Extraterrestrial Life? Not So Fast !!!

I have written several times already on this subject, but there always seems to be something new to say. I am speaking, of course, about the possibility (probability?) of life on other worlds than ours.

Reading speculative fiction from the early 20th Century, it appears that there was at least some expectation of we would eventually discover extraterrestrial life right here in our own solar system. Mars was the perennial  favorite for such speculation. From H.G. Wells to Edgar Rice Burroughs to Stanley G. Weinbaum to C.S. Lewis to Robert Heinlein to Arthur C. Clarke, it was practically taken for granted that the Red Planet would be absolutely crawling with life. But it wasn't just Mars. Stories were written about life on the Moon (First Men in the Moon) Venus (Parasite Planet), Jupiter (Call Me Joe), the moons of Jupiter (The Mad Moon), and even the asteroids (Garden in the Void).

I have to confess to a desperate optimism that the next robotic space probe would find some sort of life on one or another celestial body, only to have my inflated expectations dashed time and again by the grim reality of what was actually out there. I vividly recall making up a list (sometime around 1980) of the places that might conceivably harbor life of some sort. It's rather amusing today to look back and see what worlds I included: Mars (of course), Enceladus, Iapetus, Titan, Triton, Ceres, and Vesta, and one or two less likely places. I finally gave up all hope after the Dawn spacecraft arrived at Ceres in 2015, only to find it a battered, lifeless pile of rocks. I was actually seriously depressed for some weeks afterwards.

So now, all speculation must center on the so-called exoplanets - those circling other suns. The problem is that the chances for life "out there" aren't much better than for elsewhere in our own solar system. First off, we have to face reality about how many suitable stars are in the Milky Way. Not that many, it turns out. Oh, I know, people say "There are a hundred billion stars in our galaxy. There's just gotta be life on millions of them!" But not so fast. Remember that the first stars in the universe (which includes our galaxy) were what astronomers call "metal poor" - that is, deficient in elements heavier than Hydrogen and Helium. But you can't build planets without heavy elements - iron, nickel, carbon, and all the others. It takes at least three generations of stars before you get any that are sufficiently rich in heavy elements to suit our purposes. At least a third of the stars in our galaxy are "first generation" stars, so we have to eliminate them right off the bat as potential places to find life. That's 30 billion already. Next, the Milky Way is a far more inhospitable place than imagined even a few decades ago. A nearby supernova could conceivably sterilize a solar system, snuffing out whatever struggling organisms might have been there. And in the galactic core (comprising roughly a third of our galaxy's stars) the stars are perilously close to each other, absolutely inviting such periodic sterilizations. And we haven't even gotten to the issue of stellar mass. A full 80% of stars, not only in the Milky Way but in the entire universe, are red dwarfs, which are so "cool" that any planet hoping to harbor life would have to orbit so close to its star that it would be tidally locked, keeping the same hemisphere forever in daylight and the other in perpetual night. Any atmosphere such a world might have would over time eventually freeze out on the nightside, leaving the rest of the world to resemble Mercury more than the Earth.

At the other end of the size spectrum, stars with a mass several times greater than our sun have significantly shorter lifespans, only a few hundred million years. And when you think that it took our sun more than three billion years to bring forth just one planet (us) with complex, multicellular organisms, well... even "a few hundred million years" is simply not going to cut it.

We're now down to no more than 10 billion stars. Still a lot, you might think. But again, not so fast. Three quarters of those that remain belong to multiple star systems, making the probability of any planets being in stable orbits less than certain. Plus, we have to weed out red giants, variable stars, blue white super giants, carbon stars, stars inside globular clusters, and stars at the centers of so-called planetary nebulae. We're left with maybe a few hundreds of millions of candidate homes for extraterrestrial life. Yes, that's still a big number, but less than 1% of the more than 100 billion we started out with.

Now lets examine the many exo-solar systems we have so far discovered. One surprising discovery made since we began racking up the numbers of known solar systems is how many of them contain what are known as "Hot Jupiters", that is, a Jupiter sized planet sitting right where the inner planets (including the Earth) do in ours. Subsequent computer simulations have suggested that this may be the norm for solar systems, and that ours is a notable, and possibly rare, exception. It seems that the normal course of events is for a Jupiter sized planet to form in the outer solar system, and then for it to migrate over time into a much tighter orbit... right in the middle of a star's "goldilocks" zone (where conditions are "just right" for life to flourish).

