Dick's Blog

Reaching for the Stars

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LIFE ON MARS? OUR FIRST MAJOR STEP ON THE WAY TO THE STARS

 

“Reaching for the Stars”

 

(A Discussion About Science and Spirituality, Also “Post Cards from Alpha Centauri”)

 

I need a well-deserved break. It’s time to kick back and celebrate a great personal year. I’ll be back in about a month with “Molting”, Chapter 13 of “Inside and Outside”. I’m taking a hiatus from publishing updates and chapters of my free memoir and book. In the meantime, consider this discussion about science and spirituality, followed by a quick trip to the nearest star, Alpha Centauri (I’ll back before you get there).

 

Science and Spirituality

 

I’m worried and discouraged about the current political disparagement of science. Many people feel the same way. If you value your cell phones and computers, innovative life saving cancer treatments, and the people dedicated to the survival of our planet from both external (space), natural and man made threats, then you have to respect and support the value of science. It’s not the enemy. It’s a God given “gift” to serve and protect mankind.

At the risk of losing my reputation as a “rational” person, I will be spending some quality time goofing off and daydreaming. I’ve always been interested in far out schemes for eventually escaping our solar system. In order for humanity to survive depletion of our resources here on earth, natural, space born and man made global catastrophes, and eventual destruction of our very own earth by an ever expanding and dying sun, we must eventually reach for the stars. Science can take us there. Rest assured, if there is no life on Mars now, there will be in the near future.

Even though it’s hard to get your head around it, our greater Universe or Multiverse appears to be infinite and eternal. The proven laws of quantum mechanics teach that empty “nothing” is a seething caldron of particle, energy, space and time creation and annihilation. Bubbles pop in and out of existence. Driven by negative gravitational energy, a bubble can rapidly “inflate” to virtually infinite mass and size. This “Big Bang” is often humorously referred to as “the ultimate free lunch”.

Our bubble, among infinite creations, is 13.8 billion years old since our Big Bang. With infinite opportunities, life must be commonplace throughout our Universe and the Multiverse. Unfortunately, we are separated by mind-boggling distances. Although life may be spread throughout and across the universes, ironically, we are all still incredibly alone because of the vast separations between even the nearest stars. Only highly advanced future science can take us there.

With natural physical laws creating universes out of nothing and natural selection working its wonders, you may wonder what I consider divine, holy or sacred. Rather than the creator of universes and life, I think of God as coming with the territory. God is the “love” that gives us the ability to love and respect each other and our environment; to wonder, contemplate and marvel about all of this; to explore our world; to continue our search for the greater meaning of our existence. Utilizing these gifts of life, self-consciousness, intelligence and language, we have developed science to help us on our quest. I often wonder about my own and mankind’s existence. I answer myself with this rationalization. “We might as well accept these blessings and enjoy the ride!”

Some vocal detractors of organized religion think if they undermine the belief in God as a creator, then they have destroyed the kingpin, and religion will fall like a house of cards. They are missing the point. I have considered the possibility of God as a creator but have pretty much rejected that idea. Rather, I see God as born with and an intangible and mysterious property of our Universe. God awaits to be discovered and appreciated. The amazing thing to me is the evolution of self-consciousness, intelligence and language, which allows us to find God in ourselves.

Unfortunately, nature throws at us significant stumbling blocks from reaching the outer solar system and stars beyond. Deep space is permeated with lethal cosmic rays (high energy protons and even heavier nuclei traveling at near light speeds), the nemesis for the long-term health of astronauts (and even sensitive electronic equipment). Not good if they slice and dice your DNA creating dangerous mutations, cripple brain neurons and optic nerves! Shielding is required to absorb these lethal rays to protect future space travelers on long missions.

As an aside, it would be fortuitous if the energy of these cosmic rays could be harnessed by the shielding material to produce useful isotopes of hydrogen and helium for a fusion-powered space propulsion system. The collision of cosmic rays with Earth’s atmosphere does produce these elements. Our moon and other moons, asteroids and comets in the far reaches of our solar system have been bombarded with cosmic rays for eons creating fusible materials. Our moon is looked at as a mineable source of helium-3 nuclear fuel for fusion reactors.

