Blogging – Page 2 – Super Facts

Freedom to Roam and Concentric Circles

Image above by Kevin from The Beginning at Last

This picture reminded me of the Swedish lakes I used to swim in. This is a submission for Kevin’s No Theme Thursday

Freedom to Roam Everywhere

When I was a kid, I used to roam around a lot, in the forest and on the mountains, and I liked to swim and fish in the rivers and the famous deep lakes in the Swedish countryside. Sweden has 97,500 lakes larger than 2 acres and many of them are deep lakes with clean and clear water surrounded by forests, typically coniferous forests. A small deep clean forest lake is referred to as a “tjärn”. I can add that there are no alligators or venomous water snakes in Swedish lakes.

Sweden offers a type of freedom that is rare in the world, and it does not exist in the United States and certainly not in Texas where I live. It is the freedom to roam or more specifically allemansrätten. Whether the land is public or private you have the right to roam, to hike, to camp, to swim, to pick wild berries, to pick wild mushrooms, to fish, and no one can stop you. Landowners are not allowed to tell you to get off their land and they cannot put up fences to stop you or animals from roaming on their land. Everyone has the right to roam and swim everywhere. It is a freedom Swedes love, and if you one day come to experience it you will know why.

My son is jumping off a tire swing and into a “tjärn” in northern Sweden.

Allemansrätten

The Swedish freedom to roam or allemansrätten, is a right for all people to travel over private land in nature, to temporarily stay there and, for example, pick wild berries, mushrooms, flowers and certain other plants. It is important to point out that you must respect the landowner’s property. You can pick wild berries but not anything the landowner is growing. You cannot destroy or break things or start fires, use ATVs, cut branches off trees, etc. You also need to stay 70 meters or 230 feet away from any dwelling.

As a landowner in Sweden, you can buy land and use it for farming and forestry, and you have the right to prevent people from damaging or stealing your crops. You can buy land for mining, and you have the right to your proceeds and the right to prevent people from stealing from your mines. In addition, people don’t have the right to get close to your house. However, you do not have the right to prevent anyone from roaming on your land.

Other countries with similar laws are Norway, Finland and Iceland. Limited forms of allemansrätten exist in Austria, Germany, Estonia, France, the Czeck Republic, and Switzerland. In the United States, where allemansrätten does not exist, 63% of all land is private and in Texas 93% of all land is private. Since there is no law in the US protecting your freedom to roam there is noticeably something missing, especially if you are an outdoors person.

Concentric Circles

In addition to evoking my memories of Swedish lakes and allemansrätten, Kevin’s picture tickles my mathematical sense, specifically regarding concentric circles. Concentric circles are beautiful, dreamy, and interesting mathematical phenomena. I could watch concentric circles in the water all day long.

When you jump and play in a lake, when raindrops fall on a lake or a pond you’ll see concentric circles. You see concentric circles on a tree stumps, when you cut an onion, some flower petals, spiderwebs, etc. Concentric circles are everywhere in nature. Light can create concentric circles due to diffraction called an airy disk. Gravitational waves originating from, for example, two black holes colliding create 3D gravitational concentric circles/spheres traveling at the speed of light through space.

Concentric circles are very common in nature. You can see them in Kevin’s picture above. You can see them below my son as he falls into the Swedish lake, and you can see them in the pictures of light below. Whenever waves originate at a point and spread outward you get concentric circles.

There are many kinds of waves, water waves, sound waves, surface waves, seismic waves (earthquakes), mechanical waves, light are waves, electromagnetic waves, matter is both particles and waves, gravitational waves, and they can all make concentric circles. If the waves are moving outward with the same velocity in all directions, you will get equidistant concentric circles.

A real Airy disk created by passing a red laser beam through a 90-micrometre pinhole aperture with 27 orders of diffraction. Bautsch, CC0, via Wikimedia Commons

A computer generated an Airy disk from diffracted white light. The colorful light circles come from the hole in the left wall. Asset id: 1973771255 by Fouad A. Saad.

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Eating Locally is not Necessarily Ecological

Super fact 30: Eating locally is often promoted as an environmentally friendly choice, but that is not always the case.

Whether the food you eat is sustainable and environmentally friendly or not depends on a lot of factors including agricultural methods, whether greenhouse farming or monocropping was used, and whether the crop is natural to its environment. In addition, inefficient local transportation can result in higher emissions than faraway transport by ships and trains. If a crop is grown locally in greenhouses, the extra energy that is needed, and the resulting extra carbon emissions are often much larger than the emissions from the transport.

I consider this a super fact because it is often assumed that buying locally is the best choice for the environment. After all, transporting something across the world causes a lot of emissions, right? It turns out not to be that simple.

