Physics
This is a big page of links, some with brief explanations, divided into a few rough categories.
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Tools • Fluid Dynamics • Politics • Astronomy • Gravitation • More
Tools for Physics
VegaLite.jl: Julia bindings to Vega-Lite: “VegaLite.jl is a plotting package for the julia programming language. The package is based on Vega-Lite, which extends a traditional grammar of graphics API into a grammar of interactive graphics.”
gnuplot: Gnuplot news and information.
WebPlotDigitizer: Have a plot but need the numbers? This web service can take care of it. Reminds me of the ancient Macintosh program “Datathief.”
All about Modelica: “Modelica is a great tool for modeling cyber-physical systems, for example to study the fuel efficiency of an hybrid vehicle, or to evaluate the interactions between renewable energy sources and the electrical grid. “In this post I will provide a general overview on Modelica, and I’ll showcase some of its main features.”
Lazy Physics (and Clojure): Processing time series data from particle physics experiments using Clojure’s lazy sequences.
HTML5 Canvas Fluid Simulation: A Navier-Stokes solver in the browser.
Visualize real-time data streams with Gnuplot: “For the last couple of years, I’ve been working on European Space Agency (ESA) projects […] In the ESA project I am currently working on, I am also the technical lead; and I recently faced the need to (quickly) provide real-time plotting of streaming data. […] Gnuplot follows the powerful paradigm that UNIX established: it comes with an easy to use scripting language, thus allowing its users to prescribe actions and ‘glue’ Gnuplot together with other applications - and form powerful combinations. […] it took me 30min to code this, and another 30 to debug it. Using pipes […] we are able to do something that would require one or maybe two orders of magnitude more effort in any conventional programming language (yes, even accounting for custom graph libraries - you do have to learn their API”.
SciPy: “SciPy (pronounced ‘Sigh Pie’) is a Python-based ecosystem of open-source software for mathematics, science, and engineering.”
Diverging Color Maps for Scientific Visualization (Expanded): Shows how the commonly used rainbow palette is a bad choice for visualization and how to generate palettes with better perceptual properties, that are also better for colorblind viewers.
Fortran Standard Library: This is an interesting development.
The 100 billion frames per second camera that can image light itself: Detailed attempt to describe how the imaging system works.
SciPy Reaches v. 1.0: My article about the Python scientific library in LWN.
Plotting tools for Linux: matplotlib: My article introducing matplotlib, the plotting library for Python.
PhysicsJS - A modular, extendable, and easy-to-use physics engine for javascript: Several impressive demos.
Abramowitz & Stegun is now an iOS App: ‘The classic Handbook of Mathematical Functions, edited by Milton Abramowitz and Irene Stegun, now available on your iPhone or iPad.’ Having this heavy book on my shelf is making me feel old. The next generation of graduate students will scarcely believe that we heaved this thing over to our desks to flip through the pages.
JupyterLab: Ready for Users: My article on the evolution of the Jupyter Notebook in LWN.
Jupyter: notebooks for education and collaboration: My article on the browser-based interface to Python and more in LWN.
New features in gnuplot 5.4: My article appeared today in LWN. I take a look at five major new capabilities in gnuplot, including voxel plotting, for visualizing 3D data.
If you grew up on some form of classic fortran and need to be jolted into the 21st century, here is a good place to start.
Fluid dynamics
Competition of intrinsic and topographically imposed patterns in Bénard–Marangoni convection: An experiment.
Forecasting the weather with neural ODEs: Using Julia to forecast the weather with machine learning techniques.
Physicists Make Progress On The Bumpy Ride To Understanding Turbulence: New experiments examining vortex merging in 2D turbulent flows.
Swalbe.jl: A lattice Boltzmann solver for thin film hydrodynamics: A Julia program.
Famous Experiment Dooms Alternative to Quantum Weirdness: The Copenhagen interpretation is still our most parsimonious model of the microworld.
Turbulence, The Oldest Unsolved Problem in Physics: My article in Ars Technica.
FYFD—Celebrating the physics of all that flows: A website devoted to fluid dynamics.
Highly automated application process for innovative painting system: Lufthansa is working on an aircraft surface inspired by shark skin, containing micro-ridges.
Illuminating siphoning demonstration: Short video that illustrates the role of pressure in liquid siphoning.
A Kind of Boundary-Layer ‘Flutter’ : The Turbulent History of a Fluid Mechanical Instability: History of early turbulence and fluid stability research.
Oceananigans.jl: 
“Fast and friendly fluid dynamics on CPUs and GPUs”
“Fast and friendly fluid dynamics on CPUs and GPUs”
Origin and dynamics of vortex rings in drop splashing: Experiment with very high quality visualizations, and development of some theory and modeling.
Flow visualization: “This site is devoted to a course for mixed teams of engineering and fine arts photography and video students at the University of Colorado. In this course, we explore a range of techniques for creating images of fluid flows. Our work is motivated not just by the utility and importance of fluid flows, but also by their inherent beauty.”
Analytical Vortex Solutions to the Navier-Stokes Equation: This Ph.D. thesis contains a lot of useful work.
Preferred pattern of convection in a porous layer with a spatially non-uniform boundary temperature: “The problem of finite-amplitude thermal convection in a porous layer between two horizontal walls with different mean temperatures is considered when spatially non-uniform temperature with amplitude L* is prescribed at the lower wall. The nonlinear problem of three-dimensional convection for values of the Rayleigh number close to the classical critical value is solved by using a perturbation technique.”
Statistical and Numerical Investigations of Fluid Turbulence: Contains clear introductions to several topics in turbulence; a well-written thesis.
