In today’s excerpt – astronomers and physicists are now grappling with evidence that suggests that all the things we can observe in the universe with even the most powerful telescopes is only four percent of what is there. The rest, they posit, is dark matter and dark energy:

“In 1610 Galileo announced to the world that by observing the heavens through a new instrument – what we would call a telescope – he had discovered that the universe consists of more than meets the eye. The five hundred copies of the pamphlet announcing his results sold out immediately; when a pack­age containing a copy arrived in Florence, a crowd quickly gathered around the recipient and demanded to hear every word. For as long as members of our species had been lying on our backs, looking up at the night sky, we had assumed that what we saw was all there was. But then Galileo found mountains on the Moon, satellites of Jupiter, hun­dreds of stars. Suddenly we had a new universe to explore, one to which astronomers would add, over the next four centuries, new moons around other planets, new planets around our Sun, hundreds of planets around other stars, a hundred billion stars in our galaxy, hundreds of billions of galaxies beyond our own.

“By the first decade of the twenty-first century, however, astrono­mers had concluded that even this extravagant census of the universe might be as out-of-date as the five-planet cosmos that Galileo inher­ited from the ancients. The new universe consists of only a minuscule fraction of what we had always assumed it did – the material that makes up you and me and my laptop and all those moons and planets and stars and galaxies. The rest – the overwhelming majority of the universe – is … who knows?

” ‘Dark,’ cosmologists call it, in what could go down in history as the ultimate semantic surrender. This is not ‘dark’ as in distant or invisible. This is not “dark” as in black holes or deep space. This is ‘dark’ as in unknown for now, and possibly forever: 23 percent something mysterious that they call dark matter, 73 percent some­thing even more mysterious that they call dark energy. Which leaves only 4 percent the stuff of us. As one theorist likes to say at public lectures, ‘We’re just a bit of pollution.’ Get rid of us and of every­thing else we’ve ever thought of as the universe, and very little would change. ‘We’re completely irrelevant,’ he adds, cheerfully.

“The ‘ultimate Copernican revolu­tion,’ as [astronomers] often call it, is taking place right now. It’s happening in underground mines, where ultrasensitive detectors wait for the ping of a hypothetical particle that might already have arrived or might never come, and it’s happening in ivory towers, where coffee-break conversations conjure multiverses out of espresso steam. It’s happen­ing at the South Pole, where telescopes monitor the relic radiation from the Big Bang; in Stockholm, where Nobelists have already be­gun to receive recognition for their encounters with the dark side; on the laptops of postdocs around the world, as they observe the real­time self-annihilations of stars, billions of light-years distant, from the comfort of a living room couch. It’s happening in healthy collabora­tions and, the universe being the intrinsically Darwinian place it is, in career-threatening competitions.

“The astronomers who have found themselves leading this revolu­tion didn’t set out to do so. Like Galileo, they had no reason to expect that they would discover new phenomena. They weren’t looking for dark matter. They weren’t looking for dark energy. And when they found the evidence for dark matter and dark energy, they didn’t be­lieve it. But as more and better evidence accumulated, they and their peers reached a consensus that the universe we thought we knew, for as long as civilization had been looking at the night sky, is only a shadow of what’s out there. That we have been blind to the actual universe because it consists of less than meets the eye. And that that universe is our universe – one we are only beginning to explore.

“It’s 1610 all over again.”

Author: Richard Panek