The universe was born in 1960, or so it seemed to me at the time. From where I stood,in my cot in my first ever bedroom, the universe consisted of blankets and soft toysand faces that sometimes sang nursery rhymes. Albert Einstein said the universewould expand, and so it did to include a house and a driveway and people whoinhabited a school and a neighbourhood. It has been expanding at a fairly constantrate ever since.
The universe and I were perhaps ten years old when my older brother took me outinto the driveway one night to look at the stars. Now, I had certainly seen stars beforein my life, but as far as I can remember this was the first time I actually looked atstars. Stars were insignificant. I cared as little about stars as I cared about thepatterns on my bedroom wallpaper or the lint on my school uniform. Stars didn’tmove. Stars didn’t talk. Stars didn’t do anything to intrude upon my busy mental life,so why should I or anybody else want to look at them?
Well, I looked. I looked because my brother was fifteen years old at the time andknew everything about science, and if he asked me to look at the stars, well, it wassomehow cool to do so. So I looked. The stars didn’t do a damn thing. But while I waslooking, my brother began to tell me about them. Rigel, he said, was a blue star. Hepointed it out; the bright star above the three stars that make Orion’s Belt. I didn’tknow that stars had colours, so I had to stare at it for quite a while to convince myselfthat indeed it was a wee bit bluer than plain white.
But it was interesting to suddenly discover that stars were as individual as people.They had names and they had colour. Another star, he said, was called Betelgeuseand it was a red giant. It didn’t look very big to me, but I can confirm that the star hada faint red tinge to its glow. He went on to label other stars and tell me the things thatmade each of them special. Alpha Centauri was the closest to the Earth. Sirius wasthe brightest. Of course, it wasn’t as bright as Venus but that didn’t matter becauseVenus was a planet and didn’t really shine.
My universe was stretching quite a bit that night, and my fresh and largely untestedmind was struggling to keep up with it. Stars were suns like our own. So why did theyonly glow at night-time? And what was a planet if it wasn’t a star? I could see Venus,and it looked as much a star as any other dot in the sky.
I can only recite my side of the story. Whatever the impression my wise old brotherhad tried to make on me that night, he had condensed the nebulous, ignored materialof the universe into stars which had names, colour, size, age and distance. It hadnever occurred to me to ask how high the sky was, but now I could say with authority– because my brother had told me so – that the stars were very, very, very far away,that they were incredibly old and that,… and that quite possibly there were worlds upthere with people on them, people who right now were standing in their drivewayslooking down at us.
We decided to send them a signal using the big red torch we used for camping. Theair above our heads was laden with smog and our torch poked a glowing rod throughit as electric and scientific as any laser beam I’d seen on TV. I stood for a whilewaiting for a return signal, but my brother informed me that it might take a while for aresponse. Perhaps if I went outside the next night, I might see something.
Well, I have looked up at the stars many nights since then, and forty years havetranspired. Of the uncountable trillions of photons we released from our torch into theuniverse that night, a handful may have made it through the atmosphere and out intodeep space. In that case they are more than three hundred trillion kilometres from theEarth, more than ten thousand times the diameter of our solar system. They will havefanned out into a cone millions of kilometres wide. Some will have been scattered byinterstellar dust into unintended directions.
In the same way, my own energy has been dissipated and scattered and I have littleto show for my lack of focus. I still look up at the stars at night. I have this expectationthat I know is wrong, this remnant belief from my childhood that if I just stand hereand look up at the stars long enough, I will see something happen, somethingunprecedented and wonderful that will suddenly change the way things are done onEarth, and I will have been amongst the first to see it.
The magic of the stars is not what they do but rather, what their inaction tells us.Characters like Tycho Brahe and Charles Messier catalogued the positions andbrightnesses of the stars, four hundred and two hundred years ago respectively, andbecause of their fastidious obsession we can tell that no star has moved or witheredand died in the time since then. More significantly, because we now know how starswork, we can be sure that these same stars have been in our skies, unblemished andunfazed by our progress since at least the time of our earliest hominid ancestors.
Stars are essentially immortal; everyone who has taken the time to look up at the starshas looked up at the same stars that we see today. Aristotle looked these stars. Sodid Galileo. Columbus and Magellan navigated their ships by them. Copernicus andKepler deduced the nature of the solar system by looking at them. These are ourstars in the sense that they have been with us through every step of our journey, rightup to the present day. And yet they are just an infinitesimal sampling of thequadrillions of stars that truly make up our universe.
It was only ninety years ago that a fellow named Jacobius Kapteyn looked verycarefully at the positions of the stars and determined that they seemed to bearranged in a sort of lens-shape, not about the Earth but about some spot hiddenbehind a swath of interstellar dust. The thousands of stars that make up the MilkyWay, therefore are not the universe but are just the nearest splash of it, about asmuch of a milk bottle as the bit that dribbles on the table as we lubricate ourcornflakes in the morning.
A few years later, a fellow named Edwin Hubble looked at a strange, fuzzy starthrough his telescope and realised that it wasn’t a star at all but another lens-shapedcluster, as big as our own. This new ‘galaxy’, he determined, lay about eight times asfar from us as the farthest edge of our own galaxy, making the universe very muchbigger – and emptier – than anyone had ever guessed. What a great time to be anastronomer! Within a single decade, our concept of the universe had expanded involume a thousand times.
But then comes a fellow by the name of Willem De Sitter, who simply wanted to knowif any of these galaxies were moving towards us or away from us and found to hissurprise that almost all of them were moving away from us, the furthest of themreceding at the greatest speeds. Unintentionally, it was confirmation of amathematical requirement of Einstein’s theory of relativity, a requirement so ridiculousthat Einstein himself had even refused to believe it, which is that the space betweenthe galaxies is swelling up and pushing the galaxies apart from one another.
