Good Prediction

This wooly bear caterpillar's photo was taken last fall. His wide midriff band predicted a long winter, and gosh, it was! Click to enlarge.

Naked-Eye Universe—Part 2

An ancient Greek astronomer, Hipparchus, became extremely familiar with the heavens. Like many of his compatriots, he was not limited by city lights and thus developed an intimate understanding of the night sky. Hipparchus was the first to classify stars according to their brightness. He had no idea of the distance between Earth and the stars (he even assumed that they were all the same distance away), but he carefully classified their relative brightness into six categories, which he labeled magnitude 1 to magnitude 6. His system has endured, so we still use it today.

Now that we know stars are at various distances away from us, it raises a few questions: When I look at a specific star—shining at its particular brightness or magnitude—am I looking at a faint star that is closer to us or a bright star that is farther away? How far away is the most distant star I can see with naked eye? Again, how big is the naked-eye universe that I can see from my tub? Just how far out can my eyes go?

A little research told me that the most distant star that we can see with the naked eye is in the constellation Cassiopeia. It's an extremely bright star—as brilliant as 100,000 suns—and it's 4,000 light years away. That's a mind-boggling distance of about 24,000,000,000,000,000 miles! It's amazing that my eyes can pick up light from a very bright star that far away. That seems to indicate a pretty big naked-eye universe. But let's put that in perspective, by comparing it to the size of the whole universe, which our most powerful telescopes and detailed scientific measurements have provided us.

Suppose I could imagine myself sitting at the center of a transparent Earth, letting the diameter of the Earth represent the size of our universe. If I looked outward from that center point, therefore, the surface of the Earth would represent the edge of the universe. What then (sitting in my tub, gazing at the stars with naked eye), would be the equivalent distance I could see in this scaled-down, Earth-sized universe? I could see as far out as about a tenth of an inch... about the size of a fat grape seed! I can't even fit inside a grape seed, but if I imagine myself at its center, my naked eye could only see as far as to the edge of the seed. Everything beyond that seed would be unknown to my naked eye.

Wow! My sense of sight (not amplified by a telescope) is but a grape seed at the center of an Earth-sized ball! It makes me realize just how small I am. I get to see but the tiniest part of this grand universe. The size of my minuscule naked-eye universe is really insignificant. Nevertheless, on a starry night I peer up from my tub and take in several hundred stars. It ain't much, compared to all that's out there, but it sure is magnificent!

Last Snow of Winter

Please?

Naked-Eye Universe—Part 1

Sitting in my outdoor tub, gazing at the dark (late) winter's sky, I can see hundreds of stars, even though my field of vision is significantly reduced by overhead trees and the bulk of the house behind me. Were I to be lying on my back while floating on the ocean or reposed on the flat desert sand, I would be able to count as many as 4,000 stars above me. So tonight, with my limited view, I still may be able to discern as many as a thousand stars. That's not a bad count.

But how deep a view am I looking at? How far “out there” can I see? I know that with my naked eye I can see but a tiny fraction of the number of stars that a telescope could capture. My eyes extend nowhere near as far out as telescopes go. So just how much of the whole universe can my naked eye sample?

Our ancestors were very familiar with the night sky—far more than we moderns. We may occasionally look up, but we are either limited by city lights or are so ignorant of the sky that we quickly lose interest and turn back to our electronic screens. Our ancestors did not possess telescopes (or cell phones), so they had no idea of how far away those stars were. In fact, most of the ancients believed that the stars were all about the same distance away... maybe just a little ways above the trees. So, although they were intimate with their sky, they had little idea of just how large the universe really is.

We moderns, however, know that those stars are not scattered across a hemispherical bowl immediately overhead, but are as far away as billions of light years. (A light year is really a measure of distance. It's the distance that light—the speediest thing in our universe—travels in one year; about 6,000,000,000,000 miles. That's a hell of a distance to try to wrap your head around! So we resort to light years.) So today we know something about the true size of our universe—because telescopes have told us.

But I wander. Back to my soaking in the outdoor tub: I know I can see but a tiny part of it all. How small a part? I look up and see hundreds, if not thousands of stars, and wonder what is the size of my naked-eye universe. It's ever so smaller than the whole enchilada. Astronomers tell me that there are billions of galaxies and trillions upon trillions of stars, but I can see only a wee portion... a much smaller portion of it all.

More naked-eye universe next time...

Milk Snake Having Lunch

I watched this guy take half an hour and more, to down this toad. Click to enlarge.

Philosophy's Foreignness

I have written a few blogs about the differences between philosophy and science. I chose science as my career path, because my inherent tendencies leaned in that direction. With a science background, however, I have struggled to parse the writings of philosophers, as they are rather foreign to the thinking of a scientist. That is a fascinating fact to me, since both science and philosophy are about knowledge and understanding; you'd think they might be more similar. In fact, a couple of millennia ago they were considered to be the same. Science arose out of the discipline of natural philosophy, but like close family members, after they go their own way, they have had many family squabbles ever since.

