Featured Science Threads - Page 6

Below is a curated list of some of the most interesting and highest quality science news and discussions on Physics Forums. News and discussions are added weekly. Also check the Hot Threads page for discussions choosen algorithmically.
Featured Thread: Feynman's Notes for The Feynman Lectures on Physics
611 pages of notes Richard Feynman made in 1961-64 to plan and prepare lectures for Caltech's two-year introductory physics course, later known as The Feynman Lectures on Physics, have been posted in deep-zoomable format at The Feynman Lecture Website.
Featured Thread: Wolfram releases the free Wolfram Engine for Developers
Wolfram made what I would call a gigantic move: they released the Wolfram Engine for Developers - for zero cost! The idea of the Engine is primarily that you can call and run Wolfram Language commands from lots of different sources. I predict this will greatly enhance usage of the Wolfram Language and Mathematica, as it has always been so amazingly expensive, particularly for commercial users...
Featured Thread: NASA aluminum fraud scheme probe
"When the launch of NASA's Orbiting Carbon Observatory and Glory missions failed in 2009 and 2011, the agency said it was because their launch vehicle malfunctioned. The clamshell structure (called fairing) encapsulating the satellites as they traveled aboard Orbital ATK's Taurus XL rocket failed to separate on command. Now, a NASA Launch Services Program (LSP) investigation has revealed that the malfunction was caused by faulty aluminum materials."
Featured Thread: Mathematicians Revive Abandoned Approach to the Riemann Hypothesis
Many ways to approach the Riemann Hypothesis have been proposed during the past 150 years, but none of them have led to conquering the most famous open problem in mathematics. A new paper in the Proceedings of the National Academy of Sciences (PNAS) suggests that one of these old approaches is more practical than previously realized...
Featured Thread: Is this a horribly ambiguous A Level Physics question?
I have an OCR A level "physics A" student, and we're working through past papers. Time and time again, we've come across questions which are astonishingly ambiguous and answer schemes which are in my view, astonishingly picky or just plane bizarre. I've taken some of these to OCR but got no progress...
Featured Thread: Synthesis of a re-designed E. coli genome
All organism on earth use a genetic code consisting of 64 three-letter codons to encode the 20 amino acids found in proteins. Scientists in the field of synthetic biology have long sought to expand the genetic code to allow encoding of more than 20 natural amino acids found in most organisms...
Featured Thread: New paper about online harassment and participation in science threads
"Theories of human behavior suggest that people’s decisions to join a group and their subsequent behavior are influenced by perceptions of what is socially normative. In online discussions, where unruly, harassing behavior is common, displaying community rules could reduce concerns about harassment..."
Featured Thread: Satellite internet constellations (first Starlink launch May 15-16)
Fast, reliable high-bandwidth internet everywhere in the world - that is the promise of the upcoming satellite constellations. To get a good bandwidth with many customers this needs many satellites; to get a good latency they have to be in low Earth orbit (LEO)...
Featured Thread: The Graser as an idea
I came across a reputedly true bit of Cold War spy stuff in a book "Farewell: the greatest spy story of the twentieth century" by Sergei Kostin. It's about a KGB defector, Colonel Vladmir Vetrov who blew the structure of the KGB to the French. As a result, the US sowed the seeds of a spoof about US development of a Gamma Ray Laser to the Russians. He's mentioned in Wikipedia so it's not just fiction. What could be the basis which made them think that Nuclear transitions could be used in a laser type reaction?
Featured Thread: Bacteriophage treats antibiotic-resistant bacterial infection
Bacteriophages, viruses that infect bacteria, have long interested scientists as a potential therapy for bacterial infections. Today, in the journal Nature Medicine, scientists report the first clinical use of genetically-engineered bacteriophages to treat an antibiotic-resistant bacterial infection nodules...
Featured Thread: Physical Significance of the Laplace Transform
I have used Laplace transform during my EE studies to solve differential equations and in control system analysis, but we were taught that as a tool kit to make the math easier. The physical meaning was never explained. I know basic time and frequency domain concepts (thanks to Fourier series), but I am having a hard time understanding the physical reality of the Laplace transform...