Sometimes, this retired engineer can’t resist the siren call to think about the technology required to reach the stars. What drummer do you march to? I look outward to our mysterious Universe and inward into my equally mysterious mind for clues and answers. I would be very disappointed if we never get there. My prayers are focused in that direction. If you didn’t suspect it already, I find that writing is my form of prayer. I’ve been told my stories and essays are like sermons. Some of my previous thoughts on the propulsion technology required for future space travel are contained in my BLOG, “Post Cards from Alpha Centauri”, which I originally published on June 22, 2013.

I’ll be back in about a month with “Molting”, Chapter 13 of “Inside and Outside”. In the meantime, try reaching for (or if you prefer dancing with) a star.

 

Post Cards from Alpha Centauri

This light science essay comes in two parts. The first part is for the reader who is looking for fun and enlightenment. This is followed by an optional appendix if you would like more detail. If you skim through the appendix, I guarantee you won’t be disappointed. It’s a long way from our solar system to the nearest star, Alpha Centauri. You may want to build an arc so that your children’s children get to visit the place. For individuals, even for future generations, it’s a one-way trip.

Four light years, the distance to the nearest star Alpha Centauri outside our solar system, doesn’t sound like much when you consider our Milky Way Galaxy is one hundred thousand light years in diameter, and the edge of the visible universe, full of billions of galaxies, is about 14 billion light years away. Four light years, representing the distance light travels at 186,000 miles per second in four years, is a long way even with the most advanced means of space travel that can be imagined. Unless we can warp space (like in Star Trek) to shrink our travel distance and time, we are pretty much alone even in this giant pinwheel, the Milky Way, we call home. Just exploring, colonizing and developing the resources of the planets, moons, asteroids and comets of our own solar system will occupy us for thousands of years, a blink of the eye in cosmic time. The trip to the nearest star must remain, for now, the dream that sustains our mission.

Our present chemical rocket motor propellant propulsion technology (high pressure combustion of fuels and oxidants) got us to the moon and back. Extending that technology to advanced electric propulsion systems (e.g. propellants heated by electric power generated by nuclear fission power generators) will allow us to explore the far reaches of our own solar system. This is just not just fun and games. This capability could be used sometime in the future to save mankind from a potential global disaster. Super advances in propulsion technology of at least three orders of magnitude (three powers of ten) greater and more efficient than our present capability will be required for interstellar travel (between stars). A propulsion system capable of achieving a vehicle velocity of 10 % of the speed of light would allow a trip of 55 years or more to Alpha Centauri. Even with that capability, the travel times involved boggles the mind of humans who may have a life span of eighty years. No wonder in our science fiction we talk about suspended animation or hibernation. If you are stiff when you wake up in the morning, imagine waking up after sleeping centuries (need WD-40 lubricant to free up those creaky joints?). We even contemplate the construction of arcs, self contained worlds filled with thousands of humans, plants and animals whose progeny will finally arrive at its destination. With today’s chemical propulsion systems it would take on the order of 140,000 years to make the trip. The cost of such an adventure boggles the mind, but that should not stop our dreaming. If we only send an instrumented scientific probe, we can consider a smaller lower cost vehicle, longer transit time, and less futuristic propulsion systems.

Science fiction tries to foretell the future. Sometimes, our real scientific advances bypass the fiction and produce a completely new “who would have guessed” path to the future. This could eventually make my arguments obsolete. For now, I have trained my eyes on that distant star and thinking about how I will get there based on my limited powers of thought and imagination. Hopefully, developments in the future will brighten this story. Wouldn’t is be fantastic to receive post cards from the first travelers who reach Alpha Centauri. Imagine me in some form of cryo-hibernation starting this imaginary voyage between our sun and Alpha Centauri in 2017. I’ll send you a post card when I get there. Don’t wait up for me.

Appendix (how this humble engineer would achieve 10 % of the speed of light)

How fast and how long will it take make a one-way trip to the nearest star? This is an exercise for those who like to dream about and imagine the future. It also shows how isolated we are even from our nearest stellar neighbors. Look at the general equation below which I derived from Newton’s Second Law of Motion, which states that the acceleration of a body is equal to the force on that body divided by its inertial mass.

