Dark Matter, Ordinary Matter…

Topics: Astronomy, Astrophysics, Dark Matter, Research, Theoretical Physics

Dark matter, composed of particles that do not reflect, emit, or absorb light, is predicted to make up most of the matter in the universe. However, its lack of interactions with light prevents its direct detection using conventional experimental methods.

Physicists have been trying to devise alternative methods to detect and study dark matter for decades, yet many questions about its nature and its presence in our galaxy remain unanswered. Pulsar Timing Array (PTA) experiments have been trying to probe the presence of so-called ultralight dark matter particles by examining the timing of an ensemble of galactic millisecond radio pulsars (i.e., celestial objects that emit regular millisecond-long radio wave pulses).

The European Pulsar Timing Array, a multinational team of researchers based at different institutes that are using 6 radio-telescopes across Europe to observe specific pulsars, recently analyzed the second wave of data they collected. Their paper, published in Physical Review Letters, sets more stringent constraints on the presence of ultralight dark matter in the Milky Way.

“This paper was basically the result of my first Ph.D. project,” Clemente Smarra, co-author of the paper, told Phys.org. “The idea arose when I asked my supervisor if I could carry out research focusing on gravitational wave science, but from a particle physics perspective. The main aim of the project was to constrain the presence of the so-called ultralight dark matter in our galaxy.”

Ultralight dark matter is a hypothetical dark matter candidate, made up of very light particles that could potentially address long-standing mysteries in the field of astrophysics. The recent study by Smarra and his colleagues was aimed at probing the possible presence of this type of dark matter in our galaxy via data collected by the European Pulsar Timing Array.

“We were inspired by previous efforts in this field, especially by the work of Porayko and her collaborators,” Smarra said. “Thanks to the longer duration and the improved precision of our dataset, we were able to put more stringent constraints on the presence of ultralight dark matter in the Milky Way,”

The recent paper by the European Pulsar Timing Array makes different assumptions than those made by other studies carried out in the past. Instead of probing interactions between dark matter and ordinary matter, it assumes that these interactions only occur via gravitational effects.

“We assumed that dark matter interacts with ordinary matter only through gravitational interaction,” Smarra explained. “This is a rather robust claim: in fact, the only sure thing we know about dark matter is that it interacts gravitationally. In a few words, dark matter produces potential wells in which pulsar radio beams travel. But the depth of these wells is periodic in time; therefore, the travel time of the radio beams from pulsars to the Earth changes with a distinctive periodicity as well.”

New constraints on the presence of ultralight dark matter in the Milky Way, Ingrid Fadelli, Phys.org.

Oxymoron…

The Bulletin of the Atomic Scientists shifted the Doomsday Clock to 90 seconds to midnight at a news conference in January 2023. From left, Siegfried Hecker, Daniel Holz, Sharon Squassoni, Mary Robinson and Elbegdorj Tsakhia (Photo credit: Patrick Semansky).

Topics: Astrobiology, Civilization, Existentialism, Science Fiction, SETI, Space Exploration

A few weeks ago, I posted “Wine of Consciousness” on Friday without commentary. There were many directions I could have taken. I did want to see how readers would react. As I postulated, the viewership was limited. There were many directions that I COULD have taken the post. Still, I decided every iteration was getting a little too “pop science” for my taste, and that can quickly cross over into pseudo without critical thinking.

Avi Loeb is popularly known for his hypothesis that Oumuamua (“scout” in Polynesian) wasn’t a meteor or comet but a possible extraterrestrial probe sent by an intelligence with a similar understanding of physics and the limitations of intergalactic travel: without something like 99% the speed of light (warp velocity is still the providence of science fiction), such journeys are not possible within the normal span of lifetimes. Dr. Loeb is a theoretical physicist in the Department of Astronomy at Harvard.

I’m from the generation that grew up hearing about “UFOs” (unidentified flying objects), “flying saucers,” and “little green men.” Green succumbed to gray, grey, or “the grays/greys” (E.T.: The Extra-Terrestrial), and now we’re discussing UAPs (unidentified aerial phenomena).

