If something always goes wrong, maybe you’re the problem…
If something always goes wrong, maybe you’re the problem…
Curling is a deceptively engrossing sport with some unique physics among Winter Olympic events. Athletes slide 19kg granite stones at a target 28 meters away. Along the way, teammates sweep the pebbled ice with brooms, melting it with frictional heating to help the stone slide further. The underside of the stones is concave, so they only touch the ice along a narrow ring. Researchers think roughness in the leading edge of the sliding stone cuts into the ice, leaving scratches that the trailing edge tries to follow. This is what causes the stone’s trajectory to curl. By melting the ice, sweeping also prevents curling, so competitors must know exactly when and how much to sweep. Ice conditions shift throughout a match, and the best players can read the ice to keep their stones where they want them. (Image credit: AP; W. Zhao/GettyImages)
“There are a few fundamental facts about the Universe — its origin, its history, and what it is today — that are awfully hard to wrap your head around. One of them is the Big Bang, or the idea that the Universe began a certain time ago: 13.8 billion years ago to be precise. That’s the first moment we can describe the Universe as we know it to be today: full of matter and radiation, and the ingredients that would eventually grow into stars, galaxies, planets and human beings. So how far away can we see? You might think, in a Universe limited by the speed of light, that would be 13.8 billion light years: the age of the Universe multiplied by the speed of light. But 13.8 billion light years is far too small to be the right answer. In actuality, we can see for 46 billion light years in all directions, for a total diameter of 92 billion light years.”
Sure, the Universe is expanding, but how is it possible to see objects that are 46 billion light years away? After all, with an age of 13.8 billion years since the Big Bang, and a Universe where the cosmic speed limit is the speed of light, how can we see light that’s more than three times the expected distance away? It’s one of the most frequent questions that cosmologists get, and yet the root of the question is better framed as “how does the expanding Universe work?” While we normally think about things happening in space that doesn’t change much, or as individual objects moving relative to one another in a static space, we don’t, conventionally, have a solid intuition for how the fabric of space itself expands. But thankfully, the scientists who study it do!
Cross-country skiing, also known as Nordic skiing, is a part of many longstanding disciplines in the Winter Games. Unlike downhill skiing, cross-country events typically involve mass starts, which allow athletes to interact, using one another for pacing and tactics. Drafting can be a valuable method to save energy and reduce drag. A following skier sees a 25% drag reduction while drafting; the lead skier gets about a 3% reduction in drag compared to skiing solo. Competitors usually wear tight-fitting suits to minimize drag, but unlike speedskating, for example, cross-country skiers don’t get much benefit from roughened surfaces and impermeable fabrics. Typical race speeds are 4 – 9 m/s, and most of these high-tech fabrics don’t provide tangible benefits until higher speeds. (Image credit: Reuters/S. Karpukhin, US Biathlon, GettyImages/Q. Rooney)
“When we detect black hole-black hole events with LIGO, it’s only the last few orbits that have a large enough amplitude to be seen above the background noise. The entirety of the signal’s duration lasts from a few hundred milliseconds to only a couple of seconds. By time a signal is collected, identified, processed, and localized, the critical merger event has already passed. There’s no way to point your telescopes — the ones that could find an electromagnetic counterpart to the signal — quickly enough to catch them from birth. Even inspiraling and merging neutron stars could only last tens of seconds before the critical “chirp” moment arrives. Processing time, even under ideal conditions, makes predicting the particular when-and-where a signal will occur a practical impossibility. But all of this will change with LISA.”
The past few years have ushered in the era of gravitational wave astronomy, turning a once-esoteric and controversial prediction of General Relativity into a robust, observational science. Less than a year ago, with three independent detectors online at once, the first localizations of gravitational wave signals were successfully performed. Multi-messenger astronomy, with gravitational waves and an electromagnetic follow-up, came about shortly thereafter, with the first successful neutron star-neutron star merger. But one prediction still eludes us: the ability to know where and when a merger will occur way in advance.
“Moreover, the best evidence for changes comes at the base of the pillars, indicating an evaporation time on the order of between 100,000 and 1,000,000 years. The idea that the pillars have already been destroyed has been demonstrated not to be true. It’s one of the great hopes of science that any controversial claims will be laid to rest by more and better data, and this is one situation where that has paid off in spades. Not only has there not been a supernova that’s in the process of destroying the pillars, but the pillars themselves should be robust for a long time to come.”