By my rough reckoning, the universe has swelled by 0.0000002 percent since I firstheard about it, thirty years ago. As small an amount as it seems, it means thatAndromeda, the galaxy identified by Hubble and the nearest galaxy to our own, issome fifty billion kilometres further away than it was when I was at university. Othergalaxies further out have receded even faster.
The stars have always been just a little bit beyond our grasp, but now it is possible tostate that fact mathematically: One day, a hundred trillion years from now (give ortake) the distance between stars will be so great that the debris from their terminalexplosions will no longer be able to coalesce to form new stars. The universe will fadeto red and die like a bonfire that’s been torn apart.
A hundred trillion years may seem like a long time, but I would like to put that numberup against the (current) size of the universe to give it some context for comparison. Ifwe are ever to venture out into the universe and explore every corner of it before ourtime runs out, we will have to cover a distance in excess of two billion kilometres ayear, every year until the end of time. At that rate of exploration, we would passJupiter and Saturn within the first year, Uranus in the next year, and Neptune andPluto in the third.
This may not sound like too much of an upgrade from what we are doing already withspacecraft like Pioneer and Voyager, but remember that the stars are not all sitting ina straight line and that we will need to expand out into the universe in all directions atonce. Double the radius from home and there is suddenly four times as much territoryto explore. Increase the radius tenfold and there is a hundred times as much territoryto explore.
By the time we get to the other end of our own galaxy, the frontier of humanexploration will be a sphere with 4,000,000,000,000,000 times the area of the sphereenclosing the planets of our own solar system. By that stage we would be passingthrough a region of space as big as our own solar system once every eightnanoseconds.
Perhaps this is not the right way to look at things. Stars are not evenly distributedaround the sky. The galaxy we live in is more of a disk than a sphere and the gapsbetween the galaxies probably don’t need to be explored. So let me talk instead interms of the number of star systems to explore, irrespective of where they happen tobe:
There are (astronomers believe) a couple of hundred billion or so stars in our owngalaxy. If we explore just one star system every year, starting from today, then we willneed a couple of hundred billion years to explore just our own galaxy. During thattime all of the stars we see today will have collapsed and exploded and formedthemselves into new stars, which means we will have an entirely new galaxy toexplore even before we think of travelling any further out into space. And there areperhaps two hundred billion galaxies overhead, each containing about two hundredbillion stars.
The point is that no matter how fast we travel out into the universe, we will never get tosee it all. I’m a little sad when I contemplate that, in the way that a young man oryoung woman might feel sad knowing that there are perfect lovers and friends outthere in the world today that they will never meet because the distances are too greatand time is too short. If civilisations such as ours can develop in the universe beyondour own peculiar world, then there will be many that we will never meet.
Their stories, their wisdom, their view of the way things work, even their dirty storiesand silly jokes; we will never know of these things simply because we will not havechance to meet them. Inverting that same line of reasoning, it could happen that theaccumulated wisdom of our own species – our struggles and our aspirations, ourfunny stories and our insights – will never be shared with more than a handful of ourneighbours in space.
Last night I invited my wife to come out into the driveway and look up at the stars withme. She shared my enthusiasm for a period of time we both judged to be polite, thentold me it was cold and went back inside. I stood outside a little longer, drew a deepbreath and turned up my collar to the cold night air. I’m still looking up at those starsafter all these years but I’m no longer sure what I’m looking for. I know the stars won’tmove and I know they won’t change. Why am I out here?
My son calls me back inside and it’s to see pictures attached to an email from one ofour relatives in Singapore. I marvel at how my brother-in-law can be digitised andteleported, Captain Kirk style, up to a satellite in space and then down again to ourliving room, to appear on the screen of my laptop.
I marvel, too, at how quickly the internet was set up so that people at opposite endsof our social universe can meet and exchange details of their lives. We are socialcreatures, we humans. Our strength has always been our ability to spontaneouslyorganise ourselves into teams and apply ourselves to some greater, collective cause.The railways of the world were built by teams of largely unremembered and probablyquite unremarkable men and women. So were the telephone networks, not to mentionradio and television.
Ideas come from individuals, but implementing and disseminating those good ideashas always been the work of teams who may or may not know in their own time thetrue historic value of what they are doing.
Think of Facebook and the other social networks that some say are a blight on thecyber landscape. No spy agency could ever have hoped to compile detailedinformation about every human being alive in the world today. Yet the creators ofFacebook are well on their way to achieving just that, and all they are doing isstanding back while the biggest team in human history i.e., over a billion people jumpaboard and add their own little bit. It’s only taken a few years.
This frivolous flurry of social networking that we are living through today is just the firstclumsy step towards exchanging knowledge on a global scale, global in the sensethat it includes every living individual who chooses to participate. Perhaps ninety-ninepercent of what they will write online is worthless to ninety-nine percent of those whowill read it, but the remaining one percent of it – and which one percent? – will meansomething to somebody.
It occurs to me suddenly that on all those occasions I have stood outside at nightlooking up at the stars, I have not really been looking up but looking in. My knowledgeof those stars – their names, their colours, their size and age and so on – came notfrom the stars themselves but from books about stars and listening to people talkabout stars. It was the social universe that enabled me to understand the physicaluniverse, and so it will continue to be as we eventually progress out there in the yearsahead.
There are over six billion people in the world today, and about two hundred billion starsystems in our galaxy. That’s thirty-three star systems each. Who knows how many ofus may exist when that first task of exploration is complete and we raise our heads toconsider the other galaxies? We may or may not ever have the time and energy toexplore the universe, but as long as we continue to chat with one another we willcertainly have the numbers.