So why have we been so lucky? Why has our own solar system's Jupiter remained where it is, safely out there in the outer solar system? The answer? Saturn! The orbits of the two largest planets are in a roughly 1:2 synchronicity, which means that they tug on each other with regular frequency. The end result is that Jupiter's tendency to migrate inwards is balanced by Saturn's pulling it back out (and thus saving the Earth from annihilation). Now what are the chances of a solar system possessing both a Jupiter and a Saturn? I honestly do not know, but I would imagine their not being very high.

So... we dodged that bullet. But how many other cartridges are there in nature's gun? Another is our Kuiper Belt (made up of objects composed largely of water ice). Many planetologists believe that our oceans originated not on the Earth, but rather out in the far reaches of the solar system, out beyond Neptune and Pluto. These KB Objects are occasionally disturbed by near misses with other stars, which cause them to plunge into the inner solar system as comets, and the occasional super comet. (There's one of those lurking near Jupiter, Comet 29P, right now. The last super comet was Hale Bopp, nearly 30 years ago.) So no Kuiper Belt, no oceans. No oceans, and you likely get a dead Earth. And even the presence of an extra-solar Kuiper Belt is no guarantee than any inner, rocky planets will have oceans. The water bearing object first has to impact the planet. Ours got hit (multiple times, it would seem), but Venus has likely missed out on such watery enrichment. The Earth is rightly called the "Blue Planet" (insert political joke here), but Venus is about the driest thing imaginable.

Now let's move on to the Moon? What? The lifeless Moon? How does that effect life here on Earth? Well, as it turns out, a great deal. First of all, its enormous size in relation to its parent planet makes it (almost) unique in our solar system. I say "almost" because Charon is larger, relative to Pluto. But many astronomers don't consider Charon to be a moon of Pluto at all, the two of them being rather a double planet - the only one we know of.

And why is the Moon's size significant? Because it has an outsized influence on the Earth. We all know about the oceanic tides, of course. But the Moon not only pulls on the Earth's water, it is also pulling on the very rocks under our feet. The effect is naturally infinitesimal, but nevertheless there. (And remember that the Moon was long ago far closer to the Earth than today.) Over the millennia, this twice daily tugging could well have fractured the Earth's crust into its tectonic plates, allowing for a continual replenishment of our planet's surface. No other body in our solar system experiences plate tectonics as ours does. Sure, many moons in the outer solar system appear to have seen such activity in the distant past, but it seems to have extinguished aeons ago. Plate tectonics are what prevented the Earth from winding up today like Mars or Venus, with their dead, dead, dead surfaces. So, thank you, Moon! 

The Moon has also played a role in stabilizing the Earth's axial tilt, preventing wild gyrations in our rotation and smoothing out the seasons. An unstable axis could very well have resulted in geologic eras in which one hemisphere might be experiencing an ice age, while the oceans were boiling away in the opposite. Yikes!

Next, we have to consider our highly magnetic core. No other rocky planet has such a core. This is important to life, because it is our core which governs our world girdling Van Allen belts, which are basically our only defense against naked exposure to solar and cosmic radiation. It is believed that lack of such protection is what caused both Venus and Mars to lose whatever water they may have one had. Unfiltered solar radiation breaks water molecules down into their component atoms, which then fly off into interplanetary space. (This fact has caused me to speculate that maybe, just maybe, a significant portion of our planet's oceans originated on Mars! Who knows?}

I could go on, but by now you must realize that we live on a very unique planet indeed, one almost designed to support life. Or at least life as we know it (and we know of no other kind).

Bottom line (and personal opinion): We may very well be alone in the Milky Way. I can't speak for other galaxies.

Perspective

 

Last night I saw Venus. I was walking out to my car at about 9 PM, and low in the Western sky was the loveliest sight ever - a brilliant, piercingly white gem set in a field of pure cerulean blue. It stopped me dead in my tracks, and for several minutes I totally forgot why I had come outside. Because one so seldom encounters such absolute, unalloyed beauty.  

