Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that’s rotating into the oncoming air. Thanks to Isaac Newton’s third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that’s turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
Under the gun, Smith and Boyle went into an office and, in one hour, emerged with the basic plans for the CCD, the sensor still used in digital photography today. A CCD works like this: Light hits a tiny grid of photosensitive silicon cells, each which build a charge proportional to the intensity of the light hitting it. This charge can be measured precisely and we can know exactly how bright that portion should be. Add filters, and color can be discerned too.
Physicist James Clerk Maxwell was perhaps the first to recognize that atoms could be used to keep time. In 1879 he wrote to electricity pioneer William Thomson, suggesting that the “period of vibration of a piece of quartz crystal” would be a better absolute standard of time than the mean solar second (based on the Earth’s rotation) but would still depend “essentially on one particular piece of matter” and therefore would be “liable to accidents.” Maxwell theorized that atoms would work even better as a natural standard of time. Thomson wrote in the second edition of the Elements of Natural Philosophy, published in 1879, that hydrogen atoms, sodium atoms, and others were “absolutely alike in every physical property” and “probably remain the same so long as the particle itself exists.”
Globally, the price of solar panels has fallen 50% between 2016 and 2017, they write. And in countries with favorable wind conditions, the costs associated with wind power “can be as low as one-half to one-third that of coal- or natural gas-fired power plants.” Innovations in wind-turbine design are allowing for ever-longer wind blades; that boost in efficiency will also increase power output from the wind sector, according to Morgan Stanley.
Mind the Bullshit Asymmetry Principle, articulated by the Italian software developer Alberto Brandolini in 2013: the amount of energy needed to refute bullshit is an order of magnitude bigger than that needed to produce it. Or, as Jonathan Swift put it in 1710, “Falsehood flies, and truth comes limping after it.”Plus ça change.
The technology, developed by Carbon Nexus PhD student Maxime Maghe and Carbon Nexus General Manager Steve Atkiss, has the potential to reduce the energy used in carbon fibre production by 75 per cent and reduces the production process time from around 80 minutes to under 15 minutes.
In addition, the specialised carbon fibre production machinery required is expected to cost around 50 per cent less than current equipment.
Floating solar farms are becoming increasingly popular around the world because their unique design addresses multiple efficiency and city planning issues. These floating apparatuses free up land in more populated areas and also reduce water evaporation. The cooler air at the surface also helps to minimize the risk of solar cell performance atrophy, which is often related to long-term exposure to warmer temperatures.
Iceland’s decision to harness the heat inside the earth in a process known as geothermal energy dates back to the 1970s and the oil crisis.
But the new geothermal well is expected to generate far more energy, as the extreme heat and pressure at that depth makes the water take the form of a “supercritical” fluid, which is neither gas nor liquid.
Each telescope will point at Sagittarius A*, the supermassive black hole at the centre of the Milky Way, and measure every radio wave coming from its direction. Linking together observatories spread across such a huge area and combining their observations to filter out extra light will effectively create a powerful “virtual telescope” almost the size of Earth.
As other telescopes are added to the network in coming decades, observations of the black holes will become even more precise, and should provide fundamental insights into the workings of our universe.
If mathematics is a medium for human flourishing, it stands to reason that everyone should have a chance to participate in it. But in his talk Su identified what he views as structural barriers in the mathematical community that dictate who gets the opportunity to succeed in the field — from the requirements attached to graduate school admissions to implicit assumptions about who looks the part of a budding mathematician.