By Dr. Gary Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This is the first article in a three-part series on interstellar space travel
Since the dawn of humankind, we’ve looked up and wondered what lies beyond. In the 1980s science education television series Cosmos, the astronomer Carl Sagan spoke of how prehistoric peoples would look up at the night sky and wonder what those points of light were.
Sagan told the story of how one such people imagined that the sky was ablaze with a horrible fire, but that a benevolent deity had draped an animal skin over the Earth to protect its inhabitants. The deity poked holes in the skin so that humanity would take notice of the terror from which their god had saved them — and be forever grateful.
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Another group imagined that the Milky Way galaxy was the literal backbone of the night sky, a structure that was believed to be the only thing keeping the sky from falling.
We Now Know that a Tiny Number of Those Lights Are Planets
We’ve learned much since these ancient stories were told. We now know what the lights in our night sky are. A very small number of them are planets within our own solar system; we have since obtained a much closer look at each of these through telescopes and space probes, and we’ve even landed robotic visitors on a few.
A handful of the other points of light are whole other galaxies outside of the Milky Way. Although there are a tremendous number of galaxies in the observable universe, we can see very few of them from the surface of the Earth with the naked eye; viewing the true multitude requires advanced telescopes like the Hubble.
However, the vast majority of lights we see at night are stars within the Milky Way galaxy. There are an estimated 100 billion to 200 billion stars in the Milky Way, and because our Sun is one such star and we reside within the galaxy itself, we see our neighboring stars around us in all directions.
The Implications of the Discovery that Each of These Stars is a Sun Are Staggering
The implications of the discovery that each of these stars is a sun-like our own are staggering, if still a bit less romantic than the stories of benevolent Gods and galactic backbones.
Consider the stunning realization that billions of suns exist in our galaxy, and that some of those suns might host their own planets. It’s a hypothesis recently confirmed through initiatives such as NASA’s Kepler space telescope mission. Some of those planets might very well contain life that is looking up and thinking about the same things.
In fact, the astronomer Frank Drake, a friend and colleague of Sagan’s, developed a formula that can be used to estimate the number of planets that might support intelligent life in the Milky Way. The Drake Equation defines intelligent life as that which is capable of radio astronomy. Granted, results from the equation contain large degrees of uncertainty, but even using the most conservative estimates, there is every reason to believe that thousands, if not millions, of planets in the Milky Way may currently support intelligent life.
This is indeed a fascinating thought. But speculation is one thing. Confirmation is quite another. Although scientists are currently developing ways to use light spectroscopy to confirm the existence of organic compounds and signs of life on exoplanets (planets outside our solar system), the only way to be certain is to go and have a look around. But of course, that’s easier said than done.
In 1977, NASA launched the space probes Voyager 1 and Voyager 2 to survey the outer gas giant planets of our solar system. After their planetary missions, the Voyagers were set on trajectories into deep space, to head out of our solar system and into the great beyond.
Voyagers I, II among the Fastest Objects Ever Built with a Top Speed of 36,000 MPH
The Voyagers are some of the fastest objects ever built, with an ultimate speed of approximately 36,000 mph. Although the Voyagers were launched almost 40 years ago, NASA still receives data from them today because their nuclear power plants are still generating sufficient energy to transmit radio signals back to Earth.
As such, the Voyagers are the first spacecraft to travel as far from home as they have and still maintain communications with Earth. That said, in 2013, Voyager 1, 11.7 billion miles from home at that time, signaled to NASA that its instruments for measuring electron density had detected a significant change:
It must not be much farther to our nearest stellar neighbors then, right? Wrong! The nearest star to our own Sun is Alpha Centauri, at a distance of approximately four light-years. A light-year is the distance that light travels in one year. Light travels at almost 700 million miles per hour, making it the fastest moving thing in our known universe. To put that into context, at Voyager 1’s current speed, it would take another 40,000 years to reach our closest neighboring star.
Clearly, interstellar travel is not as readily achievable as one might otherwise think. The enormous distances aside, there are a number of other factors that present significant challenges to interstellar trips, particularly for manned missions. However, there are myriad reasons for going, from the most fanciful curiosities to the most basic survival drivers.
In part II, we’ll look at some of the biggest reasons why we would want to venture beyond our solar system to other stars in the galaxy, as well as the biggest challenges in launching an interstellar mission.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a JD in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.