A Short Voyage Towards the Center of the Earth


(orchestral music) – [Voiceover] As you’re
watching Old Faithful for the last few minutes
before an eruption, we would like to tell you
a bit about this video. A small group of scientists from the California
Institute of Technology, Arizona State University, and Yellowstone National Park, have been studying how Old
Faithful works in detail. We are especially interested in geysers since they seem to work in
very similar ways to volcanoes like Mount St. Helens, yet we can safely work
around Old Faithful. Some time ago, we made measurements of
temperature and pressure at several depths down
the vent of Old Faithful. We collected data starting from
the time that it emptied out at the end of an eruption
until it refilled and finally erupted again. From this work we learned many
details of how geysers work, but of course we still
have many questions. We’d like to know where
the water comes from. Does it come from the sides,
or from the bottom, or both? Why does it stop filling up at
about 15 feet below the top? If you look down from the top, the vent is a slot about
four or five feet long and about a foot wide. You can see down about 10 feet. But below that, we really don’t have any
idea what the vent looks like or what effect its shape may have on the way Old Faithful erupts. We wonder if the vent
fills with water quietly, or if it is boiling. Old Faithful also makes
a series of big splashes before each eruption. You have been seeing these in the video. In fact, an especially large one usually triggers off the eruption. We don’t really understand
what that’s all about. These and many other
questions have lead us to want to see what’s down there. Just recently, it’s been possible to get a very small television camera. We have put one of these cameras in a metal housing to protect
it from the boiling water, and to keep it cool. With it we have been taking video pictures down into the throat of Old Faithful. We thought you might like to see ’em. As Old Faithful again throws
a big bunch of water out, this time it probably is
going to start the eruption. And indeed that’s the case. There is Old Faithful in full eruption. Here you see that Old
Faithful’s surface vent is a slot-like structure
as I mentioned before. It’s covered with a
material called sinter, which looks like of like snow, but it’s actually made out of silica, a very hard material that coats everything that gets splashed with erupted water. The housing we built for the
camera is seen in this view. It’s a stainless steel Thermos bottle with the camera on the
inside cooled with ice. It’s attached to the
surface by a long cable. You can see the white one
foot markers on the cable. Here we are testing the lights
needed to take video pictures down the dark vent. Here is the little camera
itself out of the housing. It’s about two inches long and about three quarters
of an inch in diameter, lens and all. We now have the camera down
into the vent of Old Faithful. It’s about six feet down and it’s swinging on the end
of its cable at the moment and we will soon be on our way down to, as deep as we can get safely. At this moment, we’re still discussing exactly whether all of the hardware is working and if we have the camera
properly hooked up electrically and the right microphones running and all those sorts of things. And we want to make sure
we’ve done everything right before we go in because we have no idea what’s going to happen. You can see the near wall of the vent in the bottom left corner of the picture. The top right hand is in
sunshine and it’s overexposed. And here we go down the vent. And you can see it’s still a slot, down as far as we can see so far, it’s really quite a narrow slot, just a few inches wide. You also see occasionally
drops of water falling down. You’ll see those as we go along. That’s water that’s condensing
from the steam in the vent on our cool housing. Those drops are very convenient actually, because they tell us which
way is straight down, which we otherwise wouldn’t know and we didn’t really plan it like that but that’s the way it worked out, which was very convenient. We’re dragging most of the time
along the side of the wall. Notice at this point we
can see some fractures and cracks in the side walls, although the side walls
actually look very smooth and that’s because they’re
covered with the sinter material that we see up on the surface. Notice now that there’s lots of water coming from down below. It’s very tiny, uh, little droplets
that are being blown up with the steam that’s
coming up from below us. And now you can see we seem to be coming to a
kind of a shelf-life structure and we worry about whether
we’re going to land on that and not get off of it. And we bang into the surface of it and kind of bang up and down a little and how we go over the
edge which is very nice. But here is yet another one and this time you can see
a pool of water down there and because of the droplets, we know that we’re gonna
land just to the side of that little pool of water. There seems now to be a lot
of water coming down around us from the sides which is not
coming from our housing. Now we’re landing on this
flat little platform of rock, and banging up and down. And the folks handling
the cable at the top now think that they’re OK, but actually the camera is
laying there on that shelf and the cable is just going
on down the hole below it. Now since we can see it, why we can tell them that that’s the case, and so they will start
bringing the cable back up now to pick up the camera
and see if we’re lucky and can get over the edge
of this ledge somehow. We’ve known about this ledge
from our measurements before, and always wondered what it might be. In fact, we thought it was probably a narrow place in the slot, but in the picture as we were
coming down a moment ago, you could see that it really
was just a flat shelf. So we have some good chance that we’ll be able to work our way over the edge of it somehow. So at the moment you see
lots of water by the way moving down around the camera. Aha! Here we come off of the ledge and we’re banging around again, and now it looks as though
we’ve gone over the edge. So we’ve been lucky
and got past this ledge and we’re down into a
much bigger open area now. You can’t really even see
the far side wall quite yet. And now suddenly we see
something very striking, which is, was a big mystery to us as we were watching this in real time. It’s clearly just wildly boiling
water which is boiling up and splashing all over the camera. We had not really intended
this camera to be in, submerged in the water and so we were quite concerned about this and we actually stopped at this point and came back up a
little bit to think about what we were seeing and
watch it a little more, and we did realize at that point that what we were seeing was
this wildly boiling water. But we really didn’t think
that was a good thing to put the camera down in, so we decided that we
wouldn’t go down any further, that we would start back up and we would go up somewhat slower so that we could see in
