Thomas Stig Wikman – Super Facts

The Physics of Climate Change – Review

The goal of this blog is to create a list of what I call super facts. Super facts are important and true facts that nevertheless are surprising to a lot of people, mind-blowing, or misunderstood or disputed among non-experts. They are special facts that we all can learn something important from. However, I also make posts that are not super facts but feature other interesting information, such as this book review and book recommendation. The book is:

The Physics of Climate Change by Lawrence M. Krauss

I should mention that Lawrence M. Krauss is a renowned theoretical / particle physicist and cosmologist and not a climate scientist. However, he took a deep dive into the physics of climate change because of its importance. Below I am listing the four versions of this book. I bought and read the paperback version.

Hardback – Publisher : Post Hill Press (March 2, 2021), ISBN-10 : 1642938165, ISBN-13 : 978-1642938166, 208 pages, item weight : 13.6 ounces, dimensions : 5.5 x 0.7 x 8.25 inches. It costs $8.70 on US Amazon. Click here to order it from Amazon.com.
Paperback – Publisher : Post Hill Press (March 28, 2023), ASIN : B0BTMPFL93, ISBN-13 : 979-8888450925, 208 pages, item weight : 8 ounces, dimensions : 5.5 x 0.6 x 8.25 inches. It costs $15.01 on US Amazon. Click here to order it from Amazon.com.
Kindle – Publisher : Post Hill Press (January 26, 2021), ASIN : B08P5DK7HB, ISBN-13 : 978-1642938173, 187 pages, it costs $12.99 on US Amazon. Click here to order it from Amazon.com.
Audiobook – Publisher : Primordial Productions INC (January 26, 2021), ASIN : B08R6HT764, Listening length : 4 hours and 53 minutes. $0.00 with membership. Click here to order it from Amazon.com.

The front cover features the title and the name of author Lawrence M. Krauss author of The Edge of Knowledge. There is also a recommendation from Elizabeth Kolbert saying, “the ideal book for understanding the science of global warming.” This is on a purple/reddish/brown background with clouds. | The Physics of Climate Change by Lawrence M. Krauss Front Cover — The front cover of The Physics of Climate Change by Lawrence M. Krauss. Click on the image to go to the Amazon page for the hardback version of the book.

Amazon’s Description of the Book

The first book to briefly and clearly present the science of climate change in a way that is accessible to laypeople, providing the perspective needed to understand and assess the foundations and predictions of climate change.

“Brilliant and fundamental, this is the necessary book about our prime global emergency. Here you’ll find the facts, the processes, the physics of our complex and changing climate, but delivered with eloquence and urgency. Lawrence Krauss writes with a clarity that transcends mere politics. Prose and poetry were never better bedfellows.” —Ian McEwan, Booker Prize-winning author of Solar and Machines Like Me

“Lawrence Krauss has written the ideal book for anyone interested in understanding the science of global warming. It is at once elegant, rigorous, and timely.”—Elizabeth Kolbert, staff writer, The New Yorker, and Pulitzer prize-winning author of The Sixth Extinction

“A brief, brilliant, and charming summary of what physicists know about climate change and how they learned it.” —Sheldon Glashow, Nobel Laureate in Physics, Metcalf Distinguished Professor Emeritus, Boston University

“The distinguished scientist Lawrence Krauss turns his penetrating gaze on the most pressing existential threat facing our world: climate change. It is brimming with information lucidly analysed. Such hope as there is lies in science, and a physicist of Dr. Krauss’s imaginative versatility is unusually qualified to offer it.” —Richard Dawkins, author of The Blind Watchmaker and Science in the Soul

“Lucid and gripping, this study of the most severe challenge humans have ever faced leads the reader from the basic physics of climate change to recognition of the damage that humans have already caused and on to the prospects that lie ahead if we do not change course soon.” —Noam Chomsky, Laureate Professor, University of Arizona, author of Internationalism or Extinction?

“Lawrence Krauss tells the story of climate change with erudition, urgency, and passion. It is our great good luck that one of our most brilliant scientists is also such a gifted writer. This book will change the way we think about the future.” —Jennifer Finney Boylan, author of Good Boy and She’s Not There

“Everything on climate change that I’ve seen is either dumbed down and bossy or written for other climate scientists. I’ve been looking for a book that can let me, a layperson, understand the science. This book does just what I was looking for. It is important.” —Penn Jillette, Magician, author of Presto! and God, No!

