Researchers from the International Centre for Radio Astronomy Research (ICRAR) and The University of Western Australia (UWA) have achieved a new world record for the most stable laser signal transmission through the atmosphere.
Australian researchers collaborated with researchers from the French National Centre for Space Studies (CNES) and the French metrology lab Systèmes de Référence Temps-Espace (SYRTE) at Paris Observatory for the study, which was published recently in the Nature Communications journal.
The group combined the Australian researchers’ “phase stabilisation” technology with sophisticated self-guiding optical terminals to set the world record for the most stable transmission of a laser signal.
When used in combination, both the technologies enabled laser signals to be transmitted from one point to the other without any interference from the atmosphere. According to the lead author of the study Benjamin Dix-Matthews, who is a PhD student at ICRAR and UWA, the technique effectively removes atmospheric turbulence.
“We can correct for atmospheric turbulence in 3D, that is, left-right, up-down and, critically, along the line of flight. It’s as if the moving atmosphere has been removed and doesn’t exist. It allows us to send highly-stable laser signals through the atmosphere while retaining the quality of the original signal.”
The outcome is the most accurate method in the world to compare the flow of time between two individual locations with the help of a laser system transmitted through the atmosphere.
Dr Sascha Schediwy, a senior researcher at ICRAR-UWA, said that the study has fascinating applications.
“If you have one of these optical terminals on the ground and another on a satellite in space, then you can start to explore fundamental physics. Everything from testing Einstein’s theory of general relativity more precisely than ever before, to discovering if fundamental physical constants change over time.”
The accurate measurements of the technology could also find practical applications in earth science and geophysics.
“For instance, this technology could improve satellite-based studies of how the water table changes over time, or to look for ore deposits underground,” added Dr Schediwy.
There are additional prospective advantages for optical communications, which is an emerging field that involves using light to transfer information. Optical communications can ensure secure transmission of data between satellites and Earth, with considerably higher data rates compared to existing radio communications.
“Our technology could help us increase the data rate from satellites to ground by orders of magnitude. The next generation of big data-gathering satellites would be able to get critical information to the ground faster” she said.
The phase stabilization technology using which this record-setting link was established was originally created to synchronize incoming signals for the Square Kilometre Array telescopes. The multi-billion-dollar telescopes are planned to be set up in South Africa and Western Australia.
Thanks to AZO Optics for this report.
Science News carries an interesting report on mankind’s development of a thumb that could oppose the fingers, giving our ancestors the ability to grasp tools, and make more sophisticated tools.
Bruce Bower, writing on Friday the 28th says that thumb dexterity similar to that of people today already existed around 2 million years ago, possibly in some of the earliest members of our own genus Homo, a new study indicates. The finding is the oldest evidence to date of an evolutionary transition to hands with powerful grips comparable to those of human toolmakers, who didn’t appear for roughly another 1.7 million years.
Thumbs that enabled a forceful grip and improved the ability to manipulate objects gave ancient Homo or a closely related hominid line an evolutionary advantage over hominid contemporaries, says a team led by Fotios Alexandros Karakostis and Katerina Harvati. Now-extinct Australopithecus made and used stone tools but lacked humanlike thumb dexterity, thus limiting its toolmaking capacity, the paleoanthropologists, from Eberhard Karls University of Tübingen in Germany, found.
The researchers digitally simulated how a key muscle influenced thumb movement in 12 previously found fossil hominids, five 19th century humans and five chimpanzees. Surprisingly, Harvati says, a pair of roughly 2-million-year-old thumb fossils from South Africa display agility and power on a par with modern human thumbs.
Harvati’s team went beyond past efforts that focused only on the size and shape of ancient hominids’ hand bones. Using data from humans and chimpanzees on how hand muscles and bones interact while moving, the researchers constructed a digital, 3-D model to re-create how a key thumb muscle — musculus opponens pollicis — attached to a bone at the base of the thumb and operated to bend the digit’s joint toward the palm and fingers.
These new models of how ancient thumbs worked underscore the slowness of hominid hand evolution, says paleoanthropologist Matthew Tocheri of Lakehead University in Thunder Bay, Canada. Australopithecus made and used stone tools as early as around 3.3 million years ago. “But we don’t see major changes to the thumb until around 2 million years ago, soon after which stone artefacts become far more common across the African landscape,” he says.
Karakostis and Harvati’s 3-D models of ancient thumb dexterity represent a promising advance, says paleoanthropologist Carol Ward of the University of Missouri in Columbia. But further work needs to examine how other thumb muscles interacted with musculus opponens pollicis to influence how that digit worked in different hominid species, she adds.
In a related finding, Ward and her colleagues — including Tocheri — reported in 2014 that a roughly 1.42-million-year-old hominid finger fossil from East Africa pointed to an early emergence of humanlike manipulation skills.
Well it seems to me that these early hominids were preparing their hands to be able to play games on their cell-phones two million years later, and Africa was ahead of the pack! What do you know?
And two new COVID vaccines were reported on at the end of this past week. One is called Novavax, and the other, from Janssen, and Johnson and Johnson, is so far unnamed. The results of their phase three trials have not been reviewed or published yet, but advance notice points to their being effective in creating immunity against our South African variant. Even if their efficacy is not 100%, they nevertheless prevent those who do get COVID, in spite of the vaccine, from getting serious disease, needing hospitalization, or resulting in death. I don’t know about you, but I won’t mind getting COVID-19 if I know it’s not going to be severe enough to kill me. I’ll happily stand in the queue for one of these vaccines!
This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.