The physics behind the color of the sky on Earth and on Mars

Photo by Jose Rago on Unsplash

Why is the sky blue during the day and what makes the sunset red? Why is it almost the opposite on Mars?

Sunsets are red
Clear skies are blue
Rayleigh Scattering
Makes it all be true

Why the sky is blue

The phenomenon responsible for the color of our sky is Rayleigh Scattering. It is also the reason why a Martian sunset is blue, while the color of the Martian day sky is for different reasons, which I will discuss later.


Funny thought, but an electron would not have enough mass to bend the spacetime around it and hence make stars orbit around it (as is the case with our black hole in galactic center) or bend the light coming from behind. What would the orbiting stars be, if the supermassive black hole was an electron?


Apollo missions, China’s lunar far-side mission, and Lagrange points

The Chinese relay satellite can bridge communication between Earth and the far side of the Moon. Image credits: China Aerospace Science and Technology Corporation.

Not since Adam has any human known such solitude as Mike Collins is experiencing during this 47 minutes of each lunar revolution when he’s behind the Moon with no one to talk to except his tape recorder.
— Mission Control Statement, refering to biblical figure

Apollon missions and the far side of the Moon

Due to Earth's gravitational pull, the Moon is tidally locked, rotating at the same speed as it orbits Earth, consequently facing one side towards us, while the other is forever hidden from our sight. This is the far side of the Moon. …


My Top Medium Articles 2019–2020

Image by Comfreak from Pixabay

This is a collection of 12 of my most popular Medium stories and a little reflection on what made them popular.

1. We All Travel Through Spacetime at the Speed of Light

28K views, 9.7K reads, 277 fans, 130hr 20 min reading time (Dec 2019)

My most viewed and most-read article is about speed through the 4D Minkowski spacetime. Everything travels at the same speed if we include the 4 dimensions of spacetime, hence the three spatial dimensions and one temporal. The faster your travel through space, the slower through time. If you stand still in space, you travel at maximum speed through time.

2. How to Rewire Your Brain

13K views, 6.9K reads, 628 fans, 201hr…


How your mind makes up stuff to make sense of it all

How we perceive colors at different wavelengths of light. Photo by Mirza Babic on Unsplash

“Color is the place where our brain and the universe meet.” — Paul Klee

Is the sky really blue? Is white color made up of all colors? It sure seems like it, but it only does so, because our brain makes up such properties.

You have probably learned in school, that light is an electromagnetic wave, and the wavelength of this wave will determine the color of the light if it’s in the visible spectrum. …


An underrated material with fascinating properties

Recently, I had a muscle biopsy that was taken from my thigh — for science(!), of course. After the biopsy, the researcher said that I had a very resilient fascia. Usually, the fascia would become “mushier” with age, he said. (Did he just call me old? Oh well … 140+ is no age for a dragon!)

I was like: “The fascia? What is fascia?”

“It’s a thin film between the muscle and the rest of your body,” he said.

I got curious, and when I got home I did a little research. Apparently, it’s fascinating and not that well-known tissue…


6 categories of scientific curiosity and how to use it to your advantage

Photo by Dimitri Houtteman on Unsplash

“The cure for boredom is curiosity. There is no cure for curiosity.” — Ellen Parr

What is curiosity and how is it related to science and scientific thinking? Neil deGrasse Tyson said:

“When I think of science and scientists I think of kids who never lost their curiosity and wonder and then woke up one day as adults with the very same sense of search for what is and what is not true in the world.”

As children, we were naturally curious. We had to learn everything about the world and our place in it from scratch, we got the…


Caffeine is not the only reason for coffee!

Image by Wolfgang Eckert from Pixabay

I recently read about the natural biorhythms of hormones following our inner circadian clock. Cortisol is rising in the morning and awakens you together with higher levels of adrenaline. This means that in the very early morning, you are naturally awakened by your own body (although I am sure that it works for some better than for others. I’m already an early bird, so easy for me to say, right?).


The stars within 10 lightyears and their quirks

Image based on images from Canva Pro.

“What’s the point of racing around the galaxy if you aren’t going to have fun?”― Zoraida Córdova, A Crash of Fate

We live on a spinning globe orbiting around a yellowish star in one of the spiral arms of the Milky Way. The daily spin makes the view of the neighboring stars of the Milky way seem to rotate one round around us daily, but as we only see the stars at night when the planet surface turns away from the Sun, we only see about one half of them.

It’s a good thing that the planet also goes around…


I missed the “Three Quarks Walk Into a Bar” opportunity there, but maybe next time!

Does it have any choice?

Lenka Otap

Computer scientist and almost-astrophysicist. Curious about life, the universe, and everything. Are you too? https://www.facebook.com/groups/scienceandcuriosity

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