Long exposure of fog flow: Several minutes under moonlight; a study in fluid flow that is also a lovely photograph.
The Ancient Persian way to keep cool: using “windcatchers”.
Statistical properties of turbulence: an overview.: Good source of references.
Paradoxical ratcheting in cornstarch: A fluid with shear thickening climbs up a vibrating plate against gravity.
On the Navier-Stokes “Millenium Prize”: The problem; translation of the proposed solution.
Stripe-hexagon competition in forced pattern-forming systems with broken up-down symmetry: Copy at https://arxiv.org/pdf/nlin/0410061.pdf
The Scientific Problem That Must Be Experienced: Very interesting study of the interplay between science and art in grasping turbulence.
Reproducible and replicable CFD: it’s harder than you think: The authors find that even changes in linear algebra library versions cause a failure or replication of their CFD results.
Depletion of nonlinearity in two-dimensional turbulence: Theory and simulation.
Return to Dead Mountain: This story about the mysterious deaths of campers 55 years ago in northern Russia is really a story about fluid dynamics, starring the Kármán vortex street.
Mathematicians Find Wrinkle in Famed Fluid Equations: Determinism and the NS equations.
Politics
Let’s Cut Our Losses on Fusion Energy: My op-ed originally appeared in the Progressive, and has been picked up by about eight other papers.
Nonsense arguments for building a bigger particle collider that I am tired of hearing (The Ultimate Collection): This is both witty and to the point. From Sabine Hossenfelder.
The Miracle Cure for All Our Energy Woes?: A review of Nuclear Fusion and the Race to Power the Planet by Arthur Turrell. Hossenfelder believes that Turrell is insufficiently skeptical of the claims of the researchers and entrepreneurs he profiles, She ends with “What nuclear fusion most needs is a reality check. This book isn’t it.”
FY22 Budget Request: National Nuclear Security Administration: The budget request shows a substantial reduction in funds wasted on ICF energy programs, partly as a result of an internal review that bore out my predictions of failure to meet scientific goals.
How close is nuclear fusion power?: I’m glad that Sabine Hossenfelder is pointing these things out to her large audience, and in such a forceful manner. She’s right on every point. The misinformation has to stop.
Astronomy
Maria Mitchell’s 195th Birthday: My notice on the Arlington Planetarium website.
Rosetta’s comet ‘sweats’ two glasses of water a second: ESA’s Rosetta spacecraft detects enough water vapor coming off of comet 67P/Churyumov–Gerasimenko to fill an Olympic swimming pool in 100 days. “Glasses” and “swimming pools” are the only units of volume offered by the article on the European Space Agency website, which is otherwise quite good.
Friends of Arlington’s Planetarium: The home page of the Arlington Planetarium.
We don’t know how the universe began, and we will never know: Excellent video (with transcript) about ascientific creation myths written in the language of mathematics.
Juno Data Indicates “Sprites” or “Elves” Frolic in Jupiter’s Atmosphere: 
New results from NASA’s Juno mission at Jupiter reveal for the first time these flashes (transient luminous events, or TLEs) on another planet. The findings were published on Oct. 27, 2020, in the Journal of Geophysical Research: Planets.
New results from NASA’s Juno mission at Jupiter reveal for the first time these flashes (transient luminous events, or TLEs) on another planet. The findings were published on Oct. 27, 2020, in the Journal of Geophysical Research: Planets.
Scale Comparisons of the Solar System’s Major Moons: … in the form of a lovely presentation slide.
JWST Data Collection: Webb Telescope instruments, data collection, and links to documentation.
NASA’s Asteroid Mission Packs Away Its Cargo. Next Stop: Earth: “The OSIRIS-REX mission has been investigating a carbon-rich asteroid named Bennu for the last couple of years.”
Staff Recommends Denying Historic Designation for Potential High School Site: “Under the plan for historic designation, the Education Center and the adjacent David M. Brown Planetarium would be saved from possible demolition […] School Board members do not support pursuing historic designation”.
Risk of asteroid hitting Earth higher than thought, study shows: “A global network that listens for nuclear weapons detonations detected 26 asteroids that exploded in Earth’s atmosphere from 2000 to 2013, data collected by the Comprehensive Nuclear Test Ban Treaty Organization shows.” This data raises the impact probability above some previous estimates.
Jupiter and Saturn’s Great Conjunction Is the Best in 800 Years—Here’s How to See It: “The giant planets will appear spectacularly close together in Earth’s sky during the solstice on December 21”.
Mystery in the Perseus Cluster: ‘“I couldn’t believe my eyes,” says Esra Bulbul of the Harvard Center for Astrophysics. “What we found, at first glance, could not be explained by known physics.”’
World’s Biggest Telescope Gets Green Light: The Thirty Meter Telescope, for now the largest optical telescope in the world, has received permission to begin construction on the summit of Mauna Kea, Hawaii. [2013]
Rosetta fuels debate on origin of Earth’s oceans: Results cast doubt on the theory that Earth’s water came from comets.
Studying the Solar System with NASA’s Webb Telescope: A 2016 special issue of the Publications of the Astronomical Society of the Pacific is devoted to science that will be made possible by the telescope.
Orbital Insertion Burn a Success, Webb Arrives at L2: “Today, at 2 p.m. EST, Webb fired its onboard thrusters for nearly five minutes (297 seconds) to complete the final postlaunch course correction to Webb’s trajectory. This mid-course correction burn inserted Webb toward its final orbit around the second Sun-Earth Lagrange point, or L2, nearly 1 million miles away from the Earth.”
Atlanta Students Bring Mars to Earth: “As part of a group called Aspiration Creation, students from the Dunwoody/Sandy Springs area participated in a project with the European Space Agency (European equivalent to NASA) to take real live images of Mars.”