“The renowned physicist Lawrence Krauss makes the science behind one of the most important issues of our time accessible to all.” —Richard C. J. Somerville, Distinguished Professor Emeritus, Scripps Institution of Oceanography, University of California, San Diego

“Lawrence Krauss is a fine physicist, a talented writer, and a scientist deeply engaged with public affairs. His book deserves wide readership. The book’s eloquent exposition of the science and the threats should enlighten all readers and motivate them to an urgent concern about our planet’s future.” —Lord Martin Rees, Astronomer Royal, former president of the Royal Society, author of On the Future: Prospects for Humanity.

This is my five star review for the book The Physics of Climate Change

These Climate Change Physics Lessons will Make You Smarter

The author, Lawrence M. Krauss, is a particle physicist and cosmologist who took a deep dive into climate science, because it is an important topic that is misunderstood amongst the public. He demonstrates conclusively that the very rapid current global warming is indeed happening and is caused by us. He states that “Climate Change, evolution, and the Big Bang are all empirical facts, not speculation.” And that the existence of the greenhouse effect and its theoretical interpretation are by now essentially unimpeachable. He also states that “the basic physics is relatively straightforward and can and should be explained comprehensively to interested bystanders.”

However, this is easier said than done. Physics is hard for people without a physics education and people often underestimate what scientists understand. A famous example of this that is mentioned in this book is when former Fox TV host Bill O’Reilly notoriously claimed that no one knows why the tides happen, when in fact none other than Sir Isaac Newton explained the fundamental physics behind the tides hundreds of years ago. This book features a lot of facts, a lot of detailed explanations of complex systems, a lot of physics, some formulas, diagrams, and actual science. Even though this book is written for lay people it is not easy to read and I had to reread and think about some passages before continuing, despite having a degree in physics.

The author explains the so called carbon cycle, how carbon dioxide gets cycled through Earth’s oceans, mantle, the atmosphere, the biosphere, terrestrial soils, and the reservoirs of CO2 stored in each system and the flow absorption/emission between them. The carbon cycle diagram he provides is probably the most informative I’ve seen. One of the smallest emitters in the diagram are volcanoes, which emit about 1% of what we do by burning fossil fuels and is part of the carbon cycle, which has existed long before we did.

He explains how carbon dioxide emissions form a blanket around the Earth, the so called somewhat misnamed greenhouse effect and how it together with Earth’s overall reflectivity determines Earth’s surface temperature, which would have been 33 degrees Celsius (60 Fahrenheit) colder without the gases in our atmosphere. He explains why certain molecules are greenhouse gases, whilst other gases are not. Oxygen and nitrogen are not greenhouse gases, but carbon dioxide is a greenhouse gas whilst water vapor acts like a greenhouse gas.

To explain what is going on he invokes the electromagnetic spectrum and thermodynamics, for example, Stefan-Boltzman’s law, he does some math, examines the incoming and outgoing radiation, the absorption of IR radiation in the atmosphere, how carbon dioxide and water vapor absorb radiation at different frequencies and complement each other. For example, carbon dioxide absorbs IR radiation mostly in the 600 to 700 micrometers and water vapor in other frequencies. And by the way water vapor is not a driver behind global warming.

He explains how we can know past carbon dioxide content as well as global temperatures from ice cores going back 800,000 years. He gives us an overview of the science history of the greenhouse effect and global warming. It is hundreds of years old. For example, in 1896 the Swedish chemist/physicist Svante Arrhenius calculated pretty accurate numbers for how much the average global temperature would rise depending on how much carbon dioxide we are emitting, and roughly how the warming would distribute across the globe (not evenly). However, the author points out that calculating the average global temperature rise or environmental damage from the size our emissions is a very complicated task that not even complex models can do perfectly well.

One thing we can calculate very easily and accurately is radiative forcing. Radiative forcing is defined as the change in total radiation power (in watts per square meter) emitted by Earth into space as some quantity like the CO2 abundance. In the formula below C is the abundance of carbon dioxide and C0 is the initial abundance of carbon dioxide, and ln is the natural logarithm and Delta-P is the change in power, again in watts per square meter. (+/- 0.5) is the margin of error.

