Six Science posts #93

Two moon nights, pumpkins on Mars, coffee stains on digital documents and more

Author

Harshal Chhaya
October 28, 2025

Hi friend,

This issue is delayed because I was away from my PC, volunteering at a local high school robotics competition, on Sunday.

I enjoy volunteering at these events, at science fairs, debate competitions and other similar K-12 contests because they give me hope. It is very inspiring to see the next generation showcase their talents and learn important life skills like team work, resilience and problem solving.

Most of these volunteer roles do not need any prior technical expertise. If you are interested, let me know and I can share ways that you can get involved.

Now, on to other inspiring info - 6 posts chock full of science and engineering and technology.

Love,

Harshal

#1 🤯 

So cool!

We are in an era of two moons!

P.S. Does this mean we can re-classify Pluto as a planet?

#2 🤯 

Moore’s law is not a suggestion, it’s the law

#3 🤯 

I am very conflicted about the hundreds and thousands of satellites - they enable connectivity for everyone but mess up night-sky watching 🙃 

#4 🤯 

I love concrete goals

Let’s colonize Mars - not to escape Earth, but to grow gigantic pumpkins.

Let’s go! 🚀 

#5 🤯 

GPS and Google Maps are amazing examples of engineering success

There are cathedrals everywhere for those with the GPS to find them!

#6 🤯 

How cool that the tool allows you to choose one of 4 coffee stains

1. 270◦ circle stain with two tiny splashes

2. 60◦ circle stain

3. two splashes with light colors

4. a colorful twin splash

Documentation: https://ctan.math.washington.edu/tex-archive/graphics/pgf/contrib/coffeestains/coffeestains-en.pdf

This is issue #93. Let’s see what makes 93 an interesting number:

93 is:

  • the 9th semiprime the form (3.q) where q is a higher prime.

    • the first number in the 3rd triplet of consecutive semiprimes, 93, 94, 95

  • a repdigit in base 5 (3335), and 30 (3330).

  • palindromic in bases 2, 5, and 30.

  • The atomic number of neptunium - symbol Np

    • It’s named after the planet Neptune since it is after Uranium that was named after Uranus

  • The code for international direct dial phone calls to Afghanistan.

  • One of two ISBN Group Identifiers for books published in India.

  • The historical definition of the “astronomical unit” (AU) (a measurement of length) was the average Earth-Sun distance which was about 93 million miles.

    • The astronomical unit is used primarily for measuring distances within the Solar System or around other stars

    • In 2012, the AU was re-defined to be exactly equal to 149597870700 m (about 92.95 million miles)

About

This newsletter is my way of sharing interesting science-related news with my curious friends. I enjoy finding science and math connections in our world.

Please share this newsletter with others. Let’s encourage curiosity.

- Harshal (@hschhaya on X/Twitter)

That’s it for this issue.

Hit ‘reply’ to tell me what you think.

And hit ‘forward’ to share with your friends and family.

Let’s all celebrate science and engineering and curiosity.

Best wishes,

Harshal

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