It was, of course, the planet Venus. And, also of course, we all know that "in reality" Venus is not at all beautiful. Its surface is hot enough to melt lead, and enveloped in a mantle of poisonous gas under a pressure that here on Earth one must descend to the ocean floor to experience. So on those terms, what I was gazing could be called an illusion, and a cruel one at that.

But here I must beg to differ. By what reasoning do we declare that one perspective is the "true" one, and all others somehow less so? Please don't get me wrong here. I am not speaking of relativism, where everything is a matter of opinion and no one's opinion is more correct than another's. Not at all. What I AM saying is that all perspectives contain a grain of truth, and you can't see the whole picture unless you take all points of view into account.

From a human perspective, the table on which my laptop is at this moment sitting is a solid object which is not doing much of anything. But from an atomic viewpoint, it is mostly empty space punctuated by vibrating, rotating, and incessantly hopping here and there particles of matter (whatever that is). From a galactic viewpoint, the table, the house in which it is located, and in fact the planet on whose surface the house rests, are all too infinitesimal to worry about.

I can stand on the shore of the Pacific and be overcome by the incomprehensible vastness of its area and the astounding depths to which it reaches. But then again, from the viewpoint of the Milky Way, even the Pacific shrinks to insignificance.

So which is true? Is the Pacific vast beyond comprehension, or tiny beyond caring about? Unsurprisingly, the answer is both. The human perspective is just as valid as that of an atom or of a galaxy, but it is also just as incomplete as both of those.

So yes, from the perspective of the Milky Way as a whole, the planet Venus is simply too small to even think about. From its surface, Venus is hell itself - no place I'd want to be. But looking up at it on a summer's evening, there is simply nothing more beautiful.

Starry Night

 “There, peeping among the cloud-wrack above a dark tor high up in the mountains, Sam saw a white star twinkle for a while. The beauty of it smote his heart, as he looked up out of the forsaken land, and hope returned to him. For like a shaft, clear and cold, the thought pierced him that in the end the Shadow was only a small and passing thing: there was light and high beauty for ever beyond its reach.”

 J.R.R. Tolkien, The Return of the King

This has been for decades now one of my favorite passages in one of my favorite books, The Lord of the Rings. I myself have at times taken hope from stargazing. Our earthly troubles cannot touch the Heavens. And there are times when you positively want to be insignificant, when you want your own misery to not extend beyond your own skin. This is the lesson that Job learned in the course of his sufferings. At the start of the book that bears his name, Job curses the universe. He wishes that the day of his birth would disappear from the calendar. He calls for darkness over light, and nonexistence over.. well, over everything. Yet by the end of the drama, Job is rejoicing over wild asses in the mountains who do not know man, the self-sufficient animals who haunt the wilderness, and even over Behemoth and Leviathan who cannot in any way be tamed or mastered. His many sorrows do not touch them.

That appears to be the lesson good Samwise learns in an instant, gazing in wonder at the unsullied beauty of a single star from the unrelieved horror of Mordor. He realized that all the evils of the world - past, present, and future - were incapable of tipping the scales in the presence of the perfect light of this star. Perhaps even in our day, surrounded by omnipresent death and suffering due to the pandemic, by economic misery, and millions of lives seemingly buried in despair, perhaps even now we can take solace from looking at the stars. I know that I do.

But on an entirely different level, I have always been fascinated by what exactly an author was thinking of when he references the sky and its inhabitants. For the most part, they're sadly not thinking of anything in particular, but it is fun to attempt to match art to reality. For instance, there have been numerous attempts to match Van Gogh's Starry Night to recognizable constellations in the hope of pinning down the exact portion of the sky the painting is depicting. (It has been definitively determined that the bright "star" to the right of the cyprus tree is actually Venus.) In the same vein, I've often wondered whether the "Netted Stars" seen by Frodo in The Fellowship of the Ring are the Pleiades.