Radiative forcing Delta-P = 5.35 (+/- 0.5) ln(C/C0) Watts per meter square.

In addition, the book discusses the melting of land ice, Greenland, the different ice sheets in Antarctica, the distribution of temperature changes across Earth and across the atmosphere, potential tipping points, the potential future ill effects of global warming, including future sea level rise from thermal expansion and the melting of land ice (not sea ice). He states that under high emissions CoastalDEM (a study) indicates up to 630 million people live on land below projected annual flood levels for 2100.

In this review it seems like I’ve given a lot of detail regarding the content of the book. However, it is still just a small sample. The book is short, at less than 200 pages, but it has a lot of interesting content, perhaps even in depth content. It is well written and well organized, and Lawrence M. Krauss is a great popularizer of science. I’ve read other physics books by him. By giving some details about the content, I wanted to give potential readers an idea of what to expect and prepare them for the fact that this book is written for laymen at the same time as it is not easy reading. Please read it carefully and try to understand the content. If you can do that then I highly recommend it for you. The book will make you much smarter.

The back cover of The Physics of Climate Change by Lawrence M. Krauss features advance praise for the book. The text is on a purple/reddish/brown background. — The back cover of The Physics of Climate Change by Lawrence M. Krauss. Click on the image to go to the Amazon page for the paperback version of the book.

To see the Super Facts click here

Bad Travel Memories – Stream of Consciousness

Today is the fifth time I participate in Linda Hill’s streams of consciousness. To read about the rules and participate click here or here. To read my four previous entries (prompt was pre) click here “Prediction Failures and My Lucky Day from Hell”, or here “The Review Wars on Amazon – Stream of Consciousness”, or here, “Reindeer Hide Memories”, or here “25 Sweet Leonberger and Dog Photos”. I put this post on my Super-factful blog because it is factual, real events, and not related to Leonbergers. However, it is not a super fact.

The badge features a twig with rain drops and it says Stream of consciousness Saturday #SoCS — 2019-2020 SoCS Badge by Shelley!

Today’s prompt for Stream of Consciousness Saturday August 8, 2026, is “Travel”. Use it way you’d like. The first rule is: there should be minimal planning and no editing except typos. I did not edit but I did add a few pictures. I like adding pictures.

The first thing that came to my mind for this prompt was that I’ve travelled a lot. I’ve visited almost 50 countries, and 46 US states. I’ve been on business trips or worked in several countries. I’ve also lived in Sweden half my life and in the US during the other half of my life, and I’ve lived in five states. Most of my travel have been fun and interesting. However, not all my travel was pleasant. Below I am describing four unpleasant travel experiences.

The Salmonella Ferry

I grew up in a small town in northern Sweden in a working class family. We could not afford a lot of travel, but what we could afford was taking a trip on the ferries going from Sweden to Finland. These ferries had a car deck. You drove your car onto the car deck and then you went upstairs. The ferry between northern Sweden (Umeå or Örnsköldsvik) and Vaasa in Finland took four hours and you just stayed on the upper deck. However, the overnight ferry between Stockholm and Helsinki (or Tallin) took 15-20 hours and you stayed in small rooms underneath the upper deck. This time we took the ferry from Stockholm to Helsinki.

For dinner they had buffet with all kinds of Scandinavian dishes including dishes with eggs. Unfortunately, the eggs had a special feature and that was Salmonella. During the night more and more people started getting sick. People were vomiting and people got diarrhea. There were nearly a thousand people on the ferry and not enough bathrooms to accommodate everyone who had Salmonella. I did not get Salmonella, but I still needed to use the bathroom a couple of times. I remember people vomiting in toilets and people not able to go on time. It was an unpleasant disaster.

A large white ferry with the inscription ESTLINE. | Bad Travel Memories – Stream of Consciousness — MS Estonia in 1993/1994. Blahaaaaaaaa69420, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

However, in September 1994 something much worse happened to one of the ferries. I remember because I had just started working for a Robotics company after getting my PhD in Physics and Electrical Engineering, specialty Robotics, and two people at my workplace died. It was a ferry called MS Estonia going between Tallin and Stockholm. The ramp / door for the car deck, the so called bow visor, was leaking during a storm, letting in water and flooding the car deck making the ferry unstable. It finally tipped over very quickly. Nearly a thousand people died and not many survived.

