Now is the time to break out that copy of Jean-Michel Jarre’s Oxygène or maybe your Stars of the Lid and Their Refinement of the Decline CD. Did you get it? O.K. Good. Put it on, and let’s take a trip…

Out into the big, lonely universe.

The next time it’s dark and clear out, go outside and take a look at the sky. What can you see? If you’re fortunate, you can see quite a few sparkling stars, maybe a placid planet or two. If you’re very, very fortunate, and away from any interfering source of light, you can see the ghostly, blurred, cloudlike swath that is the Milky Way as we know it with the naked eye. If you are fortunate enough to have a telescope, you may well see wonders that stagger the mind with their beauty and strangeness. You may even see whole other galaxies. Just imagine that. When you see a galaxy you are looking at tens of hundreds of millions of stars, or, actually, the light they are emitting into the void. You can’t generally make out the individual stars when viewing a galaxy through a backyard telescope. And to think, there are billions of galaxies. The Hubble Deep Field image showed us a piece of sky “only about the width of a dime 75 feet away” and revealed over 1,500 galaxies.

Hubble Ultra Deep Field

Given an estimated size of 156 billion light years wide, it is extremely unlikely any member of our species will ever see more than the tiniest fraction of it in person. It’s been around for 13.7 ± 0.13 billion years, and in that time it has been busy expanding. During its life so far, it has managed to produce effectively countless galaxies comprising unimaginably vast clouds of gases, quasars, proplyds, stellar nurseries, countless stars—including pulsars (which are rapidly spinning neutron stars) and magnetars (neutron stars with a powerful magnetic field), brown dwarfs, white dwarfs, red dwarfs, red giants, etc.—asteroids of metal and rock and ice, gas giants, rocky planets, life and, well, thereby us. And, quite possibly, not just us.

Our Milky Way galaxy is made up of some 200 to 400 billion stars, and we now know that a great many of them have planets in orbit around them. We do not yet have the technical knowledge needed to identify planets like ours, but we have advanced to the point where we can get actual images of some of these extrasolar planets, so it’s likely only a matter of time, effort, and increased technological prowess before we finally glimpse some planet of generally the same mass and in generally the same sort of orbit as our earth. That day will be a Red Letter Day, and certainly a Scarlet Day.

Of course, neither you nor I will ever visit such places in person, and even if we were among the first crew of ape-descended bipeds to set a spacecraft down on Pluto—which is so remote in our solar system that our own sun looks like a particularly bright star among many others—those galaxies would be, relatively speaking, not a bit closer. In fact there would be little appreciable difference in the appearance of the constellations we know here on earth. Stars other than our own beloved Sol are simply too far away. Even if you wanted to go visit the red dwarf Proxima Centauri, the next closest star to us, you would have to travel a distance of 4.28 light years. It may not seem like much, but consider that in just one hour light travels around 7.2 times farther (or 671 million miles or 1,080,030,758 km farther) than the distance between the earth and the sun, which distance is just about 93 million miles or 149.6 million kilometers (a distance referred to as an Astronomical Unit, or AU). Now, keep in mind that there are about 8,766 hours in a year. It takes the light from our sun more than five and a half hours to reach Pluto (at its mean distance from the sun, 5,913,520,000 km, or a bit over 3.67 billion miles), compared to the comparatively brief eight and a half minutes it takes to reach earth. But that is only five and a half hours out of that year. It’s strange to think that it is both a long and a short time, isn’t it? But really it’s a long time versus a far, far longer time.

