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Improvements in three-dimensional (3D) scanning have enabled quick and accurate scanning of 3D objects, including cultural heritage objects, as 3D point cloud data. However, conventional edge-highlighting visualization techniques, used for understanding complex 3D structures, result in excessive line clutter, reducing clarity. Addressing these issues, a multinational team of researchers have developed a novel technique, involving independent rendering of soft and sharp edges in 3D structures, resulting in improved clarity and depth perception.

Improvements in three-dimensional (3D) scanning have enabled quick and accurate scanning of 3D objects, including cultural heritage objects, as 3D point cloud data. However, conventional edge-highlighting visualization techniques, used for understanding complex 3D structures, result in excessive line clutter, reducing clarity. Addressing these issues, a multinational team of researchers have developed a novel technique, involving independent rendering of soft and sharp edges in 3D structures, resulting in improved clarity and depth perception.

In earthquake-prone areas like Japan, there is a need for better prediction of soil stability to mitigate liquefaction risks. Towards this end, researchers have used machine learning models, including artificial neural networks and bagging techniques, to create accurate 3D maps of bearing layers using data from 433 locations in Setagaya, Tokyo. This approach can identify stable construction sites, enhance disaster planning, and contribute to safer urban development, making cities more resilient to liquefaction risks.

In earthquake-prone areas like Japan, there is a need for better prediction of soil stability to mitigate liquefaction risks. Towards this end, researchers have used machine learning models, including artificial neural networks and bagging techniques, to create accurate 3D maps of bearing layers using data from 433 locations in Setagaya, Tokyo. This approach can identify stable construction sites, enhance disaster planning, and contribute to safer urban development, making cities more resilient to liquefaction risks.

A team has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium.

A recent review suggests new temperature measuring technologies could make that process much simpler, amid growing agricultural challenges fueled by fluctuating climates.

Researchers have pored over more than two decades' worth of data from NASA's Chandra X-Ray Observatory to show there's new knotty science to discover around black holes.

It acts as a sort of molecular fumigator to battle phages and plasmids.

Researchers have strengthened the case that matter becomes dark energy when massive stars collapse and become black holes.

In 2022, countries pledged to halt biodiversity loss by protecting 30 per cent of the planet by 2030, but progress has been too slow thus far

An outlandish experiment searching for a brain network that tunes up and down the feeling of immersion is hoping to unlock the therapeutic effects of psychedelics

In a small study, women experienced more empathy for strangers who were experiencing pain after an eight-week meditation training programme

I’ve finally left the entrance to Hell, otherwise known as Las Vegas. Thank goodness the conference was there to provide respite from the noisy, jangling streets, filled with tattooed people swilling margaritas. But of course all I know of Vegas is the Strip, and I’m told there are parts of the city that resemble real urbanity.  So be it.

A few photos and a video from my stay:

The Bacchanal Buffet at Caesar’s Palace. For a mere $85 you get 90 minutes to stuff your gut with as much food as you can. And it’s good food, by and large, so I’d say the buffet is worth it. Given how fast i.5 hours pass, I didn’t have the time to photograph much of the food. This is the beginning of the carving station (the buffet is HUGE). The lamb t-bones, at lower right, are small cuts of lamb that were absolutely terrific (Mike Chen recommended them on his Bacchanal Buffet video).

Below: the beginning of the seafood station. My buffet strategy was to first eat crustaceans and oysters (crab claws, snow crab legs, oysters Rockefeller), and then head for the meats (prime rib and lamb), have an elote (Mexican ear of corn), and then fill in the remaining gastric corners with desserts. I believe I got my money’s worth. Here’s a man grabbing crab.

If you go (and you have to go to a buffet in Vegas), I’d recommend this one, but watch a few videos on YouTube about the offerings, which will help you plan your buffet strategy. 90 minutes go by awfully quick!

Caesar’s Palace is the height of kitsch, decorated with Greek and Roman statuses throughout. Here’s one with a statue next to an ATM:

Back the the Horseshoe, feeling like a python that’s ingested a small antelope.  These are scenes from the casino floor at the Horseshoe, where we were staying and the site of CSICon.

