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Today’s photos are from California tidepools and were taken by UC Davis math professor Abigail Thompson, a recognized “hero of intellectual freedom.” Abby’s notes and IDs are indented, and you can enlarge the photos by clicking on them.

September-October tidepools (Northern California).

September and October tides are not as extreme as the tides of midsummer, and by mid-October the lowest tides occur after sunset, which altogether makes finding creatures and taking pictures a bit more challenging.  As usual I got help with some of the IDs from people on inaturalist.

Phyllocomus hiltoni: this Doctor-Suessian marine worm washed up on the beach in a clump of eelgrass.    It was tiny; the photo is through a microscope.     I already thought it was amazing, but then (see the next picture) as a bonus it also sprouted tentacles:

Phyllocomus hiltoni with frills!

Porychthis notatus: these tiny fish showed up when I turned over a rock. They were very small, I assume newly-hatched:

Porychthis notatus: close-up:

Anthopleura sola (starburst anemone), one of the more spectacular sea anemones:

Phragmatopoma californica (California sandcastle worm): These worms often live in groups and form large conglomerations of the tubes they live in (the “sandcastles”).    The black shell-like thing on the left is the worm’s operculum, like a lid to close off the top of the tube when the worm withdraws.  The next picture is a close-up of the operculum:

Operculum close-up:

Triopha maculata: nudibranch; this one looks like he’s eating the pink bryozoan, but he may just be passing over it, I’m not sure what this species eats (nudibranchs are very picky eaters):

Epiactis prolifera (brooding anemone: probably): there are a few species of Epiactis sea anemones along the California coast; prolifera is the most common:

Halosydna brevisetosa: Eighteen-scaled worm, found on the underside of a rock.   There are 18 pairs of scales, with a close-up of them in the next picture.

Close-up of scales:

Low tide on this day was about an hour after sunset, which is a lovely time to be out on the beach:

Camera info:  Mostly Olympus TG-7, in microscope mode, pictures taken from above the water.  The first picture was taken with my iphone through the eyepiece of a microscope.

Think of the Moon and most people will imagine a barren world pockmarked with craters. The same is likely true of Mars albeit more red in colour than grey! The Earth too has had its fair share of craters, some of them large but most of the evidence has been eroded by centuries of weathering. Surprisingly perhaps, Venus, the second planet from the Sun does not have the same weathering processes as we have on Earth yet there are signs of impact craters, but no large impact basins! A team of astronomers now think they have secured a new view on the hottest planet in the Solar System and revealed the missing impact sites. 

Venus is the second planet from the Sun and, whilst it’s often called Earth’s sister planet, the reality is really they differ in many ways. The term comes from similarities in size and composition yet the conditions on Venus are far more hostile. Surface temperatures far exceed the boiling point of water, the dense atmosphere exerts a pressure on the surface equivalent to being 3,000 feet under water and there is sulphuric acid rain in the atmosphere! Most definitely not a nice place to head to for your next vacation. 

Venus

If you were to stand on the surface of Venus you would see beautifully formed craters. Looking down on the planet from orbit you would see none due to the thick, dense atmosphere. Yet if you could gaze through the obscuring clouds you would see a distinct lack of larger impact basins of the sort we are familiar with on the Moon. Now, a team of researchers mostly from the Planetary Science Institute believe they solve the mystery of the missing craters. 

The Moon. Credit: NASA

They have mapped a region of Venus known as Haastte-baad Tessera using radar technology and the results were rather surprising. The region is thought to be one of the oldest surfaces on Venus and is classed as tessera terrain. This type of feature is complex and is characterised by rough, intersecting ridges to create a tile like pattern thought to be the result of a thin but strong layer of material forming over a weak layer which can flow and convect energy just like boiling water. Images from the area in question reveal a set of concentric rings over 1,400 km across at their widest. The team propose that the feature is the result of two back-to-back impact events. “Think of pea soup with a scum forming on top,” said Vicki Hansen,  Planetary Science Institute Senior Scientist. 

Obviously there is no pea soup on Venus but instead, the thin crust layer formed upon a layer of molten lava. Venus of today has a thick outer shell called a lithosphere which is about 112 km thick but when Venus was younger, its thought it was just 9km thick! If an impactor struck the hot young Venus then it’s very likely it would have fractured the lithosphere allowing molten lava to seep through and eventually solidify to create the tesserae we see today. 

