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relativator

Relativator (Circular Slide-Rule) – Simulated with Desmos

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The Relativator (revisited) This is an update of my 2006 post (reconstructed in 2014) Relativator: The circular slide-rule for physicists. This is a circular slide-rule for doing relativistic calculations for elementary particle physics that I learned about from – an article by Elizabeth Wade ( “Artifact: Relativator”, Symmetry (FNAL/SLAC), 01/01/06, https://www.symmetrymagazine.org/article/december-2005january-2006/artifact-relativator  https://www.symmetrymagazine.org/sites/default/files/legacy/pdfs/200512/artifact_relativator.pdf ), which is…

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22 Comments
What causes cancer? For the most part, cancer is a disease that arises from mutations in the body that accumulate over time.  These mutations knock out…
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Understanding Buoyancy: The Limits of Archimedes

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18 Comments
It’s a principle as old as science itself, and remarkably, remains essentially unchanged in the light of revolution after revolution in our understanding…
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Radius of the Observable Universe in Light-years Is Greater than Its Age

The radius of the observable universe is about 46 billion light-years, which is considerably greater than its age of about 14 billion years. The radius…
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How to Build a Definition for Heat

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13 Comments
One of the most frustrating misconceptions in Thermodynamics centers on the actual definition of heat. Many science/engineering students often refer to…
ODE2

How to Solve Nonhomogeneous Linear ODEs using Annihilators

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3 Comments
My previous Insights article, Solving Homogeneous Linear ODEs using Annihilators, discussed several examples of homogeneous differential equations, equations…
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What Is the Steady-state Model and Why It’s No Longer Viable

Introduction to the Steady State Model Back in 2011, I wrote a FAQ entry for Physics Forums on the steady state model and why it is no longer viable.…
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Solving Homogeneous Linear ODEs using Annihilators

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8 Comments
In this Insights article we'll look at a limited class of ordinary differential equations -- homogeneous linear ODES with constant coefficients. Although…
physicsturnedmath

Trials and Tribulations of a Physicist who Became a Math Geek

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4 Comments
How did I go from the brink of changing my major from physics to ceramics (no more math) to the Math faculty of the Air Force Academy? How did I go from…
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Learn About Matrix Representations of Linear Transformations

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19 Comments
Let X and Y be finite-dimensional vector spaces. Let ##T:X\to Y## be a linear transformation. Let ##A=(e_1,\dots,e_n)## and ##B=(f_1,\dots,f_m)## be ordered…
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Why Don’t Electrons Crash into the Nucleus in Atoms?

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12 Comments
Atoms and Coulomb Forces If one describes atoms using only the Coulomb forces, the electron and the nucleus will attract each other and no stable atoms…
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How Does an Airplane Wing Work? A Primer on Lift

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Many people ask how an airplane wing works, and several answers are commonly given. You might have even seen vigorous arguments between proponents…
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Is the Universe a Black Hole?

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7 Comments
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Simple Python Debugging with Pdb: Part 2

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2 Comments
This Insight article is the continuation of the first article, Simple Python Debugging with Pdb: Part 1.In this article, let's look at another important…
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Learn Simple Python Debugging with Pdb

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6 Comments
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A Guide to Going Back to School For Math or Science

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5 Comments
Motivations for creating the series I came to Physics Forums originally to read ZapperZ’s thread about becoming a physicist back in 2013. It was one…
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Learn About Energy Gained by Charge in an Electrostatic Field

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2 Comments
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How to Self-Study Basic High School Mathematics

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5 Comments
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A Guide to Self Study Calculus

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26 Comments
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The Essential Guide to Self Study Mathematics

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12 Comments
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Have Scientists Seen an Electron?

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The Block Universe – Refuting a Common Argument

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153 Comments
The "block universe" interpretation of SR has come up repeatedly in threads here on PF. Rather than link to them, I want to summarize a common argument…
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A Geometrical View of Time Dilation and the Twin Paradox

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90 Comments
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Understanding Retrocausality and Blockworld

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Can We Tell Whether the Universe Is Rotating?

