Thomas Stig Wikman – Super Facts

EVs are Replacing the Internal Combustion Engine

Superfact 107: Electric vehicles are rapidly replacing the internal combustion engine (ICE cars) and are becoming commonplace around the world. It is analogous to how cars once replaced the horse and buggy.

In Norway close to 100% of all new cars sold in 2025 were electric vehicles. Around the world a substantial percentage of new cars sold in 2025 were electric vehicles. This phenomenon is not as visible here in the US, where I live, but if you travel, you’ll notice.

The graphs below show that the share of new cars that were sold in 2025 that were EVs was substantial, but more importantly there is a sharp upward slope of the curve(s). The share of new cars sold in 2025 that were electric was in respective region or country: Norway 97%, Denmark 71%, China 53%, European Union 27%, World 25%, the United States 10%. The graphs are taken from this page on the Our World in Data web page. I encourage you to play around with the interactive graphs. You can read more about new cars sales in Norway here.

It should be noted that electric cars include fully battery-electric and plug-in hybrids. With battery-electric cars is meant cars or other vehicles that are powered entirely by an electric motor and battery, instead of an internal combustion engine. With plug-in hybrid is meant cars or other vehicles that have a rechargeable battery and electric motor, and an internal combustion engine. The battery in plug-in hybrids is smaller and has a shorter range than battery-electric cars, so over longer distances, the car starts running on gasoline once the battery has run out.

This is a fact that is important, and that likely comes as a surprise to people living in countries that are lagging in this transition, such as the United States. Therefore, I consider it a super fact.

The Share of EVs

The sharp increase in the sale of electric cars is a recent phenomenon and therefore there are still a lot of ICE cars on the roads. Therefore, there is a significant difference between the share of electric vehicles on the road and the share of new cars sales being EVs. The share of electric cars on the roads in 2024 was in the United States 2.7%, in the world 4.5%, in China 11%, in Sweden 13% and in Norway 32%. See the graph below.

The graph shows the share of cars currently in use that are electric for the world, the United States, China, Sweden and Norway. — Share of cars currently in use that are electric, 2010 to 2024. Data source: International Energy Agency Global EV Outlook 2025. OurWorldinData.org/energy | CC BY

The graph below illustrates the sales of fully battery-electric cars versus plug-in hybrids.

The bar graph below is an alternative illustration showing the share of new cars sold that are electric in 2024 for the world and 8 countries.

The bar graph shows the share of new cars sold that are electric in 2024 for the world and 8 countries. The numbers are India 2.1%, the United States 10%, Germany 19%, European Union 21%, United Kingdom 28%, China 48%. Sweden 58%, Norway 92%, and the World 22% — Share of new cars sold that are electric, 2024. Electric cars include fully battery-electric and plug-in hybrids. Data source: International Energy Agency Global EV Outlook 2025. OurWorldinData.org | CC BY

This article states that there are now more new electric cars sold in the EU than ICEs. However, it should be noted that they include hybrids (non-plug-in) in this number.

Are EVs cleaner than ICE cars ?

Yes, they are. EV Cars emit less pollution than Internal Combustion Engine Cars, even considering manufacturing, disposal and EV Cars being charged by dirty grids. Basically, this is because burning oil to move a vehicle creates significantly more heat than motion. I created another super fact post that explains the details called: super fact (29) EV Cars Indeed Emit Less Carbon Pollution. You can read more here.

There are concerns about the mining of minerals for EV cars, such as cobalt and lithium, which has an environmental impact. However, this environmental impact should be compared to the environmental impact caused by the drilling and transport of oil (and the burning of gas/oil). In general, the environmental impact of EVs is considered much less. In addition, EV batteries last a long time, and 95% to 98% of the valuable materials in EV batteries (lithium, cobalt, nickel, and copper.) can be recycled/recovered. You can read about other EV myths here. However, this is probably a topic for a future super-fact.

To see the other Super Facts click here

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We Can See What Stars Are Made of

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The Sun is White but the Sky steals its Blue

Superfact 105: The Sun is white, but the Sky steals its Blue is a poetic way of saying that the sun’s light is scattered by the atmosphere giving the Sun a yellowish tint as well as giving us our blue sky. From space the sun looks completely white.

Viewed from space the sun is entirely white. White light consists of a mix of all the colors of the rainbow. However, viewed from earth the sun has a yellow tint, which gets more pronounced, it even dips into orange, as the sun nears sunset. That does not happen in space as can be seen below in the one minute sunset timelapse video taken from the International Space Station.

Sunset Timelapse from the International Space Station

On earth the sunset looks more like something in the picture below.