NASA - Spot The Station: See the International Space Station
Comet dust found in Antarctica: “Researchers have discovered comet dust preserved in the ice and snow of Antarctica, the first time such particles have been found on Earth’s surface.”
Talking with the ISS using LASERs: “The entire transmission on June 5th lasted 148 seconds and achieved a maximum data rate of 50 megabits per second […] 3.5 seconds to transmit a single copy of the [HD] video message, which would have taken more than 10 minutes using traditional downlink methods.”
The Space Station Accelerates: To maintain orbit, the ISS must fire its rockets now and then. This movie demonstrates the departure from weightlessness experienced inside the station.
Five major planets to line up in rare planetary conjunction: “The last time this conjunction happened was 2004 and it won’t be seen again until 2040.”
NASA Unveils New Searchable Video, Audio and Imagery Library for the Public: “NASA Image and Video Library allows users to search, discover and download a treasure trove of more than 140,000 NASA images, videos and audio files from across the agency’s many missions in aeronautics, astrophysics, Earth science, human spaceflight, and more. Users now can embed content in their own sites and choose from multiple resolutions to download.”
Astronaut’s Brother Recalls A Man Who Dreamed Big: The fascinating story of Ronald McNair, one of the astronauts killed in Challenger explosion.
The Sun’s Magnetic Field is about to Flip: “Something big is about [2013] to happen on the sun. According to measurements from NASA-supported observatories, the sun’s vast magnetic field is about to flip. ‘It looks like we’re no more than 3 to 4 months away from a complete field reversal,’ says solar physicist Todd Hoeksema of Stanford University. ‘This change will have ripple effects throughout the solar system.’
Why Charon has a red cap: Pluto and its moon share a bit of atmosphere.
The Parker Solar Probe Captures Surprising Images of Venus Nightside: ‘A visible glow from our sister planet’s nightside sheds new light on a 300-year-old observing enigma dubbed the “ashen light.”’
Satellite Licensing: FCC Should Reexamine Its Environmental Review Process for Large Constellations of Satellites: The Starlink swarm, which has interfered with astronomical observations with impunity, may finally be subject to environmental review.
Linux for Astronomers: Distro Astro: “This distribution bundles together astronomy software to help users with tasks like running observatories or planetariums, doing professional research or outreach.”
The sky will literally be the limit at new Mayland planetarium this spring: “Construction is underway on a new planetarium located at the Mayland Community College’s Bare Earth to Sky Park in Yancey County and will open to the public spring of 2021.” The location has international dark sky certification.
Postal Service Honors NASA Planetary Science: These 2016 stamps are gorgeous.
Nebulosity is now free and open-source: The capture and processing application for astronomy photography is now developed on Github. For Windows and macOS only.
Meet the largest science project in US government history—the James Webb Telescope: My article introducing the infrared telescope that was to be launched in 2018.
Confirmed: Salvaged F-1 Engine is from Apollo 11 Rocket: The salvage feat was performed by Amazon founder Jeff Bezos’ company Bezos Expeditions.
Moon Phase and Libration, 2018: Explanation and superb video of the appearance of the Moon from Earth during every moment of 2018, including tilt angle and libration.
First Hubble Views of Comet ISON: An image was captured when the comet was about as far away from the Sun as Jupiter.
Cornell postdoc detects possible exoplanet radio emission: “By monitoring the cosmos with a radio telescope array, an international team of scientists has detected radio bursts emanating from the constellation Boötes – that could be the first radio emission collected from a planet beyond our solar system.”
LIGO mirrors have been cooled to near their quantum ground state: “LIGO is designed to detect gravitational waves, but it is also proving to be a fantastic laboratory for pushing the limits of quantum physics.”
The Rings and Moons of Uranus: “captured almost exactly edge-on to Earth.”
Is the Solar System Stable?: A good summary of recent computational results.
Meteorite Phosphorus Aided Life on Early Earth: “New research shows that a key element for life on Earth was delivered to our planet on meteorites.”
You can see the Milky Way Galaxy from Earth with the naked eye: A lovely site dedicated to views of our galaxy from Earth.
Gorgeous Image of Saturn by Cassini: A mosaic of images taken by the Cassini spacecraft in the shadow of Saturn show the Earth and other planets in the background, as well as interesting ring and moon detail.
NASA Television to Air Space Station Cargo Ship Launch, Docking: “NASA will provide live coverage on NASA Television […] of the launch and docking of a Russian cargo spacecraft to the International Space Station beginning at 11:15 p.m. EST Sunday, Feb. 14. […] Following a two-day journey, the spacecraft will automatically link up to the station’s Pirs docking compartment at 1:20 a.m. Wednesday, Feb. 17.”
Kepler Finds Large Planet: NASA’s partially disabled Kepler spacecraft has discovered a large, Neptune-like planet 180 lightyears away.
Feeding Galaxy Caught in Distant Searchlight: “Astronomers using ESO’s Very Large Telescope have spotted a distant galaxy hungrily snacking on nearby gas.[…]This is the best direct observational evidence so far supporting the theory that galaxies pull in and devour nearby material in order to grow and form stars.”
Alien star system buzzed the Sun: 70,000 years ago a dwarf star passed through the Oort cloud.
NASA’s Webb Takes Its First-Ever Direct Image of Distant World: The James Webb Space Telescope has captured direct infrared images of exoplanet HIP 65426 b, first discovered by the VLT.
As Earth spins faster, Meta joins fight against leap seconds: Facebook is whining about having to handle time correctly.