Interrogated and Held at Gun Point in the Soviet Union

When I was a high school student, I joined a group of travelers to the Soviet Union from the church I was part of at the time. The year was 1980, before Glasnost, and the Soviet authorities had temporarily hardened their authority. We tried to smuggle unwanted literature such as Russian Bibles and other books, as well as printing machine equipment and supplies for the underground movement. We planned to travel with the Stockholm-Tallin ferry, but a strike forced us to take the train all around the Baltic Sea and back down to Helsinki and then East to Leningrad, now called St. Petersburg.

KGB Soviet Officer entering a train couple carrying an automatic gun. — I asked ChatGPT to draw me this. The tea cup in the picture happen to by chance look exactly like what we drank from.

Long story short, we were caught, at the Finland Station, and lined up at gun point, searched and interrogated in isolation one by one. While we were lined up, I said, in Swedish, “they are the cattle of dictatorship”, quoting a Swedish prime minister, who had said that about the Soviet Army. My friend Michael hit me in the stomach and said, “shut up Thomas, I am standing next to you”. I can add that a Sandinista who came there to learn guerrilla warfare was sitting with us and accidentally got caught up in our business.

After maybe 4-5 hours they let us go and they even let us into the Soviet Union. However, they gave us a guide from the KGB. She was watching us and making sure we did not misbehave but also giving us guided tours. She was nice and we got along with her. A note about history: The Finland Station was where Vladimir Lenin arrived in February 2017 setting the stage for the Russian Revolution.

Amnesia in Garmisch-Partenkirchen

When I was about 22 years old, I travelled with a group of friends from Sweden to Garmisch-Partenkirchen in Bavaria, southern Germany, to ski. We were travelling by bus. As it turned out I had a pretty bad accident in a black diamond slope that was closed because of too icy conditions. Yes, I know, I ignored the sign and the rules. Long story short, I fell badly, hit my head, had a concussion, and a badly dislocated shoulder. As a bonus I lost my memory.

My memory was gone for about three days. It was caused by shock and not by brain injury and that kind of amnesia resolves itself within hours up to a few weeks. Amnesia caused by brain injury is much more difficult to recover from. There were other weird things happening on this trip. You can read more about this trip here.

Mountains in the background. The town of Garmisch-Partenkirchen in the foreground. | Bad Travel Memories – Stream of Consciousness — The town of Garmisch-Partenkirchen. Photo by op23 on Pexels.com

Our Hardest Goodbye (Don’t Read if you are Sensitive)

I’ve had ski accidents at other places as well, for example, Breckridge. One time I broke my finger and got some bruises in the Horseshoe Bowl in Breckenridge. However, the by far worst ski vacation I’ve ever had was not because of an accident. My oldest son and I went to Beaver Creek, Colorado, to ski, because that is what he wanted to do. My wife took the other two kids to Ohio because that is what they wanted to do.

While we were gone, we hired a dog sitter who was going to watch our four dogs, our Leonberger dog Bronco, our Labrador Baylor, our German Shepherd named Baby, and our Japanese Chin Ryu. The agreement was that she was supposed to come to our house a few times per day and then sleep over with the dogs.

However, after we had already left, she called us and told us she couldn’t do it as agreed because she was watching other dogs at her house, so she asked us if she could take our dogs to her house. Well, there was not really any choice. A few days later she called us and told us she could not find Baylor. He had been barking at night, so she put him out in the backyard. It turned out her fence was not secured and he had escaped. It was January and a cold even in Dallas, where we live. The next day he was found dead about halfway between her house and our house. He had been hit by a car, and the driver had just left him there. The kids cried and we were all traumatized. That was by far the worst vacation we’ve ever had. That was travel we will forever regret.

A labrador is walking across the rainbow bridge. The text says “You were our favorite Hello and our hardest Goodbye.” — We lost our beloved Baylor in a horrible way. Illustration by Naomi Rosenblatt.

To see the Super Facts click here

Super Rich

Superfact 120: The amount of wealth owned by the billionaires is roughly double as much as the poorest half of the world’s population. The amount of wealth owned by the 12 richest billionaires is more than the wealth of the poorest 50% of the world’s population. The richest 1% of the global population owns approximately 38% to 45% of the world’s total wealth.