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3 Comments
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Blockworld and its Foundational Implications: Delayed Choice and No Counterfactual Definiteness

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Blockworld and its Foundational Implications: General Relativity and Closed Timelike Curves

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 In parts 1 and 2 of this 5-part Insights series, I explained the blockworld (BW) implication of special relativity (SR). In part 3, I introduced…
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Blockworld and its Foundational Implications: General Relativity and the Big Bang

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Blockworld and Its Foundational Implications: The Relativity of Simultaneity and Blockworld

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Atomic Positioning with DNA Hinges

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12 Comments
I was perusing the Nature Nanotechnology website today when I came across an interesting article by Funke and Dietz, called "Placing molecules with Bohr…
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Examples of Prequantum Field Theories IV: Wess-Zumino-Witten-type Theories

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4 Comments
  At the end of this page, we will have come full circle back to the first article in the series 20 years ago -- The M-Theory Conjecture.We…
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Examples of Prequantum Field Theories III: Chern-Simons-type Theories

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1 Comment
  After having constructed gauge fields and higher gauge fields in the previous article by systems of ##L_\infty##-algebroid-valued…
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Does the Heisenberg Uncertainty Principle Imply Energy Nonconservation?

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2 Comments
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Examples of Prequantum Field Theories II: Higher Gauge Fields

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1 Comment
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prequantumft

Examples of Prequantum Field Theories I: Gauge Fields

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2 Comments
  After having motivated the need for prequantum field theory and having laid out its principles (i. extremal action, ii. global…
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Fun with Self-Avoiding Walks Simulations

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16 Comments
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111 Comments
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Higher Prequantum Geometry V: The Local Observables – Lie Theoretically

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Do Photons Move Slower in a Solid Medium?

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Higher Prequantum Geometry IV: The Covariant Phase Space – Transgressively

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Higher Prequantum Geometry III: The Global Action Functional – Cohomologically

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A Poor Man’s CMB Primer: Bumps on a Blackbody

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Higher Prequantum Geometry II: The Principle of Extremal Action – Comonadically

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1 Comment
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Learn Time Dilation and Redshift for a Static Black Hole

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76 Comments
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Higher Prequantum Geometry I: The Need for Prequantum Geometry

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18 Comments
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Can We See an Atom?

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11 Comments
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Does Gravity Gravitate: The Wave

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17 Comments
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Can I Send a Signal Faster than Light by Pushing a Rigid Rod?

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52 Comments
One common proposal for achieving faster-than-light communication is to use a long perfectly rigid object and mechanically send signals to the other end…
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Does Gravity Gravitate? Part 2

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30 Comments
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What Proofs are in Mathematics and Why Bother?

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28 Comments
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PF’s policy on Lorentz Ether Theory and Block Universe

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81 Comments
What is the PF's policy on Lorentz Ether Theory and Block Universe?Debates about the superiority or "truth" of modern Lorentz Ether Theory (LET) and…
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Dealing with Doubt as a Science Student

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0 Comments
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gravitate

Does Gravity Gravitate?

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9 Comments
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Pluto Quiz: Think You Know Pluto?

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4 Comments
Pluto has been in the news quite a bit these past several months. Let's see if you've been paying attention. Feel free to share your score in the comments…
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A Poor Man’s CMB Primer: The Birth of a Cosmic Background Radiation

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3 Comments
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Understand the Acoustic Modulation vs. Beating Confusion

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36 Comments
A long time ago I read a paper in the IEEEProceedings recounting the history of the superheterodyne receiver. Overall it was a very interesting and informative…
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Learn Inflation Balloon Analogy Misconceptions

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62 Comments
The Balloon Analogy is a simple-minded way to help describe (but not completely describe) two facts of cosmology that are difficult for many people to…
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Why Is Acceleration Due to Gravity a Constant?