In 1995, NASA’s Hubble Space Telescope observed the Eagle Nebula, identifying the now-iconic pillars of creation, where newborn stars are forming inside a gas-rich, dusty region of space. Outside of those pillars, thousands of stars shine brightly, working to boil the gas off, while inside, the radiation from newly-formed stars works to boil it away from the inside. In 2007, the Spitzer Space Telescope, observing in the infrared, suggested that these pillars were blown apart thousands of years ago by a supernova, and that the light hadn’t simply reached our eyes yet. This was controversial, however, and follow-up observations would be required to know for certain. Well, the data has come in, and guess what?
The pillars of creation haven’t been destroyed after all, as the supernova seems to never have occurred. Instead of ~1,000 years, we should have hundreds of thousands of years before the pillars disappear completely. Come get the full story.
When it comes to winter sports, not all ice is created equal. Every discipline has its own standards for the ideal temperature and density of ice, which makes venue construction and maintenance a special challenge. Figure skating, for example, requires softer ice to cushion athletes’ landings, whereas short-track speed skating values dense, smooth ice for racing. The Gangneung Ice Arena hosts both and can transition between them in under 3 hours. Gangneung Oval hosts long-track speed skating and makes its ice layer by layer, spraying hot, purified water onto the rink. This builds up a particularly dense and therefore smooth ice.
The toughest sport in terms of ice conditions is curling, which requires a finely pebbled ice surface for the stones to slide on. Forming those tiny crystals on the ice sheet can only be done at precise temperature and humidity conditions. This is a particular challenge for Gangneung Curling Center due to its coastal location. To keep the temperature and humidity under control at full crowd capacity, officials even went so far as to replace all the lighting at the facility with LEDs! (Image credit: Pyeongchang 2018, 1, 2, 3)
In bobsleigh, two- and four-person teams compete across four runs down an ice track. The shortest cumulative time wins, and since typical runs are separated by hundredths of a second, teams look for any advantage that helps them shave time. The size, weight, and components of a sled are restricted by federation rules; for example, teams cannot use vortex generators to improve their aerodynamics. Instead bobsledders work with companies like BMW, McLaren, and Ferrari to engineer their sleds. Both computational fluid dynamics and wind tunnel tests with the actual team in the sled are used to make each sled as aerodynamic as possible. (Image credit: IOC, Gillette World Sports, source)
“We absolutely cannot let this project go down without a fight. If WFIRST gets cancelled, it’s a sign that even the most important NASA project, as determined by internal, external, and independent reviewers, is subject to political whims. These projects take more than a single presidency to design, approve, build, and launch. Federal funding for these vital missions that enhance all of society must not be allowed to disappear because one human — even if it’s the president — wills it. The joys, wonder, knowledge, and benefits that come from exploring and understanding the Universe are greater than any individual.”
When it comes to NASA, there are three main functions that make up the overwhelming majority of its budget: science, exploration, and space operations. Within science, the largest and most important missions, spread across planetary science, astrophysics, Earth science and heliophysics, are known as flagship missions. According to Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate of NASA, “What we learn from these flagship missions is why we study the Universe. This is civilization-scale science… If we don’t do this, we aren’t NASA.” When someone (ahem… Trump) comes in, after decades of planning, and proposes to scrap an already-designed flagship mission, it threatens to end science-as-we-know-it at NASA.
The United States must not cede leadership in the space and science arena to Japan, Russia, Europe, China, India and Canada the same way it did with the superconducting supercollider 25 years ago. This time, humanity’s capability of understanding the entire Universe is what’s at stake.
These days artificial snow-making is a standard practice for ski resorts, allowing them to jump-start the early part of the season. Snow guns continuously spray a mixture of cold water and particulates 5 or more meters in the air to generate artificial snow. The tiny droplet size helps the water freeze faster and the particles provide nucleation sites for snow crystals to form. As with natural snow, the shape and consistency of the snow depends on humidity and temperature conditions. Pyeongchang is generally cold and dry, so even the artificial snow there tends to be similar to snow in the Colorado Rockies. Recreational skiers tend to look down on artificial snow, but Olympic course designers actually prefer it. With artificial snow, they can control every aspect of an alpine course. For them, natural snowfall is a disruption that puts their design at risk. (Video credit: Reactions/American Chemical Society)