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This is a photograph taken by Voyager 1, past the orbit of Neptune, when it was about to leave our
solar system. In my view it is one of the most profound photographs ever taken, if not the most
humbling. It shows the earth, as Carl Sagan put it, as “a mote of dust suspended in a sunbeam.”
And there are other humbling photos like the Hubble deep field,
which is a photograph of a tiny part of the sky, about the size of a raisin held at arm’s length.
Every one of these 10,000 points of light is a galaxy,
not a star, but a galaxy, each of which has tens and hundreds of billions of stars.
One of the very faint ones would look very much like our own milky way galaxy
to some alien living on a planet billions of light years away from us.
And our Milky way galaxy, similar to this one shown, is composed of
up to 400 billion stars, and at least that many planets. Our star, the sun
is one of those billions, about a third to halfway out from the galactic center.
And we live on one rather small planet orbiting this unremarkable star
in an unremarkable galaxy, in a remote corner of the only universe we know of.
And we humans are but one of at least 9 million different forms of life on earth. What does this
mean for us humans? Are we of any significance, or are we nothing more than a burden on an
ecosystem already stressed by the insatiable appetite of our increasingly extravagant needs?
How did all this come to be? How did we get here? And what is the purpose of all this?
Let's examine this question a little more closely...coming up right now!
At first blush it would seem that we are indeed a speck of dust,
of no particular cosmic significance.
But before we start making conclusions, let’s step back and consider what we have in front of us.
Consider the improbability of not only finding ourselves in this universe,
but the formation of such a universe that would have us in the first place.
From all we know, the universe came to be about 13.8 billion years ago
in a massive expansion which we call the big bang. It could have expanded too fast
such that no structures such as galaxies, stars, or even atoms could have formed.
It could have expanded too slow, such that it could have re-collapsed into a singularity – a
theoretical point, a kind of rip in space time with infinite mass density from where it came.
But that’s not what happened. The universe expanded at such a rate that it allowed the
expansion to continue at a slow enough rate for atoms and structures to form,
and 13.8 billion years later, we see the results that we see today.
Roughly 200 million years after the big bang the first stars formed. These were relatively massive,
highly luminous and fast burning stars, made almost purely of hydrogen and helium. After
only a few hundred million years, they burned out and exploded in supernovae explosions. In doing
so they seeded the universe with heavier elements such as carbon, nitrogen, oxygen and sulfur which
had formed in the core of these early stars, but were expelled into space upon their explosions.
The remnants of these explosions formed nebulae. The Nebulae were
enriched by many such previously exploded stars.
These became nurseries for younger stars which formed from the remnants of earlier ones.
One of these newly formed stars having been enriched by prior explosions
was our own. Our own sun probably formed from such a nebula.
The heavier elements that were not consumed by the central mass resulting in the sun,
became part of the leftover debris that, over time, formed the planets around the sun.
There were sufficient quantities of heavy elements that could form several rocky planets. And
one such rocky planet was at such a distance from its star that temperatures allowed water,
perhaps the universe’s best solvent, a universal solvent, to exist in liquid form,
making it conducive for molecules to interact with each other.
These were conditions that could lead to the formation of complex chemicals.
Several sets of these complex chemicals, particularly ones based on carbon,
which happens to be a very versatile atom able to form bonds with several other atoms
allowed for the kind of chemical interactions that resulted in complex molecules.
And somehow through a process we don’t completely understand yet,
these molecules came together to form a simple self replicating molecule or proto-cell.
These cells over vast time frames of hundreds of millions of years,
through a process of chemical and eventually biological evolution resulted in ever more
complex life forms driven by natural selection and influenced by the environment, and after billions
of years of evolution, resulted in the highly sophisticated life forms that we see today.
Earth is not solely responsible for harboring such biodiversity.
It had celestial help in reaching this stage. Had our solar system not been blessed
with a giant planet in its outer reaches, like Jupiter, which acted as a vacuum cleaner ridding
the solar system of perhaps millions and billions small asteroids and other debris,
life may not have formed on earth because of the constant bombardment of this debris.
Similarly, had a mars sized protoplanet, called Theia not collided with earth about 4 billion
years ago, resulting in the formation of our moon, which stabilized earth’s orbit which gives us
predictable seasons, life as we know it may have been completely different or non existent.
Change the circumstances of earths early history, and we would not be here. Change the distance
of the earth from the sun, or the placement of the heavier planets in the solar system,
change the sun slightly – warmer or colder than it is, and we would not be here.
Alter the trajectory of one large asteroid which killed our early mammalian ancestor’s
main competitor – the dinosaurs, alter the climate change a couple of million years ago
on one of the continents called Africa, which led to tree dwelling apes having to adapt to life
on the African plains instead, and humans may never have evolved.
