Cosmos with Cosmos Episode 10: The Edge of Forever
In which we contemplate the end of all things
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"The great tragedy of Science," said Thomas Huxley, is "the slaying of a beautiful hypothesis by an ugly fact." And while I wouldn't call the facts in this case ugly, many beautiful hypotheses in this episode of Cosmos lay strewn upon the field, unmoving.
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Episode 10 of Cosmos, The Edge of Forever, expands its view to the vast structures of the galaxies, building nicely from our previous episode, "The Lives of the Stars." It also addresses the Big Questions of the cosmos: "where does it all come from?" and "where is it all going?". The episode features several poetic and haunting hypotheses regarding both, but suffers from the astonishing scientific progress in cosmology over the intervening 30 years. Most of these hypotheses turned out to be wrong, or at least irrelevant.
Carl Sagan's Cosmos Update at the end of the special edition DVD acknowledges this, though the Update itself suffers from the same problem, having been recorded in the comparatively primeval period of cosmological understanding that was 1990. Two major events occurred which revolutionized (not too strong a word, I think) the field of cosmology since then: NASA's WMAP spacecraft and the discovery that the universe's expansion is accelerating and the implication of the dark energy driving it.
WMAP measured the cosmic microwave background radiation in unprecedented detail. Careful analysis of these data led astrophysicists to the conclusion that the universe's overall geometry is flat. This implies an open cosmos (i.e. infinite), not closed, so goodbye to the hypotheses that we're living inside of a black hole or a subatomic particle in some larger universe.
The existence of Dark Energy—whatever it is—rules out a big crunch; there is not enough mass to stop the expansion of the universe. There is no Hindu-like cycle of cosmic death and rebirth. Our eventual fate is the proverbial whimpering out of existence; a frigid, featureless darkness awaits us at the end of all things.
I've been stewing on this for the past few days (as well as catching up cosmology, which I haven't studied since college), and I have to admit, I found the idea difficult to accept. Not that I disbelieve it, but the implications are quite dreary. If you are already concerned with meaning behind everyday life, do not read up on cosmology.
The heat death of the universe, if you didn't watch the video above, says that as the universe expands over great amounts of time, matter will either recede into the distance or coalesce into and collapse into black holes; the stars that escape this fate will die and slowly radiate their residual heat until they become black dwarfs. The density of matter in the universe will become too low to create new stars. Over many, many, many trillions of years, the black holes evaporate and the black dwarfs flake away. Time essentially comes to a stop as the universe approaches maximum entropy; the universe ends its days as a featureless soup of low-energy photons and fundamental particles.
This is a somewhat more depressing outcome than Sagan hoped for, given the focus of this episode on a cycling cosmos. This presents a problem. How do we reconcile our place in a cosmos in which the very presence of matter is a blip in its otherwise static existence?
This is where philosophy takes over, though I personally find the idea liberating in a strange sense. If even the achievements of Newton or Mozart and even the possibility of intelligent life will cease to exist, it's probably ok to relax and enjoy the brief life I have. At least that's what I tell myself.
ESA and the Planck Collaboration - D. Ducros
An Echo of the Big Bang
The anisotropies of the cosmic microwave background (CMB) as observed by Planck. The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380 000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.
Now Sagan was an optimist about all things, from the existence of extraterrestrials to the fate of humanity, and he held a deep conviction in the power of self-aware beings to determine their own fates. How would he have reacted to the heat death scenario?
We don't have to wonder. Sagan directly addresses this in his novel Contact, written about a decade after Cosmos. In a conversation between the main character, Ellie Arroway, and her (spoiler!) alien host, Ellie learns that Cygnus A, one of the brightest radio sources in the sky, is a vast, extragalactic engineering project:
"There are lots of cooperative projects between galaxies?" she asked. "Lots of galaxies, each with a kind of Central Administration? With hundreds of billions of stars in each galaxy. And then those administrations cooperate. To pour millions of suns into Centaurus...sorry, Cygnus A? The...Forgive me, I'm just staggered by the scale. Why would you do all of this? Whatever for?"
"You mustn't think of the universe as a wilderness. It hasn't been that for billions of years," he said. "Think of it more as...cultivated."
Again a tingling.
