What a day… After a long day of work, I head out to do the shopping. I’m dragging a trolley and several bags to my house when it starts to rain. And to top it off, just as I’m about to reach my portal, I notice that my shoe has squished a magnificent excrement. So I’ve literally and figuratively had a shit day.

The most important pixel

On days like this, when it seems that the world is against me, I often think of those famous words said by Carl Sagan speaking of a very special astronomical observation. In that image, taken in 1990 by the Voyager 1 space probe, you can see a tiny bright dot, a pale blue pixel. That insignificant, barely perceptible dot was and still is tremendously valuable today. It was not caused by a lens smudge or an image processing error. On the contrary, it was and is the most important pixel in history and the known Universe.

A bright dot in the middle of empty space
Pale Blue Dot revisited, 2020 (NASA/JPL-Caltech)

The little blue dot represents the origin of everything we know about science, humankind, nature, the Universe, and reality. Thanks to that little dot, today there are history books about discoveries, empires and artists. Everything that human beings have ever achieved is due to the existence of that seemingly insignificant pixel.

That little blue dot is Earth, seen from 6 billion kilometers away.

On that pixel is, with total certainty, where you were born, and almost certainly where you will die. It’s where you spend hours, days, months and years looking for meaning in your life. Or looking at a screen. All of humanity lives on that pixel: almost 8 billion people on the surface of the Earth, and around 10 more floating in the International Space Station. That is also where hundreds of thousands of other people are born and die every day, whose bodies will be gestated and decomposed on that same pixel. It is all we have and all we are.

The stuff we are made of

That pixel contains all the living beings in the Universe that we know of today. And all these living beings are made of the same stuff, just like the stones, the clouds and the Padrón peppers. Everything is made from the ashes of dead stars. This sounds too poetic to be scientific, but it is true. If we ask ourselves where a hammer comes from, we imagine the mine from which the iron was extracted, and the trunk of a tree from which the wood was produced. But how did that iron end up there? And where did the carbon and oxygen that made the trunk of that tree grow come from? Almost all of those elements were formed in stars.

The first stars were nothing more than hydrogen atoms floating through space, and which ended up balled up in a sphere due to gravity. Hydrogen is the simplest atom in the periodic table, as it only has one proton in its nucleus. But when lots of hydrogens get together, gravity gets so strong that some of those protons under pressure end up fusing, forming helium, with 2 protons in the nucleus. But that’s not the end of the story. Inside that star, the pressure continues to squeeze those helium nuclei, and when 2 of them fuse, they form beryllium, with 4 protons in the nucleus. Beryllium with helium: carbon; carbon with helium: oxygen. And so on until you reach iron. Boom! We already have enough to make a hammer.

But what about hydrogen? To form hydrogen, no star was needed. Individual protons already existed from the first second of the Universe’s existence. Hydrogen is therefore the most common element in the Universe, and it’s pure Big Bang debris.

So the fusion of nuclei, together with other slightly more elaborate processes, end up giving rise to all the other elements. When stars explode they spread all those elements through space. And once again, gravity does its job and pulls that stardust together to form planets like Earth, our precious little blue dot.

The immensity of space

To date, no human being has come very far from that famous pixel. Beyond the orbit of the Earth and the Moon, we have only managed to send machines buzzing through space, like Voyager 1 itself, which took the photo. This ship is the farthest human construction from Earth, and it is more than 20 billion kilometres away, that is, more or less one light day. In other words, the radio waves emitted by the ship take a whole day to reach us.

That, astronomically, is nothing. By comparison, the closest star is about 4 light-years away. And the distance to the centre of the galaxy is about 26 thousand light-years. It’s kind of sad to think that we’ll never get to see a picture of our own galaxy. You would need to travel at the speed of light for tens of thousands of years to be able to get far enough and have enough of an angle to see it all. There is no selfie stick long enough, alas.

But imagine if we managed to get that picture of our own galaxy. Earth would no longer be a dot, it would simply be impossible to find it. You wouldn’t even be able to tell the Sun apart from all the other hundred billion stars in the galaxy.

And that’s not all. There are hundreds of billions of other galaxies wandering through the observable Universe. The entire observable Universe has a diameter of about a hundred billion light-years. And it is possible that the rest of the Universe, beyond the observable, is much larger.

Thousands of galaxies in space.
Hubble Ultra Deep Field (ESA/NASA).

We are tiny.

The immensity of time

We are not only small in space, but also in time. Consider for a moment how much time a blink represents in your life. In other words, what fraction of your life is represented by the duration of a single, fleeting blink of an eye. It lasts about 1.5 tenths of a second. So compared to 30 years of life, which is the median age of humanity, those tenths of a second are a ridiculously small fraction. However, that same fraction of time, compared to the almost 14 billion years of the life of the Universe, corresponds to about 2 years.

In other words, 2020 and 2021, two years that have drastically changed the lives of billions of people around the world, shaking habits and systems that we considered unalterable, represent a period of time that, for the Universe, has passed in the blink of an eye.

Similarly, 7 seconds, compared to the 30 years of a typical human being’s life, is a minuscule fraction. But compared to the age of the Universe, that same fraction represents just over a century. In other words, your whole life, with all of its challenges, achievements, tragedies, stories, travels, romances, heartbreaks, laughs and tears, for the Universe lasts no more than a sigh.

A different perspective

Anyway, sorry for going on a rant, but I had a bad day. Although, after thinking about it a bit, it hasn’t been that bad to be fair. Really, there are far more important things that I should be worrying about than getting wet from the rain or getting my shoes a bit dirty.

Carl Sagan thought that this Voyager 1 image emphasized our responsibility to be better people, to value and care for our little blue dot. At least that’s what the image inspired in him. What’s clear is that the image gives us a different perspective from which to see our problems and frustrations.

On another occasion, we will talk about the enormous potential that resides in that pixel. But, for the moment, we can conclude that the real problems of humanity do not matter to anyone, beyond that little blue dot. It is unlikely that another much more advanced civilization is quietly studying our evolution, waiting for the opportune moment to come down and rescue us. No one is going to come help us, or save us from the consequences of our own arrogance.

If the average temperature on the Earth’s surface rises above a few degrees, if our advances in biotechnology and artificial intelligence lead us to a dystopian destiny contrary to our human desires and needs, if a pandemic much worse than the current one spreads without us having the appropriate precautions in place, or if our leaders decide to show off their opulence and press those buttons capable of initiating a large-scale nuclear bombardment in a matter of minutes, that pixel will cease to be so important. The Universe, however, is not even going to sneeze.

Everything is made of the same stuff: galaxies, stars, the Sun, the Moon, the Earth, humanity, all living beings, your family, your body, your phone, the rain, and even the dog poo you step on from time to time. Each and every one of us is made of stardust and Big Bang debris, living for as long as a Universe’s sigh.