Slot machines are everywhere, and they are no longer one-armed bandits, but are designed to appeal to the video-game generation. They are loud and big, liable to set off epileptic fits in those susceptible to their flashing lights. Plus you’re allowed to smoke on the casino floor, so it doesn’t smell all that great.

The lacunae between machines are filled with craps, roulette, or blackjack tables. Here’s a craps table for betting on dice:

Lots of action around the tables:

I found a cat-themed slot machine called “Karma Kat”!

. . . and here is a short video I took of what it’s like on the casino floor. Even when it’s not busy, as below, it’s noisy. Look at all those slots!

My friend Phil Ward, an entomologist at UC Davis, picked me up at noon for the two-hour drive to his shared house in Ivins, Utah, near St. George. We went through a bit of Arizona and then entered Utah, where I’m staying for the next three days, planning trips to the National Parks like Bryce and Zion—places I’ve never been.

First, though, we passed through an Indian reservation (“Native American” reservation?), housing what is formally known as the Shivwits Band of Paiutes, who settled in the area around 1100 B.C. and were hunter-gatherers but also cultivated crops. The only members of the tribe I saw were at the gas station/convenience store, whose sign is below.

It immediately struck me that “Shivwits” sounds like a Jewish name, and it went through my head that this might be one of the lost tribes of Israel that settled in Utah. (Remember, Mormons believed that Jesus came to America.) And then a joke went through my head if that scenario were true: A Shivwitz male could say, “I am a Man of Shivwitz.” Get it? Of course I mean no disrespect to the tribe; it’s just wordplay.

Gas was about as cheap as I’ve ever seen here: about 3 bucks a gallon (I believe things sold on Native American reservations are exempt from tax), so we filled up for the trip to Zion today. Proof:

Ivins is small and inconspiculous, with houses built only one story high and deigned to blend into the mountain scenery. It is beautiful here. Below is the view from my bedroom window (the house belongs to four people: Phil and three of his friends):

Today we head for Zion National Park, a place I’ve always wanted to visit because of its geological beauty. I’m bringing my decent point-and-shoot Panasonic Camera and will post pictures. Here’s one from the Wikipedia site, labeled “Zion Canyon at sunset in Zion National Park as seen from Angels Landing looking south.”

Diliff, CC BY-SA 3.0, via Wikimedia Commons

Recently a reader, having read my post about why the speed of light seems so fast, sent me two questions that highlight important cosmic issues.

1. Is there in fact anything within physics as it’s presently understood that indeed prevents […] there existing something other than atoms as some basic “unit”?
   
2. I’ve long wondered why it is that despite the seeming brilliance of humans at building such complex understanding, we are still pushing at such limits as the time it would take to fly a space ship to another galaxy. Is it really true that nothing could ever exceed ‘c’ and thus we are indeed doomed to take lifetimes to travel beyond our solar system? Or is it because we have not yet discovered something much more fundamental about the universe, such as an ‘alternative to’ the atom?

These deep questions are examples of an even broader pair of questions about reality.

• Which aspects of the cosmos are contingent?—in that one could easily imagine a similar universe in which these details are thoroughly altered.
• Which aspects of the cosmos appear rock solid?—in that they are so deeply integrated into the universe that it is difficult to imagine changing them without ruining everything.

Could something other than atoms serve as a basic material unit?

The answer to this question is “absolutely yes.”

If we look at the composite objects that make up ordinary matter, we are looking at specific particles and specific forces. There are four levels of composite objects:

• protons and neutrons made from quarks and gluons via the strong nuclear force
• atomic nuclei made from protons and neutrons via the residual strong nuclear force
• atoms made from nuclei and electrons via the electromagnetic force
• molecules made from atoms via the (often residual) electromagnetic force

But the details are complex and have to do with the precise natures of the particles and the forces. A universe with different particles and/or different forces might make entirely unfamiliar composite objects—or none at all.