Another theoretical physicist has tackled the challenge by publishing another book: “UFOs: Unidentified Aerial Phenomena: Observations, Explanations, and Speculations (Paperback)” in what appears to be a lucrative cottage industry.

When someone asks me if I believe there is life elsewhere in the universe, I will say yes. Amoeba is life, bacteria is life, viruses: the jury is still out on whether or not they are alive in the biological sense.

I have often wondered if intelligence is its own Entropy: that the very systems any sentient species would create for itself in governing resources, governments, commerce, and space exploration would be its undoing, which might answer The Fermi Paradox.

The hope of extraterrestrials existing and interacting with Earth mortals might be a cultural wish: a hope that despite our alarming tendency to screw things up, we either might survive our boundless hubris, or SOMEONE will save us from our stupidity, Deus ex machina, or benevolent Vulcans.

Homo Sapiens is Latin for “wise men.”

Homo Stultus (“stupid men”) seems more apropos.

Is a More Advanced Civilization an Oxymoron? Avi Loeb, Medium

Everything, Everywhere, All at Once…

The Flood by Antonio Marziale Carracci

Topics: Civilization, Climate Change, Energy, Environment, Existentialism, Global Warming

Another week, another catastrophic, record-setting, history-making flood, this time in Kentucky.

Preliminary assessments indicate rainfall in Graves County last week likely set a new record for most precipitation in a 24-hour period, with 11.28 inches of rain. This would make it yet another “1,000-year” flood event, which had, according to historical projections, less than a 0.1 percent chance of occurring in any given year. One of the towns that experienced flash flooding was Mayfield, a community still rebuilding from a 2021 tornado that killed 57 people.

This was just one of the 11 flash flood emergencies in as many days in the United States, according to Weather Channel meteorologist Heather Zons. These events have claimed multiple lives: 2-year-old Mattie Shiels, 9-month-old brother, Conrad, and their mother, Katie Seley drowned after getting swept away by flash flooding in Pennsylvania, during an event that killed at least four others. In New York earlier this month, 43-year-old Pamela Nugent was swept away trying to evacuate a flooded area; 63-year-old Stephen Davoll drowned in his home in Vermont.

Other catastrophic, deadly flooding events have occurred almost simultaneously around the globe. Just this weekend, 10 inches of rain fell on parts of Nova Scotia, Canada, which is about as much as the region experiences over a period of three months. Four people, including two children, are still missing.

Everything, everywhere, all at once: The great floods of 2023, Jessica McKenzie, Bulletin of the Atomic Scientists, July 27, 2023

Quasicrystal Legos…

A mathematical tool called a fast Fourier transform maps the structure in a way that reveals the 12-fold symmetry of the quasicrystal. The fast Fourier transform of the electron microscope image of the quasicrystal is shown on the left, while the transform of the simulated crystal is shown on the right. Image credit: Mirkin Research Group, Northwestern University, and Glotzer Group, University of Michigan.

Topics: Biology, DNA, Nanoengineering, Nanomaterials, Nanotechnology

ANN ARBOR—Nanoengineers have created a quasicrystal—a scientifically intriguing and technologically promising material structure—from nanoparticles using DNA, the molecule that encodes life.

The team, led by researchers at Northwestern University, the University of Michigan, and the Center for Cooperative Research in Biomaterials in San Sebastian, Spain, reports the results in Nature Materials.

Unlike ordinary crystals, which are defined by a repeating structure, the patterns in quasicrystals don’t repeat. Quasicrystals built from atoms can have exceptional properties—for example, absorbing heat and light differently, exhibiting unusual electronic properties such as conducting electricity without resistance, or their surfaces being very hard or very slippery.

Engineers studying nanoscale assembly often view nanoparticles as a kind of ‘designer atom,’ which provides a new level of control over synthetic materials. One of the challenges is directing particles to assemble into desired structures with useful qualities, and in building this first DNA-assembled quasicrystal, the team entered a new frontier in nanomaterial design.

“The existence of quasicrystals has been a puzzle for decades, and their discovery appropriately was awarded a Nobel Prize,” said Chad Mirkin, the George B. Rathmann Professor of Chemistry at Northwestern University and co-corresponding author of the study. “Although there are now several known examples, discovered in nature or through serendipitous routes, our research demystifies their formation and, more importantly, shows how we can harness the programmable nature of DNA to design and assemble quasicrystals deliberately.”