Confusing things slightly however is that features like this have been seen on top of flat, raised plateaus where the lithosphere is likely much thicker. The researchers have an answer for this though, “When you have vast amounts of partial melt in the mantle that rushes to the surface, what gets left behind is something called residuum. Solid residuum is much stronger than the adjacent mantle, which did not experience partial melting.” said Hansen. “What may be surprising is that the solid residuum is also lower density than all the mantle around it. So, it’s stronger, but it’s also buoyant. You basically have an air mattress sitting in the mantle beneath your lava pond, and it’s just going to rise up and raise that tessera terrain.”

The features found by the time seem to show that two impact events happened one after the other with the first creating the build up of lava and the second creating the ring structure seen today. 

Source : Impact craters were hiding in plain sight, say researchers with a new view of Venus

The post New View of Venus Reveals Previously Hidden Impact Craters appeared first on Universe Today.

Quickie with Bob: Predicting Earthquakes; News Items: Cell Phones and Brain Cancer, Gold from Earthquakes, Plastic in the Brain, Quantum Neural Network, Marmosets have Names; Your questions and E-mails: Beetles; Name That Logical Fallacy; Science or Fiction

In a few years, as part of the Artemis Program, NASA will send the “first woman and first person of color” to the lunar surface. This will be the first time astronauts have set foot on the Moon since the Apollo 17 mission in 1972. This will be followed by the creation of permanent infrastructure that will allow for regular missions to the surface (once a year) and a “sustained program of lunar exploration and development.” This will require spacecraft making regular trips between the Earth and Moon to deliver crews, vehicles, and payloads.

In a recent NASA-supported study, a team of researchers at the University of Illinois Urbana-Champaign investigated a new method of sending spacecraft to the Moon. It is known as “multimode propulsion,” a method that integrates a high-thrust chemical mode and a low-thrust electric mode – while using the same propellant. This system has several advantages over other forms of propulsion, not the least of which include being lighter and more cost-effective. With a little luck, NASA could rely on multimode propulsion-equipped spacecraft to achieve many of its Artemis objectives.

The paper describing their investigation, “Indirect optimal control techniques for multimode propulsion mission design,” was recently published in Acta Astronautica. The research was led by Bryan C. Cline, a doctoral student in the Department of Aerospace Engineering at the University of Illinois Urbana-Champaign. He was joined by fellow aerospace engineer and PhD Candidate Alex Pascarella, and Robyn M. Woollands and Joshua L. Rovey – an assistant professor and professor with the Grainger College of Engineering (Aerospace Engineering).

Artist’s impression of the ESA LISA Pathfinder mission. Credit: ESA–C.Carreau

To break it down, a multimode thruster relies on a single chemical monopropellant – like hydrazine or Advanced Spacecraft Energetic Non-Toxic (ASCENT) propellant – to power chemical thrusters and an electrospray thruster (aka. colloid thruster). The latter element relies on a process known as electrospray ionization (ESI), where charged liquid droplets are produced and accelerated by a static electric field. Electrospray thrusters were first used in space aboard the ESA’s LISA Pathfinder mission to demonstrate disturbance reduction.

By developing a system that relies on both that can switch as needed, satellites will be able to perform propulsive manuevers using less propellant (aka. minimum-fuel transfers). As Cline said in a Grainger College of Engineering press release:

“Multimode propulsion systems also expand the performance envelope. We describe them as flexible and adaptable. I can choose a high-thrust chemical mode to get someplace fast and a low-thrust electrospray to make smaller maneuvers to stay in the desired orbit. Having multiple modes available has the potential to reduce fuel consumption or reduce time to complete your mission objective.”

The team’s investigation follows a similar study conducted by Cline and researchers from NASA’s Goddard Spaceflight Center and the aerospace advisory company Space Exploration Engineering, LLC. In a separate paper, “Lunar SmallSat Missions with Chemical-Electrospray Multimode Propulsion,” they considered the advantages of multimode propulsion against all-chemical and all-electric approaches for four design reference missions (DRMs) provided by NASA. For this latest investigation, Cline and his colleagues used a standard 12-unit CubeSat to execute these four mission profiles.