Total lunar eclipse May 15-16, 2022: In a few days most of the Western hemisphere will be treated to a total supermoon eclipse.
How NASA Designed a Helicopter That Could Fly Autonomously on Mars: “This the first time we’ll be flying Linux on Mars. […] The software framework that we’re using is one that we developed at JPL for cubesats and instruments, and we open-sourced it a few years ago. So, you can get the software framework that’s flying on the Mars helicopter, and use it on your own project.”
“If you seek his memorial, look about you”: My note on Christopher Wren’s 383rd Birthday.
Webb inspects the heart of the Phantom Galaxy: A combined image from the James Webb Space Telescope and the Hubble: “New images of the spectacular Phantom Galaxy, M74, showcase the power of space observatories working together in multiple wavelengths.”
The Control and Use of Libration-Point Satellites: Orbits and stationkeeping around Lagrange points.
Solar P-P Neutrinos Detected: Their long-sought detection provides strong evidence that most of the Sun’s energy output is the result of proton-proton fusion.
Parallel Supercomputing for Astronomy: “The Celeste research team spent three years developing and testing a new parallel computing method that was used to process the Sloan Digital Sky Survey dataset and produce the most accurate catalog of 188 million astronomical objects in just 14.6 minutes with state-of-the-art point and uncertainty estimates.”
Enduring Mystery of Moon’s Toxic Dust Solved from Apollo Findings: Measurements of dust accumulation on instruments left in place during the first Moon landings reveal a rate of buildup of 1mm/1000 years, faster than geologic predictions.
Comet ISON: 12 cool facts.: Much better than the run of the mill ISON article.
New Galaxy Most Distant Yet Discovered: Found by the Hubble, we observe it as it was 700 million years after the Big Bang, producing stars at a rapid pace. It’s called z8_GND_5296.
Nasa Successfully Tests 3D-Printed Rocket Component: “Additive printing could lead to cheaper and quicker production of rockets”.
Solar Wind Triggers Lightning on Earth: The connection between space weather and actual weather just got stronger.
Shocked Astronomers Discover Strange New Type of Space Object: “It’s something that no astronomer has ever seen before, according to NASA: An asteroid with six comet-like tails that isn’t moving like a comet and it’s not made of ice. It’s just hanging up there, rotating like a crazy space spider.”
Soviet Lander Spotted by Mars Orbiter: The Soviet Mars 3 lander mysteriously fell silent after 20 seconds of transmission. That was in 1971; now [2013], NASA’s Mars Reconnaisance Orbiter has spotted it.
Amesbury Rock Came From Soviet Spacecraft: “Phil Green knew he’d found something unusual when he pulled the strange green rock out of the Merrimack River six years ago, but it wasn’t until recently that he found out his discovery was truly out of this world.”
Zoomable Moon Mosaic: Explore the moon from your computer courtesy “AstroMike247”
Is Energy Conserved When Photons Redshift In Our Expanding Universe?: By Ethan Siegel.
New Kind of Variable Star Discovered: Due to extremely accurate observations by the European Southern Observatory
The Partial Solar Eclipse of October 23, 2014: Enjoy my brief note on the Arlington Planetarium website.
How to get a photograph of the five planets: The trick is to know where to look, and when.
Rare Exoplanet Found in Cluster: “Three new exoplanets have been discovered inside a star cluster, which is a rare find as only a handful of such exoplanets are known to exist. However, one of the three new finds is even more remarkable — it orbits a star that appears to be ‘an almost perfect solar twin.’”
How Many Planets are in the Solar System?: And why Pluto is not one of them.
Forgotten Faces of Science: The Women Who Classified The Stars: In comic-book form.
Astrophysicists Tackle the Sun and One of Physics’ Biggest Unsolved Problems: Progress on the coronal heating problem.
TIC 168789840: A Sextuply-Eclipsing Sextuple Star System: “We report the discovery of a sextuply-eclipsing sextuple star system from TESS data, TIC 168789840, also known as TYC 7037-89-1, the first known sextuple system consisting of three eclipsing binaries.”
The Reason for the Darkness of the Night: A biography of Edgar Allan Poe which focusses on his engagement with science in America.
Life’s First Handshake: Chiral Molecule Detected in Interstellar Space
Neurodome: These scientists are crowdsourcing funding to create planetarium shows about the brain.
The Moon’s Changing Shape Seen From Orbit for the First Time: The tidal forces caused by the Earth’s gravity have a subtle effect on the shape of the Moon. This has now been measured by two NASA missions orbiting our natural satellite.
Infrared Star Trails Over Texas: A simple idea, but an impressive effect.
The Giant Spider of Mercury: Beautiful, detailed images of the planet closest to the Sun, courtesy of the MESSENGER spacecraft.
Mars Opportunity Rover Sets Off-World Driving Record: The rover just [2014] passed the 25-mile mark. Visit the link for a map of its travels.
One Mars Moon Eclipsing Another: A very cool movie constructed from Curiosity frames.
Voyager - The Interstellar Mission: Track the Voyager spacecraft as they leave the solar system. Notice that, at the moment, Voyager 2’s distance from the Sun is increasing while its distance from the Earth is decreasing! [2013]
CCC and the Fermi paradox: Did ancient civilizations send information to us through the Big Bang?
RS Puppis Puts on a Spectacular Light Show: A stunning Hubble image, and a time-lapse movie, showing the “light echo” from a variable star.
Upgraded Planetarium at Union Station in Kansas City: The old train station is now used as a cultural center and includes a science center. Its Arvin Gottlieb planetarium has just received a major upgrade, including a new 4K projector.
Rosetta scientists plan to eventually land the mothership: “That’s the right way to die.”
