Science

Levels of protection measles provided by the MMR jab fall by a small amount every year, according to mathematical modelling

Are you sitting or lying down? Perhaps you’re moving around at a walking pace? I probably am. And yet, unless you live in the northeastern US or in southern South America, you and I are moving relative to each other at hundreds of miles per hour.

In Chapter 2 of the book “‘Waves in an Impossible Sea”, I remarked on the this fact. (See below for the relevant passage.) At first glance it might seem puzzling. After all, the distance between your town and my town is constant; it never changes. And yet our relative motion is comparable to or faster than a jet aircraft. How can both of these things be true?

And then there’s another question: if we’re all moving so fast relative to one another, why don’t we feel the motion?

The answer to the second question: It’s the principle of relativity at work. As for the first question: Such is life on a spinning Earth.

In the book, I tried to illustrate how this works using a picture (Figure 2.) But this is one of those cases where an animation is much clearer than a static image. On this new page, I’ve presented animations that I hope will clarify the issue, in case you’re having trouble visualizing it.

Here’s the relevant quote from the book’s Chapter 2, where the principle of relativity is first discussed.

We are oblivious to our own motion, and also to the relative motion between ourselves and our friends in other parts of the world. That relative motion isn’t slow. If people sitting in Boston were to measure carefully, they’d see people standing in Miami as moving at 215 miles (345 km) per hour; meanwhile, those in Miami would perceive their friends in Boston as moving at 215 miles per hour in the opposite direction.

But wait: The distance from Miami to Boston, 1,257 miles (2050 km), never changes, so how can there be relative motion between those two cities? It’s because Bostonians view Miami as moving in a daily circle, one that leaves the distance between the two cities always unchanged—and vice versa.

An analysis of the 2021 German federal elections has found that for every 200,000 times a politician's social media adverts were viewed, their vote share increased by 2.1 per cent - a potentially low-cost way of swinging elections

The skull of Shanidar Z was found in the Shanidar cave in the Kurdistan region of Iraq, and has been painstakingly put back together

The record-breaking heat of 2023 has seen a rare disagreement break out between climate scientists, with some saying it shows Earth may have entered a new period of warming

Corals can survive heat-related bleaching, but research from the Great Barrier Reef suggests a full recovery may take longer than we thought

Blake Crouch's riveting Dark Matter sees physics professor Jason wanting out of the multiverse, after being kidnapped and dumped there by another version of himself

Scientists have dramatically reduced the time and energy required to chill materials to temperatures near absolute zero. Their prototype refrigerator could prove a boon for the burgeoning quantum industry, which widely uses ultracold materials.

The Search for Life in our Solar System leads seekers to strange places. From our Earthbound viewpoint, an ice-covered moon orbiting a gas giant far from the Sun can seem like a strange place to search for life. But underneath all that ice sits a vast ocean. Despite the huge distance between the moon and the Sun and despite the thick ice cap, the water is warm.

Of course, we’re talking about Enceladus, and its warm, salty ocean—so similar to Earth’s in some respects—takes some of the strangeness away.

Enceladus is Saturn’s sixth-largest moon, and the Cassini spacecraft observed it during its mission to the Saturn system. Scientists discovered that plumes of water originating from Enceladus’ southern region are responsible for one of Saturn’s rings. They also discovered that the water is salty. Any place we find warm, salty water attracts our immediate attention, even when it’s covered by kilometres of ice and is 1.5 billion kilometres away from the life-giving Sun.

There’s lots of talk about a future mission to Enceladus to explore the moon and its potentially life-supporting ocean in more detail. But until then, scientists are working with their current data, and using models and simulations to understand the moon better.

Enceladus’ most defining surface features are its Tiger Stripes. They’re four parallel, linear depressions on the moon’s surface about 130 km long, 2 km wide, and 500 meters deep. They have higher temperatures than their surroundings, indicating that cryovolcanism is active. The stripes are the source of Enceladus’ plumes.

Geysers erupt from Enceladus’ Tiger Stripes in this image from the Cassini spacecraft. Image Credit: By NASA/JPL/SSI – http://www.nasa.gov/mission_pages/cassini/multimedia/pia11688.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=15592605

New research suggests that strike-slip faults at the moon’s prominent Tiger Stripe features allow plumes of water from Enceladus to escape into space. It’s published in Nature Geoscience and titled “Jet activity on Enceladus linked to tidally driven strike-slip motion along tiger stripes.” The lead author is Alexander Berne, a doctoral candidate in Geophysics at the California Institute of Technology.