.Earth–Mars minimum-fuel trajectory when the CubeSat is coasting, as well as in mode 1-low thrust and mode 2-high thrust. Credit: UIU-C

“We showed for the first time the feasibility of using multimode propulsion in NASA-relevant lunar missions, particularly with CubeSats,” said Cline. “Other studies used arbitrary problems, which is a great starting point. Ours is the first high-fidelity analysis of multimode mission design for NASA-relevant lunar missions.”

Multimode propulsion is similar in some respects to hybrid propulsion, where two propulsion systems are combined to achieve optimal thrust. A good example of this (though still unrealized) is bimodal nuclear propulsion, where a spacecraft relies on a nuclear-thermal propulsion (NTP) and nuclear-electric propulsion (NEC) system. While an NTP system relies on a nuclear reactor to heat hydrogen or deuterium propellant and can achieve a high rate of acceleration (delta-v), an NEC system uses the reactor to power an ion engine that offers a consistent level of thrust.

A key advantage multimode propulsion has over a hybrid system is a drastic reduction in the dry mass of the spacecraft. Whereas hybrid propulsion systems require two different propellants (and hence, two separate fuel tanks), bimodal propulsion requires only one. This not only saves on the mass and volume of the spacecraft, but makes them cheaper to launch. “I can choose to use high-thrust at any time and low-thrust at any time, and it doesn’t matter what I did in the past,” said Cline. “With a hybrid system, when one tank is empty, I can’t choose that option.”

To complete each of the design reference missions for this project, the team made all decisions manually – i.e., when to use high-thrust and low-thrust. As a result, the trajectories weren’t optimal. This led Cline to develop an algorithm after completing the project that automatically selects which mode would lead to an optimal trajectory. This allowed Cline and his team to solve a simple two-dimensional transfer between Earth and Mars and a three-dimensional transfer to geostationary orbit that minimizes fuel consumption. As Cline explained:

“This was an entirely different beast where the focus was on the development of the method, rather than the specific results shown in the paper. We developed the first indirect optimal control technique specifically for multimode mission design. As a result, we can develop transfers that obey the laws of physics while achieving a specific objective such as minimizing fuel consumption or transfer time.”

“We showed the method works on a mission that’s relevant to the scientific community. Now you can use it to solve all kinds of mission design problems. The math is agnostic to the specific mission. And because the method utilizes variational calculus, what we call an indirect optimal control technique, it guarantees that you’ll get at least a locally optimal solution.”

Artist rendering of an Artemis astronaut exploring the Moon’s surface during a future mission. Credit: NASA

The research is part of a project led by Professor Rovey and a multi-institutional team known as the Joint Advanced Propulsion Institute (JANUS). Their work is funded by NASA as part of a new Space and Technology Research Institute (STRI) initiative. Rovey is responsible for leading the Diagnostics and Fundamental Studies team, along with Dr. John D. Williams, a Professor of Mechanical Engineering and the Director of the Electric Propulsion & Plasma Engineering Laboratory at Colorado State University (CSU).

As Cline indicated, their work into multimode propulsion could revolutionize how small spacecraft travel between Earth and the Moon, Mars, and other celestial bodies:

“It’s an emerging technology because it’s still being developed on the hardware side. It’s enabling in that we can accomplish all kinds of missions we wouldn’t be able to do without it. And it’s enhancing because if you’ve got a given mission concept, you can do more with multimode propulsion. You’ve got more flexibility. You’ve got more adaptability.

“I think this is an exciting time to work on multimode propulsion, both from a hardware perspective, but also from a mission design perspective. We’re developing tools and techniques to take this technology from something we test in the basement of Talbot Lab and turn it into something that can have a real impact on the space community.”

Further ReadingL University of Illinois Urbana-Champaign, Acta Astronautica

The post Multimode Propulsion Could Revolutionize How We Launch Things to Space appeared first on Universe Today.

China has a fabulously rich history when it comes to space travel and was among the first to experiment in rocket technology. The invention of the rocket is often attributed to the Sung Dynasty (AD 960-1279.) Since then, China has been keen to develop and build its own space industry. The Chinese National Space Administration has already successfully landed probes on the Moon but is preparing for their first human landers. Chinese astronauts are sometimes known as taikonauts and CNSA has just confirmed their fourth batch of taikonauts are set for a lunar landing. 

