The lure of the unknown

Carl Sagan once said, "Somewhere, something incredible is waiting to be known."

I think that's one of the main things that attracted me to science as a child; its capacity to astonish.  I still remember reading the kids' books on various scientific stuff and being astounded to find out things like:

• dinosaurs, far from being the "failed experiment" they're often characterized as, "ruled the Earth" (as it were) for about five hundred times longer than humans have even existed.  (I only much later found out that dinosaurs still exist; we call 'em birds.)
• when supergiant stars end their lives, they detonate in a colossal explosion called a supernova that gives off in a few seconds as much energy as the Sun will emit in its entire lifetime.  What's left is called a black hole, where the gravitational pull is so powerful even light can't escape.
• bats can hear in a frequency range far above humans, and are so sensitive to their own vocalizations that they can hear the echoes of their own voices and distinguish them from the cacophony their friends and relatives are making.
• when an object moves, its vertical and horizontal velocities are completely independent of each other.  If you shoot a gun horizontally on a level surface, and simultaneously drop a bullet from the gun's muzzle height, the shot bullet and the dropped bullet will hit the ground at the same time.

And that's all stuff we've known for years, because (not to put too fine a point on it) I'm so old that when I was a kid, the Dead Sea was just sick.  In the intervening fifty years since I found out all of the above (and lots of other similar tidbits) the scientists have discovered tons of new, and equally amazing, information about our universe and how it works.  We've even found out that some of what we thought we understood was wrong, or at least incomplete; a good example is photoperiodism, the ability of flowering plants to keep track of day length and thus flower at the right time of year.  It was initially thought that they had a system that worked a bit like a chemical teeter-totter.  A protein called phytochrome has a "dark form" and a "light form" -- the dark form changes to the light form during the day, and the reverse happens at night, so the relative amounts of the two might allow plants to keep track of day length.  But it turns out that all it takes is a flash of red light in the middle of the night to completely upend the plant's biological clock -- so whatever is going on is more complex that we'd understood.

This sudden sense of "wow, we don't know as much as we thought!", far from being upsetting, is positively thrilling to scientists.  Scientists are some of the only people in the world who love saying, "I don't understand."  Mostly because they always follow it up with "... yet."  Take, for example, the discovery announced this week by the National Radio Astronomy Observatory of a huge cloud of gas and dust in our own Milky Way Galaxy that prior to this we hadn't even known was there.

It's been named the Midpoint Cloud, and it's about two hundred light years across.  It's an enormous whirlpool centered on Sagittarius A*, the supermassive black hole at the galaxy's center, and seems to act like a giant funnel drawing material inward toward the accretion disk.

"One of the big discoveries of the paper was the giant molecular cloud," said Natalie Butterfield, lead author of the paper on the phenomenon, which appeared this week in The Astrophysical Journal.  "No one had any idea this cloud existed until we looked at this location in the sky and found the dense gas.  Through measurements of the size, mass, and density, we confirmed this was a giant molecular cloud.  These dust lanes are like hidden rivers of gas and dust that are carrying material into the center of our galaxy.  The Midpoint Cloud is a place where material from the galaxy's disk is transitioning into the more extreme environment of the galactic center and provides a unique opportunity to study the initial gas conditions before accumulating in the center of our galaxy."

[Image credit: NSF/AUI/NSF NRAO/P.Vosteen]

Among the amazing features of this discovery is that it contains a maser -- an intense, focused microwave source, in this case thought to be caused by compression and turbulence in the ammonia-rich gas of the cloud.  Additionally, there are several sites that seem to be undergoing collapse; we might be witnessing the birth of new stars.

What's astonishing to me is that this cloud is (1) humongous, (2) in our own galaxy, and (3) glowing like crazy in the microwave region of the spectrum, yet no one had any idea it was there until now.  How much more are we overlooking because we haven't tuned into the right frequency or turned our telescopes to the right coordinates?

The universe is a big place.  And, I suspect, it's absolutely full of surprises.  Hell, there are enough surprises lying in wait right here on the Earth; to give just one example, I've heard it said that we know more about the near side of the Moon than we do about the deep oceans.

How could anyone not find science fascinating?

This is also why I've never understood how people think that science's progress could be turned into a criticism -- I used to hear it from students phrased as, "why do we have to learn all this stuff when it could all be proven wrong tomorrow?"  Far from being a downside, science's capacity to update and self-correct is its most powerful strength.  How is it somehow better to cling to your previous understanding in the face of evidence to the contrary?

That, I don't think I'll ever come close to comprehending.

I'll end with another quote from a scientific luminary -- the brilliant physicist Richard Feynman -- that I think sums it all up succinctly: "I'd much rather questions that cannot be answered than answers that cannot be questioned."

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