonder how a huge, 80 m-long blade will be transported round that kind of tight angle? Trees will almost certainly have to be felled to get the blade in place, which sounds questionable for a supposedly green project. Fortunately, project leaders have been working with the local forest manager and conservationists, finding ways to help improve the local biodiversity despite the loss of trees.
As a representative of BUND (one of Germany’s biggest conservation charities) explains on the tour, a natural, or “unmanaged”, forest consists of a mix of areas with a higher or lower density of trees. But Forstenrieder Park has been a managed forest for well over a century and is mostly thick with trees. Clearing trees for the turbines will therefore allow conservationists to grow more of the bushes and plants that currently struggle to find space to flourish.
Cut and cover Trees in Forstenrieder Park have had to be chopped down to provide room for new wind turbines to be installed, but the open space will let conservationists grow plants and bushes to boost biodiversity. (Courtesy: Janina Moereke)
To avoid endangering birds and bats native to this forest, meanwhile, the turbines will be turned off when the animals are most active, which coincidentally corresponds to low wind periods in Munich. Insurance costs have to be factored in too. Thankfully, it’s quite unlikely that a turbine will burn down or get ice all over its blades, which means liability insurance costs are low. But vandalism is an ever-present worry.
In fact, at the end of our bike tour, we’re taken to a local wind turbine that is already up and running about 13 km further south of Forstenrieder Park. This turbine, I’m disappointed to discover, was vandalized back in 2024, which led to it being fenced off and video surveillance cameras being installed.
But for all the difficulties, I’m excited by the prospect of the wind turbines supporting the local energy needs. I can’t wait for the day when I’m on my balcony, solar panels at my side, sipping a cup of tea made with water boiled by electricity generated by the rotor blades I can see turning round and round on the horizon.