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2021-2022: LXVI

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THE DAILY ASTRONOMER

Tuesday, January 18, 2022

The Mardi Gras Universe

We'll begin with an indefensibly inappropriate editorial comment.

Dismiss with fire and flourish the lamentably prevalent notion that the Universe is just so much vacuum littered by accidents. This view, espoused by such scientific luminaries as the brilliant Richard Dawkins and equally gifted Steven Weinberg, is increasingly coming into vogue amongst the intellectual elite, of which I am admittedly not a member. All the same, this perception is utterly untenable. If astronomy has taught us anything since the vague early days of monoliths, cave scribblings and papyrus maps, it is that the Universe is both prodigiously creative and passionately alive. Here, I am not suggesting the presence of a designing intelligence, an issue I avoid like a swarm of flesh-eating plague spores. I am, however, suggesting that every time we've attempted to drape a wet blanket over the cosmos, the cosmos has vaporized it.

A century ago, many in the astronomical community insisted that the Milky Way Galaxy encompassed the entire Universe. Most notably, on April 26, 1920, astronomers Harlow Shapley and Heber Curtis engaged in their famous debate about this very topic. Shapley asserted that our galaxy was alone in the cosmos. Curtis argued that it was one of many. Another astronomer, Edwin Hubble, would soon after demonstrate that Curtis' view was the correct one.

Harlow Shapley (L); Heber Curtis (R)

Later in the century, the notion of exo-planets, planets in orbit around other stars, became a topic of fierce debate.   Yet again, many astronomers insisted that the existence of planets, if not exactly unique to our solar system, was still highly unusual.   They often cited as "proof" the belief that planets could only form when two stars drew close enough together.   The gasses stripped from both through tidal interactions could then coalesce to form planets.       Considering the high improbability of such encounters, planets would indeed be few and far between.    More than one expert derided the earnest search for exo-planets as a vain pursuit and waste of time.

Well.    In the mid-1990s, a planet was discovered around 51 Peg, the first active star outside our solar system found to harbor planets.  (A planet was discovered around a pulsar, a rapidly spinning supernova remnant, earlier in the decade.)       As of today, astronomers have detected 4927 planets!

Based on these detections, astronomers estimate that our galaxy could contain as many as one trillion planets.   To put that unfathomably large number in context,  realize that one trillion seconds equals 32,000 years!  Planet formation is a likely consequence of star formation and might even outnumber the stars by a significant margin. 

The James Webb Space Telescope, which has been successfully deployed much to the profound relief of  so many, will likely discover myriad other planets and should also be able to study their atmospheres

to detect evidence of metabolic activity.      Of course, many dour skeptics will argue that life is so exceedingly rare in the cosmos that such searches should be abandoned.    After all, nothing has been found yet.     Heavens.    That is akin to dipping a bucket in the ocean and after examining its contents, declaring with dismay that  "all the whales have gone extinct!"    The search has not yet yielded much because not only does so much territory need to be explored, but we have only recently obtained the means by which to conduct these searches.        

If history is any indication, the cosmos will prove to be far more fertile than we think.   Life most likely proliferates in the Milky Way.     That we think otherwise is a result of our spatial isolation.  After all, the Sun has about 330 cubic light years to itself.   All the same, we most probably live in a sprawling galactic megalopolis, but just happen to be confined -for the moment- to a small studio apartment within it.  

Regard not only life's astounding diversity, as evidenced by the myriad forms it assumes in sea, land and air, but also its stubborn resiliency.   Earth has taken quite a few beatings throughout its history and life, once it became established, retained its hold despite this series of staggering assaults.   There is no reason to suspect that such durability would be limited only to Earth life. The fierce determination to  survive hostile conditions and even thrive because of them must be a feature of vital species everywhere.    Life forms at all stages of development, from prokaryotic sludge to star-faring civilizations  exist in all directions throughout the galactic star streams.  This conclusion we confidently draw from what we've learned thus far about our Mardi Gras Universe: vibrantly alive with color, incandescent with energy and more alive than we can even imagine.

Tomorrow...the magic of the number 4800.

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