What’s Eating the Universe? Paul Davies on Cosmic Eggs and Blundering Atoms

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What’s Eating the Universe? Paul Davies on Cosmic Eggs and Blundering Atoms

Into the gravity well

In his book, What’s Eating the Universe?, the physicist Paul Davies asks us to imagine the sublime awe that Isaac Newton must have felt when the laws and mathematics, spun from the recesses of his mind, began to explain the celestial machinations of the great expanse. Suddenly, “the swooping parabolas of comets, the graceful ellipses of planets, [and] the scalloped gyrations of the moon fell into place”, writes Davies. More than that, Newton had transformed the Universe into a “gigantic clockwork”. A cosmic engine whose structure and happenings were held together by the ceaseless wrest of gravity. 

There was, however, one curiosity that troubled the seventeenth century polymath. If gravity was incessant and interminable in its tugging, why did the cosmic machine not collapse into itself along with life as we know it? Newton reasoned then that the Universe must be infinite. Without a boundary or center of gravity, the cosmic machine would have no place for everything to well into. But as Davies explains, “clever though this dodge may have been, it was something of an intellectual sleight of hand.” The “delicate equilibrium” that Newton proposed was unstable. A strong enough perturbation or unevenness would result in the same collapsing universe that Newton himself had tried to explain away.

Swellings in space

We know today, of course, that this was not the final word. Albert Einstein reordered our picturing of the cosmos once again, some two centuries later, when he conceived of his general theory of relativity. “The blandness of Newton’s immutable void”, Davies writes, “[was] replaced by a concept of space as a vibrant, dynamic entity.” One that was “stretching and shrinking…, pulsating and convulsing.” Indeed, what we feel and measure as gravity emerges actually from the warping and curving of space and time itself. Under this paradigm, even the most heavenly and picturesque of trajectories, that of starlight, are bendable.

Yet Newton’s troubles did not go away. Why did everything in the cosmos not fall into each other? Einstein, for one, had similarly assumed the Universe to be a static and homogenous thing, going as far as to fudge his equations to make this so. But the results were again unstable. A static universe, under the unending onslaught of gravity, “as with Newton’s infinite universe,… is like [balancing] needles on their tips”, Davies writes. Was the cosmos that finespun?

As it turns out, Einstein had no need to fudge his equations at the time. Some years later, at Mount Wilson Observatory on the peak of the San Gabriel Mountains, came a momentous discovery that marked the arrival of modern cosmology. The lawyer-turned-astronomer, Edwin Hubble, discovered that the Universe was not static but expanding. Every galaxy outside the Milky Way was shooting away from us. To get a feeling for it, it can help, Davies writes, to “imagine the space between the galaxies to be swelling.” That is, we have avoided collapse thus far because “cosmic expansion is literally putting space between the galaxies”. This resolution would have taken Newton by surprise. Even Einstein himself needed a few years to swallow the implications, later proclaiming his fudging of general relativity to be the “greatest blunder” of his career. 

The cosmic egg

But nature is like a nesting doll of pandora boxes. The closing of one question leads quickly to another. If space is expanding, and its innards spreading, then it stands to reason, if we’re looking back, that the cosmos itself was once very small and very dense. Already in 1927, the priest-turned-astronomer, Georges Lemaître, postulated using Einstein’s theory that the Universe began as a “primeval atom” or “Cosmic Egg”. But this was an idea so outlandish for its time that Einstein was quick to label Lemaître’s physics as “atrocious”—a position that Einstein later retracted as the observations and calculations mounted. Indeed, it was Lemaître’s bold hypothesis that paved our way to understanding the Big Bang.

Eating the Universe

Resistance and revelations of that sort, however, are not uncommon. Davies points similarly to the intellectual voyage of the Indian-American physicist, Subrahmanyan Chandrasekhar. While sailing from Madras to England to study physics at Cambridge, a young Chandrasekhar pondered upon the life and death of stars. In his mathematical musings and probings, surrounded by vast seas and oceans, a remarkable insight came to him. Chandrasekhar showed in his equations that a very massive star could eventually collapse into itself due to the overwhelmingness of its own mass. As Davie explains, “the ball of matter would plunge down its own gravitational well and disappear into what mathematicians call a singularity—a point of infinite density and geometrical curvature.”

However, when the young man shared the possibility with others at Cambridge, he was openly mocked and rejected. Blinded in part by their preconceptions of what giant stars should be, towering figures like Sir Arthur Eddington deemed Chandrasekhar’s work to be fancifully erroneous. It was an experience, Chandrasekhar recalls, that nearly pushed him to give up on physics. But the man was right. His work was a precursor to our understanding of black holes. “And in 1972, [some four decades later], the first black hole—a stellar remnant in the constellation of Cygnus—was discovered”, Davies writes. Since then, “astronomers have long accepted that the universe we can see—the stars, gas and dust—is being slowly but inexorably eaten by supermassive black holes lurking in the centers of galaxies.” So while the Universe may not be collapsing as of yet, it is literally, in some respects, consuming itself. 

Blundering atoms

But humanity is still a newborn. We are only beginning to understand the nature of ourselves and the cosmos. Again, every time a new theory or discovery is made, new problems and questions arise. One wonders how far this conquest for knowledge must stretch. Right now, nobody can say, for instance, what transpired before the Big Bang. Perhaps the Universe has always existed in some form. If so, why even have a universe? Why should anything exist?

Just as well, we do not know how everything will end. While proposals like the Big Crunch, the Big Bounce and the Big Rip are intriguing, there is much to confirm. Or maybe everything as we know it is a simulation. After all, wouldn’t it be easier to fake a universe than to make a real one? We do it all the time ourselves in literature, filmmaking, and videogames. 

Yet it is amazing that we can say anything at all about these things. That somehow, from the birth of the Universe, from the early soup of quarks and particles, from the formation of gas clouds and galaxies, that life emerged to think about such topics. In Davies’ words, “mindless, blundering atoms have conspired to spawn beings who are able not merely to watch the show, but to unravel the plot, to engage with the totality of the cosmos and the silent mathematical tune to which it dances… [And] the deeper we probe, the more beautiful and awe-inspiring the physical world appears… It is impossible to look up at the night sky and not be struck by the grandeur… [of] the sweeping arc of the Milky Way [and] the myriad [of] twinkling stars.”

The haven of freedom

I cannot help but feel the same way. And how strange and delicate all of this seems to me. If the giver of life, our nourishing Sun, was just a little warmer or cooler, we humans may not have arisen on Earth at all. Even now, as a species, we do not amount to much. We fight, we gossip, we litter. We are nothing but a tiny blip on the long lines of cosmic history.

Yet against all odds, we have also been privileged with an opportunity to learn about things more immense than ourselves. And while we ordinary mortals may not be as far-seeing as Hubble or Lemaître, we are no less able to marvel at the cosmic egg and other celestial wonders once it is shown to us.

Perhaps there is a lesson in all of this. Just as the Universe continues to march in expansion, so too should we endeavor to expand our own horizons—our own personal universe. During his banquet speech in 1983, following his receipt of the Nobel Prize in Physics, Subrahmanyan Chandrasekhar shared a poem with his audience, a passage he had committed to memory in his youth:

Where the mind is without fear and the head is held high;
Where knowledge is free;
Where the world has not been broken up into fragments by narrow domestic walls;
Where words come from the depths of truth;
Where tireless striving stretches its arms towards perfection;
Where the clear stream of reason has not lost its way into the dreary desert sands of dead habit;
Where the mind is led forward by thee into ever-widening thought and action;
Into that heaven of freedom, my father, let my country awake.

—Rabindranath Tagore

Sources and further reading