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.