Scientists Discover how Soil is Formed on Small Asteroids: The mechanism is not the same as the common model for the formation of soil on the moon.
NASA’s Juno Mission Expands Into the Future: “The spacecraft, which has been gathering data on the gas giant since July 2016, will become an explorer of the full Jovian system – Jupiter and its rings and moons.” Juno “will now continue its investigation of the solar system’s largest planet through September 2025, or until the spacecraft’s end of life.”
There Was No Big Bang Singularity: Descriptions of the Universe’s origins as a singularity, although common even on the part of cosmologists, are out of date.
ALMA Discovers Comet Factory: Observations performed by the new Atacama Large Millimeter/submillimeter Array (ALMA) have verified the existence of a theoretically proposed “dust trap,” a region near a star where comets may be formed.
First Images from the James Webb Space Telescope: Five wonderful images on NASA’s website.
Arecibo radio telescope’s massive instrument platform has collapsed: In a blow to the international radio astronomy community, to Puerto Rico, and to the standing of U.S. Science, the iconic Arecibo observatory is gone.
Annie Jump Cannon’s Birthday: An extraordinary American astronomer.
PlanetOrbits.jl: Tools for solving and displaying Keplerian orbits for exoplanets.: “The primary use case is mapping Keplerian orbital elements into Cartesian coordinates at different times. A Plots.jl recipe is included for easily plotting orbits.”
Ten New Moons Discovered Around Jupiter: ‘The newly plotted moons of Jupiter include one “oddball” that orbits in the wrong direction and may be the remnant of a head-on collision.’
SKY GUY VIEWING ALERT!!!! COMET NEOWISE: Greg Redfern explains how to see and photograph the comet. There aren’t many like this in a lifetime, so take advantage of the opportunity.
Chandra :: Photo Album :: RX J1131-1231 :: March 5, 2014: Fantastic example of gravitational lensing.
Sun Sends More “Tsunami Waves” to Voyager 1: The probe is now confirmed to be in interstellar space (but has certainly not “left the solar system”).
Experiment with Planetary Systems: A game that challenges you to create a system that can last for 500 years.
Freefall achieved on LISA Pathfinder: An amazing project for the space-based observation of gravitational waves.
Edgar Allan Poe’s engagement with American science: A review of this biography of Poe by James Dinneen. Mentions that Poe correctly described the solution to Olber’s paradox, but, sadly, Dinneen does not understand the solution, and garbles it.
Arecibo telescope faces a catastrophic collapse, must be deconstructed: A sad day for radio astronomy and for science.
Astronaut Ice Cream Is a Lie: Sorry.
Lagrange Points: A very nice interactive page that teaches you about several topics in orbital dynamics.
Astronomers find “missing matter”, solving decades-long mystery of outer space: This is big news, and some interesting observational astronomy.
IERS Bulletins: Keep track of the Earth’s rotation with the help of the International Earth Rotation Service.
Accident delays launch of James Webb Space Telescope: A minor mishap during launch preparations has pushed back the planned launch date of the James Webb Space Telescope to at least December 22.
Identification of carbon dioxide in an exoplanet atmosphere: The James Webb Space Telescope has detected CO2 in the atmosphere of a gas giant exoplanet known as WASP-39b using transmission spectroscopy. This planet has about the same mass as Saturn but is about 50% larger.
Mercury Meteorite Might Not Be: “A strange green rock discovered in Morocco last year was hailed by the press as the first meteorite from Mercury. But scientists who’ve been puzzling over the stone ever since say the accumulating evidence may point in a different direction. Maybe, just maybe, they say, the 4.56-billion-year-old rock fell to Earth from the asteroid belt located between Mars and Jupiter.”
CME Headed Toward Planet Mercury: Yesterday morning the Sun sent a large coronal mass ejection in the general direction of Mercury at 500 miles per second.
Star’s black hole encounter puts Einstein’s theory of gravity to the test: An impressive confirmation of the General Theory of Relativity.
Lightest Exoplanet Imaged So Far?: “A team of astronomers using ESO’s Very Large Telescope has imaged a faint object moving near a bright star. With an estimated mass of four to five times that of Jupiter, it would be the least massive planet to be directly observed outside the Solar System. The discovery is an important contribution to our understanding of the formation and evolution of planetary systems.”
Is It a Planet? Astronomers Spy Promising Potential World around Alpha Centauri: “The candidate could be a ‘warm Neptune’ or a mirage. Either way, it signals the dawn of a revolution in astronomy”.
Flying Cross Country in a New Horizons Space Probe: Clever visualization.
ESO Telescope Sees Star Dance Around Supermassive Black Hole, Proves Einstein Right: The “dance” is the precession in the orbit, like the precession of Mercury’s orbit that was an early confirmation of Einstein’s theory of gravitation.
Black Hole Scientists Win Nobel Prize in Physics: “The story of the discovery of black holes demonstrates vividly how powerful pure mathematics can be in the quest to understand nature.”
The Surface of Mercury: NASA spacecraft have assembled a complete map of the surface of the mysterious planet, which is displayed in this stunning movie.
50th Anniversary of Planetary Exploration: Attractive scrolling timeline of planetary exploration missions.
Mars on Earth: The ESA has a model of Mars that is “used to put prototype planetary rovers through their paces. Officially known as the Automation & Planetary Robotics Lab, its nickname is the ‘Mars Yard’.” Follow the link for a picture of the Mars Yard in use.
The Most Amazing Map You’ll See Today: Brent Tully has mapped the universe out to a distance of 100 million light years.
ISU Planetarium Has a Birthday: Illinois State University’s Planetarium just turned 50.
