For context, the most powerful particle accelerator on Earth, the Large Hadron Collider, accelerates protons to an energy of 7 Tera-electronVolts (TeV). The neutrino that was detected had an energy of at least 60 Peta-electronVolts, possibly hitting 230 PeV. That also blew away the previous records, which were in the neighborhood of 10 PeV.

Attempts to trace back the neutrino to a source make it clear that it originated outside our galaxy, although there are a number of candidate sources in the more distant Universe. //

Neutrinos, to the extent they're famous, are famous for not wanting to interact with anything. They interact with regular matter so rarely that it's estimated you'd need about a light-year of lead to completely block a bright source of them. Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.

The only reason we're able to detect them is that they're produced in prodigious amounts by nuclear reactions, like the fusion happening in the Sun or a nuclear power plant. We also stack the deck by making sure our detectors have a lot of matter available for the neutrinos to interact with.

What if the particles we hunt for in high-energy physics laboratories—those fleeting fragments of matter and energy—aren’t just out there, waiting to be found, but are, in some way, created by the very act of looking? The anomalon particle, first observed as an inexplicable anomaly in nuclear physics experiments, might not just be a curiosity of nature but a profound clue to a deeper truth: that consciousness itself could shape the physical world. This provocative idea finds its most compelling champion in the late Robert G. Jahn, a visionary physicist who spent decades exploring the mysterious interplay between mind and matter.

Here's the math behind making a star-encompassing megastructure.

In 1960, visionary physicist Freeman Dyson proposed that an advanced alien civilization would someday quit fooling around with kindergarten-level stuff like wind turbines and nuclear reactors and finally go big, completely enclosing their home star to capture as much solar energy as they possibly could. They would then go on to use that enormous amount of energy to mine bitcoin, make funny videos on social media, delve into the deepest mysteries of the Universe, and enjoy the bounties of their energy-rich civilization.

But what if the alien civilization was… us? What if we decided to build a Dyson sphere around our sun? Could we do it? How much energy would it cost us to rearrange our solar system, and how long would it take to get our investment back? Before we put too much thought into whether humanity is capable of this amazing feat, even theoretically, we should decide if it’s worth the effort. Can we actually achieve a net gain in energy by building a Dyson sphere? //

Even if we were to coat the entire surface of the Earth in solar panels, we would still only capture less than a tenth of a billionth of all the energy our sun produces. Most of it just radiates uselessly into empty space. We’ll need to keep that energy from radiating away if we want to achieve Great Galactic Civilization status, so we need to do some slight remodeling. We don’t want just the surface of the Earth to capture solar energy; we want to spread the Earth out to capture more energy. //

For slimmer, meter-thick panels operating at 90 percent efficiency, the game totally changes. At 0.1 AU, the Earth would smear out a third of the sun, and we would get a return on our energy investment in around a year. As for Jupiter, we wouldn’t even have to go to 0.1 AU. At a distance about 30 percent further out than that, we could achieve the unimaginable: completely enclosing our sun. We would recoup our energy cost in only a few hundred years, and we could then possess the entirety of the sun’s output from then on. //

MichalH Smack-Fu Master, in training
4y
62

euknemarchon said:
I don't get it. Why wouldn't you use asteroid material?
The mass of all asteroids amounts to only 3% of the earth's moon. Not worth chasing them down, I'd guess. //

DCStone Ars Tribunus Militum
14y
2,313
"But [Jupiter]’s mostly gas; it only has about five Earth’s worth of rocky material (theoretically—we’re not sure) buried under thousands of kilometers of mostly useless gas. We'd have to unbind the whole dang thing, and then we don’t even get to use most of the mass of the planet."

Hmm. If we can imagine being able to unbind rocky planets, we can also imagine fusing the gas atmosphere of Jupiter to make usable material (think giant colliders). Jupiter has a mass of about 1.9 x 10^27 kg, of which ~5% is rocky core. We'd need to make some assumptions about the energy required to fuse the atmosphere into something usable (silicon and oxygen to make silicates?) and the efficiency of that process. Does it do enough to change the overall calculation though? //

Dark Jaguar Ars Tribunus Angusticlavius
9y
11,066
The bigger issue is the sphere wouldn't be gravitationally locked in place because the sun is cancelling it's own pull in every direction. Heck even Ringworld had to deal with this flaw in the sequel. That's why these days the futurists talking about enclosing the sun recommend "Dyson swarming" instead.

