Human Vision Only Detects a Sliver of the EM Spectrum

Superfact 94: Light is electromagnetic radiation. The electromagnetic spectrum we deal with goes from long wave radiation at a frequency of 0.3 Giga Hertz to gamma rays at 30,000,000,000 Giga Hertz, and far beyond. Light that is visible to humans goes from around 428,000 Giga Hertz to 750,000 Giga Hertz. This is a very thin sliver in the electromagnetic spectrum. In addition, many animals can see beyond the spectrum visible to humans.

Esther’s writing prompt: April 8 : Vision

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If you consider wavelength instead of frequency, the electromagnetic spectrum goes from gamma rays at a wavelength of 0.00000000001 meters to long waves at a wavelength of 1,000 meters. Visible light has a wavelength of 0.0000004 meters to 0.0000007 meters. Again, human vision corresponds to only a thin sliver of the electromagnetic spectrum.

The picture shows the spectrum visible to humans as a horizontal bar at the top. This spectrum is superimposed on a wider spectrum below as a thin rainbow colored strip. The wider spectrum is also placed horizontally and goes from gamma rays to radio waves. | Human Vision Only Detects a Sliver of the EM Spectrum
The visible color spectrum. Sunlight wavelength and increasing frequency vector infographic illustration. Visible spectrum color range. Rainbow electromagnetic waves. Educational physics line. Shutterstock Asset id: 1933622132 by Shutterstock Asset id: 1933622132 WinWin artlab.
The electromagnetic spectrum is vertical and goes from long waves at the bottom to gamma rays at the top. The spectrum visible to humans is a thin sliver in the middle.
The spectrum visible to humans highlighted on a spectrum going from long waves to gamma rays. Original:  Penubag Vector:  Victor Blacus, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0&gt;, via Wikimedia Commons

It should be noted that the spectra above go from long waves to gamma rays because that’s the range of the spectra we typically deal with. However, the electromagnetic spectrum continues far beyond that.

I consider “Human Vision Only Detects a Sliver of the EM Spectrum” a super fact because it is a well-known fact among those who have studied physics, and it is an important fact, and yet I believe it is a surprise to many.

The Spectrum Visible to Animals

A lot of animals can see beyond the spectrum visible to humans. For example, animals that can see UV light including reindeer, scorpions, butterflies, bees, salmon, hedgehogs, many birds, amphibians, and reptiles. Humans cannot see UV light. You can read about various animals that can see UV light here, here, and here.

It appears that dogs and cats can see UV light as well. The color vision of dogs is in general poor, at least on the red side of the visible spectrum. However, dog vision includes UV light that we cannot see.

There are two colorful horizontal bars in the picture representing how the spectrum appears to people and dogs. The top bar depicts human’s view, and the bottom one is dog’s view. The human’s view is more colorful, but the dog’s view extends into UV light on the left.
Picture is from psychology today.

Many animals can also see or detect infrared radiation. A famous example are snakes. However, many other animals can detect infrared radiation including mosquitos, beetles, and other insects, some bats, bullfrogs, wolves, foxes, and some fish.

My Other Responses to Esther’s Prompts

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Deadliest Civil War Was the Taiping Rebellion

Superfact 93 : Around 20 to 30 million people died in the Taiping Rebellion, 1850 to 1864. It is the deadliest civil war in known history, the deadliest war in the 19th century, and the second deadliest war in all of known history. World War II was the deadliest.

The graphics show differently colored circles corresponding to selected large wars. World War II – 80 million, Mongol conquests – 45 million, Taiping Rebellion – 25 million, World War I – 18 million, Russian Civil War – 10 million, Chinese Civil War 7 million, 30 years’ war 6 million, Napoleonic Wars – 5 million, Second Congo Civil War 4 million, Vietnam War 2.45 million, American Civil War 0.7 million. | Deadliest Civil War Was the Taiping Rebellion
The number of deaths cited in the graphics above are rough midpoint values of the estimates. The area of the circles corresponds to these midpoint estimates. Note Mongol conquests correspond to multiple wars during a time period of 162 years. The ‘M” corresponds to millions.

The Taiping rebellion is estimated to have caused the deaths of 20-30 million people. However, some estimates estimate that as many as 70 million people might have died in the Taiping rebellion. The Mongol invasions and conquests cost 30-60 million lives, but they comprised many wars and took place during a time period of 162 years (1206 – 1368). Therefore, you typically don’t count that as one war. Also note that the estimate for deaths caused by World War I does not include the Spanish flu.

I consider this a super fact because it is true, an important history fact and despite the enormous losses in the Taiping rebellion, a lot of people have never heard of it.