Articles on Transportation of Food in my French Book

The first time this issue was brought to my attention was in my French class. I am learning French, just as a hobby. There was an article in our French book on the transportation of food around the world “Notre planète ne tourne pas rond!”.

We read that cashews were grown in the Ivory Coast in Africa and then sent for peeling and cleaning in Brazil and then sent to France to be sold. The cashews travelled 10,000 kilometers or 6.250 miles. We read about cod that was caught in Norway then sent to China to be cut into filets and then sent to France to be sold. That cod travelled 15,000 kilometers. We all thought it was crazy, and very bad for the environment, so much unnecessary emissions from transportation. But we all learned a few new French words.

Then at our next class, we turned the page “Consommer local, vraiment bon pour la planète?” / “Consuming locally, really good for the planet?”. Wait what? The next article confused us since it stated that in many cases eating locally was bad for the environment, not good for the environment. Transporting the food around the globe might be good for the environment.

Incidentally, at the time I was reading “Not the End of the World, How we can be the first generation to build a sustainable planet” by Hannah Richie, the research director for “Our World in Data”. “Our World in Data” is a highly regarded free and open-source website that collects and analysis vetted statistics on a large range of topics. In that book she stated that the data showed that tomatoes imported to Sweden from Spain caused less carbon emission than tomatoes grown locally in Sweden.

The Problem with Locally Grown Tomatoes

This article from University of Southern Denmark claim that importing tomatoes from warm countries are better for the environment than buying locally. The reason being that when tomatoes are grown in an open field, the production emits an average of 80 kg CO2 per ton, but if the tomatoes are grown in a greenhouse, they emit up to 700 kg CO2 per ton. In northern countries it is common to grow tomatoes in greenhouses, especially when they are out of season. The long transport of the tomatoes causes much less emissions than that.

This scientific article analyses the issue a bit deeper and concludes that “that the distance travelled by the tomatoes is not the most important environmental burden”. Whether the tomatoes were grown in greenhouses or not matters a lot, but there are many other factors. In short, it is complicated.

This study of local vs. imported tomato production in Canada concludes that locally grown tomatoes grown in greenhouses on average cause 1,070 grams of carbon emissions per kilo of tomatoes grown and tomatoes grown open field in Mexico cause 775 grams of carbon emissions per kilo of tomatoes, despite the 3,800-kilometer journey from Mexico to Ontario, Canada. The reason for the higher emissions for locally grown tomatoes is again that greenhouses use a lot of energy.

Naturally, this would change if you grew the tomatoes in season without using greenhouses. The article also notes that carbon emissions are not the only issue for sustainability. Water usage is another important factor.

The Problem with Locally Grown Vegetables and Fruits

Tomatoes are just one example. The same hold true for cucumbers, lettuce and salad greens, potatoes, bell peppers, hot peppers, green beans and other bean varieties, berries, pineapples, bananas, mangoes, other tropical fruits. In addition, some of these crops can deplete the soil and require large amounts of water, which can be bad if they are being cultivated in areas where water resources are already scarce such as growing avocados in California. In general, growing vegetables and fruits in their natural environment tends to be the most sustainable.

The Problem with Locally Grown Apples

The problem with apples tends to be the opposite, geography wise. In warmer areas, they might require significant water resources or chemical inputs to thrive. Apples from cooler climates need less water and fewer chemicals, reducing their ecological impact.

Photo by Pierpaolo Riondato on Pexels.com

Local versus Imported It’s Complicated

I should point out that growing locally sometimes being worse for the environment than importing does not mean that importing produce is better for the environment. It just means that it is complicated and that you need to make that determination on a case-by-case basis. The environment is also not the only concern. Another consideration is the protection of local farmers and the local economy.

My opinion is, instead of worrying a lot about local versus imported produce, it is better to focus on things that we know cause a lot of emissions. A dirty grid, coal power stations, a non-hybrid SUV with an internal combustion engine, unnecessary business trips, eating a lot of red meat, basically start with the low hanging fruit.

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EV Cars Indeed Emit Less Carbon Pollution

Super fact 29: EV Cars emit less pollution than Internal Combustion Engine Cars, even considering manufacturing, disposal and EV Cars being charged by dirty grids.

EV Cars emitting less carbon pollution is a Super Fact

At least here in Texas it is quite common to hear people say that EV cars do not reduce emissions. After all EV cars use electricity from the dirty grid. It is also frequently implied that environmentalists and people who care about fossil fuel emissions do not understand that the electricity for EV cars typically comes from the dirty grid. However, the environmentalists I know do know that. In fact, they typically know more and have sometimes done the math. This is why I consider it a super fact. We know that it is true that EV Cars emit less carbon pollution. This is a fact that matters, it is not trivia, and yet this fact is frequently disputed, argued over, or surprising to people.

