A new definition of kilogram went into effect today. No longer is the kilogram defined by Le Grand K, a 140-year-old weight under glass in a secret location near Paris. Now it's determined by the Planck constant, based on physicist Max Planck's theory that "electromagnetic energy at a given frequency could only be emitted in discrete amounts, or quanta, whose energy is proportional to h, now known as the Planck constant." Scientists at the 26th General Conference on Weights and Measures also redefined the kelvin, the ampere, and the mole. UP next, the second! The good news is that the changes are so small that they won't matter to most of us. From Science News:
Currently, the second is defined by atomic clocks made of cesium atoms. Those atoms absorb a certain frequency of light. The wiggling of the light’s electromagnetic waves functions like the pendulum on a grandfather clock, rhythmically keeping time. One second is defined as 9,192,631,770 oscillations of the light.
But a new generation of atomic clocks, known as optical atomic clocks, outdo the cesium clocks (SN: 11/11/17, p. 8). “Their performance is a lot better than what currently defines the second,” says physicist Andrew Ludlow of the National Institute of Standards and Technology in Boulder, Colo. Because those optical atomic clocks operate at a higher frequency, their “ticks” are more closely spaced, making them about 100 times more precise than cesium clocks.
Ideally, the length of a second should be defined using the most precise timepieces available. A switch might happen in the late 2020s, Ludlow says.
The deadly 2013 El Reno tornado was 2.5 miles (4 km) wide and killed a team of tornado experts. But as Anton Seimon explains, his colleagues turned that tragedy into an opportunity to confirm a key element of tornado formation.
Some snakes have evolved the ability to glide through the air. For example, paradise tree snakes in southeastern Asia can launch off from a branch and fly as far as 10 meters. Scientists have known that the snakes flatten their bodies to gain lift but new research reveals that they also undulate their bodies as […]
We humans are castaways on an ocean of uncertainty. Since the beginnings of history, our ancestors sought knowledge and understanding about their lives, their relationship with the cosmos, and perhaps take a peek into their future. In such effort—long before the answers of science—earthlings developed a rich variety of divination practices and systems. Many forms […]
Nearly 30 years after it started its run as the most dominant productivity software ever created, the Microsoft Office suite of programs are now virtually synonymous with personal computing. From its days bundled with Windows to its current life as Office 365 cloud-based apps, there’s no reason to think perennial hits like Word, Excel and […]
Photography isn’t just about lighting and composition anymore, especially when you’re shooting with your smartphone. While a wealth of expertise can absolutely help you grab better images, sometimes it’s just about having a great light or an amazing smoothing gimbal to instantly elevate your Instagram pics and other social videos from meh to standout. To […]
As the summer surges forward, grilling and evenings in the backyard may be the only serious outdoor excursions many of us take this season. Yet even with all of our current problems, there’s one group who doesn’t care a bit about COVID-19 and will still look to make any trip you make outside into an […]