Photo by jefe king
Photo by jefe king on Pexels.com

Deadliest Wars

Illustration of Chinese warriors preparing outside a fortified city.
Taiping Rebels at Shanghai China in 1853-54. ‘Small Swords’ refers to daggers used by warriors or martial artists in close combat. 19th century print. Stock Illustration ID: 237232531 by Everett Collection.

The links above are from Encyclopedia Britannica and from Wikipedia. Also note that after the Napoleonic Wars entry I only listed wars that happened after World War II and resulted in around a million deaths. The exception is the American Civil War. The list would be too long otherwise.

The Taiping Rebellion

The Taiping Rebellion was a civil war in China between the Qing dynasty and the Taiping Heavenly Kingdom. The Taiping Heavenly Kingdom was a theocratic monarchy that tried to overthrow the Qing dynasty. It was led by Hong Xiuquan, a religious leader who believed he was Jesus younger brother. In the end the Qing dynasty prevailed but at a great cost.

A map of China in the 19th century. It shows the extent of the Taiping Heavenly Kingdom and how it shrunk. | Deadliest Civil War Was the Taiping Rebellion
A map showing the extent of the Taiping Heavenly Kingdom. The dark area is the extent towards the end. M.Bitton, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons.

To read a related post of mine with a different perspective see “We are living in relatively peaceful times“.

To see the other Super Facts click here

Reindeer Hide Memories

A photo of a reindeer walking up a hill. | Reindeer Hide Memories
A mountain reindeer (R. t. tarandus) from Sør-Varanger, in Norway. Are G Nilsen, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons. Photo is from this Wikipedia page.

Today is the second time I participate in Linda Hill’s streams of consciousness. To read about the rules and participate click here, or here. To read my previous entry (prompt was pre) click here. Today’s prompt for Stream of Consciousness Saturday April 4 is “hide”. Use it way you’d like. The first rule is: there should be minimal planning and no editing except typos.  First thing that came to my mind was reindeer hide. Notice that this is not a super fact post, but just a general informational / factual post. In addition, to writing about my experiences with reindeer hides I also downloaded a few pictures from Wikipedia.

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

Reindeer Hide Memories

I grew up northern Sweden where there are a lot of reindeer and reindeer hides. When we drove around on the north Swedish countryside, we often saw reindeer at the side of the road. Sometimes there were flocks of reindeer blocking the road. Unlike many other animals reindeer tends to be a little bit stupid about traffic and quite often they walked right in front of the cars. The risk for collision was quite high.

Reindeer Hide Memories |Distribution of Rangifer tarandus (Caribou/Reindeer) Red - Reindeer Around The World
Distribution of Rangifer tarandus (Caribou/Reindeer) Red – Reindeer (orange: introduced populations) Green – Caribou. TBjornstad 11:46, 31 October 2006 (UTC), Public domain, via Wikimedia Commons. Image is from this Wikipedia page.

A related interesting fact is that the in northern Sweden, Norway, Finland and parts of Russia there is an Aboriginal people referred to as Sami. They are / were traditionally a nomadic people who followed and herded the reindeer. Reindeer hide is a very important item for the Samis, and used for clothing, footwear, tents, drums and musical instruments, rugs and bedding. Reindeer hide is also an important cultural item for us “regular” north Swedes. When I was a kid, we used reindeer hide for bedding, decoration, wall ornaments, and for cover when sitting outside on the snow or the ice.

A flock of reindeer with a person standing in the middle of them.
Reindeer herding. Mats Andersson, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0&gt;, via Wikimedia Commons. Photo is from this Wikipedia page.

My kids here in Texas also have some experience with reindeer hides. When they were little, we visited the ice hotel in Jukkasjärvi in northern Sweden. The ice hotel in Jukkasjärvi is the original and largest ice hotel in the world. The beds in the ice hotel are made of ice and covered by reindeer hide to make it warm and soft. We also took a dog sled tour, and the sled was covered by reindeer hide for comfort. Below are some photos of us on a dogsled with reindeer hide and photos of ice beds with reindeer hide, including our room. I got these photos from my personal and very old family website.