The Chinese National Space Administration (CNSA) is China’s equivalent to NASA. It was founded in 1993 to oversee the country’s space aspirations. Amazing results have been achieved over the last twenty years including the landmark Chang’e lunar missions. In 2019 Chang’e-4 landed on the far side of the Moon, the first lunar lander to do so and in 2021 became the third country to land a rover on Mars. In 2021 the first modules for CNSA’s Tiangong space station were launched, it’s now operational and working with other space agencies, is working on a number of scientific research projects. 

China has announced that it successfully completed its latest selection process in May. The CNSA are striving to expand their team of taikonauts. Ten were chosen from all the applicants including 8 experienced space pilots and two payload specialists. The team will now begin their program of training in August covering over 200 subject areas designed to prepare them for future missions to the Moon and other Chinese space initiatives. 

The training covers an extensive range of skills It will include training for living and working in microgravity, to learn about physical and mental health in space and specialist training in extravehicular activities. They will also learn maintenance techniques for advanced spacecraft systems and in hands-on training for undertaking experiments in microgravity. 

On her 2007 mission aboard the International Space Station, NASA astronaut Peggy Whitson, Expedition 16 commander, worked on the Capillary Flow Experiment (CFE), which observes the flow of fluid, in particular capillary phenomena, in microgravity. Credits: NASA

The program is designed to expand and fine tune the skills of the taikonauts in preparation for future crewed lunar missions. Specialist training for lunar landings include piloting spacecraft under different gravitational conditions, manoeuvring lunar rovers, training in celestial navigation and stellar identification. 

Not only will they learn about space operations but they will have to learn skills to support scientific objectives too. This will include how to conduct geological surveys and how to operate tools and manoeuvre in the micro-gravitational environments. 

Source : China’s fourth batch of taikonauts set for lunar landings

The post China Trains Next Batch of Taikonauts appeared first on Universe Today.

It was 1969 that humans first set foot on the Moon. Back then, the Apollo mission was the focus of the attempts to land on the Moon but now, over 50 years on, it looks like we are set to head back. The Artemis project is the program that hopes to take us back to the Moon again and it’s going from strength to strength. The plan is to get humans back on the Moon by 2025 as part of Artemis III. As a prelude to this, NASA is now turning its attention to the possible landing sites. 

The Artemis Project is NASA’s program aimed at returning humans to the Moon and establishing a permanent base there. Ultimately with a view to paving the way for missions to Mars. With the first launch in 2017, Artemis intends to land “the first woman and the next man” on the lunar surface by 2025.  The program began with Artemis I and an uncrewed mission which orbited the Moon. Arte is II will take astronauts on an orbit of the Moon and finally Artemis III will land humans back on the Moon by 2025. At the heart of the program is the giant Space Launch System (SLS) rocket and the Orion spacecraft. 

NASA’s Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test, Wednesday, Nov. 16, 2022, from Launch Complex 39B at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky.

As the plans ramp up for the first crewed landing, NASA are now analysing possible landing sites and have identified nine potential spots. They are all near the South Pole of the Moon and will provide Artemis III with landing sites near to potentially useful resources. Further investigations will be required to further assess them for their suitability. 

The team working upon the analysis is the Cross Agency Site Selection Analysis team and they will work with other science and industry partners. The teams will explore each possible site for science value and suitability for the mission including the availability of water ice. The final list so far, and in no particular order, are;

• Peak near Cabeus B
• Haworth
• Malapert Massif
• Mons Mouton Plateau
• Mons Mouton
• Nobile Rim 1
• Nobile Rim 2
• de Gerlache Rim 2
• Slater Plain

The South Polar region was chosen as a region was chosen chiefly because it has water locked up deep in the shadowed craters. The Apollo missions never visited that region of the Moon either so it is a great opportunity for humans to explore this aged region of the lunar surface. To settle on these 9 areas, the team assessed various regions of the south polar region using potential launch window suitability, terrain suitability, communication capability and even lighting levels. The geology team also looked at the landing sites to assess their scientific value 

Apollo 17 astronaut Harrison Schmitt collecting a soil sample, his spacesuit coated with dust. Credit: NASA

NASA will finally settle on the appropriate landing site based upon the decision for the launch date. Once that has been confirmed it will determine the transfer trajectories to the Moon, the orbital paths and the surface environment. 

