The Universe, and Defining "Far, Far Away"

Gliese 581d orbiting it's red star

 © Space.com

Copyright © 2016

by Ralph F. Couey

Except attributed images.

It is the gift of the human curiosity and the power of the mind that allows us to look up into the night sky and think about what's out there.  People have been doing that for millions of years, always curious, always wondering.  Our literature and entertainment reflect that curiosity through the frequent use of space and alien planets in books, television and movies.  We have, vicariously at least, traveled far on voyages driven by the power of imagination.  But it goes beyond mere diversions.

One of winter's singular charms is the ability for us to view the night sky in high definition.  the stars shine bright and clear and somehow seem closer.  Last night after I returned home late from work, I took a moment to look up.  Above me hung the familiar constellation of Orion the Hunter.  My eyes traced the familiar stars, Betelgeuse and Bellatrix, Saiph and Rigel marking the corners of the formation, and the belt stars, Alnitak, Alnilam, and Mintaka.  Below the belt was the fuzzy patch of the Orion Nebula where new stars were being born as I watched.  The constellation, as are nearly all of them, is an illusion born by perspective.  The stars are not adjacent to each other, but rather range in distances from 700 to 2,000 light years. If the Earth was a light year or so to the left or right, our constellations would look very different.  Still, I remain fascinated by the stars, and the universe in which they inhabit.

For thousands of years, we only knew the stars and the planets in our own solar family.  In recent years, however, planets outside the solar system have been discovered, some 1,906 in 1,208 other solar systems.  The first reaction most humans have to that news is, "Are they inhabited?"

It's a natural question.  Even for those who understand just how vast the universe is, there is still the desire to know that we humans are not alone; that somewhere out there is someone else.

People's perceptions are naturally spoiled by science fiction, where heroes surf light years with ease, and even the most distant planets can be reached over a long afternoon.  That is, of course, a story element rising out of the necessity to move the narrative forward as quickly as possible.  That occurs even on this planet.  Did you ever notice that during the popular series "24" that Jack Bauer and his Tac Teams were never more than 15 minutes away from anywhere?  If you've ever lived in LA or DC you know that to be the stuff of fiction.

Inside the solar system we use miles to measure distances.  Beyond Neptune, the Kuiper Belt, and the Oort Cloud, the decimal places become too large to be understandable.  The unit of measure used is the light year, the distance light travels in a year.  It is a good standard because the speed of light, 186,000 miles per second, is as close to a universal standard as we are ever likely to have.  At that rate, light travels 5.9 trillion miles in a year.  While this makes distances easier to digest, at the same time it masks just how far that truly is.

The fastest spacecraft ever launched by the human species (outside of fiction) is Voyager 1.  Launched September 5, 1977, it was sent on a grand tour of the outer solar system, bringing back our first close-up images of Jupiter and Saturn and a few of their family of moons.  Using gravitational slingshot maneuvers, the spacecraft was then sent out of the solar system, passing the notional edge of the sun's influence on August 25, 2012.  Voyager 1 is now traveling at better than 38,000 miles per hour.  But even at that speed, and having traversed some 12.4 billion miles in 38 years, it has only gone 1/720th of a light year. At this rate, it will take about 17,700 years to travel one light year.

And that's with the fastest thing humans have ever built.

The nearest star, Proxima Centauri, is 4.2 LY away, so if Voyager was headed in that direction, we could expect the probe to arrive in roughly 73,775 years.  Wolf 359 (a tip of the cap to Star Trek fans here) is 7.7 LY.  To go there aboard humanity's fastest craft would take 135,254 years.  Let's put that in perspective.  If Neanderthal pre-humans had launched such a craft, it would just now be arriving at its destination.

The discovery of the exoplanets caused quite a stir.  While life outside our solar system remains undiscovered, we now know there is at least the possibility because there are some places for it to appear and evolve.  One of the most promising is a planet named Gliese 581-c, slightly larger than earth with heavier gravity orbiting a red sun.  (Why it was not named Krypton perhaps suggests a stunning lack of imagination on the part of scientists.)  G581-C is 20.4 light years away, and some less-than fully informed have taken up the cry that "we should go there as soon as possible."  20.4 doesn't sound like much until you calculate the actual distance.  

120.36 trillion miles.

At 38,000 mph, the fastest any human object has ever gone...

358,335 years.

358,000 years ago, the dominant human ancestor was a creature called Homo Erectus, perhaps this handsome couple...

Painting by Zdenek Burian

This was the species that figured out how to use fire to cook food, thereby inventing (if by extension) the parking lot tailgate.

The point being, even if a multi-generation ship made that trip, evolution would continue its inexorable march and those who arrived would no longer be representative of the Earthlings left behind.

We are probably dealing with the ultimate of unanswerable questions. Our galaxy, all 200 billion stars of it, and the universe, all 300 billion galaxies could be teeming with intelligent technological species.

But we will never know of them.  Nor they of us.  They're just too far away.

Reality is a tough thing with which to deal, especially when our hearts want so badly the fantasy. But the reality in this case is that while we may not be alone in the universe, we will always feel like we're alone.

But that doesn't, for me, take away the wonder or the beauty of the night sky on a winter's night.

And I will never stop asking that unanswerable question.