My wife is sitting at the end of the sled and in front of her are the kids. Everyone is bundled up.
We are going on a dogsled tour. The ice theater is in the background, and you can see part of the ice hotel on the right. Notice the reindeer hide on the sled.
The photos show a dogsled with dogs and some people. The kåta on the left is pretty prominent in this photo. | Reindeer Hide Memories
On the left is a kåta, a movable Sami structure (indigenous arctic Scandinavian people). Kåtas were traditionally made with reindeer hide.
Stig left and Ulla right sitting on an ice bed in their room.
My dad Stig and his girlfriend Ulla came with us on the trip. Notice the reindeer hide on the ice bed.
We are all laying on top of our ice bed. We are inside our sleeping bags except my head and part of my body is out of the bag.
We are going to bed in our room. I think it was my wife Claudia who took the photo. Notice the reindeer hide on the ice bed.
There is a huge ice and snow decoration on the wall featuring an angry looking face.
Another room with a snowy wall decoration. Notice the reindeer hide on the ice bed.
A close up of an elaborate ice bed. | Reindeer Hide Memories
Some of the rooms were really beautiful. Notice the reindeer hide on the bed.
An ice room with an ice motorcycle and other ice art
Some of the rooms had beautiful ice art. Notice the reindeer hide on the bed.
A very large ice bedroom.
You had to pay more for a big room. You paid the price of Hilton and got the comfort of camping in winter. Notice the reindeer hide on the bed.
An ice bedroom with an ice statue of a moose. | Reindeer Hide Memories
More ice art. Notice the reindeer hide on the bed.
To see the Super Facts click here

College Tuition Tripled in 25 years

Super fact 92 : College tuition and fees increased by 207% between 1997 and 2022, which corresponds to a tripling.  Since 2022 it has continued to increase. Adjusted for inflation this corresponds to a 60% increase, more than any other major economic sector.

A man is being sucked into a hole filled with money. | College Tuition Tripled in 25 years
Students are sucked into a hole with money for college tuition. Shutterstock Asset id: 335014478 by alphaspirit.it.
The graph shows the percentage increase of college tuition and fees, Day care and preschool, medical care. Household energy, Housing, Food and beverages, public transport, new cars, Clothing, Computer software and accessories, toys, Televisions.
Data source: US Bureau of Labor Statistics (2026). OurWorldInData.org/technological-change. Note: Some services such as medical care are not adjusted for quality, some treatments have decreased in price rather than increased. To visit the original page for this graph click here or on the picture.

To read about the graph above in greater detail click here. To read more about the increase in college tuition click here, here, here, or here. To calculate the inflation for different periods of time click here (the inflation calculator).

It should be noted in the graphs above that Televisions have decreased in price by 98%, which seems implausible. However, it is not an April 1st joke. It is not April 1st in Texas yet (where I live). The reason for the large decline in price of Televisions is that quality is taken into account. 20 years ago, you could not easily buy the kind of TVs you can today and if you did you would cost you an enormous amount of money. You get a lot more for a few hundred bucks than you did 20 years ago.

This is a superfact because it is true, shocking, and important to how we live.

Why have college Tuition become so expensive?

College tuition has increased so much due to administrative bloat, increased student loan availability, declining state funding for public institutions, and heavy spending on amenities to attract students.

An example of heavy spending on amenities is college sports. I studied at a university called Uppsala University, which is a very large University founded in 1477. It is considered one of the world’s top Universities (top 50). However, they do not have any competitive teams associated with the University itself. In 1987 I was sent as an exchange student (electrical engineering) to Case Western Reserve University, in Cleveland, Ohio. Case Western Reserve University has some competitive teams associated with the University but only a small college football stadium.

However, I quickly came to realize that many American universities have huge college football and baseball stadiums. This is an added expense that you rarely encounter in the rest of the world. Universities are for studies and for learning. Sports teams, whether it is soccer, or American football is a separate issue.

Aerial photo of a large football stadium. | College Tuition Tripled in 25 years
BLOOMINGTON, US – Aug 04, 2025: Side-angle drone view of Indiana University Memorial Stadium with field, stands, and cityscape on a clear summer day. . – Shutterstock Asset id: 2700467103
To see the other Super Facts click here

Science History of the Greenhouse Effect by Craigvad

I came across a very interesting post about the science history of greenhouse effect: “The Greenhouse Effect: From Early Chemistry to the Keeling Curve” by Craigavad miscellany a science blog written by a retired academic. It is a very educational and interesting post related to this topic. Please take a look.

The Greenhouse Effect: From Early Chemistry to the Keeling Curve
Curve showing CO2 concentration starting 10,000 years ago. Again a very sharp uptick towards end. | Science History of the Greenhouse Effect by Craigvad
From Scripps institute. Keep two things in mind. First the warming from CO2 is delayed and may result in positive feedback that can manifest decades and centuries later. Secondly, human civilization developed during a period of stable climate. That CO2 levels and temperatures were higher millions of years ago is not much comfort.

To see the Super Facts click here