EV Cars are more efficient than Internal Combustion Engines

For starters, EV cars are much more efficient than Internal Combustion Engine cars, or ICE, and even a coal-fired power plant is less wasteful than a car engine. The net result is that the emissions caused by EVs via the electrical grid are significantly less per mile. The miles per gallon equivalent (MPGe) for electric vehicles (EVs) varies by state/grid and depends on the model of the car but in general it is much better than for an ICE . Replacing gasoline-powered cars with EVs saves energy, regardless of the energy source used to recharge the EVs. For an ICE 16-25% of the original energy goes to the wheels whereas for an EV 87-91% of the original energy goes to the wheels.

16-25% of original energy goes to the wheels. Data from FuelEconomy.gov, Image by Karin Kirk for Yale Connections.

87-91% of original energy goes to the wheels. Data from FuelEconomy.gov, Image by Karin Kirk for Yale Connections.

The Manufacture and Disposal of EV Cars

It takes more energy to manufacture an EV battery for an EV car than it does to produce a combustion engine. So, the production of an electric vehicle does emit more carbon than a petrol car. However, the lower emissions resulting from driving an EV means that an electric car quickly pays back that debt, so to speak. It is typically paid back within two years, according to Hannah Richie, the research director at Our World in Data. The statistics show that switching from an average ICE to an equally sized EV will save 1.2 tons of carbon emissions per person and year. That is a lot considering that the average carbon footprint per year is 4 tons worldwide and 14.4 tons per year for an American.

So, are electric vehicles definitely better for the climate than gas-powered cars? This article from MIT answers the question in the affirmative. The graph below includes construction of facilities, manufacturing of vehicle and battery, production of fuel, vehicle operation as well as disposal. It is taken from this government website and this article also answers the question above in the affirmative. This is an article from the Department of Energy is stating the same thing.

Lifecycle greenhouse gas emissions comparison of average gasoline car and average EV.

Hannah Richie at Our World in Data also states that other environmental damages related to EVs such as mining for minerals are less than the damage from mining and extraction for fossil fuel cars, and she claims that the price of lithium-ion batteries has fallen by 98% over the last three decades. It should be noted that EVs are becoming increasingly common. According to Our World in Data in 2022, 88% of all cars sold in Norway were EVs and 54% of all cars in Sweden were EVs.

Other EV Myths

There are other EV myths that you may want to have debunked, such as Electric vehicle batteries are unreliable and need to be replaced every few years. In 2011 battery failures were common, 7.5%, but in 2023 battery failures were 0.1%. See this article for details and other myth debunking. A related post is my post on electrification.

I should add that there are some drawbacks with EVs such as the easy with which you can charge them, depending on your location. This post is not a promotion of EVs, and I do not drive an EV for various reasons. This post, like most posts in this blog, is about correcting misinformation and getting the facts correct.

To see the other Super Facts click here

Neanderthals Never Lived in Africa

Super fact 27: Neanderthals never lived in Africa. Neanderthals, or Homo Neanderthalensis, lived in Europe and Asia but never in Africa.

Reconstruction of a Neanderthal by Natural History Museum. Werner Ustorf, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons

It is a common belief that humans originated in Africa. That is true but human ancestry is complicated, and in the past, there were many human species and subspecies. Starting with Homo Erectus, it is estimated that they lived between 1.6 million years ago until about 100,000 years ago.

Homo Erectus was the ancestor of Homo Heidelbergensis (between 700,000 and 200,000 years ago) as well as Homo Floresiensis (hobbit people – between 100,000 and 50,000 years ago). Homo Heidelbergensis in turn was the ancestor of (at least) three homo species, Homo Sapiens (between 300,000 until now), Homo Neanderthalensis (between 400,000 to 40,000 years ago), and Homo Denisova 300,000 to 25,000 years ago.

However, note that Homo Neanderthalensis is not an ancestor of Homo Sapiens. Homo Heidelbergensis was an ancestor to both. Homo Neanderthalensis originated in Europe and Asia and stayed there, whilst Homo Sapiens originated in Africa and ventured elsewhere (see picture below).

Homo Neanderthalensis and Homo Sapiens (or Homo Sapiens Sapiens) interbred, and so did Homo Denisova and Homo Sapiens, and Homo Neanderthalensis interbred with Homo Denisova. What a mess! I can add that Homo Neanderthalensis and Homo Sapiens were different species, so it may seem strange that they could interbreed.

