Weird cave phosphorescence
Evans Winner
here in Washington, near Mt. St. Hellens. We went to the bottom of
the lower cave and then took the lower crawlway all the way to where
it dead-ends. There is a little room there and so we decided it would
be a fun place to turn off all the lights (I'm not a very experienced
caver, so this kind of thing is still fun). Anyway, much to our
surprise, after a few seconds for our eyes to adjust we realized there
was something glowing on the wall. It was this green phosphorescence
that seemed to be kind-of streaked in an angled band across the wall.
We turned on the lights and it appeared to be part of or associated
with some of the water running down the wall. It was dim, but very
distinct in that darkness. Anyway, at the time we assumed it must be
some kind of phosphorescent algae, but that seems a bit far-fetched
now. Something that leached from the surface? Something inorganic,
like some mineral stuff from the soil or the volcanic rock? Maybe
someone just splattered glow-stick stuff on the walls. I was hoping
someone here knows what it was. I have never heard of anything
remotely like it. I may e-mail someone at Mt. St. Hellens Nat.
Monument if no one here has any idea.
Oh, and by the way, thanks to the Mean Old Man and Charles for their
helpful advises to me a couple weeks ago. I intend to take both.
-Evans
Brad Blackburn
to our
> surprise, after a few seconds for our eyes to adjust we realized there
> was something glowing on the wall.
Some formations can be blasted with a camera strobe and will glow for a
very brief period.
The trick is to pop the strobe with your eyes closed and immediately open
your eyes.
Colonel Boles formation in Carlsbad is one that comes to mind but I've had
similar results in Missouri caves.
Brad Blackburn
Mean Old Man
Same thing at the "Pilar of Fire" in Tumbling Rock Cave in
Northeastern Alabama. If you close your eyes and set off a flash or
two, the formation glows for a couple minutes. I was told it was from
some kind of low level radioactivity from a type of phosphorus.
See Ya!
MOM
Jamie Mergenthaler
Anyway, much to our
> surprise, after a few seconds for our eyes to adjust we realized there
> was something glowing on the wall. It was this green phosphorescence
> that seemed to be kind-of streaked in an angled band across the wall.
> We turned on the lights and it appeared to be part of or associated
> with some of the water running down the wall. It was dim, but very
> distinct in that darkness. Anyway, at the time we assumed it must be
> some kind of phosphorescent algae, but that seems a bit far-fetched
> now. Something that leached from the surface? Something inorganic,
What sorta lights didja have? Calcite fluoresces (and phosphoresces
for up to 10 seconds afterward) green in ultraviolet light. The light
gets trapped in the crystal structure, and it bounces around a bit
before the energy goes kaput. All incandescents have some UV
radiation. Some other folks here have seen it after strobes--camera
strobes have a lot of UV rays. There are some bacteria which glow
golden in dim light, and water drops themselves can appear to glow in
caves. There are, also, in New Zealand, true luminescent cave
critters. (No joke, mon.) Look up glowworms of Waitomo. I don't know
nothing about lava caves and their critters and things-- even after
hearing all the opinions in these parts, your original idea of
emailing the experts is a good one.
Evans Winner
I'd like to take the 5th amendment on that, on the grounds that it may
incriminate me... okay, it was just a Petzl micro. The other person
(at least I didn't go alone!) had a somewhat more beefy Petzl
headlamp. I don't think either used halogen bulbs. We had other
lights, but neither of us thought to try them on the glow-in-the-dark
stuff. Neither headlamp was terribly bright--nothing compared to a
photo flash.
I read in a book yesterday (I don't have it with me now, but it was an
old Searra Club caving guide) that impurities in calcitic or sulfate
based rocks can result in some phosphorescences. Not much calcium in
the lava tube, I think, but there could be volcanic sulfates in the
rock and in the voluminous ash deposits above. The glow lasted for
minutes after we had the lights on--in fact, we never saw it fade.
