“…the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths.” -Carl Sagan
As many of you know, I’m fortunate enough to live in a city that values science and scientific knowledge so highly that the our local news station, KGW, routinely brings on scientists to talk about the lastest developments in our endeavors to understand the Universe around us. Just last week, I was invited to share five wonderful minutes of airtime with the viewers of not just Portland, OR, but (thanks to the web) all over the globe.
What he said to me after that was something that I’ve heard often, but that I’ve never addressed here. He said to me,
You know, I can’t really think about something like that for too long. It makes my head hurt, and it starts to freak me out a little bit.
It’s a sentiment that is far from universal, but one that I think I understand, because when I think about it, I freak out, too.
It’s part of what drew me to this field in the first place, honestly. We are born into this world barely aware of what we are, and completely unaware of the size, scope, and history of the Universe that brought us into existence.
And when we first hear about the actual scales and ages of things in the Universe, it can be terrifying.
The entire Universe is 13.8 billion years old, and the Earth and Sun have been around for about a third of that. If you were to compress the entire history of the Universe into a single calendar year, I would have been born at 11:59 and 59.9 seconds PM on December 31st, and in fact the first homo sapiens would only have appeared for the final seven minutes!
For all the time that the Universe has been around, that the stars have been shining, that the planets have been orbiting, our own lifetimes are small, minuscule, and, at least as far as the rest of the Universe is concerned, cosmically insignificant. If you were to compare your lifespan — even if you lived 100 years — to the age of the Universe, that’s the same as if you compared 23 seconds to your entire life. In other words, your time in this Universe is very, very short.
And if instead of time, you start pondering size, the story is just as awe-inspiring.
As humans, we’re on the order of a meter in size, some ten orders of magnitude larger than the atoms that make us up. A typical human is a little under two meters tall; a typical atom is a little under two Ångströms in diameter. But ten orders of magnitude is tremendous.
A giant star like Arcturus, some 25 times the diameter of our Sun, is around ten orders of magnitude the size of a human being. And to the Universe, that’s still nothing! From Arcturus, if we scale up another ten orders of magnitude, that’s what it takes to get a typical small galaxy like — not Andromeda — but the small satellite galaxy visible just below the large Andromeda galaxy!
And a galaxy like this is made up of more than a billion Arcturus-massed objects. And to go up another ten orders of magnitude… well, you can’t. The observable Universe — all of the galaxies, all of the stars, planets, lifeforms and atoms — is “only” some 1027 meters in diameter, or just seven orders of magnitude larger than the diameter of a small galaxy.
In other words, you are small. The difference between an atom and you, in size, if you cubed it, is about the difference in size between you and the Universe.
But if you look at energy, or mass (which is where most of your energy is), you get a different perspective.
Small though you may be, ten orders of magnitude larger than an atom, you yourself are actually an entire Universe of atoms, with more than 1027 atoms making up your body! (This makes a little bit of sense, since you’re the height of 1010 atoms, and you’re a three-dimensional object.) But this is highly disproportional to the bulk of the Universe.
You see, only 1% of the Universe, by mass, is made up of elements other than hydrogen or helium. And yet, you are 90% “other stuff,” and only about 10% hydrogen.
And while a Sun-like star might be about 1027 times the mass of a person, going up another factor of 1027 would encompass more than the entire Universe.
You see, there’s no denying that we’re here for only a short time. Even if we found a way for humans to live 1,000 years, or even a million years, it would still pale in comparison to the age of the Universe. Coming to grips with our own transience and brevity in this Universe is something we all have the opportunity to do; whether we do or not won’t change that fact.
There’s no denying our smallness in scale, either, as the largest scales in the Universe are blissfully unaware of the entirety of all the goings-on ever to take place on our world. I understand the simultaneous awe and terror about this fact.
But as far as what we’re made up of — our energy, our mass — we are absolutely privileged. Generations of stars lived and died, fusing a Universe that was once 99.999999% hydrogen and helium into a tiny amount of heavy elements, which formed, after billions of years, into the stars and planets that allowed life as we know it to exist.
We are so little on our own, and so insignificant compared to the ancient, vast and incredibly massive Universe.
And yet, we’re here, we exist, and we get to bask in our existence however we so choose. Everything we are, everything we have, everything we see, is the ultimate free gift of the Universe to us.
And I can think of no better way to use that gift than to try and understand it, and by understanding it, perhaps understanding ourselves a little bit better.