Vmax = I g ln[1÷ (1-f)]

Vmax is the final vehicle speed. I is the specific impulse, a measure of how much thrust or push (force) we get divided by the consumption rate of a certain rocket propellant; g is a local gravitational constant relating what something weighs on earth divided by its inertial mass which is a constant; f is a fractional measure of how much of the initial vehicle weight is consumable rocket propellant. It could also include a measure of the fractional weight of other things we can separate and jettison overboard from our vehicle along the way. f can be maximized, to reduce mass and increase acceleration, by using light weight propellant tanks and jettisoning heavy first, second, third, etc. propulsion stages and empty tanks that are not needed to complete the mission. Vmax, the maximum or final vehicle velocity or speed, is a product of I times g times the natural logarithm of a simple function of f. As we accelerate toward the nearest star, the rocket propellant is consumed and finally depleted, and used up stages are jettisoned along the way. At that point we have achieved our maximum vehicle speed. Achievement of high speed and the shortest transit time requires a high value of I and a high effective value of f. If the rocket propellant is expended early in the mission, the travel time will be minimized by achieving the highest speed as quickly as possible.

The nearest star Alpha Centauri (actually a triple star system) is about four light years away. It takes light from that star about four years to reach the Earth. The best-known conventional chemical rocket propellant, which got us to the moon, has a specific impulse of about four hundred seconds (i.e. pounds of thrust divided by pounds of propellant flow per second). Temperatures in the rocket motor combustion chamber and exhaust expansion nozzle exceed 5000 ºF. An advanced rocket propulsion system based on laser promoted nuclear fusion of hydrogen (or more easily, deuterium, tritium, helium-3) to helium plus energy or positive matter/negative antimatter annihilation (producing pure energy) will be required to make a relatively quick trip. These propulsion technologies do not presently exist. Not all of the rocket propellant will be reacted or annihilated. Most of it will just be heated in the nuclear reactions to incredibly high temperatures and ejected from the rocket motor nozzle creating the desired thrust. Some form of magnetic rocket motor chamber and nozzle will be required to contain the pressure and extreme temperature (tens of million degrees) of these nuclear reactions.

In your wildest dreams, using a rocket propellant with a specific impulse I of one million seconds (2500 times that of a chemical rocket motor) and an f of 0.9 (our ship is 90 % rocket propellant and jettison-able hardware, 10 % payload), a maximum speed of slightly less than ten percent of the speed of light could theoretically be achieved. A voyage to the nearest star could be made in about 55 years if we consumed all our fuel early in the trip. The ability to slow down (to undo our enormous speed) to enjoy the view when we get there is whole new proposition and set of assumptions. Using conventional chemical rocket propellant would take us twenty five hundred times longer or over one hundred and thirty seven thousand years. Of course, it may take hundreds of years to develop this new propulsion technology. That says we should wait until the technology is available. A vehicle we send in the far future could beat the vehicle we send earlier. Our electronic reports back to Earth (at the speed of light) would take about four years. Let’s hope that mankind will still be around to enjoy the post cards we send back home.

You will note that above equation for maximum velocity Vmax is independent of the size of the space ship or vehicle we are sending on this mission. That allows us to contemplate a low cost unmanned mission or scientific instrumented probe to Alpha Centauri. We can ask the question, what is the smallest and most affordable advanced propulsion system we could build? Without a life support system, we could build the smallest possible vehicle including a breaking and exploration system, to allow our probe to slow down, spend years getting to know the place, see if it’s a friendly place for habitation, and send its electronic post cards back home.

Tags: My World
Dick Sederquist is a retired engineer, engineering consultant, writer, author, hiker, motivational speaker and cancer and depression survivor. Dick suffered an emotional breakdown 35 years ago, realizing that he had been depressed all his life. That started his long journey back to mental health and happiness. Dick writes motivational and inspirational nonfiction short stories and essays for general audiences on many topics including life, family, humor, spirituality, nature, science, his volunteer prison experiences, hiking and travel adventures, depression, overcoming adversity, and what the author refers to as “home improvement”, healing the mind and body we live in. Dick and his wife have been married 50 years; have two grown children and four grandchildren, all part of a close-knit, active, caring and loving family. The whole family believes that the greatest gift in life is helping others.

Comments

Guest
John Hamby Saturday, 13 May 2017

We'll make the vehicle very sexy and inviting. Send several couples and /or sperm and female "eggs" to reach an objective in several generations. This is much too simplistic and needs more thinking/detail Thanks for the chance to discuss the objective.

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Guest
Guest Monday, 21 August 2017