Vega - Crucible of Life?


Malcolm L. Kantzler

Vega within Lyra

In 1840, a new road to discovery was opened by the first application of photography to the study of the heavens, and ten years later, Vega was the first star to be the subject of a photograph  Now, Vega is again at the focus of investigation, as astronomers using the Infrared Astronomy Satellite have reported detecting a large particle belt orbiting the star at a distance almost twice that of Pluto's from the Sun, making Vega the first star known to have a solar system.

The particle belt is believed to be in the same stage of development as that of our solar system some 4-1/2 billion years ago; any planets which may orbit the star would be in the same state of evolution  Since no telescope exists sensitive enough to detect Earth-sized planets orbiting Vega, or any star, the possible accretion of a planetary body cannot be confirmed or denied. But, what if, in the 26-light-year distant Vega system, a world of Earth's size (and of similar relational-orbital distance as Earth from the Sun) does exist?  What might such a world in its earliest epoch of existence hold for a daring and inquisitive observer?  To answer, one can only speculate, guided by the factual evidence uncovered by geologists, astronomers and scientists in other disciplines, who together pursue the clues to our origins along many paths, leading them from the vastness of space to the sub-atomic structure of matter with its shrouded links to our distant past  But, the source which has provided the greatest store of evidence is the only known abode for life in the universe, the Earth itself.

Imagine that, like H.G. Wells' intrepid inventor, you are stepping into your time machine, and with calm resolve, you nudge the control lever toward you, launching yourself into a dizzying time vortex, falling back through 4-1/2 billion years on an adventure of discovery and danger in the dawn of Earth's first era.

Materialized on an ancient, barren plateau, your instruments confirm that if you stepped outside of your machine's protected environment, you would be assailed by scathing heat and doses of ultraviolet radiation transmitting immediate burns to exposed skin  But, your ship has limited power and protective shielding; its exterior surface temperature is rising rapidly, and you know that you cannot remain too much longer  The ozone layer which will filter the hazardous ultraviolet radiation is only just beginning to assemble through the process of photo dissociation, where oxygen is released from water vapor which is condensing to form the hot, primordial seas  Another three billion years will pass before the first bacteria-like cells appear, able to extract oxygen from water, releasing it into the atmosphere in sufficient quantity to prepare the way for the advanced forms of life to follow.

As you await the atmospheric and seismic analysis ordered up from your computer, you peer out into the alien proto-world you have so boldly invaded  As far as the eye can see in this ashen, clouded and light-scattered realm, there is no life of any kind  Your ship vibrates in response to what seem like constant tremors and assailing wind gusts  From the corner of your eye, a flash of light draws your gaze to an apparent horizon, where a vivid orange flare quickly diminishes to a warm, crimson glow  The hostility and desolation are disquieting and so overpowering that the span of ages separating you from your home and your humanity seems impassable  You are suddenly awed by your isolation.

A mid-pitched, pulsing tone brings your eyes inside to the status warning board, where the temperature warning light is flashing amber in time with the muted warning tone  The first tremble of fear guides your hand to the control lever and nudges it forward; the drone of your drive system begins to intensify  Suddenly, violently, you are thrown against your restraint harness; books, binoculars, a thermos and other items bounce off the canopy and are scattered to the floor  A tremor!  The seismic display reveals the epicenter was off toward the bright light of what was either an eruption or meteorite impact you just witnessed, but you are unable to see it now, as thankfully, you enter the time vortex and safety, fleeing from a world of volcanism that is more akin to Jupiter's moon, Io, than it is to modern Earth  But you know it is changing the air as well as the landscape, as the computer displays the atmospheric analysis, and it is verified that a breakdown there would have been a death sentence, quickly executed  The thin, heated atmosphere, consisting mostly of carbon monoxide, ammonia, methane, hydrogen and water vapor, would have induced searing, choking convulsions were you to inhale a single breath  The passing years accelerate on the computer display, as your ship is swept back toward the distant future from which you came, toward your next programmed stop, 500-million years away.

Only a few minutes pass, and as the time vortex dissipates and the drone of your ship's drive system fades, a flash of lightening is your greeting into a world four-billion years from home. Although you've jumped half a billion years, it's a rather short step on the evolutionary path, and the environment remains alien, albeit somewhat less hostile than the world you've just escaped  Another crack of lightening strikes as you complete a sample of the atmosphere. Here, the lightening is doing a lot more than stimulate your sensitive nerves; along with the Sun's ultraviolet rays, it has sparked the chemistry that creates the first amino acids, proteins and organic molecules from the atmosphere's gases.

Your real-time clock shows it has been only forty minutes since you left home, but you left with only enough oxygen for a few hours, and the lightening is active and could disable your ship, so it's back to the vortex and the next leg of the journey, three-billion years back to the future, which is six-times more distant, to your scheduled arrival at the next significant observation point.

After an uneventful passage, your machine stands here, a billion years from home, where you find DNA and other polymers have formed, and the first multi-cellular life forms have finally taken a firm hold in the ancient seas  You are no longer alone!

