The above image is the oldest I can find illustrating the camera obscura —forerunner of the pinhole camera and operating along exactly the same lines.
No one knows how long ago the principle was discovered, tho one can
imagine it being held as something of a secret:
An image of the
external situation viewable from behind closed doors? Yeah, hello,
Ring Camera! Tactical advantage, there.
Not that the camera obscura, or even the pinhole camera, per se, functioned as what we might consider a camera —that is, no permanent record of the projected image could necessarily be produced.
In fact, what we call a camera takes its name from the
Latin word for “room” and a “camera obscura” means merely: dark
room.
That a darkroom may be associated with the
development of film from a camera is just one of those quirks
or kinks in the working out and expression of human knowledge. Don't let it confuse you.
This image comes from a 1545 treatise on astronomical and geometrical radiation by Gemma Frisius, in which he describes viewing the solar eclipse on January 24th of the previous year by employing just such a structure as we see here.
Even in those days, fools knew not to look at an eclipse.The illustrator has depicted the sun as a flat disk, not terribly far
away, and has given it a human face.
While none of this
represents the reality of ol' Frizzies experiment, it suits my purposes
not to have to deal with the giant globe of boiling plasma 93 million
miles from here.
So if I had reason to observe a painted disk on a brightly lit wall
from within my dark room, this setup serves admirably.
Notice that the illustrator intends to depict cones of light
—or a cone that passes through a small hole, inverting all its parts.
The resulting projection cone reveals an image, for all its
clarity, upside-down and reversed left-to-right, relative to
the original.
Since the illustrator would have had no knowledge of anything so abstract as photons it's worth imagining rays of light moving always in straight lines, such that, from the original image's 12 o'clock, as it were, a straight line passes through the little hole and lands on the projection's 6. From the image's 3 o'clock a ray can be traced to the projection's 9.
It may be worth noting that the smallness of the aperture, the hole
through which the light must pass, gives rise to the entire phenomenon.
A window would show the sun, not project it. We need all the light
to pass through what is essentially a point within a plane.
But moving on…
A question I had as a kid, seeing images like this —whether intended to show the functioning of a lens, a pinhole camera or whatnot— might have amounted to: How does the light know where the hole is?
I don't know that I articulated it in quite this way, but
there was a strong feeling that the hole (or lens) somehow drew the
light through itself.
The actual state of things is harder to grasp.
It is, in fact, astounding.
Let's get rid of the camera obscura for now, and just admire this image of an anthropomorphized sun that I've had painted on the wall. What the camera taught us is that light bounces off this painting and goes ABSOLUTELY EVERYWHERE.
Let's bring in a mirror, put it in the corner, look at it from near the painted disk. If we arrange everything correctly, what that mirror reveals is that, from every part of the painted disk, rays of light are pointing at the mirror. That we can see the image in the mirror indicates that those rays of light recross the room and land directly in our eye.
Now do something absurd. Sit on the floor. In the mirror now, what?
SOME OTHER PART OF THE ROOM.
From every part of the room, light rays are
traveling to every other part and these rays completely fill the
space of the room.
I imagine we're feeling a bit crowded, so let's just close our eyes and imagine a different room, one with no one in it. To simplify, let's make it a dark room, a camera obscura, but leave somewhere within it, a single candle burning.
There, that's soothing to the overtaxed inner eye.
Until we imagine
the light from the flame radiating out in all directions.
It must touch
literally all points reachable by straight lines.
Of
course, under the table or the shelf on which the candle sits must now
be pitch black, no?
No. Because now we must imagine that all the points at the end of straight lines from the flame, also reflect that light in all directions.
If we add a mirror to any part of the room, it will coherently reflect every point reachable in a straight line from the mirror, and the proof is that, no matter where we put our eye (also in a straight line from the mirror) we'll see some part of the room reflected. The mirror is not only collecting rays of light but sending them out again!