Being a lava tube it is close to the surface (we even saw roots in one
crawlway that went up high), so I assume there could be something in
the soil above that is leached into the ground water and soaks
through. Whenever we would turn on our lights we would see that the
glowing spots were all where there were water droplets on the wall.
Maybe some kind of phosphorus salt leached out of the soil or out of
the basalt? Does ionic phosphorus phosphor? I guess it must, eh?
Well, I don't know. Anyway, the official website for the Nat.
Monument doesn't provide any leads or even any e-mail addresses.
> There are some bacteria which glow
> golden in dim light, and water drops themselves can appear to glow in
> caves.
This was green, but yes, I think it was the water itself that was
glowing. I'll look more closely for some e-mail address for someone
there.
E
Steve
Jamie Mergenthaler wrote:
> What sorta lights didja have? Calcite fluoresces (and phosphoresces
> for up to 10 seconds afterward) green in ultraviolet light. The light
> gets trapped in the crystal structure, and it bounces around a bit
> before the energy goes kaput.
Let's see.... 10 seconds times 186,000 miles per second is 1,860,000
miles, times 5,280 feet per mile. You're suggesting that the crystal
faces of calcite are such great reflectors that the light from a typical
electronic flash will be reflected nearly ten billion times before all
of the light energy escapes? I'm being charitable in assuming a crystal
that's fully a foot across.
Under the right circumstances, adding energy to an atom will kick
electrons into a higher energy state, and eventually those electrons
will lose that extra energy, which has to be emitted in one form or
another. Just about everybody has seen things that fluoresce under the
UV radiation of a black light, and they've definitely been someplace
with flourescent lighting. Flourescence stops (esssentially)
instantaneously when the energy source is removed. Again, under the
right circumstances, the electrons will remain in a higher energy state
for a while before dropping back to the ground state. When this happens
the energy will continue to be emitted after the light source has been
removed, and since it's a slightly different process it gets its own
name, phosphorescence. Some minerals exhibit phosphorescence all on
their own while others need impurities, known as activators.
As for the original question and the cause, I don't know what caused it,
but there are all sorts of possibilities. That the glow existed without
having been exposed to an electronic flash, and may have been present
well after the lights were turned out (an assumption since it took a
while for their eyes to adjust and notice the glow, and the post seems
to suggest that it didn't fade rapidly after they noticed it) suggests
that what they saw was some form of luminescence, meaning that something
was emitting light independently of external sources introduced by the
cavers. Unless there was energy from radioactive decay, I think it's
unlikely that the phenomenon was caused by any characteristics of
mineralogy.
> There are some bacteria which glow
> golden in dim light, and water drops themselves can appear to glow in
> caves. There are, also, in New Zealand, true luminescent cave
> critters.
Which seems like a good possibility in this case. I've seen
bioluminescent fungus while hiking at night, the seas are full of
bioluminescent critters, and we're all familiar with lightning bugs.
--
Steve
The above can be construed as personal opinion in the absence of a
reasonable
belief that it was intended as a statement of fact.
If you want a reply to reach me, remove the SPAMTRAP from the address.
Hoyt McKagen
Calcite for example, has propogation velocity of about 70% of a vacuum.
Hehe, that phenom is precisely what produces Cherenkov radiation.
--
Regards,
Hoyt McKagen
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My dog drove off in my pickup truck, but left my wife behind!!
Evans Winner
ca. 70% that in a vacuum (c?) (and I read that in water it is about
75% c), then the light bouncing around thing does still seem a little
odd, as it would still require some billions of bounces, I guess. As
for cerenkov radiation, I am a physics idiot, but what I read seems to
be saying that in order to happen, a very hightly charged particle
must travel through the medium in order for it to occur--like aroung
nuclear reactors, and such. I certainly hope there were not too many
haghly charged particles romping around down there.
--Evans
Hoyt McKagen <Phuc...@nowhere.com> wrote in message news:<3D864F...@nowhere.com>...