Debris in space presents a hazard. When you consider that there are more than 27,000 pieces of space debris bigger than the size of a softball currently orbiting the Earth, and that those objects are traveling at speeds of up to 17,500 mph, which is fast enough for a small chunk to damage a satellite or spacecraft like an intergalactic cannonball. By way of contrast the bullet shot from a common hunting rifle is travelling at about 1,700 mph, the damage from space debris can be massive to anything it hit.
Cleaning up this space junk will be an important task if agencies are to shoot more rockets and satellites into orbit. University of Utah mechanical engineering professor Jake J. Abbott is leading a team of researchers that has discovered a method to manipulate orbiting debris with spinning magnets. With this technology, robots could one day gently maneuver the scrap to a decaying orbit or further out into space without actually touching it, or they could repair malfunctioning objects to extend their life.
The concept involves moving metallic, non-magnetized objects in space with spinning magnets. When the metallic debris is subjected to a changing magnetic field, electrons circulate within the metal in circular loops, “like when you swirl your cup of coffee and it goes around and around,” says Abbott.
The process turns the piece of debris into essentially an electromagnet that creates torque and force, which can allow you to control where the debris goes without physically grabbing it.
While the idea of using these kinds of magnetic currents to manipulate objects in space is not new, what Abbott and his team have discovered is that using multiple magnetic-field sources in a coordinated fashion allows them to move the objects in six degrees of movement, including rotating them. Before, it was only known how to move them in one degree of movement, like just pushing them.
“What we wanted to do was to manipulate the thing, not just shove it but actually manipulate it like you do on Earth,” he says. “That form of dexterous manipulation has never been done before.”
With this new knowledge, scientists for example could stop a damaged satellite from wildly spinning in order to repair it, something that would not have been possible before.
“You have to take this crazy object floating in space, and you have to get it into a position where it can be manipulated by a robot arm,” Abbott says. “But if it’s spinning out of control, you could break the robot arm doing that, which would just create more debris.”
This method also allows scientists to manipulate objects that are especially fragile. While a robot arm could damage an object because its claw applies force to one part of it, these magnets would apply a gentler force to the entire object so no one section is harmed.
To test their research, the team used a series of magnets to move a copper ball on a plastic raft in a tank of water (the best way to simulate slow-moving objects in microgravity). The magnets moved the sphere not only in a square, but they also rotated the ball.
Abbott says this newly discovered process could be used with a spinning magnet on a robotic arm, a stationary magnet that creates spinning magnetic fields, or a spinning super-conductive electromagnet like those used in MRI scanners.
Abbott believes this principle of manipulating non-magnetic metallic objects with magnets could also have applications beyond the clearing of space debris.
“I’m starting to open my mind to what potential applications there are,” Abbott says. “We have a new way to apply a force to an object for precise alignment without touching it.”
But for now, this idea could immediately be applied to help fix the problem of space junk orbiting the Earth.
“NASA is tracking thousands of space debris the same way that air traffic controllers track aircraft. You have to know where they are because you could accidentally crash into them,” Abbott says. “The U.S. government and the governments of the world know of this problem because there is more and more of this stuff accumulating with each passing day.”
Loughborough (UK), Dec 2 (The Conversation) Before the end of this century, most of the Arctic will for the first time receive more rain than snow across a whole year. That’s one of the key findings of a new study on precipitation in the Arctic which has major implications – not just for the polar region, but for the whole world.
While a reduction in frozen ocean surface is one of the most widely recognised impacts of Arctic warming, it has also long been anticipated that a warmer Arctic will be a wetter one too, with more intense cycling of water between land, atmosphere and ocean.
The shift from a frozen region towards a warmer, wetter Arctic is driven by the capacity of a warmer atmosphere to hold more moisture, by increased rates of evaporation from ice-free oceans, and by the jet stream relaxing.
The Arctic water cycle is expected to shift from a snow-dominated one towards a rain-dominated one during the 21st century, although the timing of this is uncertain. Now, a team of scientists have published a study in the journal Nature Communications which suggests that this shift will occur earlier than previously projected.
The effect will be particularly strong in autumn, with most of the Arctic Ocean, Siberia and the Canadian Archipelago becoming rain-dominated by the 2070s instead of the 2090s.