Here’s where the power of theoretical physics shows itself. We can in some cases calculate what would happen in an imaginary universe with its own types of particles and forces, and gain some insights into the composite objects that might result. More challenging is to figure out whether some macroscopic material, analogous to the ordinary large-scale solids and fluids we’re familiar with, could exist in that universe. But it’s easy to show that many types of composite objects could potentially exist in other, imaginary universes, and though different from our familiar atoms, they could nevertheless serve as building blocks for complex materials.

How about in our own, real universe? There’s still a lot we don’t know about it. Experiments leave open the possibility that there are types of particles that we haven’t yet discovered, perhaps entire classes of them. There are two reasons we might not have found them.

• Too Much Mass: If a particle’s mass is very large (roughly a thousand times the mass of a typical atom, or more), then we can’t make it directly in our particle accelerators; and if such particles are also rare in the universe, with very few of them surviving from the Big Bang, then we would neither find them on purpose nor by accident. They might form unknown forms of composite objects, through either known or unknown forces.
• Too Hidden: If a type of particle is insensitive to the known types of forces (excepting gravity), then our experiments would neither detect their presence nor be able to produce them directly. Such particles are referred to as “hidden” or “dark”. They might even make up dark matter, giving us a hint of their existence through their gravity, but no other direct information that would help us learn their details. If they interact with each other via their own set of forces, those forces might allow them to make unknown and hidden composite objects.

For some types of particles, both of these reasons could simultaneously be true.

Composite objects formed by these unknown particles, through known or unknown forces, could potentially be as complex and variegated as atoms. As an example, researchers have taken seriously the possibility that dark matter is made from some sort of exotic atom, formed from dark elementary particles and forces, and asked about the particle physics and astrophysics consequences. (Here’s one paper on the subject; here’s another more recent one.)

And so, both theoretical considerations and existing experiments allow for the possibility of an unknown material made from unknown basic building blocks or units. This is true both in the abstract, where we imagine other possible universes, and in the concrete, in that it may even be true in our own universe. It may be that dark matter, or some other substance as yet unknown, has this property.

Can the speed of light be exceeded?

Before answering this, one must state carefully what one means by this question; I have pointed out pitfalls here. The proper form of the question is:

• When two objects pass each other, could an observer traveling with one object find that the speed of the second object is higher than the cosmic speed limit?

(If you ask the question in the wrong way — for instance, if you ask, can I observe two objects whose relative motion is faster than the speed of light from my point of view? — then the answer is “yes, and it happens all the time; just look at two oppositely-directed flashlight beams, or, as viewed from the laboratory, the two proton beams in the Large Hadron Collider.” Clearly that’s not what the reader is asking.)

In any universe in which Einstein’s view of gravity (known as general relativity) is true, for which local processes are described by special relativity, taught in first-year physics classes, the answer would be firmly “no.” In such a universe, there is a unique, unbreakable cosmic speed limit that applies to all objects equally. The very nature of space and time prevent anything from breaking it.

For example, if you tried to overtake a light beam, you’d find that the faster you go, the faster the light would seem to go, too, making it impossible for you to catch up to it. (In my book, I called this the “nightmare property” of the universe, since it sounds uncannily like a certain type of bad dream.) No matter what you do to improve your chances, your experience of time and space will adjust in such a way that your efforts will fail. It’s not a matter of better technology. Even infinitely powerful technology cannot beat the universe’s basic structure.

It is widely believed that, in our universe, Einstein’s general relativity is correct to a very good approximation. It can’t be exactly correct, because it doesn’t meld well with quantum physics, which we know is another feature of our universe. When quantum physics meets space and time, it might not even be meaningful to define “speed”, at least not in a straightforward way. So there might be circumstances in which the cosmic speed limit does not apply in the ways we are used to.

However, it seems to me profoundly unlikely that any violation of the cosmic speed limit, induced perhaps by quantum physics, will permit humans to travel faster than light. We ourselves are creatures of ordinary space and time, and in any situation in which space and time behave in an extraordinary way, or in which we try to move across it an extraordinary way, would probably kill us. (I’ve just finished reminding you how fragile we are and why this means that we must travel slowly relative to our surroundings. As another unrelated but amusing example of this point, see section 3.4 of this paper, a light-hearted yet scientifically rigorous look at just how difficult it would be to make wormholes that humans or spacecraft could safely cross through.)