At present the Voyager 1 spacecraft is around 108.75 AU from the sun, over 10 billion miles (16.2 billion km) away, and it takes over a day for round-trip lightspeed communication. That certainly sounds like a long way, sure, and yet the Voyager 1 spacecraft would have to travel over 587 times as far just to reach a light year in distance. It took Voyager 1 over thirty years to get to its current location. So, traveling at its recent speed of 37,800 mph., it would take approximately 17,580 more years to reach the distance light travels in one, and over 75,370 years to reach Proxima Centauri. Traveling to our neighbor at the top speed of the Apollo 11 spacecraft—the fastest manned spacecraft to date—would take 110,000 years (source). Clearly, we’ll have to fly faster than that if we want to get anywhere in space. But even the spacecraft envisioned in Project Longshot, utilizing a technically feasible nuclear pulse propulsion system, would take a century to arrive at the red dwarf.

Let’s say we decided to take that trip. Imagine that in the near future our technology has overcome the problems of radiation and our spacecraft spins to create gravity on board almost as strong as earth’s. We leave in our spacecraft in the summer of 2050, say, and head on our way. Utilizing some sort of deep hibernation that effectively stops the aging process (currently not feasible), we travel for a hundred years to see the red dwarf from up close. Our research lasts the better part of two years while we are there. Then we return home, again in hibernation, again traveling for a hundred years. We arrive home in the year 2252.

What might have changed? Looking back from today’s year, 2009, what can we say was different back in 1807? Well, the 28th of January was the anniversary of London’s Pall Mall being the first street to be lit with gaslight (the first electric light would not be invented for another two years, and the first true light bulb would not come along until 1854). Meanwhile, Napoleon’s Grande Armée had only recently in the month fought a horrific and indecisive battle with the Russian army. The slave trade was abolished in the British Empire. The Tokugawa Ienari shogunate of Japan continued the longstanding effort to keep the nation secluded from the rest of the world. Thomas Jefferson was president of the United States. Lewis and Clark had returned but the year before from their most historic journey, and William Clark would soon be headed out again, at President Jefferson’s bidding, to look for mammoth bones in Big Bone Lick, KY. Charles Darwin had not yet been born. Charles Babbage was 15 years old. Human flight was still over ninety years away.

I list these diverse examples to illustrate a simple point: a lot changes in the course of two centuries. Our intrepid crew of astronauts (or, perhaps, taikonauts or cosmonauts) would be returning to a very different world than the one they departed. It becomes even more pointed an issue when you start talking about traveling to more remote locations. Just to get to Alpha Centauri AB, to which Proxima Centauri is nominally the third partner, one would have to travel an additional 12,000 AU or more. That’s over 337 times as far as Pluto is from the sun. Travel to Sirius and its companion white dwarf in our proposed NPPS spacecraft would take approximately twice as long as our trip to Proxima. We would be gone for over four centuries, there and back.

Hubble Picture of Sirius AB

Assuming we were gone for 402 years and our launch date was 2050, we’d get home in 2452.

Run the timeline backwards from 2009 and we get 1607: Jamestown was founded in 1607, and John Smith met Pocahontas; flooding along the Bristol Channel killed over 2000 people; Pieter Bruegel the Younger painted “The Wedding Dance”; Johannes Kepler had not yet published his Laws of Planetary Motion and Galileo Galilei had not yet seen the moons of Jupiter with his telescope; Shakespeare was writing plays as usual, and one of the first ‘modern’ novels was becoming very popular: Miguel de Cervantes Saavedra’s Don Quixote (published in 1605); the Ch’ing Dynasty was established in China; Muslim empires in what is now known as the Middle-East were, at the time, at the height of their power. In 1607 there were no trains, no planes, no automobiles; no computers or phones or televisions; no refrigerators, washing machines, or air conditioners. Less than 600 million people lived on earth. The population has grown over 11 times larger since then.

Bruegel's ''The Wedding Dance''

These voyages are all “short jumps” on the cosmic scale. Even with our very fast NPPS spacecraft, longer trips begin to look ridiculous.

Let’s assume a trip (with all the previous parameters) from our solar system to HD 189733b, an extrasolar planet orbiting its star some 63 light years away. Our round trip would take our heroic crew almost 3000 years to make. Following rough calculations, the equivalent time in the past for us now would be 935 BCE.