Featured Thread: Some comments on the 2019 Planetary Defense Conference
The 6th Annual International Academy of Astronautics Conference on Planetary Defense ended this past Friday. I watched about half of the presentations. I have little astronomy background but was interested in what was being done about NEO detection, characterization effects and mitigation of potential hazardous asteroids...
Featured Thread: Math Challenge - May 2019
Some of the question will probably require to look up or ask about some definitions or formulas on the internet, which shouldn't be a problem nowadays. It is part of our new world. They might look harder than they are. Topics include: Chevalley Eilenberg Complexes, Buildings, Measure Theory, Linear Operator, Affine Variety and more!
Featured Thread: Universe younger and faster than thought
"Riess observed 70 Cepheid stars — stars that pulse at a well-observed rate — calculated their distance and rate, and then compared them with a certain type of supernovae that are used as measuring sticks. It took about two years for the Hubble telescope to make these measurements, but eventually Riess calculated an expansion rate of 74." - APnews | Thoughts on this finding? Does it really require new physics to explain?
Featured Thread: New Deccan Trap turns out to be downed power line
"The local residents took the substance to be volcanic lava, which, however, later turned out to be rocks. The rocks had melted after coming in contact with a high tension power cable of the state electricity distribution company that had fallen to the ground."
Featured Thread: Anomaly during Crew Dragon test
While SpaceX tested the engines of a Crew Dragon capsule something went wrong. A lot of smoke was released, no one was harmed. Unfortunately that is the end of official statements already. It was planned to do an in-flight abort test of Crew Dragon in June or July and a crewed flight (first crewed US spaceflight since the retirement of the Space Shuttle) not earlier than August, but this timeline is now obsolete....
Featured Thread: If Maxwell's equations are linear...
In the course of my career, (in the years 1986-1990), on two occasions I discussed with two very intelligent physics PhD.'s a problem that surfaces in regards to interference patterns. The first PhD. knew very little Optics and (around the year 1986) was asking me, "how can you possibly get an interference pattern? Are you telling me...
Featured Thread: Disappearing lakes on Titan - seasonal cycles
Earth and Titan are the only objects in the Solar System with stable liquids on its surface. Earth has water oceans, lakes, rivers and rain, Titan has methane/ethane oceans, lakes, rivers and rain. Earth has seasons, and so does Titan. They are just much longer as Saturn's orbital period is 29.5 years...
Featured Thread: Riddles and Puzzles: Extend the following to a valid equation
Extend the following to a valid equation, using only mathematical symbols!

Example: ##1\; 2\; 3 \;=\; 1 \longrightarrow - (1 \cdot 2) + 3 = 1##. Solutions are of course not unique.
Featured Thread: Long live Multiplication
A new way to multiply one that only a computer could love if only it had enough bits to do it...
Featured Thread: Event Horizon Telescope Results Released Today (April 10, 2019)
*Breaking Now* Media Advisory: Press Conference on First Result from the Event Horizon Telescope
April 10, 15:00 CEST (13:00 UTC. In 8 days and 13 hours)
Livestream links are on that website.
Featured Thread: Dark Matter is real
Two recent studies have found galaxies with little or no apparent dark matter, indicating modifying gravity can't work. Read more inside...
Featured Thread: Late Water Flow on Mars
Perhaps this thread would be better located in the Earth forum (where hydrologists might more likely see it), but it is Mars not Earth. I recently read about a study on riverbeds (size, catchment size, meandering) on Mars that claimed large water flows in some riverbeds "late" in Mars history (post-dense atmosphere)...
Featured Thread: Dinosaur Tomb Raider
Robert A. DePalma, a 37 year old curator of paleontology at the Palm Beach Museum of Natural History, in Florida, as well as a graduate student at the University of Kansas discovered and started mining a huge fossil deposit found in North Dakota...
Featured Thread: Belle II starts collisions in 2019
No LHC this year (long shutdown), but Belle II at SuperKEKB started taking data a few days ago. Here is a press release. Belle II started last year with a low luminosity (low collision rate) - still good for detector calibration and so on. The goal for this year is to increase the luminosity and eventually collect enough data for interesting physics analyses.