Nanoparticle quasicrystal constructed with DNA, Kate McAlpine, University of Michigan

Graphite to Gold…

Artist’s rendition of the electron correlation, or the ability of electrons to talk with each other, can occur in a special kind of graphite (pencil lead). @ Sampson Wilcox, MIT Research Laboratory of Electronics

Topics: Entanglement, Graphene, Materials Science, Nanomaterials, Nanotechnology

MIT physicists have metaphorically turned graphite, or pencil lead, into gold by isolating five ultrathin flakes stacked in a specific order. The resulting material can then be tuned to exhibit three important properties never before seen in natural graphite.

“It is kind of like one-stop shopping,” says Long Ju, an assistant professor in the MIT Department of Physics and leader of the work, which is reported in the October 5 issue of Nature Nanotechnology. “Nature has plenty of surprises. In this case, we never realized that all of these interesting things are embedded in graphite.”

Further, he says, “It is very rare to find materials that can host this many properties.”

Graphite is composed of graphene, which is a single layer of carbon atoms arranged in hexagons resembling a honeycomb structure. Graphene, in turn, has been the focus of intense research since it was first isolated about 20 years ago. Then, about five years ago, researchers, including a team at MIT, discovered that stacking individual sheets of graphene and twisting them at a slight angle to each other can impart new properties to the material, from superconductivity to magnetism. The field of “twistronics” was born.

In the current work, “we discovered interesting properties with no twisting at all,” says Ju, who is also affiliated with the Materials Research Laboratory.

He and colleagues discovered that five layers of graphene arranged in a certain order allow the electrons moving around inside the material to talk with each other. That phenomenon, known as electron correlation, “is the magic that makes all of these new properties possible,” Ju says.

Bulk graphite–and even single sheets of graphene–are good electrical conductors, but that’s it. The material Ju and colleagues isolated, which they call pentalayer rhombohedral stacked graphene, becomes much more than the sum of its parts.

 Reference
 Correlated insulator and Chern insulators in pentalayer rhombohedral-stacked graphene

Tonghang Han, Zhengguang Lu, Giovanni Scuri, Jiho Sung, Jue Wang, Tianyi Han, Kenji Watanabe, Takashi Taniguchi, Hongkun Park & Long Ju

https://www.nature.com/articles/s41565-023-01520-1

Massachusetts Institute of Technology

The Wine of Consciousness…

Credit: Fanatic Studio/Gary Waters/Getty Images

Topics: Education, Existentialism, Philosophy, Physics

Physicists and philosophers recently met to debate a theory of consciousness called panpsychism.

More than 400 years ago, Galileo showed that many everyday phenomena—such as a ball rolling down an incline or a chandelier gently swinging from a church ceiling—obey precise mathematical laws. For this insight, he is often hailed as the founder of modern science. But, Galileo recognized that not everything was amenable to a quantitative approach. Such things as colors, tastes, and smells “are no more than mere names,” Galileo declared, for “they reside only in consciousness.” These qualities aren’t really out there in the world, he asserted, but exist only in the minds of creatures that perceive them. “Hence, if the living creature were removed,” he wrote, “all these qualities would be wiped away and annihilated.”

Since Galileo’s time, the physical sciences have leaped forward, explaining the workings of the tiniest quarks to the largest galaxy clusters. But explaining things that reside “only in consciousness”—the red of a sunset, say, or the bitter taste of a lemon—has proven far more difficult. Neuroscientists have identified a number of neural correlates of consciousness—brain states associated with specific mental states—but have not explained how matter forms minds in the first place. As philosopher Colin McGinn put it in a 1989 paper, “Somehow, we feel, the water of the physical brain is turned into the wine of consciousness.” Philosopher David Chalmers famously dubbed this quandary the “hard problem” of consciousness.*

Scholars recently gathered to debate the problem at Marist College in Poughkeepsie, N.Y., during a two-day workshop focused on an idea known as panpsychism. The concept proposes that consciousness is a fundamental aspect of reality, like mass or electrical charge. The idea goes back to antiquity—Plato took it seriously—and has had some prominent supporters over the years, including psychologist William James and philosopher and mathematician Bertrand Russell. Lately, it is seeing renewed interest, especially following the 2019 publication of philosopher Philip Goff’s book Galileo’s Error, which argues forcefully for the idea.