Edgar Allan Poe’s Physical Cosmology: In Poe’s Eureka, he anticipated parts of modern cosmology, presenting, for example, the correct resolution of Olber’s paradox.
Planetariums — not just for kids: “Planetariums are not just for education, or even astronomy: they could display all sorts of data, if only scientists thought to use them”.
Spacecraft may have captured interstellar dust particles: The Stardust spacecraft has probably collected seven dust particles from beyond the solar system.
Voices from the Sky: The Friends of Arlington’s Planetarium are hosting a fun, online, music-based program about space science and history with Dr. Jim Thorne, Sunday, November 15th, 3pm EST.
Smartphone Photos From Orbit: The three smartphones[@NASAlaunches2Smartphones] that are currently [2013] in orbit are now taking pictures of the Earth.
60 Second Adventures in Astronomy: Fun little movies teaching astronomy concepts.
First Ever Comet Material Found on Earth: 28 million years ago a comet exploded over Egypt, leaving behind molten glass and microscopic diamonds.
USGS Releases First-Ever Comprehensive Geologic Map of the Moon: 
“Have you ever wondered what kind of rocks make up those bright and dark splotches on the moon? Well, the USGS has just released a new authoritative map to help explain the 4.5-billion-year-old history of our nearest neighbor in space.”
“Have you ever wondered what kind of rocks make up those bright and dark splotches on the moon? Well, the USGS has just released a new authoritative map to help explain the 4.5-billion-year-old history of our nearest neighbor in space.”
Elon Musk’s Starlink satellites hindering detection of near-Earth asteroids: “A new study has concluded that the sheer amount of Elon Musk’s Starlink satellites in orbit is causing streaks to appear on telescope imagery, obstructing the observation of asteroids.”
Space Germs: Interesting history of the efforts to avoid both infecting, and becoming infected by, microbial life on other worlds.
A Solar Windsock: Using a comet’s tail to measure the turbulence in the solar wind.
Out of Helium, Herschel Telescope Ends Mission: “Herschel has exceeded all expectations, providing us with an incredible treasure trove of data that that will keep astronomers busy for many years to come.” Visit the link for beautiful images provided by Herschel.
Critical Test of General Relativity: In amazing work using observations by the European Southern Observatory’s Very Large Telescope, Einstein’s theory of gravity was confirmed, while more recent, competing theories, devised to attempt reconciliation with quantum mechanics, failed.
Planar Choreographies: Although a general solution to the gravitational N-body problem is not known, there exist a handful of periodic solutions with equal masses. Here is a lovely visualization of some of these.
The leap second: Because our clocks are more accurate than the Earth: The surprising physics of the planet’s rotation: my article in Ars Technica.
Saturn’s Mysterious Hexagon Shows its True Colors: Stunning image from NASA’s Cassini orbiter.
Amazing Solar Flare: A strong solar flare on May 3 produced some unique images.
Gravitation
Putting Relativity to the Test: A useful popular brief summary of the major experimental confirmations of GR.
The Renewal of Einstein’s Theory of Relativity in the Post-War Era: After a period of intense interest following the eclipse expeditions, there was a deep lull in general concern with GR, followed by a revivial in the 1950s.
General relativity: 100 years of the most beautiful theory ever created: My article contains an overview of the theory, its authorship, and its experimental verifications.
Einstein Versus the Physical Review: The story of Einstein’s surprise that his article about gravitational waves was sent to a reviewer, and his withdrawal of his manuscript.
A Century Ago, Einstein’s Theory of Relativity Changed Everything: A breezy summary of the development of the theory and its impact.
Energy is Conserved in General Relativity: Undated manuscript claiming, with detailed examples, that the various claims of energy non-conservation in GR are fallacies. I believe the author is mistaken.
Belated Decision in the Hilbert-Einstein Priority Dispute: Hilbert did not beat Einstein to the Theory of General Relativity.
Observation of Gravitational Waves from a Binary Black Hole Merger: A historic day for science.
Einstein’s Spacetime: Good tutorial.
On the foundations of generalised relativity: An English translation of Einstein’s review article submitted March 1916.
The Wormhole Publicity Stunt: “The best way to understand the ‘physicists create wormholes in the lab’ nonsense of the past few days is as a publicity stunt”.
Energy Is Not Conserved: Popular and clear note on conservation of energy in general relativity.
Arch and scaffold: How Einstein found his field equations: “In his later years, Einstein often claimed that he had obtained the field equations of general relativity by choosing the mathematically most natural candidate. His writings during the period in which he developed general relativity tell a different story.”
On the Hypotheses Which Lie at the Bases of Geometry: The famous paper, posthumously published, wherein Reimann introduces curved space and speculates on its application to the real world. This version translated by W. K. Clifford.
An eerie quantum effect of magnetic fields also applies to gravity: The gravitaional Aharonov-Bohm effect.
Scientists use the Tokyo Skytree to test Einstein’s theory of general relativity: … by measuring the difference in the rate that time passes at the top and base of the tower.
How Einstein reinvented reality: Einstein and Hilbert race to produce the equations of General Relativity. Part of the Scientific American special issue: “100 Years of General Relativity”.
Noether’s first theorem and the energy-momentum tensor ambiguity problem: From the abstract: ‘Noether’s theorems are widely praised as some of the most beautiful and useful results in physics. However, if one reads the majority of standard texts and literature on the application of Noether’s first theorem to field theory, one immediately finds that the “canonical Noether energy-momentum tensor” derived from the 4-parameter translation of the Poincaré group does not correspond to what’s widely accepted as the “physical” energy-momentum tensor for central theories such as electrodynamics.’
Which falls faster—a feather or a hammer?: The equivalence of inertial and gravitational mass demonstrated on the Moon.