If you step into the room, it does not appear ablaze with light, but
your eye is only collecting the straight rays which land in it.
If you
could place your eye everywhere at once the light would be
blinding.
A pinhole is not collecting a cone of light, it's
excluding all light not already in that cone.
dM
20260812 Reading, PA
What we call empty space is not entirely empty. It's filled throughout with quantum
fields —like the famous Higgs, which lends elementary particles their mass.
Such fields are configured everywhere the same —so ubiquitous, we call it “vacuum.” And it's been stable for 14
billion years, give or take.
But it's just possible this vacuum state is merely metastable rather than absolutely so.
If a theoretical lower vacuum energy could exist, some point in the universe might eventually lapse into true
vacuum, with startling results.
It's highly doubtful that baryonic matter (protons, neutrons) could survive such a transition.
A bubble of the true vacuum, churning through spacetime in a widening gyre, things would fall apart —new
paradigm consume the old.
Cosmos re-emergent, from its own body: offspring eating its way free —leptons leaping!
Electrons (that's if they survived) liberated from their atomic prisons, from making
circles in that yard…
The structure of spacetime itself rewritten within the expanding sphere. The very concept of time
redefined——
The term is “false vacuum decay” and its possibility is well known, though incompletely
understood.
How could we even tell if our false vacuum had already, somewhere, failed?
Say it happened nearby: in the Centauri system, just 4.31 mean-light-years away.
Expanding outward at the speed of light —driven by the energy differential between false vacuum
and true— the bubble's edge reaches Earth some 52 months later. The first —and last— we'll know of it
No warning is possible, because the destructive front approaches at light speed. We
won't have time to say: Well, finally...
But the likelihood that a truer, more vacuum-y vacuum might form next door to the only beings capable of
anticipating it? Seems low.
One could only expect such a nucleation in our vicinity if it resulted from our own bungling
experimentation.
Someone fooling around with zero-point energy —in hot pursuit of perpetual motion— is as
likely an eventual cause of the demise of the status-quo as anything.
But it probably remains outside our power to fuck up quite that badly just yet, so:
- The bubble forms naturally, somewhere in the interstitial void, between galaxies
- Forms right now, out there, just seventeen billion light-years away
Well, here's the thing:
It can never reach us
I hear you shouting, inappropriately, Bullshit! Because you know that
we see, today, galaxies farther away than that:
Our visible universe extends some 46 billion years!
I hear you say.
But the universe is expanding. And that expansion is accelerating. The
bubble's edge, moving at c, will remain beyond what we call the cosmic event horizon.
In the far
future, our weird descendants may see no galaxies beyond our Local Group. Unless we keep good records, they'll
never know how small their universe has become.
At large enough scales, even now, spacetime's expansion is faster than light. This is
somehow allowable because nothing moves:
Everything only gets farther away
Maybe vacuum decay has already occurred, maybe more than once. We don't know how big the
universe is.
But if it happens far enough away, we might all yet be spared.
dM
20260805 Reading, PA
I decided to become more involved with SFWA ( you may know it as the Science Fiction Writers of America, but the name has changed, while the acronym hasn't) so I "volunteered" —always a mistake, really.
As a full member, and because I teach in Game Design and, yeah, specialize in Interactive Narrative, I've been invited to contribute to the Game Writing committee —and as I've worked a bit in publishing, to the committee running the brand new Games and Comics Quarterly magazine.
So far I've mostly done nothing. I mean, I cast a sort of vote on the cover image for
vol.2 of the magazine... And proposed a panel for a coming event:
An Arrow in the Knee: NPCs, the writer and AI —which, lemme tell you, reopened the can
of worms that is AI, today, in the writerspace.
But these are not my worms! This is not my can!
I'm just interested in helping those seeking professional development to wrangle all the freakin worms let loose upon the world by AI. Heck, I'm not even the messenger!
Don't Shoot!
dM
20260729 Reading, PA