With the magic of modern software, we are able to duplicate the sky for any particular time or date one wishes. According to Appendix B of The Return of the King, Sam saw his star on the 17th of March. The Mountains of Mordor were to the west of Frodo and Sam on that date, and since they were close to their base, anything low on the western horizon would have been behind the mountains. Assuming the star was one of the brighter stars in the skies and that Sam was looking up before midnight, that narrows our candidates down to (from north to south) Capella, Aldebaran, and Rigel. We can rule out Aldebaran, because Tolkien tells us the star in question is white, whilst Aldebaran is most definitely orange. My own vote goes to Rigel, because Capella would have been too close to the zenith to qualify as being "above" the mountains.

Of course, all bets are off, if Tolkien (like Van Gogh) was referring to a planet, rather than a true "star". And since we don't know how the years in the Third Age match up with our own calendar, it would be anyone's guess whether the star in question could be Venus, Jupiter, or even (but not likely) Saturn.

So now, while COVID-19 is ravaging the land, and our "leaders" (irony intentional) are divided like never before, we can look up at Orion, and admire the matchless beauty of its component stars... and hope.

Celestial Drama

 "Dramatic" is not a word often used to describe any Deep Sky Object. Beautiful, yes. Spectacular, awesome, breathtaking, even mind boggling. But dramatic? Very seldom, and most often when the term is used, it's not really appropriate. For drama requires action - action that can be seen. And for the most part, the stars (and everything else outside our Solar System) are, from our human perspective at least, eternal. To witness movement, change, and events... well, you have to stick closer to Home. Fortunately however, the Solar System provides drama enough. No one need bemoan any lack of activity there!

I thought about this Tuesday night, as I observed the Grand Conjunction (one day late, due to some unfortunate clouds on the night of closest approach). Here was drama indeed! Yes, I am aware that the characters in this celestial play were separated by a half billion miles, but they appeared to have survived a near miss. My eyepiece was positively crowded with planets and moons. Once again, as with the 2019 Transit of Mercury, I could feel in my bones that we lived in a Solar System, and not just in a collection of planetary odds and ends circling a sun.

I'm no scientist, but I have faith that someday there will be a science of planetary ecology, and we will study the interdependence of the various components of the solar system in the same way that we today study biological habitats here on Earth, in which every lifeform is dependent upon all the others to survive. Perhaps the concept of a "Goldilocks Zone" is way too simplistic. The habitability of the Earth may depend on our distance from Jupiter, and even on Jupiter's distance from Saturn, as much as our own distance from the Sun. And this is not to mention the likely role of Kuiper Belt Objects (or else comets) in explaining our watery surface, and the Moon's possible role in plate tectonics.

So enjoy the drama the solar system offers! On the way home from observing the Grand Conjunction, I considered where did this experience rank with other similar occurrences I've observed? And list maker that I am, I couldn't resist coming up with a "Top Ten" dramatic events I've seen in my time.

And here they are:

1. The 2017 Total Solar Eclipse - no contest there.

2. The Grand Conjunction - hard to beat that crammed field of view.

3. The Transit of Venus - made even more significant by the rich history of past transits.

4. The Perseid Meteor Shower during my first Stellafane (about 6 years ago) - never before or since did I ever see so many meteors (more than 60) in so short a time (a little over 3 hours).

5. The Transit of Mercury - not as photogenic as Venus's, but I did get to see the whole thing.

6. Comet Garradd - not my first comet (that was Halley in 1985), nor even the most spectacular (that honor would go to Hale-Bopp), but I followed Garradd for months, as it traversed the sky from Pegasus to Ursa Major while passing by a number of Messier objects. Whenever it was right up against a globular cluster (which was several times), I could understand why Messier called them "false comets".

7. Any Mars Opposition - I've been paying attention to them ever since 2010, and I positively get "Mars Fever" whenever one is approaching. I love just looking at Mars naked eye, appearing like a baleful red eye staring back at me. I have no difficulty in understanding why the ancients believed the planet was a portent of doom!

8. Any Jupiter shadow transit - a test of my observing skills. I also love watching one of the Galilean moons emerging from behind Jupiter.

9. Lunar sunrise - never gets old. If there was nothing else to observe up there, I'd still want a telescope. The ever shifting shadows remain endlessly fascinating.