The sun is setting over distant mountains. There are some clouds, a forest, and field in the foreground. The sun has a yellow tint; the clouds are slightly yellow-orange and sky above is blue. | The Sun is White but the Sky steals its Blue — The sky dusk has a dramatic background featuring a summer season golden sunset landscape. The light is at the horizon is an orange and yellow color with blue sky above. Shutterstock asset id: 2670235703 by Nature Peaceful

The sun is a so called yellow dwarf star, or a G-type main-sequence star. The term yellow dwarf is a bit of a misnomer, because they range in color from white, for more luminous G-types like the Sun, to only very slightly yellowish for less massive and less luminous G-type main-sequence stars. The sun emits all the colors of the rainbow simultaneously, but the most dominant color is green. However, this looks white to us.

When sunlight enters Earth’s atmosphere, tiny air molecules scatter shorter, blue wavelengths of light in all directions. This scattering is what makes the sky look blue. This is called Rayleigh scattering. Because much of the blue light is removed, the remaining wavelengths of light that reach your eyes combine to make the sun appear yellow. This is a super fact because it is a basic but surprising fact, and we know it is true.

Rayleigh Scattering

The blue color of the sky is caused by Rayleigh scattering of sunlight by the gases in the Earth’s atmosphere. The image below shows the degree to which Rayleigh scattering occurs at different wavelengths / frequencies of light. Blue has the shortest wavelength (highest frequency) for visible light and red the longest (lowest frequency). The curve shows that blue light scatters more than red light. It should be noted that UV light (not shown) scatter even more. The scattering curve shown is calculated for sunlight passing vertically through the atmosphere.

The graph shows the amount of scattering going from shorter wavelengths (higher frequences) on the left, to longer wavelengths (lower frequences) on the right. Blue has shorter wavelengths and red has longer wavelengths. The graph shows that blue scatter the most. — Figure showing the greater proportion of blue light scattered by the atmosphere relative to red light. Robert A. Rohde derivative work:KES47 (talk) (converted to SVG)., CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons.

To see the Other Super Facts click here

Stars Twinkle but Planets Do Not

Super fact 102: Stars twinkle but planets do not. Planets reflect sunlight, like the moon, whereas stars emit intense light like the sun. However, stars are thousands of times further away.

The Sun and the Moon appear to have roughly the same sized disk in the sky, about 0.5 degrees of arc, because the Sun is roughly 400 times wider than the Moon but also about 400 times farther away. However, the moon, which reflects sunlight but does that emit any, is much fainter than the sun in our sky. The Sun provides approximately 400,000 times more light to Earth than the full Moon. If you were to move the sun farther away until it provided the same amount of light as the moon you would have to move the sun 632 times farther away until it became a tiny point in comparison to the moon.

The planets in our solar system, Venus, Jupiter, Mars, Mercury, Saturn, etc., appear in the sky as small discs reflecting light whereas the stars appear as intense points of light with a disc diameter that is thousands of times smaller than that of the planets. However, we can’t see the difference with the naked eye. Both planets and stars appear like points of lights to us, but the difference in disc size in the sky is very big.

The picture shows a big bright star (but much smaller than the sun) shining down on planet Earth lighting up the planet a bit. The light from the star is intense. | Stars Twinkle but Planets Do Not — Planets reflect light whereas the stars appear as intense points. Shutterstock asset id: 2709145593 by buradaki

Because stars are tiny intense points of light Earth’s atmosphere can easily refract (bend) their light. This is known as scintillation. I can add that the light from stars that are low in sky go through more atmosphere and therefore twinkle more. Since planets appear as tiny discs rather than tiny points, planets create a steadier beam of light, which averages out atmospheric turbulence. In addition, dust particles in space and in the atmosphere can more easily block the light from stars compared to that of planets, because the planets have much larger discs in the sky (thousands of times larger).

In the picture there is a disc representing a planet and a little yellow star and a small piece of space dust. The text says, “In a telescope the planet looks like a little disc whilst the star is still a bright point. However, to the naked eye both look like a star. Guess which one the space dust can make to twinkle by passing in front of it.” — To the naked eye a planet and a star point look light points of light. In a telescope the planet will turn into a disc, but the star will remain a bright point of light. For example, a piece of space dust can easily make the star twinkle by moving in front of it but won’t do that to the planet. Note: planets are much smaller than stars, but they are much closer and can look bigger.

Since this fact is not scientifically under question, a lot of people don’t know it, and it is kind of important to anyone interested in the night sky, I consider it a super fact. I should say that I borrowed this super fact from Jacqui Murray’s blog worddreams.

Planets Reflect Light like the Moon

Planets reflect light. They don’t shine and emit light like the sun or the stars.

A colorful photo of Jupiter (orange and white) including the Great Red Spot. — Jupiter in true color, taken by the Hubble Space Telescope in January 2024

A photo of Saturn including the impressive rings. — Saturn and its prominent rings, as captured by the Cassini orbiter. This natural color view of the planet Saturn was created from images collected shortly after Cassini began its extended Equinox Mission in July 2008.

