A camera that “sees” infrared. That’s it.
This experiment is one of several optical projects and its one of the quiet ones. Yes, sometimes it give me some headaches, but nothing compared with the radars so far. These experiments fetch data from to the light that we get around here in Antarctica, either from the Sun, reflected from the Moon or even the infrared radiation emitted from particles in the atmosphere.
This camera is lodged in one of my many cabooses – C5 in this case. This caboose is the one farthest from the base since it is also the one that can be most affected by it. Here we want to measure what the atmosphere is doing with the light that we get from it and don’t want our data messed up because someone turned on the toilet light in the middle of the night.
Infrared radiation, somewhat like the radiation that we use in the radars, is a type of light that is invisible for us humans. We can’t see it because our eyes can only work in a very narrow band of the light spectrum – the so called visible light. This band is in practice a set of seven different wave frequencies, which are nothing more than the seven colors of the rainbow. If we look at one of them, we can see red, the radiation with the lowest frequency, in one end and violet, the one with highest frequency, in the other. Infrared, as the name implies, its all the light “bellow” red, i.e, all light with a frequency lower than the red light one. By opposition, ultraviolet is the same thing, but “above” the violet right in this case.
This camera is more sensitive that regular ones. Its so sensible that just a small sliver of the sun in the horizon is enough to flood the reception with glare. It turns any picture completely white since the sensor gets overloaded with light. As such, this camera only works at night time. Witch also means that is only operational during the months where we get such a thing in Halley, basically from March to October, which also simplifies this project a great deal and leaves me slightly rested.
What do we want to capture with this camera then? Just like the radars, this camera also “looks” to the intersection zone between to atmospheric layers. Specifically, with this camera we hunt gravity waves (do not mistake these with gravitational waves, which are a completely different and weirder animal).
Gravity waves are nothing more than the same waves we can see in a beach or when we throw a pebble to a pond, but this time several quilometres higher and instead of water we have gases.
Water waves are the result of the interaction of two elastic mediums (the gaseous air and the liquid water). The air that we breathe and the water in the pond are both malleable, that is, they are not rigid as a rock for instance. When one of the mediums is disturbed (with a rock thrown into it for example), a “dance” is created while they try to recover the same equilibrium that had before the idiot start throwing stuff into it. This “dance” are the molecules of water and pushing themselves and the air and vice versa, but we can only see the oscillation in the surface of the pond. Now, between layers of our atmosphere we have the same behavior. Instead of water and air, we have layers of air with different compositions and densities. And instead of a rock we have an ascending air current, that can simply be a wind blow in Earth’s surface that used the face of a mountain as a ramp, for example. It happens all the time, literally. Now, this waves cannot be seen with a naked eye because:
1 – The occur at hundred of kilometers up in the atmosphere and no one spends a day looking at the sky.
2 – Air is still invisible to human eyes.
Yet, some of these atmospheric layers are continuously sending infrared radiation to the Earth. And its a good thing that we can’t see it or otherwise the sky would be so lit up, even at night, that would be a hindrance for someone that likes to sleep outdoors. Mas if we could see it, than we probably would also see these gravity waves. Since we can’t, we need to use these gizmos for that.
The observation of these waves is used to retrieve important atmospheric data, such as the constitution of the higher atmosphere, gaseous dynamics or even to produce weather forecasts. Certain high atmospheric currents are also relevant in some atmospheric events and sometimes the only way that we have to identify them is trough the direction in which these waves propagate.
Due to this camera’s high sensitivity, during the night the caboose is completely dark. And I’m not just talking about the ceiling lights. All computers and electronic equipment inside of it have their monitors turned off and pieces of black duct tape covering the presence LEDs. If someone decides to have fun with a flashlight less than a kilometer from the caboose, I can see it on the camera.