Virtual Image SunBreak by David Palermo

But, it hardly feels that way, and although it is only another short evolutionary step, it is chilling to know if you were stranded here, you would have a 650-million-year wait for the arrival of the Dawn of Man  But, you don't dwell on that  The interesting relationship of time and evolution that you have observed has captured your attention, as you realize that on the cosmic clock, the half-billion Earth years required for the formation of the building blocks of life--proteins, amino acids and simple molecules--was a relatively short span of time, and the same short period of time passed for the earliest descendants of man to evolve from the first primitive, multi-celled life forms able to make crude copies of themselves, while the time in between these two stages, from the building blocks to the evolution of those first multi-celled life forms, was about six times greater, which is more representative of the evolutionary rate scientists expected it should have taken to go through all the steps at the end of the evolutionary ladder--from the plants, amphibians, insects, dinosaurs, and mammals to man's early descendants; yet it didn't  Simply put, it seems that once the environment permitted, the building blocks were quick in forming  And again, much later, when the environment permitted the formation of complex carbon molecules and DNA, the evolution of multi-cellular forms began, and from there, through the succeeding steps up the complex evolutionary ladder to the age of man, evolution was just as rapid.

Could this be the denouement for a planet orbiting Vega now?  Questions remain to be resolved before making a cognitive speculation that bodies harboring the proto-structures of life might accompany Vega's newly discovered particle belt  The first consideration is the star itself, and how the known facts about it affect the life equation for its system.

Vega, a first-magnitude star of the constellation Lyra, is the brightest star in the northern hemisphere  Glowing bluish white, it is almost three times more massive than the Sun, generating higher core temperatures (the Sun's core is 10-20,000,000 degrees kelvin) and a surface (photosphere) temperature about 50% higher than the Sun's 6000 degrees kelvin  As a consequence, Vega's life zone--the orbital belt around a star, located at a critical distance, wherein water neither boils or freezes--is more distant from it than is the Sun's  The Earth's orbit, coincidentally or divinely, is centered within the Sun's life zone, at 92.9 million miles. If there is to be valid speculation of carbon-based life in the Vega system, a solid planet must be identified, equally as fortunately placed, orbiting within this zone.

For the existence of solid planets, there must be heavy elements present within the primordial nebula from which the system condenses, elements other than helium and hydrogen  Vega's absorption spectra reveals high levels of hydrogen, but only trace lines of the heavier elements. This may account for a particle belt, which probably has a great amount of ice crystal content, and it may mean that any planets there would be metal deficient  The heavy elements necessary for iron- and nickel-core planets are created by previous-generation stars after they deplete their hydrogen and helium fuel and begin burning carbon, subsequently converting each new fuel into progressively heavier elements, a process which, in stars more massive than the Sun, eventually leads to the production of iron, a precursor to the star's impending, massive collapse, as the outward force of energy from burning (fusion) is unable to counteract the opposing, gravitational force of the growing mass of spent material  Since iron cannot be further burned and converted, stars at this stage enter the final phase of their life cycle, ejecting their refined materials into space as they go supernova  Subsequent stars and their systems incorporate these processed materials into their structures as they form; the Sun was such a star, condensed from a primordial nebula which contained native hydrogen and the pre-processed materials of parent, grand- and great-grandparent stars that lived and died long, long before.

So far, the available evidence would not justify budgeting a Vega-system probe mission  And, there are yet other factors which weigh against the development of advanced life there, or in any blue-star system  Blue stars, like Vega, aside from being much hotter than yellow dwarfs like the Sun, emit correspondingly higher amounts of lethal short-wave radiation  They also have shorter life spans and even shorter periods of stable burn  Main sequence is a term used to describe a stage in the life of stars--the longest stage, where they burn hydrogen at steady, predictable rates  After that, fuel exhaustion initiates the processes culminating in the star's destruction, which depending on mass, can be either a quiet or spectacular event  If the Earth's example of rapid initial development of the rudimentary composites of life is the rule, then these precursors may exist widely, wherever conditions remain favorable for the short periods of time necessary to permit their creation  But, advancement to more complex and sophisticated life forms seems to be requisite on the time provided by smaller, longer-lived stars than Vega.

While the Sun, like Vega, is a main sequence star, or in adulthood, it is only near the middle of its estimated 10-1/2 billion-year, main-sequence life  Vega will have as little as half a billion years before its hydrogen is depleted and it begins to change, its outer shell of helium ash and remaining hydrogen expanding to engulf any interior planets and making an inferno of any which may be orbiting within the life zone, vaporizing seas and incinerating any life that may have evolved in that short half-billion years; there will be insufficient time for advanced life to develop and suffer the, what in Vega's case, will be a terminally spectacular demise.

Elsewhere, the outlook is brighter; scientists widely believe that life is not a unique occurrence to the Earth  Aside from the short evolutionary period required for development of Earth's life proto-structures, this belief is also supported by the abundant presence of organic chemicals (upon which the evolution of carbon-based life depends) which are known to exist in space, in meteorites, and in gas clouds (nebula) within which new stars are forming, and by the readily available power sources (lightening and its shock waves, volcanism, and ultraviolet light from stars), needed to furnish the energy to trigger the formation of nucleic acid-, sugar- and protein-based building blocks from these organic chemicals  Of course, all of these elements and conditions must co-exist on a planet of sufficient mass to retain a life-sustaining atmosphere, and for advanced life evolution, orbiting within the life zone of a stable and enduring star.