Even if you just wanted to send a message faster than light, you would presumably still want to be sending it across normally-defined space and time. The structure of the cosmos would likely ensure that you would fail.

This is not to say that we should be closed-minded about this question. Sometimes our understanding of the universe takes a strange twist, and there’s a lot about space and time that we don’t yet understand. But being open-minded is not the same as being empty-headed. Any chance of violating this basic cosmic constraint on space-time, at least in any way that would affect our ability to cross the cosmos, currently seems like a very, very long shot.

One more point: could there be imaginary universes with no cosmic speed limit at all? Maybe. But in such a universe, extremely distant events in the universe could potentially have an instantaneous impact on our lives. Cause and effect might be harder to understand, and it’s not clear (to me, anyway) that such a universe would function well.

Final cosmic thoughts about speed and time

The bottom line:

1. No principle or experiment forbids the existence of unknown materials made from unknown basic objects, much as familiar matter is made from atoms.
2. The existence of a cosmic speed limit seems to be a basic structural element of the universe; this statement is suggested by theoretical principles and has a solid experimental basis (see for instance this recent paper).

So it turns out, though this would hardly have been obvious a century ago, that it’s much easier to imagine replacing atoms with something else than to evade the cosmic speed limit.

As a last thought, let me add something regarding this part of the reader’s second question:

• Is it really true that nothing could ever exceed ‘c’ and thus we are indeed doomed to take lifetimes to travel beyond our solar system?

“Yes” for the first half of the question; but “no” (in a sense) for the second.

Even though nothing can exceed the cosmic limit under any familiar circumstances, it is still true that time can play tricks, as it behaves unexpectedly in our universe. It is possible in principle (though probably impossible practically, due to the difficulty of building suitably safe rockets) for you to travel to many stars, even all across our entire galaxy, in your lifetime. Unfortunately, for those left behind on Earth, your trip will take far longer than their lifetimes.

This is sometimes called the “twin paradox” (and it underlies the emotional plot of the movie Interstellar) but there’s nothing paradoxical about it. It’s just unfamiliar. It rests on a basic fact: the amount of time that you measure between one event and another depends on the nature of the journey that you took to get from the initial event to the final one.

Said another way: time is something experienced by each object separately, as measured by a clock carried along with that object, and it depends on how the object moves around within the universe. There is no universal clock that exists across the universe, and outside individual observers and objects, that can measure some universal notion of time.

Specifically, the amount of time that elapses for someone traveling far from Earth to distant stars and then returning home can be far less than the amount of time that elapses meanwhile on Earth. This is not an illusion or a trick; it’s just a fact about time that’s not at all obvious from daily life. The consequence is that you yourself could visit many stars, but your friends or family (and multiple generations after them) would be long dead when your rocket landed back on Earthly soil.

(Note: In a perfectly smooth and uniform universe, there would be some reasonable notion of “universal time”; and since our universe is approximately uniform on very large distance scales, there is an approximate notion of universal time, which is quite similar to Earth time, that is useful on very large distance scales. That’s why we can talk about “the time since the Big Bang”, using this approximate universal time, and say that the universe is 13.8 billion years old; it’s approximately true for observers and objects that have not moved rapidly relative to the average objects in the universe, such as typical galaxies and our own planet. But this universal time does not apply to, say, individual observers taking extremely rapid, complex round trips around the galaxy. Such observers may live far longer than 100 years of approximate universal time — though for each of them, life will feel just as long as it does for us, because the rate of their thinking, breathing and metabolism relative to the time they experience is the same as it is for any human. Again, see the movie Interstellar for illustrations of this effect.)

Single-celled organisms called archaea can become multicellular when compressed, highlighting the role of physical forces in evolution

This idea really is quite a fascinating one. Currently a trip to Mars would require large amounts of air, water and other resources to sustain human life but would also expose travellers to harmful levels of radiation. A wonderful solution has been proposed in a new paper recently published by researchers from Ukraine. They propose that asteroids which already travel relatively close by Earth, Mars and even Venus already could be used to hop between the planets. They are already making the journey anyway and so perhaps the cosmos already provides the solution to interplanetary travel. 