Source : NASA Provides Update on Artemis III Moon Landing Regions

The post NASA Focusses in on Artemis III Landing Sites. appeared first on Universe Today.

The discovery of the accelerated expansion of the Universe has often been attributed to the force known as dark energy. An intriguing new theory was put forward last year to explain this mysterious force; black holes could be the cause of dark energy! The theory goes on to suggest as more black holes form in the Universe, the stronger the pressure from dark energy. A survey from the Dark Energy Spectroscopic Instrument (DESI) seems to support the theory. The data from the first year of operation shows the density of dark energy increases over time and seems to correlate with the number and mass of black holes! 

Cast your mind back 4 billion years to the beginning of the Universe. Just after the Big Bang, the moment when the Universe popped into existence, there was a brief period when the Universe expanded faster than the speed of light. Before you argue that nothing can travel faster than the speed of light we are talking of the very fabric of space and time expanding faster than the speed of light. The speed of light limit relates to travel through the fabric of space, not the fabric of space itself! This was the inflationary period. 

This illustration shows the “arrow of time” from the Big Bang to the present cosmological epoch. Credit: NASA

The energy that drove the expansion in the early Universe shared similarities with dark energy, the repulsive force that seems to permeate the Universe and is driving the current day accelerated expansion of the Universe.

What is dark energy though? It is thought to make up around 68% of the Universe and, unlike normal matter and energy seems to have a repulsive force rather than attractive. The repulsive nature was first inferred from observations in the late 1990’s when astronomers deduced the rate of acceleration when observing distant supernova. As to the nature of dark energy, no-one really knows what it is or what it comes from, that is, until now. 

Artist’s illustration of a bright and powerful supernova explosion. (Credit: NASA/CXC/M.Weiss)

A team of researchers from the University of Michigan and other institutions have published a paper in the Journal of Cosmology and Astroparticle Physics. In their paper they propose that black holes are the source of dark energy. Professor Gregory Tarle said ‘Where in the later Universe do we see gravity as strong as it was at the beginning of the Universe?’ The answer, Tarle goes on to describe is the centre of black holes. Tarle and team propose that what happened during the inflation period runs in reverse during the collapse of a massive star. When this happens, the matter could conceivably become dark energy. 

The team have used data from the Dark Energy Spectroscopic Instrument (DESI) which is mounted upon the 4m Mayall telescope at Kitt Peak National Observatory. The instrument is essentially 5,000 computer controlled fibre optics which cover an area of the sky equal to about 8 square degrees. The evidence of dark energy is achieved by studying tens of millions of galaxies. The galaxies are so far way their light takes billions of years to reach us. We can use the information to determine how fast the Universe is expanding with unprecedented precision. 

Stu Harris works on assembling the focal plane for the Dark Energy Spectroscopic Instrument (DESI), which involves hundreds of thousands of parts, at Lawrence Berkeley National Laboratory on Wednesday, 6 December, 2017 in Berkeley, Calif.

The data shows evidence that dark energy has increased with time. This is not perhaps in itself surprising but it seems to accurately mirror the increase in black holes over time too. Now that DESI is operational, more observations are required to hunt down the black holes and try to quantify their growth over time to see if there really is merit in this new exciting hypothesis. 

Source : Evidence mounts for dark energy from black holes

The post The Connection Between Black Holes and Dark Energy is Getting Stronger appeared first on Universe Today.

A bird flu virus that has been circulating in dairy cattle for months has now been found in a pig in the US for the first time, raising the risk of the virus evolving to become more dangerous to people

Inside a hunk of a material called a semimetal, scientists have uncovered signatures of bizarre particles that sometimes move like they have no mass, but at other times move just like a very massive particle

Soil is full of an uncountable number of viruses, and scientists are only beginning to understand just how substantial their role in the carbon cycle may be

If there are alien civilizations in the Universe, some of them could be super advanced. So advanced that they can rip apart planets and create vast shells surrounding a star to capture all its energy. These Dyson spheres should be detectable by modern telescopes. Occasionally astronomers find an object that resembles such an alien megastructure, but so far, they’ve all turned out to be natural objects. As best we can tell, there are no Dyson spheres out there.