Featured Thread: Interesting Timelines of Computer History
I found these timelines on the Computer History Museum which are quite interesting to checkout... For me, it brought back memories of machines long past. They even mentioned the construction of my robot persona for the Forbidden Planet movie. Those were the days!
Featured Thread: On the Planck Blackbody Function
On the fraction of radiated power that lies to the left of the peak of the Planck blackbody function of spectral intensity vs. wavelength...
Featured Thread: Example of a technology that was long underestimated?
I'm wondering how and in what time frame new technologies emerged and found application in the history of science. I could make several examples of those which suddenly and unexpectedly changed the world, but not the vice-versa. In particular, I'm wondering which didn't find an application or remained undeveloped for a long time (say at least a couple of decades) but then found its way to success?
Featured Thread: Tips to keep your house cool in summer
There are a lot of strategies that can help to avoid it being total hell indoors in this hot weather. We've had many threads about Air Con and Air Coolers but these things are not widely used in the UK and it's too late to contemplate AC because they've all been sold!! There are other ways, though.
Featured Thread: Boeing 737 Max MCAS System
Is it not a huge error in the flight laws and the MCAS software to execute a nose down maneuver at any altitude? Should the system not have a rule to prohibit such a maneuver below a minimum altitude threshold?
Featured Thread: March 14 coming (Einstein, Hawking, Pi-Day)
At least three items around March 14: new documents from Einstein, a coin commemorating Hawking, Pi-Day, Albert Einstein was born on March 14, 1879. Among various documents of Einstein (acquired by Hebrew University to update their collection of his documents in time to celebrate 140 years since Einstein's birth), there was a page that had been missing from his attempt at a unified field theory...
Featured Thread: What if we had commercial fusion power?
Let's assume that the technical problems were solved and we had a working design for a fusion reactor with similar economics to existing fission reactors. Then my question is, is there any reason to believe that there would be greater public acceptance of this technology than there is of fission technology?
Featured Thread: Bad astronomy = bad statistics?
Phil Plait, creator of Bad Astronomy, has an article on Planet 9. Overall, it's pretty good, but there was one part that got my hackles up: "Mike Brown and Konstantin Batygin (who have been the leading force behind the idea of Planet Nine being out there) have published a paper showing that the alignments are not from any observation bias, and in fact the chance of the alignments..."
Featured Thread: Math Challenge - March 2019
1.) Using the notion of double integrals prove that $$B(m,n) = \frac{\Gamma (m) \Gamma (n)}{\Gamma (m + n)}\; \;(m \gt 0\,,\, n\gt 0)$$ where ##B## and ##\Gamma## are the Beta and Gamma functions respectively.
Featured Thread: Measuring off target mutations during CRISPR gene editing
CRISPR gene editing is a newly developed tool that allows researchers to easily make changes to an organism's DNA. There is much interest in using this technology in clinical applications, but there have been major concerns surrounding the safety of the technology, including whether the gene editing approach leads to unintended, off-target mutations elsewhere in the genome...
Featured Thread: Periodic Table Revisions
The Periodic Table is 150 years old sometime this year (I could not find its exact birthday).
Good job Mendeleev! Here is a Science magazine news info graphic on how it has changed over time (before and after Mendeleev). The graphic came out a while ago, but was not working then. Now it does.
Featured Thread: Compiling LaTeX Pet Peeves
I am writing a document for my students about the proper use of ##\LaTeX##. There are some things that always scorch my eyes, like improper italics [##sin(x)##] or incorrect typography of units [##128kg##]. I wonder those of you who are sticklers for typography have other pet peeves of the kind.
Featured Thread: What's the meaning of "random" in Mathematics?
Physics, Economists, Biologists, Astronomers and my brother all love the word "Random", as that allows allows them to get out of clockwork processes and allow for variations due to unknowns or whatever else. But, how does a Mathematician reconcile itself with the idea of random? There's no axiom for "choice", no function for "random value", no explanation of what "chance" is...
Featured Thread: Is YouTube Responsible For Creating Flat-Earth Believers?