Esther’s writing prompt: July 15th : Rich

Click here or here to join in.

A one hundred US Dollar bill sailing through a cloudy sky. | Super Rich — US 100 dollar bills falling through the air Shutterstock Asset id: 2555911235 by Caito

There are at the moment of this writing 3,428 dollar billionaires in the world worth 20.1 trillion dollars together. For comparison the poorest 50% of the world’s population holds between $9 trillion to $12 trillion dollars of wealth (about half). According to this report the amount of wealth owned by the poorest half of the world is less than the amount owned by just the 12 richest billionaires. By the time you read this the numbers have probably changed (likely upwards). You can also read more in Wikipedia.

I am specifying that it is in dollars and not let’s say in the Iranian Rial. With respect to the Iranian Rial, I am also a billionaire, and you are probably too (if you own a phone or computer). One dollar can buy roughly 1,300,000 to 1,600,000 IRR. You just need $700 to be a billionaire in the Iranian Rial.

This is a bar graph showing the number of billionaires and combined wealth starting in 2013 and ending in 2026. — World’s billionaires. Number and total wealth by year. Trillions of dollars. The graph comes from here. <<Link-6>> Katharina Buchholz. Cropped and edited by User:Timeshifter using freeware IrfanView., Public domain, via Wikimedia Commons.

I should say that initially I was just going to list interesting statistics about the super-rich. However, I found myself surprised by the statistics, and I am sure I am not the only one. Therefore, I picked a couple of facts I decided super facts.

The ten richest billionaires in the World

The numbers below are from Forbes Magazine. To see a list of all billionaires in the world, click here. To see a list with numbers that are updated minute by minute, click here.

Elon Musk – 839 billion dollars – source Tesla, SpaceX
Larry Page – 257 billion dollars – source Google
Sergey Brin – 237 billion dollars – source Google
Jeff Bezos – 224 billion dollars – source Amazon
Mark Zuckerberg – 222 billion dollars – source Facebook
Larry Ellison – 190 billion dollars – source Oracle
Bernard Arnault & family – 171 billion dollars – source LVMH
Jensen Huang – 154 billion dollars – semiconductors
Warren Buffet – 149 billion dollars – source Berkshire Hathaway
Amancio Ortega – 148 billion dollars – source Zara

Wealth share of the richest 1%

The richest 1% of the global population owns approximately 38% to 45% of the world’s total wealth, which is more than what 95% of humanity own according to Oxfam. The richest 1% of the global population is not about billionaires, it may very well include you and me. Our World in Data has collected and analyzed the statistics for each country in the world. The top richest 1% in the United States own 34.78% of the wealth in the United States. The top richest 1% in Russia own 48.99% of the wealth in Russia. The top richest 1% in Sweden own 27.49% of the wealth in Sweden. The top richest 1% in the Netherlands own 13.98% of the wealth in the Netherlands. See the graphs below from Our World in Data.

This is a world map showing the share of wealth owned by the richest 1% of the population in each country. The darker the color, the greater the wealth of the 1% in that country. | Super Rich — The share of wealth owned by the richest 1% of the population. Wealth is defined as the total value of non-financial and financial assets (housing, land, deposits, bonds, equities, etc.) held by households, minus their debts. Data source: World Inequality Database (WID.world) (2026) – Learn more about this data OurWorldinData.org/economic-inequality | CC BY

As you can see from the graphs below the extreme inequality is nothing new. Europe was extremely unequal in the 19th century. The 1% owned 58.01% of the wealth in 1900. The United States was relatively equal in 1978 when the 1% owned 21.79% of the wealth. Russia became very unequal since 1995. I suggest that you play around with the graphs yourself .

The graphs show the share of wealth owned by the 1% for Russia, Europe and the United States from 1820 to 2024. — The historic share of wealth owned by the 1% for different countries around the world, starting in 1820. Data source: World Inequality Database (WID.world) (2026) – Learn more about this data OurWorldinData.org/economic-inequality | CC BY

ABBA’s Money, Money, Money

Note: This post is not an implicit suggestion that we should tax billionaires more or less, and not about how or whether we should solve inequality, and it is not about politics. It is just surprising statistics regarding wealth and the reality of inequality.

