Tiny microrobots could prove powerful for performing precision tasks in biomedical and industrial applications, but the design of such cellular-scale automata poses considerable challenges. By studying how sperm cells collaborate to improve the odds of fertilization, researchers, led by Islam Khalil of the University of Twente in the Netherlands and Veronika Magdanz of the University of Waterloo in Canada, are uncovering mechanisms of locomotion that could be replicated to power future microrobot units.
Spermatozoa travel under their own power using long tails known as flagella, which oscillate rhythmically to propel the cells forward. Although fertilization is inherently a competitive, zero-sum game, spermatozoa from some species can assemble into larger bundles that collectively gain an edge in terms of travel speed. This behaviour intrigued the authors, who work in the field of biologically-inspired robotics. “Sperm cells have a fascinating design and excellent capability to adapt to various environments,” says Khalil.
Scientists have struggled to dissect this bundling behaviour, which involves the complex interplay between multiple sperm cells and diverse environmental factors. Khalil, Magdanz and collaborators, including a researcher at The German University in Cairo, Egypt, were able to tackle this analysis by combining mathematical modeling with an experimental setup that allowed them to image the process by which individual bovine spermatozoa interact and assemble into collaborating pairs.
They identified a three-step process in which two sperm cells initially interact via their heads, then rotate relative to each other until they are aligned, before finally moving forward together with enhanced swimming efficiency. “Our study shows that the beating pattern of the cells is synchronized upon their interaction,” explains Khalil. This allows the cells to collectively move faster together while also consuming less energy.
These results could help illuminate a still-enigmatic aspect of reproductive biology. “It is very important for us to understand how sperm interact with nearby sperm through the fluid between them,” says Chih Kuan Tung, who was not involved in the study and investigates spermatozoa locomotion at North Carolina A&T State University, USA. He praises the team’s modeling approach and hopes to see further experimental investigation of this process in the future.
For Khalil and Magdanz, the next step will be to leverage their findings to turbo-charge the movement of future microrobots with multiple flagella. “Our group is working on a new method… to artificially glue sperm cells into artificial bundles,” says Magdanz, adding that they will be coupling these to metallic nanoparticles that enable magnetic steering of these multi-spermatozoa assemblies.
Green comet making its closest approach to Earth in 50,000 years – Yahoo Movies Canada
A rare green comet, that has not been seen for 50,000 years, is about to make its closest pass by Earth, becoming visible in a once-in-a-lifetime opportunity.
Called C/2022 E3 (ZTF), this celestial object hails from the Oort cloud at the outermost edge of the solar system.
Its green glow is a result of ultraviolet radiation from the sun lighting up the gases surrounding the comet’s surface.
The icy ball orbits the sun once every 50,000 years, which means the last time it went past the planet was during the Stone Age – when Neanderthals roamed the Earth.
It is due to pass closest to the planet – still some 42 million kilometres away – on Wednesday night, into the early hours of Thursday and in a very dark sky will appear as a faint smudge to those looking for it with the naked eye.
However, even if the moon is too bright for stargazers to spot the comet on Wednesday night, they might be able to catch a glimpse of it a week later when it passes Mars.
Professor Don Pollacco, from the department of physics at the University of Warwick, told the PA news agency: “Comet C/2022 E3 passes closest to Earth tonight, on 1 February.
“It has been christened the “Green Comet” as pictures show the head of the Comet to have a striking colour.
“We understand this as due to light emitted from carbon molecules ejected from the nucleus due to the increase in heat etc during its closest approach to the sun, which happened around 12 January.
“Some comets approach the sun much closer and are completely evaporated by the intense radiation.”
He added: “As the comet approaches Earth (it’s still 42 million km away, so no chance of a collision) it appears to move more quickly across the sky on a night-by-night basis.
“Tonight the comet is about halfway between the pole star and the bright star Capella, overhead about 11pm.
“However, the waxing moon will make the Comet much harder to spot. To see it you’ll need a clear sky, binoculars and a bit of luck.
“Alternately, if you wait a few days to around 10 February, the moon will be less bright and the comet will be clearer to see in the southern part of the sky, passing Mars.”
The Greenwich Royal Observatory says that from the northern hemisphere, the comet is already visible in the night sky using a telescope or some binoculars.
It adds: “Comet C/2022 E3 (ZTF) will be closest to Earth on February 1. This will also be the moment the comet appears at its brightest, and currently it is expected to reach a brightness magnitude of +6. That would mean it would be visible to the naked eye.
“It’s worth noting, however, that comets can be unpredictable, and it’s hard to say with accuracy how bright the comet will be or what it will look like ahead of time.
“The comet looks like a fuzzy green ball or smudge in the sky. This green glow is a result of UV radiation from the sun lighting up the gases streaming off of the comet’s surface.”
Advising on where the comet can be seen in the night sky, the Observatory says: “When it passes near Earth in February, the green comet will be in the constellation of Camelopardalis.
“After its closest approach, the green comet will move through Auriga and end up in Taurus mid-February.
“The comet will dim over the month as it moves away from us, and the time that it will be up in the sky during the night will get shorter and shorter.”
New AI algorithm helps find 8 radio signals from space
A new artificial intelligence algorithm created by a Toronto student is helping researchers search the stars for signs of life.