However, species is a complex concept and at certain points in history you could consider Homo Neanderthalensis and Homo Sapiens to be different subspecies rather than different species. That is why you sometimes hear the terms Homo Sapiens Neanderthalensis and Homo Sapiens Sapiens. Now when you know how complicated it is, I suggest you take a look at the map below.

The spread of Homo Erectus (yellow), Homo Sapiens (red) and Homo Neanderthalensis (dark yellow). NordNordWest, Public domain, via Wikimedia Commons

I can add that genetic testing can reveal how much Neanderthal DNA you have. I took a test with 23AndMe to find out about my ancestry (it was 98% Scandinavian and Finnish) and to find out about my risk for genetic illnesses. 23AndMe also told me that I was in the 99 percentiles with respect to carrying Neanderthal genes, meaning that I had unusually many Neanderthal genes (but not 99%). However, no one has called me a Neanderthal to my face yet.

The Extent of the Neanderthal Habitat

The map below indicates where skeleton remains of Neanderthals had been found as of 2017.

Known Neanderthal range in Europe (blue), Southwest Asia (orange), Uzbekistan (green), and the Altai mountains (violet), as inferred by their skeletal remains (not stone tools). There were 165 such places by 2017. Nilenbert, N. Perrault, auteur du guide complet du canotageI, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons

Other Neanderthal Facts

There are a lot of other interesting and surprising facts about Neanderthals, such as:

They lived in caves, but they also built shelters.
They had complex tools and skills, cooked and processed food and created art and jewelry, cooked glue, and had musical instruments (for example a bone flute).
Neanderthals not only used fire, they were able to control and maintain fire, and they used it to cook food, make tools, and for warmth and shelter.
Neanderthals were stockier and more muscular than modern humans, with broader rib cages and shorter limbs. This helped them conserve heat and survive in the cold environments in Europe and Asia during the ice ages.
They might have spoken language.
There’s evidence that they were seafaring as far back as 200,000 to 150,000 years ago.
Their brains were larger than ours. The braincases of Neanderthal men and women averaged about 1,600 cm3 and 1,300 cm3, respectively, which is considerably larger than the modern human average (1,260 cm3 and 1,130 cm3, respectively).
They had medical knowledge. They had knowledge of medicinal plants and well-healed fractures on many bones indicate the setting of splints. They also knew how to treat wounds.
They hunted big game.
They interbred with modern humans.

The Cause of the Ice Ages

Regarding the Ice Ages, which were a great challenge to Neanderthals, they are caused by earth’s orbital cycles. However, keep in mind that does not mean that orbital cycles are causing the current rapid global warming. NASA keeps track of the orbital cycles, and they should slowly be causing a cool down right now, not a rapid warming. In addition, if the warming was caused by orbital cycles (or the sun), the upper troposphere would be warming as well as the lower troposphere.

However, what we are seeing is a warming of the lower troposphere and cooling of the upper troposphere consistent with greenhouse gas emissions causing the warming (the blanket effect). To read more about what is causing the current global warming, click here.

Illustration of Milankovitch cycles from MIT’s Climate Primer.

Above from PBS explanation and overview of earth’s three orbital cycles.

Endangered Species

When I was a teenager, I read a few of Jean M. Auels novels about pre-historic humans. I loved them and I saw the movie. Now I am reading Jacqui Murray’s novels about pre-historic humans. Jacqui Murray’s books are even more fascinating and very realistic and well researched.

The latest Jacqui Murray book I’ve read is Endangered Species, the first book in her new series Savage Lands. This book is set to take place 75,000 years ago among Neanderthals and ancient Homo sapiens. I love all her books, but especially Endangered Species. I was also happy that she included canines as heroes in the book (Ump, White Streak, etc.) I am a dog lover after all. I can add that at the end of the book there are a lot of interesting Neanderthal Facts.

You can read my Amazon review for Endangered Species by clicking here and you can read my Virtual Book Blast post for Endangered Species (promoting this book) by clicking here. All the Virtual Book Blasts for Endangered Species feature interesting Neanderthal facts. To see a few more Virtual Book Blasts for this book click on the links in the list below.

Virtual Book Blast for Endangered Species – Darlene Foster – Click here
Virtual Book Blast for Endangered Species – Liz Gauffreau – Click here
Virtual Book Blast for Endangered Species – Carol Cooks – Click here
Virtual Book Blast for Endangered Species – John Howell – Click here
Virtual Book Blast for Endangered Species – Booomcha, Kymber Hawke – Click here

Front cover of Endangered Species. Click on the image to go to the Amazon page for the paperback version of the book.