more detail what was, we were going by and what
the walls of the vent really look like and see if
we could see water coming in from the side and other things like that that we were interested in. Also, this would allow us to measure uh, the dimensions of the vent because we had calibrated
the camera in the laboratory so we could actually make
measurements of sizes of things. Here you see us going back up this kind of the side of that platform that we landed on a bit ago. We’re actually going up
about a foot at a time, waiting for a few seconds so we’ll have a chance
to see things pretty well and then going up another foot. Now you can see our puddle of water again and see where we actually landed from the drops of water from our camera. We see large amounts of… these uh, drops of water coming in seemingly all directions. Not only from the bottom but also seems that we seem to see some
coming from the sides. As we move up, we occasionally come out into an open area and we swing as we are doing now, and that gives us a view of a little wider area than when we’re dragging along
the side walls of the vent. You can see that the uh… The picture sometimes
gets a little fainter. That’s because we had to adjust the lights as we went up and down and of course when we
got close to the wall, then we had to turn the lights down to keep from overexposing the video. And then as we got out
into a big open areas, we had to turn ’em on more intensely, we uh, didn’t do that very perfectly. Notice by the way, in the bottom right hand
corner you can see a waterfall uh, falling down the side. Seems to be coming from kinda
in underneath this slot. It’s not very much water, so we don’t think that that’s
a major source of the water that’s filling the uh, the vent. Now we’re back up into really
quite a fairly narrow slot and uh, we seem to have gotten up above so much splashing and um, other things. Now occasionally as
just then, you see fog. That’s because the wind
is gradually getting a little higher up at the top and it’s blowing down into the vent and that allows fog to form as it cools the steam in the vent. And you will see that
occasionally as we go along when a gust of wind um… causes some uh, some air
to get down in the vent. The vent is full only of steam, normally and the steam is quite clear fortunately, otherwise we wouldn’t be able to see much because everything is at the
boiling temperature of water so you don’t get a fog of steam as you do out of a chimney
or something like that. Big blast of water right then, coming from down below, continuing at some level here. It gets onto the window of the camera uh, and makes the image a little uh… a little bit fuzzy. There’s another blast of air. We’ve stopped now. We’re about 11 feet and we’ve stopped now to decide what we’re going to do, whether we’re going to
give up at this point thinking that we’re lucky
and we didn’t bust our camera or decide whether we want to get brave and go back down again and see now that we understand
better what’s going on, see a little more details about that. And um, so we decide in
fact to go back down again. We have an awful lot of nice video there and if somehow we do the
camera in in this process, well we uh, we tried. (laughing) And we’d have a lot of
information that will keep us busy for quite some time. So now that we kinda know what to expect, we’ll see and recognize things better than we did the first time down. Notice how very smooth the walls are uh, that’s the sinter coating everything. There’s our waterfall again, uh, really quite striking in the
right hand side of the picture. But really there’s not very
much water in that and uh, you can see there are little
puddles of water all over that shine in the lights and
now we can already see the uh, the top of the boiling water. It’s coming very much
higher up into the vent than it was when we were
down just a few minutes ago. We’ve come to our little shelf again. (laughing) And the first of the little shelves, and we bang around on it again and uh, we manage to get by it. Notice though that there’s lots of uh, water boiling around. It’s turning the camera around. There’s our shelf where
we got stuck last time and we have to worry about whether we’re gonna get stuck again. And uh, sure enough we do. The camera’s now not moving, but then suddenly something happens uh, probably a big uh, splash of
water from the wild boiling and it kind of knocks us off of the shelf and now we’ve gone down
a little ways and uh, we really are seeing
the wildly boiling water and water pouring around
us in all directions and looks like a tornado now and again as it twists the camera, spins the camera around
on the end of its cable. We really became very concerned whether our camera was going
to survive all of this. It certainly wasn’t
made with that in mind. Never had any idea that
we were gonna be involved in anything so wild as this. Notice the big blast of water from the side wall at that time. That was a lot of water, but it was just a sudden burst, so we don’t really know whether that’s uh, one of the sources of water for filling it that somehow doesn’t run in a steady way, or whether it’s just water
that splashed over the edge and kind of off to the side
and is now running back in. We’re coming back up again slowly uh, coming up a foot and
waiting two or three seconds and then another foot
and every once in a while we get just completely
drowned in water and foam and uh, you can’t see anything at all. We’re coming up again
now on the little shelf, and notice how much water’s
running down the side of it now. Clearly just from the
splashing of the water and the wild boiling. Things really are getting very much wilder um, as we are down there this time. The vent is clearly filling up with water. We’re still about 20 or 25 minutes before the next eruption, so we’re not concerned that we’re going to suddenly get caught in an eruption, which I’m sure the
camera would not survive. So what have we learned? We didn’t see an obvious
large source of water, so we think it must be coming
from below 40 feet somewhere. We also saw no side
channel that would explain why the vent doesn’t
full up above 15 feet. We’ll need to watch what happens when the water level
actually reaches that depth to understand what’s
happening there, I think. We saw that the vent continues as a slot down to about 35 feet and then
opens up to a bigger shape and that helps us understand somewhat how the eruption works. We found that the filling
process is certainly not a calm activity. And we now understand the
pre-erupts and splashes are just the top of the
wildly boiling water as it nears the surface. Clearly there’s much to be learned using this down hole camera. We hope you enjoyed looking
down into Old Faithful with us, and we’d like to thank the folks from the Yellowstone National Park for permission to put our
camera in Old Faithful and for assistance in doing so. (orchestral music)

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