Scientific studies quantify results, which is important. Even if you know an effect is there, knowing how big the effect is and what variables change the results and by how much gives you insight into how to attack/leverage the phenomenon. Also — and the article only mentions this in passing — conventional wisdom isn’t always right. It’s necessary to do studies to confirm that actions are having the outcomes we think they are, even if nine times out of ten they do. One of the more famous examples is the conventional medical wisdom that peptic ulcers were caused by stress or spicy foods, and how that colored their treatment. Because that conventional wisdom was challenged, we learned that most of these ulcers are cause by the Helicobacter pylori bacterium.
[A]irships got left behind. Why? They have an Achilles’ heel. No, it’s not the weather, hydrogen, or the materials of the day—and it’s not some conspiracy or a crewman with a bomb on the Hindenburg ruining it for everybody. Like a lot of things, the facts are simple and scientific, and thus boring—unless you’re intrigued by simple scientific facts. Either way it’s this: airships are inefficient.
The purpose of transportation is to get a thing from one place to another. The measure of any vehicle’s efficiency—be it by land or by sea or even by air—is how much it carries vs. how hard you have to push it and how fast it goes. At the end of the day, we all want to get it there fast, and we all want to get it there cheap.
Corvallis, OR is the metro area with the lowest risk of natural disasters in the US.
Small quake and drought risk; little extreme weather.
In the six years I lived there we did have a drought and an earthquake (Magnitude 5.6, ~ 30 miles away), so it was more exciting/dangerous when I was there. Lots of cities in the northwest rated as low-risk.
The entire machine was rebuilt using spares from BT telephone exchanges that were remodelled in the 1980s. All of the engineers that worked on the rebuild were ex-BT employees and had contacts at other museums, and so could lay their hands on the components, Whetter added.
Slightly smaller than a square tissue box, AIRprint houses two 1.3 megapixel cameras and a source of polarized light. One camera receives horizontally polarized light, while the other receives vertically polarized light. When light hits a finger, the ridges of the fingerprint reflect one polarization of light, while the valleys reflect another. “That’s where the real kicker is, because if you look at an image without any polarization, you can kind of see fingerprints, but not really well,” says Burcham. By separating the vertical and the horizontal polarization, the device can overlap those images to produce an accurate fingerprint, which is fed to a computer for verification.
I’m guessing that what they mean is that the light source is polarized and the cameras have polarizing filters in front of them to see the two components. Reflectivity generally depends on the polarization and angle of the incident light; the whole reason that polarized sunglasses are effective is that light scattered off of a surface tends to be polarized parallel to that surface, and at Brewster’s angle absolutely none of the perpendicular component will be reflected. So it seems reasonable that detection of the two polarizations improves the contrast of the image you get. Light at normal incidence will reflect the polarized light with no change, but light scattered off of the valleys will mix in some of the orthogonal polarization, which gets picked up by the other camera.
To our best present knowledge these constants are indeed constant, but you can imagine varying them and ask what happens to the theory then. In many cases this corresponds to some physical limit. For example, if your theory contains terms in v/c, where v is velocity, then the limit of velocities small compared to c (i.e. non-relativistic) formally corresponds to taking c to infinity, ie 1/c to zero.