Archive for the ‘science’ Category
Claudette "C.J." Walker (Eden Duncan-Smith), Sebastian (Dante Crichlow), and their lab mate, Eduardo (Johnathan Nieves), carefree and excited about science. [credit: YouTube/Netflix ]
Director Stefon Bristol's See You Yesterday is something of an anomaly in the pantheon of time travel movies, straddling multiple genres. With its central tragedy, theme focused on the unintended consequences of new technology, and strong social conscience, it's more Black Mirror than Back to the Future. As such, it fits nicely into a small subgroup of quietly innovative time travel films like 2012's Safety Not Guaranteed.
The premise: two teenage science nerds in the Flatbush neighborhood of Brooklyn build a makeshift time machine to right a tragic wrong. C.J (Eden Duncan-Smith) and her best friend and fellow science whiz Sebastian (Dante Crichlow), nicknamed Bash, have just wrapped their junior year at the Bronx High School of Science. They're putting the finishing touches on a pair of portable time travel devices for an upcoming science fair, and they're naturally ecstatic when they succeed on their next attempt at a Temporal Relocation Test, traveling back one full day.
That light-hearted tone quickly turns dark. In an all-too-familiar scenario, C.J.'s older brother Calvin (the rapper Astro) runs afoul of a trigger-happy NYPD officer, who mistakes Calvin pulling a cell phone out of his pocket for a weapon and shoots him dead. C.J. figures she and Sebastian can use their science project to travel back in time to save Calvin. Who among us wouldn't want to try to reverse such a tragedy? But as you might expect, there are some serious unintended consequences to her plan.
For most of our history, humans got hold of food like any other animal: by hunting and foraging, moving around to find the best resources. Settling down in one place to cultivate crops is a comparatively recent development. But once it started around 12,000 years ago, agriculture spread through human cultures across the world, fundamentally changing our societies, genomes, and possibly even languages. In many ways, farming seems to have been terrible news for the people who adopted it, leading to poorer nutrition and greater social inequality—but it also resulted in higher fertility rates and a massive population expansion.
Understanding how and why this technological change was adopted remains a challenge. Studies mostly rely on fossil evidence, but there are also clues in the modern world, as some present-day groups of people are moving away from hunting, fishing, and gathering their food and toward agriculture.
A paper published in Nature Human Behaviour explores how this shift affects the time budgets of hunter-gatherers in the Philippines, finding that women who participate more in agricultural work have less leisure time—around half the leisure time of women who prioritize foraging. The results fall in line with past research that challenges the concept of hunting and foraging as arduous work with scant rewards, and this work contributes to a growing understanding of the social dynamics that go along with a shift to agriculture.
Welcome to Edition 2.01 of the Rocket Report! This week marks one year since the first report. What started as an experiment has grown into something that a lot of people read. So thank you for joining. And if you appreciate this weekly report and the effort that goes into it, I encourage you to subscribe to Ars Technica. It doesn't cost much, and there are perks. But mostly you'll know you're supporting independent journalism like this. Thank you for considering it.
As always, we welcome reader submissions, and if you don't want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.
Virgin performs full-duration hotfire test. On Tuesday, Virgin Orbit announced that it had performed the "final full-duration, full-scale, full-thrust—hell, full everything—test firing" of its LauncherOne rocket's first stage. The firing lasted for more than 180 seconds and was entirely successful, the company reported. Virgin said the rocket, which will be launched from beneath the wing of an airplane, was within an "arm's reach" of its first orbital flight test.
Most of our building practices aren't especially sustainable. Concrete production is a major source of carbon emissions, and steel production is very resource intensive. Once completed, heating and cooling buildings becomes a major energy sink. There are various ideas on how to handle each of these issues, like variations on concrete's chemical formula or passive cooling schemes.
But now, a large team of US researchers has found a single solution that appears to manage everything using a sustainable material that both reflects sunlight and radiates away excess heat. The miracle material? Wood. Or a form of wood that's been treated to remove one of its two main components.
With the grain
Wood is mostly a composite of two polymers. One of these, cellulose, is made by linking sugars together into long chains. That cellulose is mixed with a polymer called lignin, which is not really a single polymer. The precise chemical formula of its starting material can vary among species, and it typically contains multiple places where chemical bonds can form, turning the polymer into a chaotic but extremely robust mesh.
Launch of the Falcon 9 rocket on Thursday evening from Cape Canaveral, Florida. [credit: Trevor Mahlmann ]
11:40pm ET Update: The Falcon 9 rocket launched. Its first stage landed. And then the second stage coasted for the better part of an hour before making a final burn and deploying its payload of Starlink satellites.
About 1 hour and 3 minutes after the launch, the entire stack of 60 satellites floated away from the Falcon 9's second stage. Slowly—very slowly, it appeared—the 60 satellites began to drift apart. The SpaceX webcast ended without saying whether this deployment went as anticipated, and it probably will take some time for the Air Force to begin identifying, and tracking the individual satellites.
In any case, this all made for an interesting evening in space.