My Other Responses to Esther’s Prompts

Prompt : Small : Small Microscopic Subatomic and Strings
Prompt : Kind : Leonbergers Are Kind Dogs
Prompt : Window : What Does Rollo See Out His Window
Prompt : Charge : Electric Charge is not the only type of Fundamental Charge
Prompt : Promises : Promises To My Dog
Prompt : Shade : A Total Solar Eclipse the Ultimate Moon Shade
Prompt : Money : Ten Money Facts
Prompt : Edge : The Edge of the Observable Universe is 46.5 billion Light Years Away
Prompt : Fish : Ten Amazing Fish Facts
Prompt : Promise : I Promise Not to Post AI Generated Comments
Prompt : Respect : Respect your Dog
Prompt : Giving : Leonbergers Giving Gifts to Pugs
Prompt : Family : Dogs Are Family
Prompt : Snow : Snow and Ice in Norrland
Prompt : Red : The Universe has a Redshift and its Increasing
Prompt: Shapes : Conic Sections are the Shapes that Shape Our World
Prompt: Flying : 10 Wind Blowing Facts About Birds
Prompt: Drive : Letting Your Dog Drive the Car
Prompt: Memories: False Memories Strange Memories Unpleasant Memories and Amnesia
Prompt: Magic: Magic In New Orleans a Travel Overview
Prompt: Vision: Human Vision Only Detects a Sliver of the EM Spectrum
Prompt: Flower: Leonberger Dogs with Flowers
Prompt: Capture: Carbon Capture and Storage an Unfulfilled Promise
Prompt: Eyes: The Evolution of Eyes is Convergent
Prompt: Pet: The Joy of Having a Pet
Prompt: Cross: Why did the Dog Cross the Road
Prompt: Close: Close Encounter with Grizzly Bear Number 399
Prompt: Block: 60 million Lego Blocks
Prompt: Bank: The Riverbank of Moälven

To see the Other Super Facts click here

Light is Beyond the Reach of Time

Superfact 116: Time and space do not exist for light particles (called photons) and not for other particles without mass either. All massless particles travel at the speed c = 299,792,458 meters per second compared to all other objects regardless of how fast those other objects are moving. Objects / particles that have mass will always travel slower than c = 299,792,458 meters per second. The speed of light, c, is not really a speed. It is a conversion factor between space and time. It is therefore a universal constant.

Light does not travel through a medium, like a sound wave, or a water wave does. There is no medium for light to travel in. Photons are massless, which means that an extremely tiny force, an infinitesimal smallest possible force, could send a photon off at infinite speed. There is no mass to hold the photon back.

However, the conversion factor between space and time c = 299,792,458 meters per second will prevent that and the photon will travel at this “speed”. Since c is a conversion factor, a physical constant describing time and space, this is not motion, or movement, in a normal sense. Space and time won’t allow any physical event to have any effect faster, and no information of any kind can travel faster than c = 299,792,458 meters per second.

One of the effects of the speed of light being a universal constant is that different observers measure different distances and time durations, and even the order of events may be in different orders for different observers. As you travel ever closer to the speed of light the time it will take to travel between two points will shrink towards zero as you approach the speed of light. In addition, the distance between the two points will shrink. You can read Albert Einsteins original paper on the topic here, and about space-time here.

This means that from the photon’s perspective there will be no time at all. A photon, or a light beam, will travel from Earth to a distant galaxy a billion light years away in an instant. It will not take a billion years. It will not take one year. It will not take one second. It will not take one microsecond. It will not take a nanosecond, or a picosecond, or a trillionth of a picosecond. It will take zero seconds. The Big Bang and the end of the Universe (if there is one) happen at the same exact moment to a photon. Time does not exist for a photon (or a gluon, or any other mass-less particle).

This is a mind-blowing fact, and it is true and important to our understanding of the Universe. Therefore, I consider it a super fact.

What does the Speed of Light Being a Universal Constant Mean ?

A spaceship on the right is shooting out a laser beam towards the left. Alongside the laser beam are four rockets trying to catch up with the light beam. — Four rockets, A, B, C, and D, are traveling along a light (laser) beam. No matter how fast they travel along the light beam, the light beam will always travel c = 299,792,458 meters per second faster than they do. I generated this picture with the help of ChatGPT.