The plumes above the Tiger Stripes aren’t stable and continuous. They wax and wane as the moon follows its 33-hour orbit around Saturn. Tidal heating keeps the moon’s water in liquid form, and according to the researchers, the same tidal forces are responsible for the intermittent plumes. Theory shows that tidal forces open and close faults at the Tiger Stripes like an elevator door, and that turns the plumes on and off.

However, those theories can’t accurately predict the timing of the plumes’ peak brightness. They also show that tidal forcing alone doesn’t provide enough energy to open and close the faults.

This research digs deeper into the question and provides an answer. The authors say that rather than acting like an elevator door, strike-slip faults at the Tiger Stripes open and close to regulate plume activity. This is similar to what happens on Earth in places like the San Andreas Fault. It’s a strike-slip fault where one side shears past the other, causing Earthquakes. The critical part of this is that strike-slip faults require less energy than the elevator opening and closing scenario.

Models are more effective as they’re fed more detailed and accurate data. Berne and his co-researchers built a numerical model that simulates the strike-skip faults on Enceladus. They included friction, compressional forces and shear forces. The numerical model showed the faults acting in concert with the changing plumes. This strongly suggests that Enceladus’ orbit and the tidal forces acting on the moon cause the strike-slip faults to open and close.

This illustration from the research explains how strike-slip faults are responsible for the plumes erupting from Enceladus’ Tiger Stripes. As the moon orbits Saturn, tidal forces open and close the faults. Image Credit: Berne et al. 2024.

The Tiger Stripes have bent sections that pull apart under strain. Since they’re bent, an opening appears as they slide. The plumes come from these openings.

The research team’s work and previous research into the Tiger Stripes by NASA’s Jet Propulsion Laboratory both support the idea that the plumes come from these strike-slip faults.

“We now appear to have both geologic and geophysical reasons to suspect that jet activity occurs at pull-aparts along Enceladus’s tiger stripes,” said lead author Berne.

This figure from the research shows the degree of displacement and slip at the Tiger Stripe faults at two different points in Enceladus’ orbit. Image Credit: Berne et al. 2024.

Enceladus gets most of its attention because of its potential to support life. The plumes themselves aren’t part of what life needs, but they’re a window into the moon’s potential habitability.

“For life to evolve, the conditions for habitability have to be right for a long time, not just an instant,” said study co-author Mark Simons, Professor of Geophysics at Caltech. “On Enceladus, you need a long-lived ocean. Geophysical and geological observations can provide key constraints on the dynamics of the core and the crust as well as the extent to which these processes have been active over time.”

There’s a lot more work to be done to understand Enceladus. On Earth, satellites can monitor the movement at strike-slip faults and use it to better understand Earthquakes. Once we get a spacecraft to Enceladus, it could do the same.

“Detailed measurements of motion along the tiger stripes are needed to confirm the hypotheses laid out in our work,” Berne says. “For instance, we now have the capacity to image fault slip, such as earthquakes, on Earth using radar measurements from satellites in orbit. Applying these methods at Enceladus should allow us to better understand the transport of material from the ocean to the surface, the thickness of the ice crust, and the long-term conditions which may enable life to form and evolve on Enceladus.”

When we get a spacecraft to Enceladus, it can monitor the faults and jets over multiple orbits. That will allow researchers to test their predictions.

“These observations could provide key constraints on the mechanical nature of the crust, tidal controls on jet activity and the evolution of the south polar terrain,” the authors conclude.

The post Enceladus’s Fault Lines are Responsible for its Plumes appeared first on Universe Today.

Few things in life are certain. But it seems highly probable that people will explore the lunar surface over the next decade or so, staying there for weeks, perhaps months, at a time. That fact bumps up against something we are certain about. When human beings spend time in low-gravity environments, it takes a toll on their bodies.

What can be done?

Scientists have studied the effects of microgravity and low gravity on the human body. Several problems crop up, like muscle atrophy and bone demineralization. Cardiovascular conditioning suffers, as does neural control of body posture and movement. But while researchers are learning more and more about the effects, solutions are lagging behind.

A new paper published in Royal Society Open Science suggests a novel, low-tech solution for these problems. Its title is “Horizontal running inside circular walls of Moon settlements: a comprehensive countermeasure for low-gravity deconditioning?” The lead author is Alberto Minetti, a Physiology Professor at the University of Milan.

Minetti and his co-authors point out that specific exercises for specific problems may not be the best approach. Instead, whole-body exercise could be a powerful tool for supporting astronaut health. “Rather than training selected muscle groups only, ‘whole-body’ activities such as locomotion seem better candidates,” they explain. However, there’s a problem with that. “But at Moon gravity, both ‘pendular’ walking and bouncing gaits like running exhibit abnormal dynamics at faster speeds,” they write.