Edit: A little additional note. You can't really get the centrifugal force needed to generate artificial gravity across an entire sphere like you can with a ring. A swarm doesn't negate this. If you orbit fast enough to generate that artificial gravity, you're now leaving the sun behind. Enjoy drifting endlessly! No, rather each of these swarm objects are just going to have to rotate themselves decently fast.

Four golden lessons -- advice to students at the start of their scientific careers.

-- Steven Weinberg

Nature, Vol 426, 27 Nov 2003

The Hafele–Keating experiment was a test of the theory of relativity. In 1971,[1] Joseph C. Hafele, a physicist, and Richard E. Keating, an astronomer, took four caesium-beam atomic clocks aboard commercial airliners. They flew twice around the world, first eastward, then westward, and compared the clocks in motion to stationary clocks at the United States Naval Observatory. When reunited, the three sets of clocks were found to disagree with one another, and their differences were consistent with the predictions of special and general relativity. //

Hafele, an assistant professor of physics at Washington University in St. Louis, was preparing notes for a physics lecture when he did a back-of-the-envelope calculation showing that an atomic clock aboard a commercial airliner should have sufficient precision to detect the predicted relativistic effects.[11] He spent a year in fruitless attempts to get funding for such an experiment, until he was approached after a talk on the topic by Keating, an astronomer at the United States Naval Observatory who worked with atomic clocks.[11]

Hafele and Keating obtained $8000 in funding from the Office of Naval Research[12] for one of the most inexpensive tests ever conducted of general relativity. Of this amount, $7600 was spent on the eight round-the-world plane tickets,[13] including two seats on each flight for "Mr. Clock." They flew eastward around the world, ran the clocks side by side for a week, and then flew westward. The crew of each flight helped by supplying the navigational data needed for the comparison with theory. In addition to the scientific papers published in Science,[5][6] there were several accounts published in the popular press and other publications. //

Presently both gravitational and velocity effects are routinely incorporated, for example, into the calculations used for the Global Positioning System.

Do split flaps produce lift? I don't see how, because there is no change in camber. It seems like an upside down speed break, producing only drag.

A:

Well, after all lift is created by deflecting air downward, which is exactly what a split flap does - although in a very inefficient way i.e. with a lot of drag.

This NACA TN shows how Cl and Cd increase with the deflection δf of the split flap (left plot):

They hold the keys to new physics. If only we could understand them.

Somehow, neutrinos went from just another random particle to becoming tiny monsters that require multi-billion-dollar facilities to understand. And there’s just enough mystery surrounding them that we feel compelled to build those facilities since neutrinos might just tear apart the entire particle physics community at the seams.

It started out innocently enough. Nobody asked for or predicted the existence of neutrinos, but there they were in our early particle experiments. Occasionally, heavy atomic nuclei spontaneously—and for no good reason—transform themselves, with either a neutron converting into a proton or vice-versa. As a result of this process, known as beta decay, the nucleus also emits an electron or its antimatter partner, the positron.

There was just one small problem: Nothing added up. The electrons never came out of the nucleus with the same energy; it was a little different every time. Some physicists argued that our conceptions of the conservation of energy only held on average, but that didn’t feel so good to say out loud, so others argued that perhaps there was another, hidden particle participating in the transformations. Something, they argued, had to sap energy away from the electron in a random way to explain this.

Eventually, that little particle got a name, the neutrino, an Italian-ish word meaning “little neutral one.” //

All this is… fine. Aside from the burning mystery of the existence of particle generations in the first place, it would be a bit greedy for one neutrino to participate in all possible reactions. So it has to share the job with two other generations. It seemed odd, but it all worked.

And then we discovered that neutrinos had mass, and the whole thing blew up. //

Nazgutek Ars Scholae Palatinae
23y
866
That was a fun read. I feel like I've climbed a single Dunning-Kruger step and now I feel like I know that I know less about the universe than I did before reading this article! //

NameRedacted Ars Praetorian
7y
445
Subscriptor
karadoc said:
such that relative to you the neutrino's direction of motion would then be reversed (compared to before you overtook it)... so then I'd expect that to be a right-handed neutrino from the point of view of that speedy observer.

I may be very wrong here, but I think that the entire point of chirality is that you can’t just reverse it by changing your perspective.NameRedacted Ars Praetorian
7y
445
Subscriptor

karadoc said:
such that relative to you the neutrino's direction of motion would then be reversed (compared to before you overtook it)... so then I'd expect that to be a right-handed neutrino from the point of view of that speedy observer.