Empty out the drawer: Following Einstein’s path to General Relativity: Brief, engaging history of the development of GR. Mentions that Einstein called the drawer at the patent office where he stashed his physics work “his ‘Department of Theoretical Physics.’ Einstein’s Department had more revolutionary ideas than most actual departments.”
Of pots and holes: Einstein’s bumpy road to general relativity: Einstein’s early GR publications; his discovery of a special case of Noether’s Theorem several years before Noether discovered the general theorem.
Here’s the first person to spot those gravitational waves: Marco Drago saw the first gravitational wave on 14 September 2015.
More physics
Peacock Crests Are Vibration Sensors, Tuned to Shaking Tail-Feathers: Report of a beautiful piece of biophysics research.
Physics without determinism: Alternative interpretations of classical physics: “…we propose a model of classical indeterminism based on finite information quantities…”
Publicity Stunt Fallout: The ongoing train wreck of the false hype around the “wormhole in a lab”. Scientific misconduct, shameless hype, and dishonesty from physicists have gotten worse since the cold fusion scandal, not, as we might have hoped, better.
GitHub - JuliaDynamics/NonlinearDynamicsTextbook: coming soon: A repository for the book Nonlinear Dynamics.
One of quantum physics’ greatest paradoxes may have lost its leading explanation: An experiment rules out some models of gravity mediating wavefunction collapse.
The Big Bang: John C. Mather discusses the concept of the Big Bang in the popular imagination.
Newtonian physics IS deterministic (sorry Norton): Brilliant discussion of Norton’s dome thought experiment. Davies’ conclusion is that it does not demonstrate a failure of determinism.
Fusion reactors: Not what they’re cracked up to be: The waste disposal, proliferation, and efficiency problems of D-D and D-T fusion reactors. A pessimistic view which I think is accurate.
Poisson’s Equation is the Most Powerful Tool not yet in your Toolbox: If you aren’t used to staring at math, Poisson’s equation looks a little intimidating:
Why Julia is the most suitable language for science: Engaging presentation by the maintainer of the Julia dynamical systems package.
What’s Wrong with these Equations?: How to write papers that contain equations: principles of mathematical prose.
Emmy Noether: An Announcement on her Birthday: On Emmy Noether’s 140th birthday I am happy to announce my forthcoming book about this history-making mathematician and her invention of modern physics with her eponymous theorem.
The future of solar power technology is bright: My article in Ars Technica on recent advances in photovoltaic technology and research.
Lorentz Transformations with a Mechanical Time-Globe: A very clear and intuitive geometrical approach to Lorentz transformations, good for beginners and experts alike.
The Country Gentleman of Physics: “Julian Barbour’s ideas about time and the universe have always roamed free of academia.”
Physics and Philosophy:: An interesting book by Heisenberg.
Negative Probabilities: Nice discussion of various approaches to negative probability. Links to a replica of Feynman’s paper on negative probabilities. I’m pretty sure that this is by Baez and that it is from 2013, although, weirdly, neither author nor date are listed on the page.
Exotic fifth state of matter made on the International Space Station: The exotic state of matter is a Bose-Einstein condensate. It is hoped to exist for a longer time than can be achieved in terrestrial laboratories.
An Introduction to Pluto: Pluto is a new computational notebook for the Julia programming language.
The accelerating adoption of Julia: The programming language Julia and its importance to science.
Alexander piano- the longest piano in the world: Fascinating project to make a longer piano. This should reduce the linear density of the lower strings, which should reduce their inharmonicity, and make it possible to tune the piano more accurately. Has videos of performances.
Why String Theory Is Still Not Even Wrong: An interview with Peter Woit, who has some interesting thoughts on the health of theoretical physics and mathematics. Woit runs the website Not Even Wrong, which has a permanent place in my feed reader.
foreXiv: Jess Riedel’s website. Fascinating articles about physics, mathematics, and more.
Matter-antimatter asymmetry confirmed in baryons: Preliminary results from the LHCb may explain why our universe is made from matter.
Why Stephen Wolfram’s research program is a dead end: Matt Ranger: “Today, I’ll explain why I think this entire research programme is a dead end, and largely a waste of time.”
Symmetry and the Standard Model: From the publisher: “the first volume of a series intended to teach math in a way that is catered to physicists. Following a brief review of classical physics at the undergraduate level and a preview of particle physics from an experimentalist’s perspective, the text systematically lays the mathematical groundwork for an algebraic understanding of the Standard Model of Particle Physics.”
What is Quantum Field Theory, and What Did We Think It Is?: Contains both a recounting of the history and speculations about future theories.
The ideal gas law: This seems obvious. Why does it also seem unfamiliar?
Physics from Symmetry: An interesting textbook “that derives the fundamental theories of physics from symmetry.” The author’s story and more about the book at http://physicsfromsymmetry.com/.
I am writing a Julia book: The preliminary title is Practical Julia; it will be published by No Starch Press.
The Lazy Universe: An Introduction to the Principle of Least Action: Inspired by Lanczos’ classic text.
Multipole Methods for the Masses: Excellent introduction to the fast multipole method, with illuminating animations. The author, Andy Jones, applies the algorithm, commonly used in physics for such things as calculating the gravitational interactions among a bunch of masses, to the spread of an infection.
Feynman Lectures on the Strong Interactions: “Available at the arXiv […] is something quite fascinating. Jim Cline has posted course notes from Feynman’s last course, given in 1987-88 on QCD. There are also some audio files of a few of the lectures available here. The course was interrupted by Feynman’s final illness”.