After a return to the Moon, the red planet Mars is next on the list for human exploration. On average it is 225 million km away so a round trip would require astronauts to be away from home for about 3 years! Spending this length of time in space raises a number of serious health risks many of which are caused by prolonged exposure to radiation and microgravity. Over time, muscles and bone density will decline so that the skeletal part of the body will no longer bear enough weight to sustain a return to Earth’s gravity. The cardiovascular system would adjust to microgravity too making heart issues likely upon return. There would be an increased risk of cancer and damage to the nervous system as a result of the prolonged exposure to radiation. The list goes on! 

Mars, Credit NASA

The paper recently authored by A. S. Kasianchuk and V.M. Reshetnyk from the National University of Kyiv in Ukraine they report upon their analysis of the orbit of more than 35,000 near-Earth asteroids. They have been looking for the possibility of successive approaches to all pairs of planets Earth – Venus and Earth – Mars within a time range of 2020 to 2120. If successive passes exist then why not, the team suggest, use the asteroids as interplanetary busses to provide a fast transfer between the planets, possibly even as fast as 180 days. 120 candidates were discovered for Earth-Mars, Earth-Venus, Mars-Earth, Venus-Earth, and even Mars-Venus and Venus-Mars!

Image of Venus taken by NASA’s Pioneer-Venus Orbiter in 1979. (Credit: NASA)

It is a tantalising prospect that instead of mounting a massive rocket based mission to get to Mars or even Venus, that the use of Near Earth Objects (NEO) might provide a natural solution. They would certainly provide a fast transfer between planets but would still require some form of technological solution to radiation protection. The quicker the journey, the lower the risk from radiation so careful selection is an important part of the process. 

The team have produced quite an extensive list of potentials NEO’s for transfers between the inner planets but as new NEO’s are discovered the list will grow. The work provides a snapshot in time of the possible candidates but it requires on going work to keep the list up to date as more asteroids are discovered and orbital elements are refined. NASA’s NEO Surveyor mission has been set the challenge to find more than 90% of all  NEO’s larger than 140 metres in diameter. This will certainly provide a useful resource to the study.

An artist’s conception of an NEO asteroid orbiting the Sun. Credit: NASA/JPL.

Among the asteroids identified, size and proximity to the target planet needs to be considered. Analysis of the overall mission needs to be carefully worked too. If a spacecraft stays in open space for a longer period of time than inside a NEW for example, the effectiveness of the approach must be carefully weighed up. 

It’s an interesting proposition though. With appropriate technological solutions, a carefully selected asteroid can serve not only as a fuel station but also, if shelter is taken beneath the surface for example in caves, could offer radiation protection too. There are significant challenges ahead before this all becomes a reality but with the ever increasing drive to reduce the cost and ecological impact of space flight it is one that most definitely needs further careful analysis. 

Source : The search for NEOs as potential candidates for use in space missions to Venus and Mars

The post Astronauts Could Take an Asteroid Ferry from Earth to Mars appeared first on Universe Today.

Ancient stone goods found across France may have been made by skilled craftspeople in what is now Paris, who traded along vast networks

Meanwhile, in Dobrzyn, Hili notices the changing seasons, but Andrzej is not optimistic:

Hili: We have autumn again. A: This time it’s the autumn of Enlightenment.

Hili: Znowu mamy jesień.
Ja: Tym razem to jest jesień Oświecenia.

 

 

In a post on X/Twitter, antivaxxer turned Trump supporter Robert F. Kennedy, Jr. declared MAHA war on the FDA, should Trump be elected. What would this actually mean in practice?

The post RFK Jr. declares MAHA war against the FDA first appeared on Science-Based Medicine.

Some wires must have gotten crossed, as Matthew hasn’t put up today’s Hili dialogue. But no worries–I called Malgorzata and got it. A day without Hili is like a day without sunshine! So here you go:

Hili: What do you think will happen now? A: Predicting the future is not my business. In Polish: Hili: Jak sądzisz, co teraz będzie.
Ja: Przewidywanie przyszłości to nie mój biznes.