10. The Lunar Eclipse of August 6th, 1971. Why this one, you ask? Because I remember it so well. I was not "into" amateur astronomy at the time. I was a student at Arizona State University, and walking home from class with a good friend, talking about God knows what. There was a full moon that evening, so even back in those days when streetlights were a rarity in Arizona, the night was pretty bright. But then I happened (for no particular reason) to look up, and was shocked to see that half the moon had disappeared! I had no idea that an eclipse was going on, and I remember being actually frightened. What had happened to the moon?  I was positively relieved to learn that it was "only" an eclipse.

Sure on this Shining Night

SURE ON THIS SHINING NIGHT, by James Agee

Sure on this shining night
Of star made shadows round,
Kindness must watch for me
This side the ground.
The late year lies down the north.
All is healed, all is health.
High summer holds the earth.
Hearts all whole.
Sure on this shining night I weep for wonder wand'ring far
alone
Of shadows on the stars.

Click on the link (SURE ON THIS SHINING NIGHT) to hear the music, and think of this, the next time you're out at Carrs Mill (or Alpha Ridge).

The Stargazer's Bookshelf

 Quarantined as I've been these past several months, staring at my library, I've been thinking a lot about what's on all those shelves. To make a long story short, what do I consider the most important books to have on a stargazer's bookshelf? Here is my very idiosyncratic list.  You are welcome (and in fact encouraged) to counter with your own list. The more, the merrier!

1. Sky and Telescope's Pocket Sky Atlas - Jumbo Edition (An oxymoron if I've ever heard one. I don't know anyone with an 8 1/2 by 11 inch pocket.). I particularly love this version because of its large size, and because it matches pretty much precisely what I see through my 8X56 Celestron binoculars.

2. The Night Sky Observer's Guide, Volumes 1 and 2, by George Robert Kepple and Glen W. Sanner. Whenever I get the (stupid) notion that there's nothing new to see "up there", I pull out these guides to the constellations and realize how little I've actually seen. There's enough in these books to keep anyone busy for several lifetimes of stargazing.

3. URANOMETRIA 2000.0 Deep Sky Atlas, All Sky Edition, for when the S&T pocket atlas doesn't have enough detail. My one wish is that they would publish a mirror imaged version.

4. Atlas of the Moon by Antonín Rükl. Whereas the above volumes supply all the detail you'll realistically ever need on the universe outside of our Solar System, Rükl's masterpiece will do the same for the Moon. The hand drawn maps in this atlas are not only superlatively detailed, but are true works of art. They are beautiful! Sadly, the Atlas of the Moon is currently out of print, but used copies are available (at ridiculous prices) from numerous booksellers on the web. My own copy once graced the shelves of a high school in Huntley, Illinois.

5. The Brightest Stars by Fred Schaaf has several pages of history, lore, and cold hard facts about each of the 21 brightest stars in the sky. Trust me, you'll appreciate much more just looking naked eye at Vega, Antares, Sirius, Arcturus, or whatever after reading this very entertaining book.

6. Voyager by Stephen J. Pyne. Now here we move from the purely "reference book" portion of this list to the more philosophical. Voyager is the finest book I have ever read on the robotic exploration of our Solar System. A deep dive into the origins, rationale, development, and execution of the Voyager missions, with wonderful digressions into history, politics, and the meaning of life.

7. Epic Moon by William P. sheehan and Thomas A. Dobbins. I cannot praise this book highly enough. As the subtitle says, "A History of Lunar Exploration in the Age of the Telescope", it ranges from Galileo to NASA's mapping of the lunar surface in preparation for the Apollo landings.

8. Imagining Mars, a Literary History, by Robert Crossley. Mars is more than dark smudges on an orange disk in your eyepiece. It is a world that has punched far above its weight in the human imagination over the past 2 centuries. Extremely entertaining, and you'll never look at the Red Planet in the same way again, ever.

9. Let There Be Night, ed. by Paul Bogard. A collection of essays on why preserving our dark skies is so important, and not just for stargazing. This is not a dry polemic or an ecologist's Jeremiad, but a deeply human look into why we need for night to be dark.

10. A Portfolio of Lunar Drawings, by Harold Hill. A glorious reminder that star (and Moon) gazing is more than just a hobby, but can be a window into a world of beauty and wonder far beyond what we encounter in most of our daily lives, and is accessible to most everyone.