By definition, philosophy is, at its etymological root, the “love of wisdom”. Those who immerse themselves in philosophy are constantly examining and evaluating the nature of human ability to know. Philosophers explore the big, general questions that we often cannot answer, given our present state of knowledge.

This inability to currently know what the nature of the universe is, is in direct contrast to science's task: to describe what we do know. Science is practical and systematic. Scientists want to describe precisely what we know about our world. Philosophers often ask the questions about what we don't know. Science is more about today. Philosophy is more about what we might someday come to understand.

I just finished an online course on philosophy, presented by a professor at MIT. What drew me to try this course was its being offered by what many people consider to be the premier technical university in the world. So I hoped to learn better how to understand philosophy from someone teaching in a technical environment... maybe it'd be less foreign to me.

One beneficial result of my struggling through this course of introductory philosophy was finally arriving at the professor's last lecture. With my head spinning from the foreign (to me) way that philosophers express their ideas, he pointed out one of the major functions of philosophy: to be asking and pondering the big questions about knowledge that cannot be answered by what we currently understand. In other words, to ruminate on those questions that science cannot yet answer.

His example was to look back at the ancient Greek philosophers of two millennia ago. One of the central questions for them was, What are things made of? What is the fundamental essence of matter? Some suggested water, some air, some fire. A few prescient individuals (Democritus was one of them) suggested that there existed fundamental building blocks, which they called “atoms”—meaning individual entities that could never be further split. The insight into which of those alternative answers were correct required nearly another 2,000 years for humanity to generate—as science came into its own and was finally able to demonstrate the existence of atoms.

So philosophers today are often raising questions that we cannot answer today. Is there a God? What is knowledge? What does it mean to know? What is consciousness? What is free will? Science—let alone philosophers—cannot yet provide answers... maybe some day. In the meantime philosophers will debate and discuss.

I think that a crucial role that philosophy plays in civilization is to ask these and other unanswerable questions. Moreover, with today's understanding we often don't even know how to properly ask the questions. So maybe it's the job of philosophers to debate the issues, if only to frame good questions. If so, philosophy and science need not lock horns, but recognize that their disciplines are complementary and collaborative.

Part of Our Universe

Many galaxies, as taken by the Hubble Telescope (NASA)
Click to enlarge

Universes: Parallel or Unique? (Part 2)

There's a second way in which the concept of parallel universes comes up in modern physics: Not so long ago our understanding of the cosmos was far more limited than today. It was literally a smaller universe. The more we learn, however, the bigger it all appears to be. In fact, some scientists pose the possibility that the universe is unimaginably huge; even infinite. There is currently no known reason why it couldn't be. If so, it opens up the possibility for something very weird: If the universe is actually infinite, there may be an infinite number universes contained within it. No limit.

Since there are only a finite number of elements that make up everything, an infinite universe offers the chance of an infinite number of ways that things can arrange themselves. Sooner or later, you and I will find ourselves being duplicated. It's like giving 100 monkeys 100 typewriters to play with (OK, today, it'd be 100 PCs). Given enough time (infinite), they would write all of Shakespeare's plays. It's a crazy thought... but it's theoretically possible.

And finally, there's a third way that parallel universes come up: via string theory. There are currently three contrasting ways that physicists model our universe: (1) classical mechanics (Newton's baby), (2) relativity (Einstein's baby), and (3) quantum mechanics. Each one uses a type of mathematics that works quite well within its domain—either large and slow, very fast, or at atomic scales. But when two of these domains intersect or overlap, they clash in their predictions of how things behave. These three approaches disagree with one another in that overlapping zone—something that causes the stomachs of physicists to wildly churn, or creates painful scientific headaches.

A few decades ago a novel theory came into existence to deal with this disagreement: string theory. It irons out a lot of overlapping wrinkles in the old theories—providing a seamless description of our world; big, small, fast, slow, etc. String theory has introduced a few wrinkles of its own, however. One is that science may never be able to come up with experiments to test its validity. That's a bummer in the eyes of physicists who know they'll eventually have to have experimental verification of their theories. So string theory, although attractive, awaits (maybe forever) some kind of proof. (Interestingly, Einstein's theory of relativity remained an abstract curiosity for a couple of decades until an experiment in 1919 proved it true, and Albert became an overnight sensation.)

A particular aspect of string theory also suggests the possibility of parallel universes. So science now has at least three ways to suggest the possibility of parallel universes: quantum mechanics, the realization that the universe may be infinite, and string theory. As a result, other universes are coming into vogue and several new terms have entered the discussion: parallel worlds, the multiverse, the metaverse, the megaverse, alternative universes, etc. The imaginations of science fiction writers have been stimulated by all these developments. The possibilities are endless.

As yet, however, the evidence for parallel universes is only conceptually possible. There is no proof. There may never be. That's disturbing for some physicists and has others toying with the many potential implications. Nobody yet knows. So expect ongoing speculation for some time yet... and maybe the dilemma will foster a bunch more great science fiction stories and movies.