The first thing to acknowledge about the speed of light (in vacuum) is that it is a universal constant as explained in my post “The Speed of Light in Vacuum Is a Universal Constant”. However, I am explaining this fact slightly differently in the next few paragraphs with the help of the picture above.

In the picture above we are emitting a light beam from our spaceship using our super laser. There are also four rockets that travel along the light beam. The rocket on the lower right (rocket A) travel at 1% of the speed of light v = 2,997,924.5 meters per second (or 2,998 miles per second). That is extremely fast, but much slower than light. You would think that the light beam would travel a little bit slower compared to this rocket at the relative speed c – v = 299,792,458 – 2,997,924.5 = 296,794,533.5 meters per second. But it doesn’t. The light beam is still speeding ahead of rocket A at exactly c = 299,792,458 meters per second.

What happens if you compare the beam with the rocket in the lower left (rocket B)? That rocket travels at 10% the speed of the light beam. Shouldn’t the light beam move 10% slower compared to that rocket? No, the light beam speeds ahead at exactly c = 299,792,458 meters per second compared to rocket B, once again.

Now take rocket C in the upper right corner. It also travels along the light beam but at half the speed of light. Shouldn’t the light beam travel at half of the speed of light compared to rocket C? No, it will stubbornly travel at exactly c = 299,792,458 meters per second compared to rocket C. Not less and not more.

The same is true for the rocket in the upper left, rocket D. It travels at 99.99% of the light speed compared to us in the spaceship, and yet the light beam will stubbornly travel at exactly c = 299,792,458 meters per second compared to rocket D. Not less and not more.

The universal speed c = 299,792,458 meters per second is not so much about light. As mentioned, it is a conversion factor between space and time. You take this conversion factor with you everywhere you go and regardless of how fast you move. That’s the way time and space works.

The fact that the speed of light is a universal constant that is exactly the same for all observers, no matter how fast they move, should tell you that it is not a speed in a normal sense. It is not really a “speed” at all. As mentioned, it is a conversion factor between space and time. Light isn’t really travelling super-fast. It is just conforming to the geometric reality of time and space, and to us it looks like it is travelling at the speed c = 299,792,458 meters per second.

The Space-Time Interval for Light is Zero

I mentioned that from the photons perspective time does not exist but that from our perspective light travel through space or seem to travel through space and that takes time. However, for us space and time are separate things. If you combine them and measure space-time intervals instead you get a more complete picture. In 3D space you get the distance between two points by adding the differences between the coordinates using Pythagoras theorem, s^{2}=x^{2}+y^{2}+z^{2}. (x, y, and z, are differences in the coordinates) As long as you are consistent with the units you will always get the same distance regardless of position and orientation of your coordinate system. You can read more here.

If you add time to Pythagoras theorem you will get the space-time interval, which interestingly enough is the same for all observers. There is no time dilation or length contraction in the interval. s^{2}=x^{2}+y^{2}+z^{2}+(it)^{2} As you might suspect, intervals involving light travelling from one event to another will always be zero for all observers, and not just from the photons perspective. And again, the same applies to all massless particles. Below are the Pythagoras formulas for different versions of the interval. In the top picture it is assumed that the conversion factor c = 299,792,458 meters per second has already been baked into to the time variable and in the bottom it has not. This is not any stranger than converting feet to meters.

The image shows three formulas for the spacetime interval Euclidian: “(s^{2}=x^{2}+y^{2}+z^{2}+(it)^{2}”. For Time like intervals, the standard form: “(s^{2} = t^{2} – (x^{2}+y^{2}+z^{2}))”. For distance like intervals: “(s^{2} = ((x^{2}+y^{2}+z^{2}) – t^{2}))”. | Light is Beyond the Reach of Time — The three formulas for the spacetime interval above all assume that the unit used for time is the time it takes light in vacuum to travel the distance unit used. If that is meters, it would be the time it takes light to travel one meter. The top formula is the Euclidian form of spacetime. It contains only the ‘+’ operator at the expense of adding the imaginary number (square root of -1) in front of the time coordinate. The second form is typically used with time like intervals and considered the standard form. The third form is used when the distance between two events is larger than the time distance, or distance like intervals.