Is Consciousness Part of the Fabric of the Universe? Dan Falk, Scientific American

Gas Nephilim…

Artist’s depiction of an extra-solar system that is crowded with giant planets. Credit: NASA/Dana Berry

Topics: Astronomy, Astrophysics, Planetary Science, Space Exploration

Giant gas planets can be agents of chaos, ensuring nothing lives on their Earth-like neighbors around other stars. New studies show in some planetary systems, the giants tend to kick smaller planets out of orbit and wreak havoc on their climates.

Jupiter, by far the biggest planet in our solar system, plays an important protective role. Its enormous gravitational field deflects comets and asteroids that might otherwise hit Earth, helping create a stable environment for life. However, giant planets elsewhere in the universe do not necessarily protect life on their smaller, rocky planet neighbors.

An Astronomical Journal paper details how the pull of massive planets in a nearby star system is likely to toss their Earth-like neighbors out of the “habitable zone.” This zone is defined as the range of distances from a star that are warm enough for liquid water to exist on a planet’s surface, making life possible.

Unlike most other known solar systems, the four giant planets in HD 141399 are farther from their star. This makes it a good model for comparison with our solar system, where Jupiter and Saturn are also relatively far from the sun.

“It’s as if they have four Jupiters acting like wrecking balls, throwing everything out of whack,” said Stephen Kane, UC Riverside astrophysicist and author of the journal paper.

Taking data about the system’s planets into account, Kane ran multiple computer simulations to understand the effect of these four giants. He wanted specifically to look at the habitable zone in this star system and see if an Earth could remain in a stable orbit there.

Giant planets cast a deadly pall: How they can prevent life in other solar systems, Jules Bernstein, University of California – Riverside, Phys.org.

A Hole in the Sky…

This map shows the size and shape of the ozone hole over the South Pole on September 21, 2023, the day of its maximum extent, as calculated by the NASA Ozone Watch team. Moderate ozone losses (orange) are visible amid widespread areas of more potent ozone losses (red).

NASA Earth Observatory

Topics: Antarctica, Atmospheric Science, NASA, Ozone Layer

Goddard Spaceflight Center: What is Ozone?

Editor’s note: This article has been updated to clarify the ranking of the 2023 ozone hole.  It is the 12th largest single-day hole on record and the 16th largest when averaged from Sept 7 to Oct 13.

The 2023 Antarctic ozone hole reached its maximum size on Sept. 21, according to annual satellite and balloon-based measurements made by NASA and NOAA. At 10 million square miles, or 26 million square kilometers, the hole ranked as the 12th largest single-day ozone hole since 1979.

During the peak of the ozone depletion season from Sept. 7 to Oct. 13, the hole this year averaged 8.9 million square miles (23.1 million square kilometers), approximately the size of North America, making it the 16th largest over this period. 

“It’s a very modest ozone hole,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Declining levels of human-produced chlorine compounds, along with help from active Antarctic stratospheric weather, slightly improved ozone levels this year.”

2023 Ozone Hole Ranks 16th Largest, NASA and NOAA Researchers Find

Bitcoin and Gaia…

“What are the environmental impacts of cryptocurrency?” Written by Paul Kim; edited by Jasmine Suarez Mar 17, 2022, 5:21 PM EDT, Business Insider.

Image: Ethereum, the second biggest cryptocurrency on the market, plans on changing to proof of stake mining in the future. Rachel Mendelson/Insider

Topics: Applied Physics, Computer Science, Cryptography, Economics, Environment, Star Trek, Thermodynamics

In what is now “old school Internet” (or web surfing for fogies), I will get a friend request from someone on Facebook/Meta who is in cryptocurrency. I quote myself in the first paragraph of what I refer to as my “public service announcement):

I am not INTERESTED in crypto. As someone who worked with cryptography as a matter of national security, holding a TS/SCI clearance, when you start your message with “let me explain to YOU how crypto works,” expect to get blocked.