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This question has popped up many times. So here is an attempt to address it.To answer this question at the elementary level, several assumptions will…
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Struggles With the Continuum: Point Particles and the Electromagnetic Field

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20 Comments
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Explosion-Generated Collapsing Vacuum Bubbles Reach 20,000 Kelvin

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5 Comments
In a recent paper published in Physical Review Letters (PRL), one of the top physics journals, Jérôme Duplat and Emmanuel Villermaux developed a method…
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What Is Evolution and How Does It Happen?

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0 Comments
What is evolution? In every field of scientific endeavor, there comes now and then a quantum shift in knowledge, a grand denouement of the way things…
cardinalnumbers

Informal Introduction to Cardinal Numbers

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Cardinal numbers We will now give an informal introduction to cardinal numbers. We will later formalize this by using ordinal numbers. Informally, cardinal…
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A Poor Man’s CMB Primer: Orientation of the Universe

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4 Comments
 This is a picture of the cosmic microwave background:Fig 1. The cosmic microwave background as seen by the European Space Agency's…
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Why Does C Have a Particular Value, and Can It Change?

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53 Comments
Short answer: Because c (speed of light) has units, its value is what it is only because of our choice of units, and there is no meaningful way to test…
planck

What Planck Length Is and It’s Common Misconceptions

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29 Comments
The Planck length is an extremely small distance constructed from physical constants. Many misconceptions generally overstate its physical significance,…
spacetime2

Struggles With The Continuum: Quantum Mechanics of Charged Particles

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39 Comments
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The Best Methods to Deal with Procrastination

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0 Comments
It's 6:30 in the morning. You've just woken up and you feel so sleepy you think to yourself "A few more minutes can't hurt." And so you drift on to sleep…
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How Fast Do Changes in the Gravitational Field Propagate?

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20 Comments
General relativity predicts that disturbances in the gravitational field propagate as gravitational waves, and that low-amplitude gravitational waves travel…
imagination

Why Imagination Without Knowledge Is Ignorance Waiting to Happen

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15 Comments
Introduction My feelings on people who think that imagination is more important than knowledge are well-known. These people simply are parroting Einstein's…
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Exploring a Paper on Scaling Laws and the Speed of Animals

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19 Comments
Introduction In a recent American Journal of Physics issue, I read an interesting paper by Nicole Meyer-Vernet and Jean-Pierre Rospars examining the top…
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Learn the Top 5 Misconceptions About Infinity

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17 Comments
Introduction Understanding the behavior of infinity is one of the major accomplishments of mathematics. Sadly, the infinite is often misunderstood and…
man_on_moon

Last Man On The Moon | Look Back at Previous Missions

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0 Comments
On December 11, 1972, astronaut Eugene Cernan became the last person to walk on the lunar surface, marking the conclusion of NASA's Apollo missions—a…
spacetime

Struggles With the Continuum: Is Spacetime Really a Continuum?

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29 Comments
 Is spacetime really a continuum?  That is, can points of spacetime really be described---at least locally---by lists of four real numbers…
photoelectric

“Violating” Einstein’s Photoelectric Effect Model

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4 Comments
One of the most spectacular theoretical descriptions that Einstein had ever produced is the corpuscular nature of light that he used in his 1905 photoelectric…
999

Is There a Rigorous Proof Of 1 = 0.999…?

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101 Comments
Yes.First, we have not addressed what 0.999... means. So it's best first to describe what on earth the notation [tex]b_0.b_1b_2b_3...[/tex] means.…
CosmologicalHorizons

Inflationary Misconceptions and the Basics of Cosmological Horizons

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45 Comments
Introduction It is a common saying that during inflation "space expanded faster than the speed of light."  This statement is meant to articulate the…

The History and Concept of the Number 0

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7 Comments
The goal of this FAQ is to clear up the concept of 0 and specifically the operations that are allowed with 0.The best way to start this FAQ is to look…
lightswitch

What Happens When You Flip the Light Switch: From Zero Seconds to 20 Years

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47 Comments
Introduction Few people know what happens when a customer does something like flipping a light switch. The full explanation requires descriptions of topics…
matterphoton

Will All Matter Be Converted to Photons?