The image shows the formulas for the spacetime interval with the constant representing the speed of light in vacuum “(s^{2}=x^{2}+y^{2}+z^{2}+(ict)^{2}”, “s^{2}= (ct)^{2} – (x^{2}+y^{2}+z^{2})” and “(s^{2}=x^{2}+y^{2}+z^{2}-(ct)^{2}”. — If you measure the space coordinates in meters and the time in seconds you must adjust the units to match by inserting the speed of light in vacuum c = 299,792,458. The three forms of the space interval now have the constant c attached to the time coordinate.

What about the speed of light in water ?

It is well known that the speed of light in transparent materials such as water and glass is slower than the speed of light in vacuum. The speed of light it water is about 75% of the speed in vacuum and about 70% or less in glass (depending of the type of glass) compared to the speed in vacuum. In some materials the speed of light can be much less than that. This seems to violate what I said above about the speed of light always moving at c = 299,792,458 meters per second for all observers regardless of their speed.

What is going on is that when light moves through matter it is being absorbed and emitted as it “travels” between the atoms in the material, and this absorption and emittance process takes time. This time is extremely short but long enough to be measurable. As the photons move in between the atoms they travel at the “speed” c = 299,792,458 meters per second, the time to space conversion factor I’ve been talking about. See the illustration below.

From left to right, an atom absorbs a photon, which excites an electron that jumps into a higher orbit. Then it emits a photon and the electron falls back to the ground state again. | Light is Beyond the Reach of Time — From ground state to excited state, absorption and emission of a photon in an atom. Shutterstock asset id: 2180385419 by rktz.

More about the mass of a Photon

I’ve said photons have no mass. According to Einstein’s theory of special relativity, time does not pass (or effectively “exist”) from the perspective of a massless particle. However, this is the intrinsic mass or so called proper mass or invariant mass. It is the mass of an object as measured by an observer who is completely at rest relative to it. This intrinsic mass is the mass that a photon does not have.

The mass of an electron is 511 Kilo Electron Volts, which is 0.0000000000000000000000000009109 grams. That is the intrinsic mass of the electron. If an electron is sped up to close the speed of light its mass increases and goes toward infinity. If its speed is very close to the speed of light its mass could be much bigger than that of the entire Universe. That’s because as you are increasing the speed of the electron, you are increasing its kinetic energy and as you increase the total energy of the electron you also increase its total mass according to E = mc².

As the electron’s speed approaches the speed of light the kinetic energy goes toward infinity. That is one reason why it is impossible to travel at exactly the speed of light for anything but massless particles. Infinite energy and infinite mass are not realistic. We, the objects that have mass, can move closer and closer to light speed but never get there.

However, the intrinsic mass for photons is zero and therefore the photon is travelling at exactly the speed of light, c = 299,792,458 meters per second. E = mc² still applies to light but the mass is not the intrinsic mass, which is zero, but the total mass, and the total mass can pretty much take on any number.

What about Warp Drives ?

So, nothing with mass can travel at the speed of light, and nothing can exceed it. What about the warp drive in Star Trek? As I said, the speed of light is not really a speed but the conversion factor between time and space. It is a geometric fact of space-time. That is a pretty difficult reality to get around, just like it is pretty difficult to push Earth out of its orbit by pushing on the floor. However, there is a way to cheat and that is to stretch space-time itself. This is theoretically possible, but it requires colossal amounts of mass-energy and enormous amounts of negative energy. We don’t even know if negative energy exists on a macroscopic scale.

So, no one knows if a warp drive is possible, and if it isn’t, then we are stuck moving slower than the speed of light, which would make interstellar travel very difficult and inconvenient.

Richard Feyman’s Lecture on Why Light Is NOT Moving Through Space?

The YouTube video below is very long, 48 minutes. However, Richard Feyman, Nobel prize winner in physics, has a knack for explaining extremely abstract concepts so that they are easy to understand. If you are very interested in this topic and have some extra time, this is a fascinating lecture. He certainly explains this topic better than I can.

Other Super Facts Related to the Speed of Light

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Smorgasbord Blog Magazine Sharing Accents are very difficult to lose

Smorgasbord Blog Magazine – Thomas Wikman’s Superfacts – #Accents are very difficult to lose

Please visit this Smorgasbord Blog Magazine post, which is sharing my post Accents are very difficult to lose, as well as showcasing my Leonberger dog book.