Dark Universe

I have written before (“The Dark Stuff,” 10/7/08) about the fact that scientists who study our universe (cosmologists and astronomers) are sort of befuddled by the fact that only a small fraction of the composition of our cosmos is visible to us. In fact, recent results published by researchers using the European Space Agency's Planck spacecraft have nailed down the conundrum with accuracy—telling us that only 5% of the universe is visible matter. The other 95% is made up of so-called dark matter (27%) along with dark energy (68%).

It's a bummer to be part of what we consider to be advanced science, but are able to identify only one-twentieth of reality. What's the rest? Where is it? What are its properties? Why is it not visible? How do you try to describe something that you know impacts your world—and you can even quantify that impact by its effect on visible matter—but find impossible to detect directly? It's like watching your easy chair on Halloween Eve levitate on its own and having no idea what causes it. And since you're a scientist, you can't come up with supernatural forces as an explanation, so you’re stumped!

OK, so 95% of the universe is invisible and is causing serious gravitational influence on the stuff we can see. But we'd still like to think that the real interesting stuff going on is happening with the 5% we can see... the part that's us. That's where stars and planets and people do their fascinating things. All that dark stuff does seem to be out there, but it must really be rather dull; it's probably some type of formless cloud or invisible glue that holds together all the things we can see… nothing more. Our bewilderment about the dark stuff makes us want to minimize and simplify its qualities, just like the ancients thought that those points of light in the night sky were just specks of light, nothing more. We humans have a way of denigrating things that we are ignorant of.

Hold on though: recent observations by a couple of astronomical teams suggest that the dark matter may be more than just a bland soup of strange particles. It may be more than just a diffuse cloud sitting out there, with enough mass to alter our universe's movement. In fact, it just may be its own peculiar kind of matter—though invisible to us—that moves around on its own and clumps together in various ways; just like the 5% of stuff that makes up us. In fact, it just may be that the dark matter has been able to form its own universe of dark stars, dark planets, and even dark life!

These recent observations have a few astronomers buzzing about the strange possibilities. Some of them think that we may be coexisting with a dark universe that is twenty times heavier and bulkier than we are, but unable to see it—like ghosts who drift through the wall in the hallway.

One scientist—with a sense of humor about the conundrum—has made up a fanciful tale about a Professor Dark Matter, an astronomer in the Dark Universe. From his recent observations, he's formulated a theory of a missing ingredient in his universe that's much lighter than reality (it’s only 5%), and that he's dubbed “visible matter.” So far, however, his unorthodox ideas have just earned him ridicule from his colleagues.

Brouhaha Brewing—Part 1

Physicists in recent years have been confronted with a number of intractable problems that just keep mocking their attempts to resolve them. Some of the brightest researchers (count Albert Einstein and Stephen Hawking among them) have unsuccessfully banged their heads against a brick wall of seemingly insoluble problems for much of their careers.

Here are a few examples: Why can't scientists get Einstein's theory of relativity and quantum mechanics to agree? What the hell is all the mysterious “dark matter” and “dark energy” that constitutes some 96% of the universe, and why can't we find it? Why can't a single unified theory describing and relating all the fundamental forces of the universe be found? How can the confusing soup of fundamental particles be sorted out and finalized? Why is it that string theory—which appears to be an elegant “theory of everything”—started out so promising a few decades ago, but has gotten bogged down in the last few years, such that all attempts to resolve it have either led to a dead end or even more puzzling mysteries? What is the nature of the bizarre mechanism that causes “quantum entanglement,” in which information seems to travel faster than light—in fact, instantaneously? (That last one really bugged Einstein.)

Now comes a mathematician who claims to have solved all these quandaries (and more) by taking a completely new approach. His theory, which he's dubbed “Geometric Unity,” is a work that he's devoted his last 20 years to developing. This remarkable announcement has been issued by one Eric Weinstein. He has a PhD in mathematical physics, but dropped out of academia 20 years ago to pursue his dream as a lone wolf.

It's both a startling and a romantic story: an unknown genius toiling away for two decades in the shadows, eclipsing what legions of physicists and mathematicians have failed to do for a couple of generations. Weinstein was invited this past May to give a lecture at Oxford University, to describe his theory and its implications. He says there is no missing dark matter in his calculations; it's all present and accounted for. His model is apparently straightforward and elegant, and it makes many new predictions about particle physics.

This is an amazing development—one fit for sensational press headlines; and it's gotten a few, though the topic is a bit too complicated for your typical tabloid sound bite shrieks. Has Dr. Weinstein truly made the work of countless scientists futile? Some non-scientists may jump on this announcement and get carried away with its implications, but let's hold on a minute here.

This situation is reminiscent of the sensational news a year or so ago, that Italian experimentalists had measured neutrinos exceeding the speed of light. Gracious! Einstein was wrong! The speed of light is not an absolute limit, after all! What furious sound-bite reporting zinged around the world's cyber lanes at the time! A few months later, however, further investigation showed that they had made an experimental error. So Einstein was right after all! I doubt that even one of all those newspapers and TV “news” shows—those that had earlier trumpeted the amazing “discovery”—even noticed the retraction. If they did, they'd certainly not regard it as news worthy.

More on the brouhaha next time...

The Dark Stuff

The story of our marvelous universe has been revealing itself to us at an ever-increasing pace. Nearly every day it seems that another piece of the puzzle is added, and we come to better understand how this cosmos has unfolded and what its true nature is. It’s an astounding world—beautiful beyond words; so I’ll not even try to do so. Go out in the country, lay on your back some clear, dark night, and gaze at the sky for awhile.

The details of the universe’s story have been coming hot and heavy in recent years—what with the Hubble Telescope and all its related stellar tools. On another front, DNA analysis peers deep into inner space and reveals secrets of life. I find it fascinating how rapidly these stories get amended, as new discoveries flesh out and correct details. We’re learning so much, so fast.

And yet our ignorance of the cosmos remains monumental. The more we come to know, the more we comprehend all that we don’t know. A door to knowledge opens, revealing a roomful of additional doors. It’s a wonderful check on our hubris, if you pause for a moment and realize just how much more we have yet to discover.

One of the best examples of how little we understand our universe—despite the impressive advances we’ve made in recent years—is that we have no idea what constitutes 95% of it! We have built a pretty good story of the 5% or so that we can see and measure (although that needs a lot of fleshing out). Yet 95% of it all remains a Great Mystery. We can’t see it; we can only infer its presence, and we have no idea of its physical properties. Oh, what we don’t know!

Scientists have appropriately dubbed our 95% ignorance as Dark Matter and Dark Energy. (It’s more like some plot for Star Wars than the real world.) About ¼ of this stuff—the Dark Matter—is what seems to keep galaxies held together more tightly than we can explain. If you count up all the stars in a galaxy and give them suitable mass and subsequent gravitational attraction, computer models tell us that the galaxy should not be as compactly clustered as it is. Some kind of unseen stellar glue is holding it together. What could it be? Guess I’ll call it Dark Matter.

That was a tough enough blow to some astronomers’ egos, but more recently those marvelous telescopes we’ve trained on the heavens (backed up by marvelous computers) tell us that the universe is expanding much faster than we thought it should. It seems as if there must be some unknown energy that’s pushing all those galaxies apart—a form of energy that we’ve never detected. What could it be? Guess I’ll call it Dark Energy.

It tickles my fancy that most of our cosmos seems to consist of dark stuff that is hiding beyond our stupendous science. Just think, as smart as we are, we know virtually nothing about 95% of our universe! Still, just a few years ago we didn’t even know that we didn’t know. That’s scientific progress.