"But what for? What's there to cultivate?"
"The basic problem is easily stated. Now don't get scared off by the scale. You're an astronomer, after all. The problem is that the universe is expanding, and there's not enough matter in it to stop the expansion. After a while, no new galaxies, no new stars, no new planets, no newly arisen lifeforms—just the same old crowd. Everything's getting run-down. It'll be boring. So in Cygnus A we're testing out the technology to make something new. You might call it an experiment in urban renewal. It's not our only trial run. Sometime later we might want to close off a piece of the universe and prevent space from getting more and more empty as the aeons pass. Increasing the local matter density's the way to do it, of course."
Is this not the ultimate optimism? Sagan reminded us that trillions of years is a long time to figure things out. And when we face the end of the universe, we can treat it as a problem to be solved, not a fate to endure. Optimism was one of Sagan's gifts to the world. It was sorely needed during the cold war, and it is just as necessary today. Science and technology gives us more than apps and Facebook and 140 characters. It gives us hope within an indifferent universe, a chance to alter our own destiny.
As I've been pondering the birth and death of the cosmos this week, another thought struck me: how many TV shows force you to contemplate the end of all things? Or even the beginning? Most apocalyptic shows tend to focus on the collapse of civilization on Earth. You have a few, like Battlestar Galactica, that deal with the death of a world, but none, save a few science shows, that focus your thoughts on the great birth and death of our physical reality. And even though this episode of Cosmos was more dated more than most, it stirs the soul like very few other hours of television can. It makes you question and ponder, grieve and hope, and helps you stand on the edge of forever without falling in yourself.
You'll notice I didn't address many episode-specific segments in this writeup. For what it's worth, I enjoyed the detour into Flatland and found the description of redshift and blueshift reasonably good, though rather unimaginative (in the new Cosmos, will they still reference locomotives?).
The sequence with Humason reminded me of Stephen Jay Gould's excellent book, Wonderful Life: The Burgess Shale and the Nature of History, which celebrates the painstaking, laborious nature of most scientific discoveries. Cosmos reminds us (and probably introduces many viewers to the concept) that science depends on careful observation and collection of data over long periods of time.
The opening sequence about the human experience of birth is, oddly, not included at all in the book. Does it suggest that the religious cosmological concepts featured later in the episode are some expression of a deep cultural knowledge of the big bang? I don't know.
Note Sagan's careful approach to (for lack of a better term) atheism, or at least skepticism, when addressing the religious questions that quite reasonably arise while discussing cosmology. I know of no other public figure who could so respectfully approach the question while maintaining a fundamental commitment to scientific reality. He raises the question "if the universe was created, then who was the creator?", and then, with calm rationality, suggests that "if the creator just came into existence, why not save a step, and say that the universe just came into existence." By posing the idea as a question, instead of a direct statement of fact, Sagan avoids the natural human tendency to become defensive when presented with an authoritative statement challenging long-held beliefs (the "who do you think you are to tell me there that?" type of reaction). He raises the question and leaves it up the viewer to ponder the answer. It's hard to get defensive about a question.
Many, as I mentioned above. Particularly with new information gleaned from the cosmic microwave background. The European Space Agency's Planck mission just mapped the CMB at a higher resolution than WMAP, so expect even further refinements and new discoveries within the next few years.
There is also the issue of Dark Matter, not discussed in this episode, though there were hints of its existence even when Cosmos was filmed. Recent analysis shows that dark matter seems to account for 26.8% of the universe, compared to a meager 4.9% of "regular" matter, though it's not enough to stop the expansion.
It's no longer possible that the universe is a sub-atomic particle in a much larger universe, but Sagan would have enjoyed the multiverse hypothesis, which states that our universe is just one of an infinite number of universes that bubble into existence, each with a different set of physical constants. Some universes are stable, most of are not. We just happen to live in one that supports life as we know it.
Quasars, presented as a mystery in this episode, are now known to be the jets streaming out of a massive galactic black hole and pointed directly at us. Jets that don't point straight at us look less luminous and weren't classified as quasars. These are all types of active galactic nuclei.
"Pitch is to sound as color is to light"
"Cosmology brings us face-to-face with the deepest mysteries, questions that were once treated only by religion and myth."