SPACEX STARSHIP is Elon Musk’s ambitious plan to carry crew and cargo to the Moon, Mars and beyond. Now, the SpaceX CEO has revealed significant tweaks to the Starship’s extraordinary design.
One of the fundamental challenges of physics is the reconciliation of Einstein’s theory of relativity and quantum mechanics. The necessity to critically question these two pillars of modern physics arises, for example, from extremely high-energy events in the cosmos, which so far can only ever be explained by one theory at a time, but not both theories in harmony. Researchers around the world are therefore searching for deviations from the laws of quantum mechanics and relativity that could open up insights into a new field of physics.
For a recent publication, scientists from Leibniz University Hannover and Ulm University have taken on the twin paradox known from Einstein’s special theory of relativity. This thought experiment revolves around a pair of twins: While one brother travels into space, the other remains on Earth. Consequently, for a certain period of time, the twins are moving in different orbits in space. The result when the pair meets again is quite astounding: The twin who has been travelling through space has aged much less than his brother who stayed at home. This phenomenon is explained by Einstein’s description of time dilation: Depending on the speed and where in the gravitational field two clocks move relative to each other, they tick at different speeds.
For the publication in Science Advances, the authors assumed a quantum-mechanical variant of the twin paradox with only one twin. Thanks to the superposition principle of quantum mechanics, this twin can move along two paths at the same time. In the researchers’ thought experiment, the twin is represented by an atomic clock. “Such clocks use the quantum properties of atoms to measure time with high precision. The atomic clock itself is therefore a quantum-mechanical object and can move through space-time on two paths simultaneously due to the superposition principle. Together with colleagues from Hannover, we have investigated how this situation can be realised in an experiment,” explains Dr. Enno Giese, research assistant at the Institute of Quantum Physics in Ulm. To this end, the researchers have developed an experimental setup for this scenario on the basis of a quantum-physical model.
Radio program The Current had me on this morning discussing #transhumanism, specifically #robots & #AI running for political office. It’s Canada’s most listened to radio program with millions of listeners. Here’s a fun write-up of it:
We ask if we should ditch flesh-and-blood politicians, and give the robots a go at leadership.
Researchers at Tufts University School of Engineering have developed silk materials that can wrinkle into highly detailed patterns—including words, textures and images as intricate as a QR code or a fingerprint. The patterns take about one second to form, are stable, but can be erased by flooding the surface of the silk with vapor, allowing the researchers to “reverse” the printing and start again. In an article published today in the Proceedings of the National Academy of Sciences, the researchers demonstrate examples of the silk wrinkle patterns, and envision a wide range of potential applications for optical electronic devices.
The smart textile takes advantage of the natural ability of silk fiber proteins—fibroin—to undergo a change of conformation in response to external conditions, including exposure to water vapor, methanol vapor and UV radiation. Water and methanol vapor, for example, can soak into the fibers and interfere with hydrogen bond cross links in the silk fibroin, causing it to partially ‘unravel’ and release tension in the fiber. Taking advantage of this property, the researchers fabricated a silk surface from dissolved fibroin by depositing it onto a thin plastic membrane (PDMS). After a cycle of heating and cooling, the silk surface of the silk/PDMS bilayer folds into nanotextured wrinkles due to the different mechanical properties of the layers.
Exposing any part of that wrinkled surface to water or methanol vapor causes the fibers to relax and the wrinkles to flatten. The smooth surface transmits more than 80% of light, while the wrinkled surface only allows 20% or less through, creating a visible contrast and the perception of a printed pattern. The surface can be selectively exposed to vapor using a patterned mask, resulting in a matched pattern in the textured silk. Patterns may also be created by depositing water using inkjet printing. The resolution of this printing method is determined by the resolution of the mask itself, or the nozzle diameter of the inkjet printer.
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A trio of researchers from the U.S. and the UK has won the 2019 Nobel Prize in Medicine, the first of five prizes to be announced this week. On Monday in Sweden, the Nobel committee announced that Americans William Kaelin Jr. and Gregg Semenza, along with Peter Ratcliffe, would split the nearly million-dollar prize for their work in unraveling a fundamental aspect of life: how our cells keep track of and respond to fluctuating oxygen levels.
This year’s prize was decades in the making.
Though we’ve long known that our cells need oxygen to produce energy and keep us alive, we were largely in the dark on how cells sensed oxygen, or how they managed to adapt in times of low oxygen, a state known as hypoxia. In the early 1990s, Gregg Semenza, currently of Johns Hopkins University, and his team discovered some of the key genetic machinery that cells use to detect hypoxia and then respond by producing a hormone called erythropoietin (EPO).
Uncrewed and jet-powered, the Romanian design hopes to overcome the airframe style’s long history of unsuccessful flight.