Warmer and wetter isn’t necessarily better Such a profound change to the Arctic water cycle will inevitably affect ecosystems on land and in the ocean. You might intuitively expect that a warmer and wetter Arctic would be very favourable for ecosystems – rainforests have many more species than tundra, after all. But the plants and animals of the Arctic have evolved for cold conditions over millions of years, and their relatively simple food web is vulnerable to disturbance.
For example, warmer temperatures can cause larval insects to emerge earlier, before the fish species that feed upon them have hatched. More rainfall means more nutrients washed into rivers, which should benefit the microscopic plants at the base of the food chain.
However, this also makes rivers and coastal waters more murky, blocking light needed for photosynthesis and potentially clogging filter-feeding animals, including some whales or sharks. Brackish water typically supports fewer species than either freshwater or seawater, so increasing flows of freshwater offshore may well reduce the range of animals and plants along Arctic coasts.
Further into the Arctic Ocean, there are more reasons to doubt the potential benefits of warmer temperatures and greater freshwater circulation. The dissolved constituents of rainfall, river water and melting snow and ice reduce the alkalinity of Arctic surface waters, which makes it harder for marine organisms to build shells and skeletons, and limits chemical neutralisation of the acidifying effects of CO₂ absorbed in seawater.
At the same time, rivers flowing through degrading permafrost will wash organic material into the sea that bacteria can convert to CO₂, making the ocean more acidic. Fresh water also essentially floats on denser seawater.
This causes the ocean to become stratified, impeding exchanges of nutrients and organisms between the deep sea and the surface, and restricting biological activity. Therefore the likely impacts of a warmer, wetter Arctic on food webs, biodiversity and food security are uncertain, but are unlikely to be uniformly positive.
Arctic change is decades ahead of global averages Temperature increases in the Arctic have raced ahead of the global average. This will only be reinforced as snowfall is reduced and rainfall increases, since snow reflects the sun’s energy back into space. As the land becomes less snowy and less reflective, bare ground will absorb more solar energy, and thus will warm up.
The Arctic is set to continue warming faster than elsewhere, further diminishing the difference in temperature between the warmest and coldest parts of the planet, with complex implications for the oceans and atmosphere.
The recent COP26 climate summit in Glasgow focused on efforts to “keep 1.5°C alive”. It is worth remembering that the 1.5°C figure is a global average, and that the Arctic will warm by at least twice as much as this, even for modest projections.
The new study underscores the importance of the global 1.5°C target for the Arctic. For instance, at that level of warming Greenland is expected to transition to a rainfall-dominated climate for most of the year. While at 3°C warming, which is close to the current pathway based on existing policies rather than pledges, most regions of the Arctic will transition to a rainfall-dominated climate before the end of the 21st-century.
It’s research that adds further weight to calls for improved monitoring of Arctic hydrological systems and to the growing awareness of the considerable impacts of even small increments of atmospheric warming. (The Conversation) SCY SCY
(Disclaimer: This story is auto-generated from a syndicated feed; only the image & headline may have been reworked by www.republicworld.com)
Two NASA astronauts completed a 6-1/2 hour spacewalk on Thursday to replace a faulty antenna on the International Space Station, a mission NASA said carried slightly higher risk posed by orbital debris left from a Russian missile test weeks ago.
Astronauts Thomas Marshburn and Kayla Barron exited an airlock of the orbiting research lab some 250 miles (400 km) above Earth to begin their work at 6:15 a.m. Eastern time (1115 GMT), an hour ahead of schedule.
The “extra-vehicular activity” (EVA) followed a 48-hour delay prompted by a separate orbital debris alert – believed to be the first such postponement in more than two decades of space station history – which NASA later deemed inconsequential.
The origin of the newly detected debris was left unclear by NASA. A spokesperson said there was no indication it came from fragments of the defunct satellite that Russia blew to pieces https://www.reuters.com/world/us-military-reports-debris-generating-event-outer-space-2021-11-15 with a missile test last month.
Thursday’s outing was the fifth spacewalk for Marshburn, 61, a medical doctor and former flight surgeon with two previous trips to orbit, and a first for Barron, 34, a U.S. Navy submarine officer and nuclear engineer on her debut spaceflight for NASA.
