The photograph at right surely has to be a contender
for “Photograph of the Century” (at least, so far.) The photograph was taken by
the James Webb Space Telescope earlier this year.1 It shows a galaxy
cluster that is 4.6 billion light years away from us, as well as a number more
in front of, and behind, the cluster.
What’s more – this is just a tiny tiny portion of the universe. If you were to hold a grain of sand at arm’s length up against the night sky, then this is the picture you would see (if you had the same optics as the James Webb Telescope.) Now ask yourself: How many grains of sand at arm’s length would encompass the whole sky? Mind boggling isn’t it?
Current estimates of the total number of galaxies in the universe vary between 100 billion and 200 billion. Within each of these galaxies somewhere between 100 billion and 400 billion (depending upon the size of the galaxy) stars exist.
If you wanted to you could multiply the number of galaxies by the number of stars per galaxy to get a rough estimate of the number of stars in the universe. The number is enormous. To write it out longhand is rather tedious. It is much easier to say it is a 10 followed by twenty-two 0s. The number defies our ability to conceive of it.
That’s the numbers. What about the size?
First, I need to define a light-year (for those who may not know.) A light-year is the distance that light travels in one Earth year. Again, it is an astonishingly huge number of kilometres. Consider that light travels at just over 18 million kilometres per minute, then the distance travelled in a year has to be enormous.
Consider just our own galaxy, the one we know as the Milky Way. It takes light around 100,000 years or more to travel from one side to the other. It is quite thick as well – approximately 1,000 light-years thick.
That is just our galaxy. Look back at that James Webb photograph. Those galaxies are 4.6 billion light-years away!! Hence, we are not seeing them as they are now. We are seeing them as they were – 4.6 billion years ago, about the same time that the Earth was being formed.
Let’s take a further step. Let’s ask how many possible intelligent lifeforms exist in the universe? This question has intrigued astronomers for decades. One such astronomer, Dr Frank Drake, formulated an equation in 1961 to attempt to answer this. Unsurprisingly, this equation became known as the Drake Equation. The equation uses seven parameters to estimate the number of civilizations in our own galaxy.2
The original estimates for the number (in 1961) varied considerably – from 20 to 50,000,000. Since then, refinements to the input data have enhanced this variability, so that now the lowest estimate is zero, and the highest 15,600,000.
So, if there are as many as 15,600,000 civilizations in our home galaxy, then where are they? This is exactly what Italian-American physicist, Enrico Fermi, wondered in 1950. Apparently, he and other physicists were casually talking about UFO sightings when Fermi blurted out, “But where is everybody?” (or words to that effect.) With the possibility of civilizations existing in our galaxy being reasonably large, and the seemingly lack of evidence for them, to Fermi’s mind this was a paradox. Indeed, it has been known as Fermi’s Paradox ever since.
Many explanations have been put forward to resolve Fermi’s Paradox. Reasons for the paradox range from: that intelligent civilizations are rare (even though life may exist), that civilizations are under-developed, that civilizations are over-developed and (similar to the trajectory we seem to be on) developed themselves into extinction, that colonization of other worlds is not the norm elsewhere in the galaxy, that we do not have the technology to hear any communication, that civilizations are being deliberately isolationist, or (as some suggest) aliens are already here, but not making a song-and-dance about it.
When we consider all this (the number of galaxies and stars, the sheer immense size of the universe, the small and/or large possibility of other life-forms in the universe) then we are struck by two paradoxical observations.
Looking out from Earth we are insignificant in the vastness,
Looking from beyond the Universe inwards towards the Earth we are unique.
It is a paradox. We are both insignificant and unique at the same time (and space.)
Then, if we ponder this further, one conclusion (arrived at from two different directions) can be made.
Our insignificance displays how we must care for the Earth we live in. Our insignificance shows how much we need to step up to our role as guardians and caretakers of this beautiful planet.
Our uniqueness displays how we must care for the Earth we live in. Being unique we must embody our role as guardians and caretakers of this beautiful planet.
In our insignificance we have a unique role to play.
In our uniqueness we have a significant role to play.
1. Source: https://www.nasa.gov/webbfirstimages The image is the one labelled SMACS 0723. Images released on 12 July 2022.2. The seven parameters are: Average rate of star formation, the fraction of these stars that have planets, the average number of planets that could support life per star, the fraction of planets that could support life to develop, the fraction of planets that go on to develop intelligent life, the fraction of these civilizations that develop the technology to release detectable signs of their existence and, the length of time during which these detectable signs are released into space.