And when you think about it, building a Dyson sphere is the cosmic endgame of a capitalist dystopia. In the never-ending quest to capture and consume every last bit of energy, your civilization rips worlds asunder, moving heaven and earth to create an orbitally unstable, unlivable engine. If you can traverse light-years and transform planets, why not just move Earth-like planets and moons into a star’s habitable zone and have a nice cluster of comfy planets to live on? If this kind of stellar-punk civilization is out there, could astronomers detect it? This is the question behind a study on the arXiv.

The authors begin by noting that when Freeman Dyson proposed the idea in 1960, our solar system was the only known planetary system. Star systems were thought to be rare at the time, but now we know better. Most stars have planets, and even our solar system has a dozen water-rich moons that could be made habitable with a shift of their orbits and a bit of terraforming. Since this would be much easier than building a Dyson sphere, the authors argue that modified systems should be much more common. The only question is how to detect them.

One way would be to look for planetary systems that don’t seem to have formed naturally. For example, if you find a system with a dozen worlds in a star’s habitable zone and few other planets, that isn’t likely to have happened by chance. Less obvious would be to look for systems that are orbitally unusual. Perhaps the planets have orbital resonances that aren’t stable in the long term, or have unusually perfect orbits. Maybe the chemical composition of some worlds don’t match that of the system as a whole. Anything that stands out might be worth a closer look.

Using lasers to change a planet’s orbit. Credit: Narasimha, et al

Another way would be to look for signs of systems under construction. The authors note that planets could be moved or captured slowly over time using high-power directional lasers to accelerate them. Stray light from those lasers would be visible across light years. If we detect monochromatic laser light coming from a potentially habitable star, it could be aliens building a better home.

It’s not likely that we’ll find this kind of evidence, but the idea is no stranger than those of giant alien megastructures. Besides, it’s fun to think about just how many habitable planets you could pack into a single star system. It turns out to be quite a lot!

Reference: Narasimha, Raghav, Margarita Safonova, and C. Sivaram. “Making Habitable Worlds: Planets Versus Megastructures.” arXiv preprint arXiv:2309.06562 (2023).

The post Will Advanced Civilizations Build Habitable Planets or Dyson Spheres appeared first on Universe Today.

Enough landmines are buried underground worldwide to circle Earth twice at the equator, but the identification and removal of these explosives is costly and time-consuming. New research could help solve the problem.

Biomedical engineers have invented a 3D printing system, or bioprinter, capable of fabricating structures that closely mimic the diverse tissues in the human body, from soft brain tissue to harder materials like cartilage and bone.

SURD, an algorithm, reveals causal links in complex systems. Applications may include forecasting climate to projecting population growth to designing efficient aircraft.

Despite ongoing efforts to curb CO2 emissions with electric and hybrid vehicles, other forms of transportation remain significant contributors of greenhouse gases. To address this issue, old technologies are being revamped to make them greener, such as the reintroduction of sailing vessels in shipping and new uses for hydrogen in aviation. Now, researchers have used computer modeling to study the feasibility and challenges of hydrogen-powered aviation.

Singlet fission (SF) is an exciton amplification phenomenon in which two triplet excitons are generated from a singlet exciton produced by the absorption of a single photon in chromophores. A team of researchers has demonstrated that SF can be promoted by introducing chirality and controlling chromophore orientation and arrangement. Their innovative study is expected to promote diverse applications in energy science, quantum, and information materials science, photocatalysis, solar cells, and life science.

A new method for determining causality gives scientists a more holistic view of the causal role that contributing factors play within just about any system.

Teams of astronomers used the combined power of NASA's Hubble and James Webb space telescopes to revisit the legendary Vega disk.

Researchers found that a 12-week therapeutic virtual yoga program for chronic low back pain can be a feasible, safe and effective treatment option.

Microplastics have been steadily increasing in freshwater environments for decades and are directly tied to rising global plastic production since the 1950s, according to a new study by an interdisciplinary team. The findings provide insight into how microplastics move and spread in freshwater environments, which could be important for creating long-term solutions to reduce pollution, the researchers said.