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41 Comments
Will all matter be converted into black holes and then photons? No. There is a misconception that a lot of laypeople seem to be picking up recently from…
photonmass

Do Photons have Mass?

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5 Comments
Do photons have mass? The quick answer: NOHowever, this is where it gets a bit confusing for most people. This is because, in physics, there are several…
relativitytherorm

Learn the Relativistic Work-Kinetic Energy Theorem

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19 Comments
I was bothered for a long time by the reasons for the relativistic validity of the work-kinetic energy relation ##\Delta E=Fd##, which holds without any…
supergravity

Emergence From the Superpoint

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6 Comments
 In the previous article we saw that the generalization of super-Lie algebras to homotopy super-Lie n-algebras (super L-infinity algebras)…
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An Equation for the Centrifugal Force Reversal Near A Black Hole

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15 Comments
My goal in this article is to derive a simple equation for the proper acceleration of an observer traveling on a circular path around a Schwarzschild black…
liealgebra

Homotopy Lie-n Algebras in Supergravity

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1 Comment
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birktheo

Learn A Short Proof of Birkhoff’s Theorem

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8 Comments
Birkhoff's theorem is a very useful result in General Relativity, and pretty much any textbook has a proof of it. The one I first read was in Misner, Thorne,…
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It Was 20 Years Ago Today — the M-theory Conjecture

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2 Comments
  While the world didn't end, after all, 15 years back at the turn of the millennium, in hindsight it is curious that, almost unnoticed,…

Why You Should Not Use Wikipedia As Your Primary Source

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108 Comments
It is no secret to anyone who has read my posts in this forum for a while that I do not like Wikipedia. I think that there's a fundamental flaw with the…
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What Is the Bell Spaceship Paradox, and How Is It Resolved?

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33 Comments
Bell describes two spaceships that start out at rest relative to each other, with an elastic string between them, one end attached to each ship, which…
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Learn a Misconception of the Heisenberg Uncertainty Principle

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26 Comments
One of the common misconceptions about the Heisenberg Uncertainty Principle (HUP) is that it is the fault of our measurement accuracy.A description…
quantum_tunneling

Why You Can’t Quantum Tunnel Through a Wall

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64 Comments
Can You Quantum Tunnel Through a Wall? The short and sweet answer if a tennis ball, a bowling ball, or any other kind of ordinary macroscopic object can…
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What is relativistic mass and why it is not used much?

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58 Comments
It happens that the term relativistic mass is used, in particular in the introductory text on special relativity. It should be noted that whether or not…
learnfrompf

The Most Important Thing You Can Learn from Physics Forums

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15 Comments
It is a bit pompous of me to think that I can tell you the most important thing you can learn from Physics Forums (PF). After all, each one of us here…
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Plus/minus What? How to Interpret Error Bars

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20 Comments
People sometimes find themselves staring at a number with a ± in it when a new physics result is presented. But what does it mean? This Insight aims to…
LCDM4

Approximate LCDM Expansion in Simplified Math (Part 4)

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14 Comments
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False Physics Major Dichotomy: Theorist or Experimentalist?

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27 Comments
Many physics majors believe that pursuing a Ph.D. in physics requires them to choose between theory and experiment. Due to my weaknesses in math, I…
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Your Curriculum Vitae As a Physics Graduate

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1 Comment
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Isaac Newton Quiz: Test Yourself on Isaac Newton

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44 Comments
One of the great heavy weights of history. How much do you really know about him? Let's find out!"To myself I am only a child playing on the beach,…
LCDM3

The LCDM Cosmological Model in Simplified Math (Part 3)

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5 Comments
  Part 3: Important Cosmological Horizons and Distances A question that often comes up is: "how big is the observable universe?"The question…
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How to Get a Postdoctoral Physics Position

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1 Comment
  If you intend to pursue an academic/research career, chances are, you will need postdoctoral experience. This is typically a 2…
lcdmjorrie

Approximate LCDM Expansion in Simplified Math (Part 2)

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14 Comments
  Part 2: Time and Distance In Part 1 we have seen how one of the simplest ways of expressing the fractional expansion rate of the universe,…