I may be very wrong here, but I think that the entire point of chirality is that you can’t just reverse it by changing your perspective. //

NameRedacted Ars Praetorian
7y
445
Subscriptor
Back when I first graduated with my engineering degree, I really wanted to go back and get a PHD in physics because I loved QM so much.

Every time I read one of these articles, I’m glad I didn’t. Don’t get me wrong, this stuff is exciting: but I don’t think I could handle how much the universe “wants” to perplex us.

I have little doubt that the physics world will need to completely change everything to figure out all four of the big “mysteries”: Neutrinos, Dark Matter, Dark Energy, and the Hubble Constant. I also have little doubt that the solution will be complex, expensive, and be an advancement on the level of QM (I.e. atomic energy and semiconductors).

I hope I’m alive for when it happens, but *$&@ am I ever glad I haven’t spent my career trying to sort it out. //

Simk Smack-Fu Master, in training
4y
56
Subscriptor++
I really enjoyed that article! I'm none the wiser for having read it, but that seems fitting for the subject matter. //

neil_w Ars Praetorian
13y
464

Well, the properties of neutrinos don’t line up like this. They’re weird. When we see an electron-neutrino in an experiment, we’re not seeing a single particle with a single set of properties. Instead we’re seeing a composite particle—a trio of particles that exist in a quantum superposition with each other that all work together to give the appearance of an electron-neutrino.

For a moment I considered just closing the browser tab after reading this paragraph.

This was a very good article, trying to explain the nearly unexplainable. Hat tip to the physicists who are able to grasp it all. //

dmsilev Ars Praefectus
14y
5,375
Subscriptor
The sum of all three neutrino masses cannot be more than around 0.1 eV/c2
The absolute value of the square of the difference between m2 and m1 is 0.000074 eV/c2
The absolute value of the square of the difference between m2 and m3 is 0.00251 eV/c2

One thing which the article didn't mention is that there's an additional question hiding in these constraints. Usually, mass scales with family; the electron is lighter than the muon is lighter than the tau, and similarly for the quarks. We assume that that's the case for neutrinos as well, that m1 (the major constituent of electron neutrinos) is less than m2 is less than m3. That's called the "normal hierarchy" solution. However, the data doesn't prove that. There's also an "inverted hierarchy" fully consistent with the data which swaps the ordering. And we can't tell which one is correct. The only reason for the somewhat prejudicial names "normal" and "inverted" is the sense of elegance that the laws of physics should be somewhat consistent.

Dear Dr. Zoomie – I was watching The Man in the High Castle and there was a bit about weapons-grade uranium posing a health risk to people around it. Is this true? //

The short version is that uranium – even highly enriched uranium – is simply not very radioactive. I can confirm this from personal measurements – I’ve made radiation dose rate measurements on depleted uranium, natural uranium, and enriched uranium and none of them are very radioactive. Here’s why: //

. It takes about 100 rem to cause radiation sickness, about 400 rem to give someone a 50% chance of death (without medical treatment), and nearly 1000 rem to be fatal. With a dose rate of 1 R/hr at a distance of 1 meter this part’s easy – it’ll take 25 hours of exposure to cause a change in blood cell counts, 400 hours to give a 50% risk of death, and 1000 hours to cause death. At a speed of 60 mph it takes about 50 hours to cross the US – not even enough time to develop radiation sickness. And that’s for a person sitting for that whole time at a distance of 1 meter from the uranium...

What price common sense? • June 11, 2024 7:30 AM

@Levi B.

“Those who are not familiar with the term “bit-squatting” should look that up”

Are you sure you want to go down that rabbit hole?

It’s an instant of a general class of problems that are never going to go away.

And why in

“Web servers would usually have error-correcting (ECC) memory, in which case they’re unlikely to create such links themselves.”

The key word is “unlikely” or more formally “low probability”.

Because it’s down to the fundamentals of the universe and the failings of logic and reason as we formally use them. Which in turn has been why since at least as early as the ancient Greeks through to 20th Century, some of those thinking about it in it’s various guises have gone mad and some committed suicide.

To understand why you need to understand why things like “Error Correcting Codes”(ECC) will never by 100% effective and deterministic encryption systems especially stream ciphers will always be vulnerable. //

No matter what you do all error checking systems have both false positive and false negative results. All you can do is tailor the system to that of the more probable errors.

But there are other underlying issues, bit flips happen in memory by deterministic processes that apparently happen by chance. Back in the early 1970’s when putting computers into space became a reality it was known that computers were effected by radiation. Initially it was assumed it had to be of sufficient energy to be ‘ionizing’ but later any EM radiation such as the antenna of a hand held two way radio would do with low energy CMOS chips.