Meshes.jl: Computational geometry and meshing algorithms in Julia
Is Energy Conserved in General Relativity?: A good rundown of the situation in general, using accessbible mathematics.
PlutoUI Demonstration: A live demonstration of PlutoUI controls, served with the PlutoSliderServer.
Symmetry and emergence: Clear, technical discussion of gauge and other symmetries in particle physics, and their histories, by Edward Witten.
The Philosophy and Physics of Noether’s Theorems: A Centenary Volume: A 55 “new edition” of conference papers from 2018. Appears to have some good content by good authors.
A new release for GNU Octave: My article about the open source environment for numerical computing appeared today in LWN. This is a free link for my readers. Please consider subscribing to this fine publication while you’re there.
Yesterday’s Hype: “The field that was once one of the greatest examples of the power of the human mind and the strength of the scientific method has become something very different and quite dangerous: all-too-visible ammunition for those who want to make the case that scientists are as deluded and tribalistic as anyone else, so not to be trusted.”
Changing Physics education with Julia: Interactivity in physics education; why Julia is an ideal language for physics education; applied to teaching dynamical systems and the DynamicalSystems library, of which the author is the maintainer, and his textbook.
Thermodynamic Entropy as a Noether Invariant: “We study a classical many-particle system with an external control represented by a time-dependent extensive parameter in a Lagrangian. We show that thermodynamic entropy of the system is uniquely characterized as the Noether invariant associated with a symmetry for an infinitesimal nonuniform time translation t → t + ηℏβ , where η is a small parameter, ℏ is the Planck constant, β is the inverse temperature that depends on the energy and control parameter, and trajectories in the phase space are restricted to those consistent with quasistatic processes in thermodynamics.”
Subtle Is the Lord: The Science and the Life of Albert Einstein: A detailed scientific biography.
JuliaAstroSim/AstroNbodySim.jl: “Unitful and differentiable gravitational N-body simulation code in Julia”.
Boltzmann brain: Covers a lot of very interesting ground.
Physics-informed neural networks (PINNs) solver on Julia.: “My project aim was to design a general solver for different types of PDEs using a deep learning approach base on the Physics-informed neural networks(PINNs) algorithm as part of NeuralPDE library using the ModelingToolkit PDE interface for the automated solution.”
Particle Simulations with Julia: Excellent tutorial and demonstration available as a web page and as a Pluto notebook. Contains fascinating animations of error propagation in a running simulation.
3 Simple Reasons Why Wolfram’s New “Fundamental Theory” Is Not Yet Science: Read this lucid article before you invest time in delving into Wolfram’s latest obsession. And remember that his “New Kind of Science” is a decade old, had all the problems identified by Siegel, and led nowhere.
The Sad Story of Heisenberg’s Doctoral Oral Exam: Summary of Heisenberg’s work on turbulence and his difficult oral exam for his doctorate.
Steven Weinberg (1933-2021): a personal view: Scott Aaronson’s reminiscences of his long personal acquaintance with the great physicist, who died on July 23rd.
Experimental realization of Feynman’s ratchet: A beautiful experiment. From the New Journal of Physics, so it’s free to read online.
Aliasing: Lecture notes that contain a very clear discussion of the problems of undersampling.
New study cracks the case of why food sticks to center of nonstick pans: An interesting effect of surface tension gradients.
Nonlinear Dynamics: “A Concise Introduction Interlaced with Code”.
Genius in Exile: The Rise and Fall of Göttingen’s Mathematical Institute: Interesting historical data about Noether, Hilbert, Klein, and others. With original photographs.
The Mystery of Spin: More nonsense from Scientific American, this time about spin in quantum mechanics.
Biologists Home In on Turing Patterns: “For the work that led to his 1952 paper, Turing wanted to understand the underlying mechanism that produces natural patterns. He proposed that patterns such as spots form as a result of the interactions between two chemicals”.
Noether’s Theorem in a Nutshell: John Baez’s neat demonstration of a special case of Noether’s Theorem.
Cameras and Lenses: Wonderful interactive tutorial about optics, sensors, and the physical and technological process of photography. Well done and well written.
The Feynman Lectures on Physics Audio Collection: “These are the tape recordings of Richard Feynman’s 1961-64 Caltech Introductory Physics lectures, which form the basis of the book The Feynman Lectures on Physics. The original recordings were made on 1/4’’ reel-to-reel tapes, now preserved in Caltech’s Archive. In 2010 the entire collection was digitized by media preservationist George Blood, at a sampling rate of 96 kHz with 24-bit samples, PCM-encoded in tiff files about 2 GB each in size. For this online publication we are serving more compact versions, downsampled to 48 kHz with 16-bit samples, reencoded as AAC-HE (mp4) and Opus (ogg) at a data rate of 48 kbps.”
Constructor Theory: “Constructor Theory is a new approach to formulating fundamental laws in physics. Instead of describing the world in terms of trajectories, initial conditions and dynamical laws, in constructor theory laws are about which physical transformations are possible and which are impossible, and why. This powerful switch has the potential to bring all sorts of interesting fields, currently regarded as inherently approximative, into fundamental physics. These include the theories of information, knowledge, thermodynamics, and life.”
Exclusive: Laser-fusion facility heads back to the drawing board: The failure to replicate the alleged ignition of a fusion target one year ago suggests that the event was an accident, in the sense that we still don’t understand how to create the conditions leading to ignition in an indirect-drive laser experiment.
Hiro’s Soliloquy: Animations made with gnuplot, illustrating all kinds of things from mathematics and physics. A wonderful site, whether your interest is gnuplot techniques, computer animation, or educational visualizations.
Kid tries to make breeder reactor
Heavens-Above: This page helps you to track artificial sattelites.
