Monday, April 16, 2012

Cataclysmic Event

This is an image of the Cassiopeia A supernova remnant — a composite of images in infrared, visible and x-ray wavelengths.

Cassiopeia A supernova remnant
NASA/JPL-Caltech/Oliver Krause (Steward Observatory)

To think that such a cataclysmic event could be so beautiful, especially if you were from a planet where your eyes took in all wavelengths of the light spectrum, but hopefully not too near the scene of the crime of this exploded star.

I don't know, if your eyes could see all wavelengths, would you be blinded by the brilliance, or would natural selection cleverly protect you as your species evolved?


Daniel [] said...

We want to distinguish frequency from amplitude here. Even with just one frequency, we could destroy the eye if the amplitude (which, in this case, would be the number of photons per unit time) were sufficiently high. But the full range of frequencies could be experienced if the amplitude of each were kept in check, and the detectors were robust.

In the case of our eyes, the rods and cones determine which frequencies we can sense, and the pupils determine the amplitude by clamping the over-all intake of photons. It's an imperfect arrangement, both because some visible frequencies are more common than others, and because the energy of a single photon increases with its frequency. If the range of frequencies that we could sense were expanded, then we'd want something more involved, to filter input more selectively. Some of the possibilities (such as, well, more eyes) are signally unappealing to me!

BTW, some women have rods of a sort apparently not found in the eyes of any men, and so can experience colors that we cannot.

Thomas Haller Buchanan said...

Well, thanx Daniel, i knew I could count on you for that info.

From my layman's, admittedly ignorant, point of view, I could imagine an alien critter guy having a set of corneal filters that could slide into place and work separately or in layers to see the universe in all its glory.

And in fact, that's an invention that I'd love to see, a pair of optics that could do the same thing, artificially, for people like you 'n' me, prohibitively expensive though it would be.

Daniel [] said...

In some sense, we already have that, as illustrated by the image around which you've written this entry: mathematicians, physicists, and engineers have built equipment which translates from frequencies such as those of x-rays into frequencies that our retinæ can register.

One thing that we obviously don't have yet is portability.

But the deeper problem is that our nervous systems seem to be wired for a finite number of colors — far, far fewer, in fact, than can be distinguished by a 32-bit encoding! Even within the “visible” range, we cannot really see most colors at any given moment! If we translate, or even if we were to somehow alter the rods so that they become sensitive to colors out of the present range, we have to sacrifice previous distinctions. To truly see more, we'd probably need not only better optic nerves, but different brains.

(And think of how hard it would be on artists who aspire to realism if they had to paint with such a terribly enlarged palette!)

Thomas Haller Buchanan said...

In my mind's eye, I see a billyum colors!

Darrell said...

I am generally not a fan of false color astro imaging. Some of the IR/visible/UV combo images are rather nice, though. Many of the famous Hubble images had unusual colors assigned, instead of the usual red for H alpha, green for O3,etc.

buzz said...

I've often thot Superman's "x-ray vision" is really an ability to see in all wavelengths simultaneously. To him we look like walking / talking Visible Man and Visible Woman models.

Thomas Haller Buchanan said...

Ah, yes, and in order to live as a man among people, his task is to focus and control his vision, his hearing and his strength, so that he sees and hears locally and doesn't kill someone with a wave of his pinky. His cross to bear is that he is under constant stress to limit his abilities.