The abnormal dynamics mean that astronauts don’t benefit much from that type of exercise. It’s hindered by an ” … imbalance between the kinetic and potential energy of the body centre of mass,” the authors write. That means it can’t be used to get the same kind of exercise it would provide on the Earth. “Additionally, the metabolic demands of bouncing gaits are reduced at Moon gravity, limiting their potential stimulus for cardiorespiratory fitness,” the authors explain.

There are some potential solutions out there to help lunar astronauts maintain their health in low gravity. One is a centrifuge, where the rotating motion simulates gravity, encouraging the body to maintain muscle and bone mass. But they’re energy-intensive and impractical.

The authors are proposing a novel solution. Have you ever seen a Wall of Death?

A stuntman riding on a Wall of Death. Friction and centripetal force allow him to ride on the wall’s vertical surface. Image Credit: By SeaDave from Fairlie, Scotland – Owner of the Wall of Death, in his family for 80 years.Uploaded by MaybeMaybeMaybe, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=22817835

“Here, we propose a novel solution: lunar inhabitants could engage in running on the inside of vertical circular walls, hence running parallel to the Moon’s surface,” the authors write. Exercising in a Wall of Death (WoD) would help maintain muscle mass, bone density, cardiovascular fitness, and neural control.

On Earth, the gravity is too strong for humans to run around the sides of a WoD. Only motorized vehicles and bicycles can do it. But on the Moon, the weaker gravity makes them practical.

The researchers simulated a lunar WoD and tested the performance of subjects running in it. They hired a WoD for one day and used a harness of bungee cords to reduce participants’ body weight, simulating the Moon’s lower gravity.

The researchers removed the roof from the WoD and used a crane to support the harness. The middle inset image is unrelated to the research and illustrates the peculiar upward leaning posture of someone in the WoD. Image Credit: Minetti et al. 2024.

Two participants took part in the tests: a 36-year-old man and a 33-year-old woman. The bungees were tuned so each participant weighed one-sixth of their body weight. The harness unloaded one side of the subjects’ bodies to further mimic lunar conditions. Each participant’s data from the WoD was combined with treadmill data to give robust results.

Once inside the WoD and connected to the harness, this is what the experiment looked like.

In this image, the 33-year-old female subject is connected to the harness and running around the inside of the Wall of Death. Image Credit: Minetti et al. 2024.

The participants quickly got the hang of the unusual motion required to run horizontally inside the WoD. “This process required only 5–8 attempts and allowed them to start running with no assistance,” the authors write. The participants “… ended their performance by safely slowing down their pace and descending from the horizontal posture on the wall down to the upright one on the WoD floor, with no injuries,” they explained.

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The authors say they’ve successfully demonstrated the basics of using a WoD to support lunar astronaut health. “We have demonstrated for the first time that humans can safely run horizontally in low gravity conditions inside a cylinder, sized as a terrestrial ‘WoD’, through a speed-driven, self-generated higher artificial gravity,” they explain.

The researchers are confident that the Wall of Death idea can help lunar astronauts deal with the chronic effects of lunar gravity. At the same time, they’re cognizant of their small sample size and the study’s other limitations.

“In conclusion, while being aware of the small sample size, of the crudeness of kinematics acquisition in such a peculiar field experiment, and that dedicated bed rest studies will be needed to refine this topic, we are confident in our findings,” they write in their conclusion.

Though normal running on the Moon is impossible, the WoD provides a way to gain the benefits of running in short WoD exercise sessions daily. Participants using the WoD created “… a sufficiently high (lateral) self-generated artificial gravity likely capable of maintaining, through a few short, almost ‘terrestrial’ running laps a day, an acceptable cardio-motor fitness and bone mineral status, useful to locally move and work around, to prepare the long trip to Mars, and to return home in good condition.”

There’s an elegance around low-tech solutions to confounding problems. A simple WoD could be the solution to the Moon’s low gravity instead of a complicated, energy-hungry device like a centrifuge.

“All of this, by using an inexpensive and passive facility already built in their circular inhabited units,” the authors conclude.

The post Lunar Explorers Could Run to Create Artificial Gravity for Themselves appeared first on Universe Today.

Space debris is a growing problem, so companies are working on ways to mitigate it. A new satellite called ADRAS-J was built and launched to demonstrate how a spacecraft could rendezvous with a piece of space junk, paving the path for future removal. Astroscale Japan Inc, the Japanese company behind the satellite, released a new picture from the mission showing a close image of its target space debris, a discarded Japanese H2A rocket’s upper stage, captured from just a few hundred meters away.