HD 189733 and Dumbbell Nebula

That’s around the time King Solomon supposedly died. The long-lived Zhou Dynasty was still going strong in China. The Lapita, the common ancestors of the cultures of Hawaii, New Zealand, and Easter Island, were burying their dead in Vanuatu. Nothing remotely like the world you know was extant. Can you imagine if a spacecraft were to arrive one day carrying people from some 3000 years ago?

What about a trip of just 1/10 the length of the Milky Way galaxy, 1000 light years, and back? That would equate to a journey lasting over 46,700 years. Our ancestors were busy wiping out megafauna on the continent of Australia back then. Neanderthals and humans were still sharing what would one day become Europe long, long after the Neanderthals had been pushed to extinction. The famous paintings in Lascaux were thousands of years off. Early on in the Upper Paleolithic or Upper Stone Age, humans were just beginning to create art of a sort. Dogs had not yet been domesticated. Society and culture as we know them were utterly non-existent and ages away.

Paleolithic Ornamental Shells

In our hypothetical journeys we have come fact to face with a rather stark fact. Travel between the stars is, at this stage of our technological development, purely speculative. Space is too big, too spread out, and we are hindered in our ability to get anywhere by a great many factors that will remain insurmountable unless we discover hitherto unknown means of circumventing them. And yet, we must one day figure out how to leave our home planet and spread out into the vastness of our galaxy. We literally cannot stay here forever. In the long run the odds are stacked against us. The sun will one day die, and before then we are a sitting duck just waiting for that cosmic killer to fall out of the sky on us.

As we struggle to survive and thrive in the universe, we must tangle with our limitations at every turn. We live for such short spans of time, any one of us, and as a whole we have not been around for so long a time. We are very aggressive in our grasp for control, but in a way we are like adolescents who have real trouble thinking beyond ourselves and considering long-term needs. We are still living out our creation story. We are still living in the cradle of our human civilization. The impact we have had on our home planet is not a positive one, and we have yet to comprehend the results of our misunderstandings and reckless folly. But we are also industrious and clever, and we can move forward with care, leave behind our mistakes, having learned from them, and envision a greater realm where we belong.

It may be that one day a fleet of so-called generational spacecrafts will leave from our solar system traveling at four times the speed of our antiquated NPPS ships. In our super fast ships we will travel past Proxima in a mere 25 years, pass HD 189733b in less than four centuries. Our local region of space will feel more local. Still, were we to leave our own galaxy and attempt to reach the Andromeda galaxy, which is 2.5 million light years away, our spacecraft would have to travel for 14,602,805 years. Were we to travel back in time for the length of just the one way trip, the equivalent age of the earth would be the Miocene Epoch. Human beings did not exist yet. That fleet would be leaving everything behind forever to make that trip. Nothing would be the same were it to return some 29,205,610 years later.

Our future as a species will, in all probability, be contained in our portion of the Milky Way galaxy. What we may become over the trackless ocean of time ahead of us is unknowable to us now. Yet it feels like a profound comfort to me that this is so. The possibilities will never really end, and the ways we deal with those possibilities will further mold us, change us, and possibly renew us in perpetuity. We may well become different species as we spread out from our original home. Evolution may lead to wholly new forms over the course of time, favoring those who survive better in interstellar space. It’s amazing to think about. All the history of humankind that we have been able to put together is the smallest blink of time compared to the deep time of the future. And the future, as always, is coming inevitably. However much this post has been filled with speculation and projection, it points to a future that will arrive as surely as the death of the sun. You and I will not be here to see it when it gets here, but we live in the age when the dream is gaining a structure in the waking world. Our descendants will look back on us as… what? What are we, now? Children just learning our real place in the universe? Young gods learning our powers? Herd animals in need of a shepherd from the stars? Responsible ancestors to our star-faring progeny? Who are we? Who do we want to be?