Alter the process of natural selection that resulted in highly dexterous hands,
or the change in diet, or other biological and environmental forces
that resulted in larger brains, and we humans would not be
the super intelligent, highly curious, innovative, and resourceful creatures that we are today.
And all these details do not take into account the fact that the laws of physics
and the constants of the universe are such that allow for atoms and large structures to from,
and chemistry to take place that sets the stage for life to exist in the first place.
Anyway you look at it, we have won the cosmic lottery. We have been given a royal flush.
You may complain. You may not be happy. That’s understandable given the level of misery that
exists in our world. It is not perfect nor the best it could have been for our existence. But the
fact that we exist, even though it may only be for a moment, is probably nothing short of improbable.
No matter how closely we look, so far we have not been able to answer the question
of what existed before the Big Bang. This may not even be a good question because time itself
is thought to have come from the big bang. Stephen Hawking said,
it is like asking the question what is North of the North Pole.
There is nothing further north. Similarly, there may not be a “before the big bang.”
Given that there are hundreds of billions of stars in galaxies and hundreds of
billions of galaxies in the universe, are we presumptuous to assume that ours is the
one and only universe? Might there be hundreds of billions
of other universes with slightly different constants, slightly different quantum
fluctuations at the moment of inflation that resulted in completely different universes?
There is no evidence nor consensus among scientists, but it feels to me a bit conceited
given the vastness of what we can see, that we should default to the idea of our universe
being the only one. Might this be a mistake like our many mistakes of past presumptions
when we thought, the earth was unique, or the sun, or the galaxy was the entire universe?
What about the uniqueness of life? Exoplanet data appears to indicate that most stars have
planets orbiting them. If true, there are quadrillions of planets that likely exist.
It is highly unlikely that we are the only planet that harbors life.
However, highly intelligent life is likely much more rare.
We have seen no evidence that intelligent life like ours exists elsewhere in the universe.
You might say well, given the quadrillions of stars in the universe, surely there has to be
plenty of other intelligent life. It is possible, but no such evidence exists.
Give the improbability of intelligent life on our own planet, it is possible that the odds
against a replication of such a combination of fortuitous events could be in the hundreds of
billions of even trillions. If that is the case, it is not inconceivable that we may be the only
intelligent life in the Milky Way galaxy. And other intelligent creatures may be millions of
light years away no where near us, perhaps so far, that we may never learn about them.
We have not even detected simple life on any other planets in our solar system, let alone exoplanets.
Enrico Fermi asked the question, "where are they?" If intelligent life forms are common,
some would have evolved millions of years ago, or even billions of years ago. If we go by the
exponential progress of technology we have seen on our planet, is it illogical to think that at
least some of these ancient intelligent aliens should have evolved the capability to detect us,
communicate with us, or even visit us? While this is not a particularly strong argument,
it does highlight a point, and that is that while we may not be unique, we are probably rare.
And given the myriad of fortuitous events that seemed to have gone
our way, from the location of earth in its orbit around the sun,
to the large moon that stabilizes earth’s wobble, to the giant asteroid that killed
off the dinosaurs, it is a data point indicating that we may indeed be very rare.
And it is truly astonishing if you think about it, how much
we have come to know in just the past 500 years of our existence. In fact, if the distance from
central London to times square in New York city represented the total age of the earth.
All of recorded human history would be contained within the final 5 meters of this distance.
Einstein said the most incomprehensible thing about the universe is that it is comprehensible.
We not only live in this universe, but we are made of the stuff of this universe.
But what seems to make us different from lifeless objects is that through our senses,
our emotions and our brains, we can connect to the rest of the cosmos. We can see,
feel, and react to the abundant sensations that the cosmos provides.
And in this regard, perhaps no other living thing on earth is so deeply connected than we are.
Carl Sagan said: “We are the custodians of life’s meaning…it’s really up to us”
Does it really matter if we are a speck of dust in the vast space of the
cosmos? Must we play make-believe in order to have meaning or purpose?
Is our connectedness, and the absurd improbability of our existence not enough?
I can only speculate, but maybe the purpose of the cosmos is to provide this deep connection
to a rare few of its inhabitants, so that at least some can appreciate the beauty of
their fleeting existence and strive to understand how it all came to be.
If that is the case, then it should be a personal and international priority to gain knowledge
and better understand the universe which has made itself comprehensible to us - the scarce few.
There is no denying that we may be a speck of dust, but in our quest for knowledge
and enlightenment, for at least a vanishing moment, we could be a SHINING piece of dust.
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And if you have a question, please post it in the comments, because I try to answer all of them.
I will see you in the next video my friend!