Peter Xiangyuan Ma, a University of Toronto undergraduate student and researcher, said he started working on the algorithm while he was in Grade 12 during the pandemic.
“I was just looking for projects and I was interested in astronomy,” he told CTV News Toronto.
The idea was to help distinguish between technological radio signals created by human technologies and signals that were potentially coming from other forms of life in space.
“What we’re looking for is signs of technology that signifies if the sender is intelligent or not. And so unsurprised to us, we keep on finding ourselves,” Ma explained. “We don’t want to be looking at our own noisy signals.”
Using this algorithm, Ma said researchers were able to discover eight new radio signals being emitted from five different stars about 30 to 90 light years away from the Earth.
These signals, Ma said, would disappear when researchers looked away from it, which rules out, for the most part, interference from a signal originating from Earth. When they returned to the area, the signal was still there.
“We’re all very suspicious and scratching our heads,” he said. “We proved that we found things that we wanted to find … now, what do we do with all these? That’s another separate issue.”
Steve Croft, Project Scientist for Breakthrough Listen on the Green Bank Telescope, the institute whose open source data was the inspiration for Ma’s algorithm, said that finding radio signals in space is like trying to find a needle in a haystack.
“You’ve got to recognize the haystack itself and make sure that you don’t throw the needle away as you’re looking at the individual pieces of hay,” Croft, who collaborated on Ma’s research, told CTV News Toronto.
Croft said algorithms being used to discover these signals have to account for multiple characteristics, including the position they are coming from in the sky and whether or not the transmission changes over time, which could indicate if it’s coming from a rotating planet or star.
“The algorithm that Peter developed has enabled us to do this more efficiently,” he said.
The challenge, Croft says, is recognizing that false positives may exist despite a signal meeting this criteria. What could be signs of extraterrestrial life may also just be a “weirdly shaped bit of a haystack,” he added.
“And so that’s why we have to go back and look again and see if the signal still there. And with these particular examples that Peter found with his algorithm, the signal was not there when we pointed the telescope back again. And so we sort of can’t say one way or another, is this genuine?”
Researchers have been searching the sky for technologically-generated signals since the 1960s, searching thousands of stars and galaxies for signs of intelligent life. The process is called “SETI,” or “the Search for Extraterrestrial Intelligence.”
But interference from our own radio signals has always proven to be a challenge. Croft says most pieces of technology have some kind of Bluetooth or wireless wave element that creates static, resulting in larger amounts of data needed to be collected.
“That’s a challenge but also computing provides the solution,” he said.
“So the computing and particularly the machine-learning algorithms gives us the power to search through this big haystack, looking for the needle of an interesting signal.”
Ma said that while we may not have found a “technosignal” just yet, we shouldn’t give up. The next step would be to employ multiple kinds of search algorithms to find more and more signals to study.
While the “dream” is to find evidence of life, Ma says he is more focused on the scientific efforts of actively looking for it.
This sentiment is echoed by Croft, who said he is most fascinating in working towards answering the question of whether humans are alone in this universe.
“I don’t show up to work every day, thinking I’m going to find aliens, but I do show up for work. So you know, I’ve got sort of some optimism.”
How to spot the green comet in Manitoba
Space enthusiasts in the province will get the chance to potentially see a rare green comet over the next couple of days.
The comet was discovered by astronomers in southern California last year and it was determined the last time it passed Earth was around 50,000 years ago.
Mike Jensen, the planetarium and science gallery program supervisor at the Manitoba Museum, said the time between appearances and the colour of the comet makes this unique compared to others.
“The last time it would have appeared anywhere within the region of visibility to Earth, we’re talking primitive humans walking the Earth,” said Jensen. “And then yes, its colour. Most people associate comets, they’re often referred to as ghosts of the night sky because they often have a bit of a whitish-blue appearance. This one’s got a bit of green to it. Comets are all made up of different types of material, this just happens to have a bit more of some carbon elements in it.”
Jensen notes the green tint on the comet will be subtle, comparing it to the subtle red that surrounds Mars in the night sky.
Wednesday and Thursday are the best days to see the comet as Jensen said that’s when it will be closest to Earth – 42 million kilometres away.
“That proximity to us means it does get to its best visibility for us. The added advantage is it’s also appearing sort of high up in the northern sky, which puts it amongst the circumpolar stars of our night sky. In other words, the stars that are circling around the North Star.”
Now, just because the comet is close enough to be visible doesn’t mean it will be the easiest to see in the night sky according to Jensen. He said there are a few factors that play into having a successful sighting.
First, he suggests getting out of the city and away from the lights, noting, the darker it is, the better. If people head outside city limits, Jensen recommends people dress warmly, saying comet watching in the winter is not for the “faint of heart.”
Secondly, he said even though it might be possible to see the comet with the naked eye, he still suggests bringing binoculars to improve people’s chances. He also recommends checking star maps before leaving to get the most accurate location of where the comet may be.
Lastly, even if all of that is achieved, Jensen notes people will have to battle with the light of the moon, as it is close to a full moon.
“I’m not trying to dissuade anybody from going out to see it, but certainly, there’s going to be some hurdles to overcome in order to be able to spot it on your own.”
If people don’t want to go outside to see it, he said there are plenty of resources online to find digital views.
– With files from CTV News’ Michael Lee
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