A researcher from Texas Tech University presented her findings at the recent AAAS Meeting, and found that most people started to believe in the Flat Earth idea after viewing YouTube videos! Interviews with 30 attendees revealed a pattern in the stories people told about how they came to be convinced that the Earth was not a large round rock spinning through space but a large flat disc doing much the same thing...
Featured Thread: Researchers double the size of the DNA alphabet
Published this week in the journal Science, researchers report that they have devised a eight letter alphabet for DNA and RNA: The work builds off of previous work, which had expanded the genetic alphabet to six letters. The researchers call their eight-lettered nucleic acids "hachimoji," Japanese for eight letters. The four new letters seem to function just as well as the original four DNA letters, and the researchers...
Featured Thread: A physics perspective needed on how the Mitochondria machine works
Mitochondria are the energy producing organelles in the body which make energy by adding a chemical bond converting a di-phosphate ADP to ATP (tri-phosphate). The problem is the precise machinery about how this works is not entirely known. The oxidative phosphorylation system which is composed of 5 large protein complexes known as complexes I-V are responsible for making ATP which is shown in any high school textbook...
Featured Thread: General Relativity as a Challenge for Physics Education
This week I am at "General Relativity as a Challenge for Physics Education". Here are a few slides from Bernard Schutz Monday morning talk "Intuition in physics: What is a physicist anyway?"
Funny... he says that, recently, he has been using Hartle's textbook for his undergraduate class
because he felt his audience needed a "Physics-first" text rather than a "Math-first" text like his own...
Featured Thread: Math Challenge - February 2019
Time for our new winter challenge! This time our challenge has also two Computer Science related questions and a separate section with five High School math problems. Enjoy!
Featured Thread: Are no chemical elements truly stable?
I recently learned that Bismuth is actually radioactive with its longest lived isotope having a half-life of about 20 quintillion years. As a very basic question, what determines whether an element/isotope will be radioactive? Is there something special about certain isotopes that makes them stable? Are no elements truly stable, but just have half-lives too long to accurately measure?
Featured Thread: Who would win a perfect game of chess?
While chess hasn't been solved yet, other games have. For example, I know that in in some games, like connect four, if both players play perfectly, the player who goes first will always win. On the other hand, some games, like tic tac toe, a perfect game will result in a draw; in fact, I recently found out that this is true for checkers as well. What I'm wondering though, is if it's possible to predict which scenario a perfect game...
Featured Thread: Anti-Cancer Virus Treatment
This Science News article reports that researchers using a modified adenovirus (that normally causes mild respiratory infections) that only grows in retinoblastoma tumor cells, researchers were able to improve upon (but apparently not cure) the results of cancer drugs in rabbits and mice. Trials in children (where most cases occur) are beginning...
Featured Thread: Astro Image Stacking (optimize DSS image stacking and post processing)
I created this thread because every online resource I have examined to date has been largely worthless- either totally over-engineered complexity or superficial garbage (can you tell I am irritated?). The problem is simple: optimize DSS image stacking and post processing based on quantitative image data. The essential metrics are 1) signal-to-noise ratio and 2) dynamic range...
Featured Thread: Summary of Frauchiger-Renner
Since there seems to be a bit of confusion on this, I thought I'd just post a brief summary. Just some terminology: Superobserver: Somebody who measures another observer, i.e capable of resolving the complete quantum state of another observer and performing measurements on it. Hyperobserver: Like a Superobserver, but also capable of using a unitary evolution to reverse...
Featured Thread: Best Engineering in the Past 100 years
We commonly see lists of "best science" both here on PF and elsewhere. I think it is time for a little friendly rivalry from the engineering side. I arbitrarily chose 100 years as the period. The wheel and Roman aqueducts were great engineering but not much fun for us to talk about because we don't know much about the engineers...
Featured Thread: Math Challenge - January
Rules: a) In order for a solution to count, a full derivation or proof must be given. Answers with no proof will be ignored. Solutions will be posted around 15th of the following month. b) It is fine to use nontrivial results without proof as long as you cite them and as long as it is "common knowledge to all mathematicians". Whether the latter is satisfied will be decided on a case-by-case basis...

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