This picture features the photo of Pluto taken by NASA’s New Horizons spacecraft in 2015 plus some text. | Stars Twinkle but Planets Do Not — Pluto from NASA/JHUAPL/SwRI. NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute, Public domain, via Wikimedia Commons. NASA’s New Horizons spacecraft captured this high-resolution enhanced color view of Pluto in 2015.

To see the other Super Facts click here

We Can See What Stars Are Made of

Super fact 101: We can see what stars are made of and calculate their speed and distance compared to us just by looking at their light.

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. | We Can See What Stars Are Made of — 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.

Electromagnetic radiation, including visible light, features a lot of different frequencies, which for light correspond to different colors. Red has a lower frequency, and blue has a higher frequency. For more information about the electromagnetic spectrum and light see Human Vision Only Detects a Sliver of the EM Spectrum.

If you place a light bulb (white light includes a spectrum of colors) in front of a container filled with hydrogen and then you let the light pass through a prism, it will split into the different colors (red, yellow, blue, etc.) forming a rainbow, as prisms do. You see this every time you see a rainbow in nature. However, if you measure carefully, as in the experimental setup below, you will notice that some frequencies are missing. That’s because the hydrogen gas will absorb certain frequencies.

This is true, not just for hydrogen, but for all elements/atoms and molecules. Atoms and molecules have light absorption patterns that are unique to the atom/element in question. The dark lines in the spectra are referred to as Frauenhofer lines. In a sense, all elements have a thumb print resulting from their so called absorption spectra. This makes it possible to identify the elements in a star and their proportions.

On the left a light bulb generating white light, which is split into a rainbow by a prism. On the wall behind the prism you’ll see all the colors, except a few frequencies indicated by black lines, will be missing. — Absorption spectrum / Frauenhofer lines of the hydrogen atom. Shutterstock asset id: 1305568666 by Emir Kaan

Before the discovery of absorption spectra, it was sometimes believed that humanity would never know the chemical elements of stars. Even today many people are surprised to hear that we can indeed know what stars are composed of just by looking at their light. In addition to identifying elements in the upper layers / atmosphere of stars you can use the same absorption spectra to determine the relative velocity of stars compared to us and sometimes the distance to the stars. This is an old discovery that is surprising and important to our understanding of the world and therefore a super fact in my opinion.

Examples of Absorption Spectra

An interesting, related fact is that Helium was discovered in the Sun before it was found on Earth, with the help of emission spectra (August 18, 1868). Emission spectra are the opposite of absorption spectra. It should be noted that while emission spectra are commonly used for identifying the composition of interstellar gas, absorption spectra are commonly used for identifying the composition of stars.

Absorption spectra showing the colors of visible light with black lines characteristic for Helium. — Absorption and Emission Spectrum of Helium Shutterstock asset id: 1724296909 by MoFarouk

Absorption spectra showing the colors of visible light with black lines characteristic for Carbon. — Absorption and Emission Spectrum of Carbon Shutterstock asset id: 1725934867 by MoFarouk

Absorption spectra showing the colors of visible light with black lines characteristic for the sun. | We Can See What Stars Are Made of — Solar spectrum with Fraunhofer lines as it appears visually. The solar spectrum is a combination of spectra from multiple elements: nl:Gebruiker:MaureenVSpectrum-sRGB.svg: Phrood~commonswikiFraunhofer_lines_DE.svg: *Fraunhofer_lines.jpg: Saperaud 19:26, 5. Jul. 2005derivative work: Cepheiden (talk)derivative work: Cepheiden, Public domain, via Wikimedia Commons.

Using Redshift to Determine how fast Stars are Moving Compared to us

A star or galaxy that is moving towards us will have a blue shifted spectrum. A star or galaxy that is moving away from us will have a red shifted spectrum. Red shifted means that the absorption lines have moved towards red because the frequency of the light has been shifted due to the motion.

This is called the doppler effect. You can notice this phenomenon for the case of sound when an ambulance is coming towards you and then speeding by you. The sound changes. The astronomer Hubble was using redshift to the determine that the further away a galaxy was from us the faster it was moving away from us. Measuring the redshift of a faraway galaxy or star, not only tells us its speed compared to us but can indirectly help us determine the distance to the galaxy or star.

The top shows a colorful spectrum from blue to red with absorption lines in black. The bottom portion of the picture shows the same thing expect the black absorption lines have moved a bit to the right. | We Can See What Stars Are Made of — Visualization of redshifted absorption lines are redshifted due to velocity away from observer. Top lines are for an object at rest and in the bottom picture the object is moving away. Maxmath12, CC0, via Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.

There are other things you can tell from the light from stars and from their electromagnetic spectrum such as the type of star, the size of the star, and the age of the star, but that is for another post. This post is long enough.