Invariably, I still do, which makes me wonder if they read the PSA or think “they will be the one” to sign me. News flash, pilgrim…I now have another pertinent reason to ignore your blockchain solicitations, actually, several good reasons.

Every time we turn on a light in our homes, there is a thermal budget that we are being charged for (that’s how Duke Power makes its money in North Carolina and Perdernales Electric Cooperative in Texas). Bitcoin/Blockchain (I think) caught the imagination because it seemed like a “Federation Credit” from Star Trek, where no one explains fully how a society that is “post-scarcity” somehow feels the need for some type of currency in utopia. It’s kind of like magic carpets: you go with the bit for the story – warp drive, Heisenberg compensators, Federation credits. The story, and if you are thoroughly entertained after the denouement, not the physics, is what matters.

You might not be extracting anything from the planet directly, but Bitcoin mining has a massive impact on the planet’s environment.

Mining resources from our planet can take a devastating toll on the environment, both local and global. Even beyond this, using the resource could cause disastrous effects on our planet, and dependence on a single resource can wreak havoc on a country’s economy. Yet, many of these resources are needed for our daily lives — sometimes as a luxury, sometimes as a necessity. Any responsible country or company should always take pause to consider what impact mining of any kind can have on the planet.

It turns out that these days, one type of mining might be the worst for Earth’s environment: bitcoins. Yes, the “mining” of virtual currency makes its mark on our planet. The unequal distribution of Bitcoin mining across the globe means that some countries are making a much larger dent into the planet’s climate and environment than others … all for a “resource” that is far from necessary for our society.

Bitcoin mining uses a lot of computing power to solve the cryptographic puzzles that lie at the heart of the industry. As of today (October 30, 2023), each Bitcoin is worth over $34,000, and with the multitude of other cryptocoins out there, using computers to unlock more can be a profitable endeavor. Almost half a trillion dollars of the global economy runs on these “virtual currencies.”

Worst Kind of Mining for the Environment? It Might Be Bitcoin. Erik Klemetti, Discover Magazine

In Medias Res…

Image source: Link below

Topics: Applied Physics, Astrophysics, Computer Modeling, Einstein, High Energy Physics, Particle Physics, Theoretical Physics

In the search for new physics, a new kind of scientist is bridging the gap between theory and experiment.

Traditionally, many physicists have divided themselves into two tussling camps: the theorists and the experimentalists. Albert Einstein theorized general relativity, and Arthur Eddington observed it in action as “bending” starlight; Murray Gell-Mann and George Zweig thought up the idea of quarks, and Henry Kendall, Richard Taylor, Jerome Freidman and their teams detected them.

In particle physics especially, the divide is stark. Consider the Higgs boson, proposed in 1964 and discovered in 2012. Since then, physicists have sought to scrutinize its properties, but theorists and experimentalists don’t share Higgs data directly, and they’ve spent years arguing over what to share and how to format it. (There’s now some consensus, although the going was rough.)

But there’s a missing player in this dichotomy. Who, exactly, is facilitating the flow of data between theory and experiment?

Traditionally, the experimentalists filled this role, running the machines and looking at the data — but in high-energy physics and many other subfields, there’s too much data for this to be feasible. Researchers can’t just eyeball a few events in the accelerator and come to conclusions; at the Large Hadron Collider, for instance, about a billion particle collisions happen per second, which sensors detect, process, and store in vast computing systems. And it’s not just quantity. All this data is outrageously complex, made more so by simulation.

In other words, these experiments produce more data than anyone could possibly analyze with traditional tools. And those tools are imperfect anyway, requiring researchers to boil down many complex events into just a handful of attributes — say, the number of photons at a given energy. A lot of science gets left out.

In response to this conundrum, a growing movement in high-energy physics and other subfields, like nuclear physics and astrophysics, seeks to analyze data in its full complexity — to let the data speak for itself. Experts in this area are using cutting-edge data science tools to decide which data to keep and which to discard and to sniff out subtle patterns.


Opinion: The Rise of the Data Physicist, Benjamin Nachman, APS News