“It was awesome,” Barron told Marshburn afterward.
During the spacewalk, they removed a defective S-band radio communications antenna assembly, now more than 20 years old, and replaced it with a spare stowed outside the space station.
The space station is equipped with other antennae that can perform the same functions, but installing a replacement system ensures an ideal level of communications redundancy, NASA said.
Marshburn worked with Barron while positioned at the end of a robotic arm maneuvered from inside by German astronaut Matthias Maurer of the European Space Agency, with help from NASA crewmate Raja Chari.
The four arrived at the space station Nov. 11 in a SpaceX Crew Dragon capsule launched from the Kennedy Space Center in Florida, joining two Russian cosmonauts and a NASA astronaut, Mark Vande Hei, already aboard the orbiting outpost.
Four days later, an anti-satellite missile test conducted without warning by Russia generated a debris field in low-Earth orbit, forcing the seven ISS crew members to take shelter in their docked spaceships to allow for a quick getaway until the immediate danger passed, NASA said.
The residual cloud of debris from the blasted satellite has dispersed since then, according to Dana Weigel, NASA deputy manager of the ISS program.
NASA has calculated that remaining fragments continue to pose a “slightly elevated” background risk to the space station as a whole, and a 7% higher risk of puncturing spacewalkers’ suits, as compared to before Russia’s missile test, Weigel told reporters on Monday.
NASA determined those risk levels fall within an acceptable range and moved ahead with preparations for a spacewalk on Tuesday as originally planned, only for mission control to delay the EVA mission hours before it was to start.
The operation was postponed after NASA received notice from U.S. military space trackers warning of a newly detected debris-collision threat. NASA concluded later there was no risk to spacewalkers or the station after all, and the antenna replacement was rescheduled for Thursday morning.
Thursday’s exercise marked the 245th spacewalk in support of assembly and upkeep of the space station, and the first on record delayed due to a debris alert, NASA spokesperson Gary Jordan said. (Reporting by Steve Gorman in Los Angeles and Brendan O’Brien in Chicago; Editing by Angus MacSwan and Rosalba O’Brien)
The discovery of a new fossil from central Colombia could shed light on the evolution of marine reptiles. The well preserved metre-long skull discovered by researchers from Canada, Colombia, and Germany is one of the last surviving ichthyosaurs — ancient animals that look like living swordfish.
The marine animal has been named Kyhytysuka, which translates to “the one that cuts with something sharp” in an indigenous language from the region in central Colombia where the fossil was found.
Hans Larsson, Director of the Redpath Museum at McGill University and a lead author of the study said that the animal evolved a unique dentition that allowed it to eat large prey. “Whereas other ichthyosaurs had small, equally sized teeth for feeding on small prey, this new species modified its tooth sizes and spacing to build an arsenal of teeth for dispatching large prey, like big fishes and other marine reptiles,” he added.
Skeleton of Kyhytysuka compared to a human for scale. Known bones are shown in white. Credit: (Photo: Dirley Cortés)
Researchers said that they decided to name it Kyhytysuka, to honour the ancient Muisca culture that existed in the region where the fossil was found.
In a bid to clarify the evolution of the unique animal, researchers compared it with other Jurassic and Cretaceous ichthyosaurs and defined a new type of ichthyosaur. They concluded that the species comes from an important transitional time during the Early Cretaceous period when the Earth was coming out of a relatively cool period, had rising sea levels, and the supercontinent Pangea was splitting into northern and southern landmasses.
Dirley Cortés working with the skull of Kyhytysuka. (Photo: Dirley Cortés)
“We are discovering many new species in the rocks this new ichthyosaur comes from. We are testing the idea that this region and time in Colombia was an ancient biodiversity hotspot and are using the fossils to better understand the evolution of marine ecosystems during this transitional time,” Dirley Cortés, a graduate student under the supervision of Hans Larsson and Carlos Jaramillo of the Smithsonian Tropical Research Institute said.
Researchers concluded that the new discovery shakes up the evolutionary tree of ichthyosaurs and “lets us test new ideas of how they evolved.”
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