When is your next stellar birthday?

Introducing the first way to connect yourself with the Universe and how to start thinking as an interstellar civilization

The concept of Stellar Birthday

It’s 2.14pm, I’m looking at the blue sky and the sun is shining. Let’s imagine the sun would turn off NOW. What would happen? Yes, I would realize the sun turned off only 7 minutes later.

As you probably know, when you look at the sky and see a star, you actually see the star as it was x years ago, with x depending on the distance from Earth. Astronomical distances are expressed in light years. 1 light year is the distance that light travels in vacuum in one Julian year. The speed of light in vacuum equals to 299,792,458 m/s, so 1 light year is equal to just under 10 trillion kilometers (or about 6 trillion miles).

Sirius (the brightest star in the sky) is 8.6 ly distant from Earth. It means that at any time we see Sirius we see it as it was 8.6 years ago. Assuming a year being of 356 days and therefore 0.6 years being 214 days, we could all celebrate our “Sirius” birthday 8 years and 214 days after our birth: looking at the star we would be reached by photons that left Sirius the day we were born.

This is the idea of the stellar birthday.

Agricultural Birthday vs Stellar Birthday

I had never heard about stellar birthday before. I was introduced to the concept just few weeks ago over lunch by one of the many differently free people I’ve the pleasure to encounter daily in our community at Exosphere, and it was presented as an alternative to the agricultural birthday.

The Gregorian Calendar and therefore birthdays have an agricultural genesis. For thousands of years life for almost every man on Earth has been a daily effort to feed himself or others. Especially after the agricultural revolution, seasons had a huge impact on that effort. Life meant going from season to season, from harvest to winter again and again. It was reasonable to start divide time in years. And ultimately there is an astronomic reason to this: a year is the orbital period of the Earth moving in its revolution around the Sun.

But isn’t the celebration of birthdays becoming absurd in the era of social networks and space exploration? Our human civilization is starting to be an interplanetary one. Tomorrow, when you will live on Earth but your son will grow up in Mars, or Venus, how are you going to connect his age in years with yours?

The main point is that the agricultural birthday is geocentric. It works when our “universe” is constrained to this planet. We share the context of a planet and its revolution around a star, and therefore we can count time based on this. But as soon as our civilization will expand to other planets we will need to find a non-geocentric way of counting time. As interplanetary civilization we will have to upgrade our calendars.

Even if the Stellar birthday is planet-centric as well, it could be a good alternative as long as our civilization will stay in the context of the solar system: it would work because the distance between planets in the solar system is forgettable from the perspective of the speed of light and light years. Another solution will be needed when we will go beyond the borders of our solar system.

There are more thoughts to put in this. For example counting time with stellar birthdays we loose regularity as there is no fix repetition (as with years). Probably we will integrate our julian calendar with the new Julian calendar (interplanetary based) and then with the newnew Julian calendar (interstellar based).

How to know when your next Stellar Birthday will be

Open this page and scroll down. The list shows the stars within 50 light years and relative information about coordinates, visual magnitude, and more. You are interested in the column 10, Dist (ly), which provides the distance between the star and Earth. Find the closest to your age, calculate exactly when the light will reach our planet and discover your next stellar birthday.

For example, I just turned 24. Scrolling the list I found the closest star to be HR222, with 24.33 light years distance. I assume 0.33 years equals 118 (I’m using 356 for 1 year, so I approximate 117,48 to 118, as 1 year has actually 356,25 days). So I calculate that 118 days after November 3rd, 2014 is February 28th, 2015. My HR222 birthday!

Unfortunately though, HR222 is part of the Pisces constellation and therefore can be seen from the southern hemisphere only during the spring (September to December). So I’ll not be able to see the photons that started from HR222 the day I was born. Also the next one, 107 Piscium, is part of Pisces. It seems like Beta Hydri will be the first stellar birthday i will be able to consciously live and see: March 18, 2015.

You are lucky enough that we automated the process! We created an application so that you can insert you agricoltural birthday and you will get a list of your future stellar birthdays with other info. Open the Stellar Birthday App spreadsheet, make a copy and have fun!

Is all this useful in any way (and not only intellectually cool) ?

Until we will get to the point of having humans in other planets, there isn’t really practical usefulness attached to the stellar birthday.

On the other hand though, this concept might be interesting enough to be used for educational purposes. As now kids know the nearest planets to Earth, in 10 years or less they may know all nearest stars. Helping this process would be beneficial as there will be much more Universe in the life of kids, some of them will fall in love with stars and more and more energies and minds will be focused into expanding our civilization beyond our small planet.

From my discussion with Aliaksei about this during his last visit out our headquarters (and here we get into a field where I humbly report what I have been said), it seems that another future use of stellar birthdays will be for localization. In the future, if you tell somebody who lives in our galaxy when you have, for example, Arcturus day and Sirius day, he can not only know your age, but also solve, by triangulation, your location in the galaxy.

This principle is actually already implemented in the plaque of Pioneer 10, in the bottom-left part showing the relative position of the Sun to the center of the Galaxy and 14 pulsars.


Googling I can’t find anything else than a website that offers products based on stellar birthdays: http://www.stellarbirthdays.com/c5/. Not much. It looks very old and I’m sure there are more creative ways to create value around this concept. You might want to think of this as an opportunity. I’m interested in your ideas, so message me if you have any.

Enjoy finding (and celebrating?) your next stellar birthdays.

This article is the result of my discussions about the topic with Aliaksei, who is also the person that introduced me to it in the first place!