This was due to metastability. In practice the logic gates we use are very high gain analog amplifiers that are designed to “crash into the rails”. Some logic such as ECL was actually kept linear to get speed advantages but these days it’s all a bit murky.

The point is as the level at a simple logic gate input changes it goes through a transition region where the relationship between the gate input and output is indeterminate. Thus an inverter in effect might or might not invert or even oscillate with the input in the transition zone.

I won’t go into the reasons behind it but it’s down to two basic issues. Firstly the universe is full of noise, secondly it’s full of quantum effects. The two can be difficult to differentiate in even very long term measurements and engineers tend to try to lump it all under a first approximation of a Gaussian distribution as “Addative White Gaussian Noise”(AWGN) that has nice properties such as averaging predictably to zero with time and “the root of the mean squared”. However the universe tends not to play that way when you get up close, so instead “Phase Noise in a measurement window” is often used with Allan Deviation. //

There are things we can not know because they are unpredictable or beyond or ability to measure.

But also beyond a deterministic system to calculate.

Computers only know “natural numbers” or “unsigned integers” within a finite range. Everything else is approximated or as others would say “faked”. Between every natural number there are other numbers some can be found as ratios of natural numbers and others can not. What drove philosophers and mathematicians mad was the realisation of the likes of “root two”, pi and that there was an infinity of such numbers we could never know. Another issue was the spaces caused by integer multiplication the smaller all the integers the smaller the spaces between the multiples. Eventually it was realised that there was an advantage to this in that it scaled. The result in computers is floating point numbers. They work well for many things but not with addition and subtraction of small values with large values.

As has been mentioned LLM’s are in reality no different from “Digital Signal Processing”(DSP) systems in their fundamental algorithms. One of which is “Multiply and ADd”(MAD) using integers. These have issues in that values disappear or can not be calculated. With continuous signals they can be integrated in with little distortion. In LLM’s they can cause errors that are part of what has been called “Hallucinations”. That is where something with meaning to a human such as the name of a Pokemon trading card character “Solidgoldmagikarp” gets mapped to an entirely unrelated word “distribute”, thus mayhem resulted on GPT-3.5 and much hilarity once widely known.

Simultaneity Ain't what It Used to Be

One of the most fundamental deductions Albert Einstein made from the finite speed of light in his theory of special relativity is the relativity of simultaneity—because light takes a finite time to traverse a distance in space, it is not possible to define simultaneity with respect to a universal clock shared by all observers. In fact, purely due to their locations in space, two observers may disagree about the order in which two spatially separated events occurred. It is only because the speed of light is so great compared to distances we are familiar with in everyday life that this effect seems unfamiliar to us. Note that the relativity of simultaneity can be purely due to the finite speed of light; while it is usually discussed in conjunction with special relativity and moving observers, it can be observed in situations where none of the other relativistic effects are present. The following animation demonstrates the effect. //

... by extracting transmissions from the LM from those originating in mission control onto separate tracks with the Audacity audio editor, I was then able to time-shift transmissions originating from the Earth by the light delay of 1.2865 seconds to reproduce what Buzz Aldrin and Neil Armstrong heard through their headphones in the cabin of the Eagle lunar module on the surface in Mare Tranquillitatis. During the landing phase, an on-board tape recorder in the lunar module captured the voices of Armstrong and Aldrin even when they were not transmitting on the air to ground link. From this noisy source, I have restored the few remarks by Armstrong which were only heard within the cabin. This is, then, the lunar touchdown as heard by the astronauts who performed it.

Now it's obvious what happened to Armstrong's post-landing transmission! Right before he began the call, Duke's message, sent a second and a quarter earlier, arrived at the Moon. While, from an earthly perspective, this was spoken well before Armstrong said “Houston”, on the Moon this message “stepped on” the start of Armstrong's transmission (especially considering human reaction time), and caused him to pause before continuing with his message. Note also that on the Earth-based recording, Duke's response occurs almost immediately after the end of Armstrong's transmission, but on the Moon, the astronauts had to wait for the pokey photons to make it from the home planet to their high gain antenna on its distant satellite.

that one in the cornerSilver badge
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Re: Makes you proud

The one that gets me is when you find and fix a long-standing bug in some code and wonder how in hell it managed to keep going in its original state for so many years!

You have to tread carefully around those sorts of bugs, just in case it turns out to be a Schroedinbug - and you have just observed that, unfixed, it can't possibly work. Which collapses its wave function and, through spooky action at a distance, every running copy of that program will suddenly stop working!