ADRAS-J stands for Active Debris Removal by Astroscale-Japan, and is the first satellite ever to attempt to safely approach, characterize and survey the state of an existing piece of large debris. This mission will only demonstrate Rendezvous and Proximity Operations (RPO) capabilities by operating in near proximity to the piece of space debris, and gather images to assess the rocket body’s movement and the condition of the structure, Astroscale Japan said.

ADRAS-J Launch. Credit: Astroscale Japan, Inc.

The mission launched from New Zealand on February 18 and is part of Phase 1 of the Japan Aerospace Exploration Agency’s plan to deal with space debris. Shortly after launch, the ADRAS-J spacecraft began its maneuvers to rendezvous with the chosen piece of space debris. On April 9, mission engineers maneuvered the spacecraft to a desired position several hundred kilometers away from the rocket stage. Then, by April 16, the spacecraft was able to match the orbit of the rocket stage. By the next day, using  navigation inputs from the spacecraft’s suite of rendezvous payload sensors, ADRAS-J was able to attain close approach of several hundred meters.  

“The unprecedented image marks a crucial step towards understanding and addressing the challenges posed by space debris, driving progress toward a safer and more sustainable space environment,” Astroscale Japan said in a press release.

This particular rocket stage was chosen because it did not have any GPS data. Instead, the operations team had to rely on ground based observational data to approximate its position to make the approach. This provided a realistic target for testing debris analysis activity.

The next task, ADRAS-J will attempt to capture additional images of the upper stage through various controlled close approach operations. Astroscale Japan said the images and data collected are expected to be crucial in better understanding the debris and providing critical information for future removal efforts.

A future mission, ADRAS-J2, will also attempt to safely approach the same rocket body through RPO, obtain more images, then remove and deorbit the rocket body using in-house robotic arm technologies.

The post This is an Actual Picture of Space Debris appeared first on Universe Today.

Finnair has cancelled flights to Tartu in Estonia this month because of an ongoing GPS jamming attack – and there is evidence that the attack is being controlled from Russia

A team of 19 prominent researchers has published guidelines for the responsible use of machine learning in science. They say it could avert a crisis that's smoldering in every field.

Scientists have adapted a device called a microwave circulator for use in quantum computers, allowing them for the first time to precisely tune the exact degree of nonreciprocity between a qubit, the fundamental unit of quantum computing, and a microwave-resonant cavity. The ability to precisely tune the degree of nonreciprocity is an important tool to have in quantum information processing. In doing so, the team derived a general and widely applicable theory that simplifies and expands upon older understandings of nonreciprocity so that future work on similar topics can take advantage of the team's model, even when using different components and platforms.

A research team has created an innovative method to control tiny magnetic states within ultrathin, two-dimensional van der Waals magnets -- a process akin to how flipping a light switch controls a bulb.

A research team has created an innovative method to control tiny magnetic states within ultrathin, two-dimensional van der Waals magnets -- a process akin to how flipping a light switch controls a bulb.

A study describes a new computer algorithm which can be applied to Earth System Models to drastically reduce the time needed to prepare these in order to make accurate predictions of future climate change. During tests on models used in IPCC simulations, the algorithm was on average 10 times faster at spinning up the model than currently-used approaches, reducing the time taken to achieve equilibrium from many months to under a week.

By ignoring declining air pollution, regional climate models have greatly underestimated how hot Europe's summers and heatwaves will become

From the Chicago Maroon:

The statue of Carl von Linné, located on the Midway, has been spray painted with several phrases, including “death 2 amerikkka” and “death 2 academy.” The Midway is part of the Chicago Park District and the statue is not on University property.

– Nathaniel Rodwell-Simon, News Reporter

Now we can’t be sure that the protestors encamped here defaced this statue, but I haven’t seen it defaced in the 38 years I’ve been here.  And the correlation with The Encampment, as well as the message, is striking.  Defacing it makes no statement except “I am ignorant and hateful.”

If you don’t know who Linnaeus was (also called Carl von Linné after he became a nobleman), you can read about him here.  He was a Swedish botanist and formulated the system of Latin binomials to identify organisms. (I visited his house, which still stands, when I lectured at Uppsala, but don’t have time to post the pictures.) He was amazingly productive, widely admired, and is known as “the Father of Modern Taxonomy.” Why some chowderhead would deface his statue defies me.

Here’s the lovely statue from the front, which I always admire when I walk by it on the Midway. It was created by Frithiof Kjellberg in 1891, installed the same year, and then relocated in 1976.  And what a great thought to memorialize a famous biologist whom almost nobody has heard of!

Photographed by Joe Lothan, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Chris French, who runs the Anomalistic Psychology Research Unit at Goldsmiths, explores what lies behind claims of ghosts, aliens and reincarnation in his new book