So there's my list. What have I missed? What's on your shelf?

 

Eclipse

"Last Light"

The above image was taken on August 21st, 2017, from Jefferson City, Missouri, using a smartphone camera pressed against the eyepiece of my (properly filtered) 60mm Stellarvue refractor with a 9mm Televue Nagler eyepiece, just moments before totality. As stunning as this image is, it was NOTHING compared to the awe and wonder of totality. I had never seen anything like it, and the truly unbelievable sight of that jet black disk, looking like nothing so much as a hole in the universe, surrounded by the solar corona like a halo, was burned into my mind forever.

In the days and weeks following the eclipse, the internet was inundated by truly countless people expressing how they experienced an overwhelming sense of Oneness with the Universe, how they could feel the Earth, the Moon, planets, and the Sun spinning and moving through space in a Great Dance. More than one likened it to actually, physically hearing the Music of the Spheres.

And perhaps they were. For myself, my own feelings were mainly that I had not anticipated the beauty of the event. I had (mostly) anticipated the awe and wonder, but that it would be a Work of Art took me by surprise.

The "Belt of Venus"

Photo taken by my brother, Andrew Prokop, at sunset from the shore of Lake Superior.

The dark band just above the horizon is the Earth's shadow, just coming into view.

We think of eclipses (especially total solar eclipses) as super rare events, lasting at most a few brief minutes, and that one had to travel great distances to see. But have you ever realized that we (each and every one of us) experience a total solar eclipse every day? For just what is an eclipse? It is one celestial body passing in front of the Sun. A solar eclipse is the Moon passing in front of the Sun as seen from the Earth. A lunar eclipse is the Earth passing in front of the Sun from the vantage point of the Moon. But what is night? Is it not the Earth getting between us and the Sun? The fact that we are standing on the Earth's surface does not change that fact.

The Apollo astronauts marveled at finding "space" to be not cold and dark, as we are apt to think of it, but rather basking in an eternal noon. Michael Collins, Apollo 11 Command Module Pilot, perhaps expressed this feeling the best (in his memoirs, Carrying the Fire):

"As the radio commercial describes sunset: "When the sun just goes away from the sky..." Baloney. The sun doesn't rise or fall: it doesn't move, it just sits there, and we rotate in front of it. Dawn means we are rotating around into sight of it, while dusk means that we have turned another 180 degrees and are being carried into the shadow zone. The sun never "goes away from the sky." It's still there sharing the same sky with us; it's simply that there's a chunk of opaque earth between us and the sun which prevents our seeing it. Everyone knows that, but I really see it now. No longer do I drive down a highway and wish the blinding sun would set; instead I wish we could speed up our rotation a bit and swing around into the shadows more quickly."

A similar sentiment was expressed as far back as 1938, in C.S. Lewis' science fiction novel, Out of the Silent Planet. The novel's hero, Dr. Ransom, has been kidnapped by the evil scientist Dr. Weston, and carried off against his will in a spacecraft to an unknown celestial destination. Shortly after waking up aboard the ship, Ransom wonders aloud about how bright it is outside the window:

"I had always thought space was dark and cold," [Ransom] remarked vaguely.

"Forgotten the sun?" said Weston contemptuously. 

Ransom went on eating for some time. The he began, "If it's like this in the early morning," and stopped, warned by the expression on Weston's face. Awe fell on him: there were no mornings here, no evenings, and no night - nothing but the changeless noon which had filled for centuries beyond history so many millions of cubic miles.

And so we have the opportunity, without having to fly to the Moon, to viscerally experience our motion through space every single day. For me, the Earth's motion is most evident in the last minutes just prior to sunset, sitting on my back patio in shadow, while the tops of the trees in my neighbor's yard are still in bright sunshine. I realize that I am poised on the knife's edge of daylight. From space, from an observer on the Moon, I would be smack on the terminator, moving at approximately 700 mph into the Earth's night side.

I believe it is important to not just intellectually understand our place in the universe, but to feel it in our bones. I don't often manage to do this. I know I've succeeded when at a star party, the stars no longer seem to be above me, but rather in front of me. Try it sometime. Word of warning however - it can make you dizzy.