To see the other Super Facts click here

The Special Theory of Relativity by David Bohm

The goal of this blog is to create a list of what I call super facts. Super facts are important and true facts that are nevertheless highly surprising to many, disputed among the public, or unnecessarily misunderstood. 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 Special Theory of Relativity by David Bohm

David Bohm a close colleague of Albert Einstein was one of the most interesting theoretical physicists of the 20^th century. This book “The Special Theory of Relativity” is one of the most interesting and thorough introductory books on the Special Theory of Relativity that I have come across. It is a series of lectures on the topic. It features algebra, equations, and a little bit of differentials but not too much.

You may want to have some math, physics and some relativity under your belt before you tackle this book. In my estimate it is written for those who have taken high school AP physics and AP algebra, maybe calculus as well, or one or two college level physics classes and math classes (or more). It is probably too basic for professional physicists, but it is not written for laymen. I bought the paperback version.

Hardback – Routledge; 1st edition (October 10, 1996), ISBN-10 : 0415148081, ISBN-13 : 978-0415148085, 256 pages, item weight : 13.6 ounces, dimensions : ‎ 5.75 x 0.75 x 9 inches. It is out of stock, and it costs $75.60 – $144.00 on US Amazon. Click here to order it from Amazon.com.
Paperback – Publisher : Routledge; 1st edition (September 4, 2006), ASIN : 0415404258, ISBN-13 : 978-0415404259, 304 pages, item weight : 12 ounces, dimensions : 5.08 x 0.69 x 7.8 inches. It is out of stock, and it costs $12.36 – $17.21 on US Amazon. Click here to order it from Amazon.com.
Kindle – Published : Routledge; 1st edition (September 29, 2015), ASIN : B009W3W6MG, 306 pages, it costs $10.10 – $13.77 on US Amazon. Click here to order it from Amazon.com.

Front cover of the paperback version of The Special Theory of Relativity by David Bohm. Click on the image to go to the Amazon page for the paperback version of the book.

Amazon’s Description of the Book

In these inspiring lectures David Bohm explores Albert Einstein’s celebrated Theory of Relativity that transformed forever the way we think about time and space. Yet for Bohm the implications of the theory were far more revolutionary both in scope and impact even than this. Stepping back from dense theoretical and scientific detail in this eye-opening work, Bohm describes how the notion of relativity strikes at the heart of our very conception of the universe, regardless of whether we are physicists or philosophers.

This is my five-star review for The Special Theory of Relativity

Note, I wrote this review in 2014, so it is relatively old, pun intended.

Lorentz Electrodynamics, Special Relativity, and our Perception of Reality

This book is a thorough and well written introduction to the “Special Theory of Relativity”. In addition to the basics of special relativity it covers the history of Special Relativity and it includes 60-pages of Lorentz Electrodynamics. The book also discusses Minkowski Diagrams, the Twin Paradox, relativistic Doppler effects, K-Calculus, and philosophy related to relativity. The book does not discuss General Relativity.

Bohm does not derive many formulas for electrodynamics, optics, quantum physics, thermodynamics, etc., and therefore this book does not resemble a textbook. Bohm’s focus is on a deeper understanding of the special theory of relativity itself, and on time and space.

He discusses perception of reality and includes discussions on child development, psychology and neurology related to perception, the meaning of the relational concepts in relativity, the structure of scientific revolutions (T.S. Kuhn), our perceptions of time and space, philosophy, and other related topics that cannot be classified as physics.

In K Calculus you draw the world lines of light pulses sent at constant intervals between different observers. Then you calculate what is essentially the Doppler factor K and uses it to explain what is going in relativity. In contrast the Lorentz transform is concerned with the space-time coordinates that you measure after taking into account that light have to travel a certain distance and that this takes time. Basically, the “actual time and space coordinates”.

K Calculus on the other hand is including both relativistic effects and the distance and time it takes for light to travel. K Calculus is thus not what you “measure” but what you “observe”. K Calculus makes it very easy to explain special relativity to an audience that is not strong in math and it also adds a new understanding to the special theory of relativity.

However, I see an inherent risk with K-Calculus in that it can end up fooling the student into believing that he understands relativity, for example, if a student incorrectly comes to believe that time dilation is some form of Doppler Effect.

Except for the fact that some of the mathematical derivations were unnecessarily complex I thought this book presented relativity lucidly, the philosophical discussions were insightful, and it added to my understanding of the topic. It should probably not be your first book on Special Relativity but it is a very good second book. I highly recommend it for those who want to think through the concepts of relativity a little deeper.

Back cover of the paperback version of The Special Theory of Relativity by David Bohm. Click on the image to go to the Amazon page for the kindle version of the book.