Considering the vast expanse of the universe and the prolific distribution of matter-energy (modern physics accepts matter and energy as being the same, but in different states of existence; water, in the state of a vapor, or as ice, is a very over-simplified analogy), the odds seem favorable for all of the necessary elements to come together, with the evolution of advanced life as the outcome  However, letting that bet ride may be an over-optimistic option, as for the present, despite considerable effort to prove otherwise, and with no cause to speculate the situation might at any time change, Earth remains the only home for all life that is known. As a desolate time traveler, still in your fragile ship, observing the beginning of life more than a half-billion years in the past, you may well contemplate the Earth's enviable and fortuitous set of circumstances:  that it evolved from a nebula containing the heavy elements necessary for the formation of your world, its life and the mineral resources that its civilization's industry and technology would depend upon, and that the conditions of gravity, angular velocity, distribution of matter and its location in the nebula resulted in matter accretion which placed Earth's orbit in the middle of the life zone of a single, stable, middle-aged, main-sequence star; and having done so, you may justifiably consider yourself fortunate to be standing at the brink of life and anxious to make the final leg of the return home.
August 1983

Epilogue - A Blast from the Past

November 1, 1994 -- The successful repair of the Hubble Space Telescope (HST) may soon provide more definitive answers about the universe to a world of reportedly bored and indifferent observers  With this instrument, properly functioning, astronomers will be able to see farther and with greater clarity then ever before  It will for the first time be possible to see planets in orbit around nearby stars  Observations have been made of variations in the proper motion of the 5.9 light-year-distant Barnard's star, betraying the existence of at least one orbiting body more massive than Jupiter, making it a likely first candidate for visual discovery  Hubble should also shed light on many other modern and ancient mysteries:

Are planets commonplace, as current theories and models closely tying stellar development with that of associated planets suggest?  If research with Hubble's improved optics shows that collateral planetary development is the rule in observable single-star systems, then the mathematical probability that intelligent life exists elsewhere in the universe will be greatly increased.

Will the number of objects known in the universe remain unchanged?  Each refinement allowing sharper investigation of the universe has revealed previously unknown objects and expanded the known distribution of matter to new boundaries.

Do the farthest quasars discovered to date mark the actual near-edge of the universe, or will there be even more energetic and inexplicable phenomenon awaiting the deepest-ever probe to the edges of space and time?

Will new information include answers about the unknown epoch that began after the Big Bang, lasting a billion years until the galaxies formed?

Will our knowledge of the structure of the cosmos be validated or cast into doubt?

Will the debate of the closed or open nature of the universe be ended by more precise calculations of the amount of dark matter that exists?  In this, Hubble has fulfilled its promise. Recent observations with the repaired mirror have already refined the Hubble constant--the rate of expansion of the universe--to 80 kilometers per second per megaparsec (3.3 million light-years), which implies that the age of the universe is about 8 billion years, half the previous believed maximum of 16 billion years old.

On January 8, 1998 the Space Telescope Science Institute--mission control for the HST--announced that HST observations of type Ia supernovae explosions have provided evidence to answer this, one of astronomy's landmark questions: Is the universe open or closed?

The answer, pondered by Newton, Galileo and Einstein, based on the Supernova Cosmology Project's (SCP) observations of the spectra of a particular type of supernovae, the type Ia, is open--the Universe will continue to expand...forever. The alternate possibility, a closed Universe, was that gravity would eventually halt expansion and trigger a falling-in to collapse that would ignite another big bang to begin the never-ending cycle of the Universe anew.

Type Ia supernovae produce specific spectra results over varying stages of their short period (several weeks) of observable activity, and what has recently been confirmed by the SCP, using the HST, is that the spectra of this supernovae category is constant, from the latest (nearest) events observed to the oldest (most distant), which occurred 7 billion years ago.

Now knowing that the spectra is constant, astronomers measured the redshift of the spectra from the newly discovered, distant events and, measured against the known constant of the nearby Ia spectra, calculated the distance of the event and determined the rate and angular velocity of expansion, which it turns out is too great to be halted by the mass-gravity of the Universe.

The most profound benefit of mankind’s brief search for understanding and life in the universe has, in this writer’s view, already been secured:  the knowledge that an extraordinary chain of circumstances has occurred with critical timing in a highly restrictive environment, providing us this benign speck we call Earth, upon which, adrift in an incomprehensible vastness, we live out our lives with only an instant--cleverly veiled by a kind twist of our perception--to discern the terrible reality of our universal insignificance.

Singularly alone, or as only one among a vast community of civilized worlds, we are supreme only to ourselves, and all that matters in this cosmic-millisecond lifetime of humanity is what we do, or fail to do, that either nourishes or deprives the intellect and spirit of one another.
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