Thread: Contrails/Chemtrails from jets

Commercial airliners also produce contrails. This does seem to have been more prominent a decade or so ago though. I can remember laying in the field with my binoculars mostly bird/squirrel watching, but also watching the passenger and military planes (B52s mostly) from Barksdale AFB flying overhead. Both types left big huge contrails, though the B52s left bigger ones. But both types would leave trails that could last for an hour or more on a still day. So the question in my mind is "Why don't they leave those massive long-lived contrails anymore". Maybe because the new planes are more fuel-efficient, so less particulates in the trail? This would be consistent with the explanation for why military planes still leave big long-lived contrails.

There's enough crazy stuff going on in the real world to be going about making up imaginary new ones.

I got a book for a girlfriend one time that was called something like "UFO defense" (long story)... according to that book, contrails are part of the super secret, special handshake and codeword required, worldwide conspiracy fueled, earth defense system keeping us safe from ET.

Here I am again.

First of: the contrails is mainly water, the soot-particles I mentioned is only a detail.
When you talked about how the military planes (B52) has got more of a contrail it is probably because the military planes are mainly using turbojets which is an old engine technology. The turbojet is capable of greater speeds, but is considerably less fuel efficient.
Newer airliners use a turbofan engine which is a lot more efficient and gives of less noise.

The reason the contrail sometimes takes a very long time to disappear is that some days the atmosphere has got conditions up there so that when the stripes are there they can not just evaporate again. On all the pictures in this thread there are high-altitude clouds together with the contrails. Clouds means the air cannot hold more water-vapor, so the contrails stay droplets for a long time.

yep, its all about the atmospheric conditions. Under some they stay longer and with others the remain. Mostly wind actually and the fronts that come through. Most of those aircraft fly between 30-40,000 feet where the temperature is about -40 degrees C and the moisture is about zero.

Most civilian aircraft burn much cleaner than military. the civilian versions have to meet strict noise and pollution guidelines. the Military can do anything they damn well please.

I live in central N.M which is a main crossover for intercontinental flights and at any time you can see at least a dozen contrails in the sky. Some days they last forever and some days they disappear very rapidly.

Yes, it is correct htat there are almost no humidity up there, but I as talking about Relative humidity which is a measurement of how saturated the air is. 100% relative humidity is the point where the atmosphere is no longer able to keep the moisture in as a gas and it condensates. For clouds to exist the air around them has to be close to 100% relative humidity. The same goes for contrails. If the air has a low relative humidity they will disappear relatively fast and if the air has a high relative humidity they will last for a long time, sometimes even trigger a cloud-layer to form.

I, too, have wondered about contrails and their longevity. I don't know if it is true or not, but I have heard that chemicals are sometimes used for weather predicting purposes. It is supposed to make it easier to track cloud and wind formations at different altitudes when it is hard to see through different layers of the atmosphere. Again, I have no idea about the correctness of that statement. It makes some sense to me, though, as they would be able to collect data from a line a mile wide rather than data from a line going straight up, like with a weather baloon.

As far as doping the general public from that altitude, there just aren't enough chemicals in a contrail to do it. Not to mention that the chemicals would be miles away before they reached the ground, if they reached the ground.

Originally Posted by crazycliff200843

I, too, have wondered about contrails and their longevity. I don't know if it is true or not, but I have heard that chemicals are sometimes used for weather predicting purposes. It is supposed to make it easier to track cloud and wind formations at different altitudes when it is hard to see through different layers of the atmosphere. Again, I have no idea about the correctness of that statement. It makes some sense to me, though, as they would be able to collect data from a line a mile wide rather than data from a line going straight up, like with a weather baloon.

As far as doping the general public from that altitude, there just aren't enough chemicals in a contrail to do it. Not to mention that the chemicals would be miles away before they reached the ground, if they reached the ground.

very true.

Its one of the reasons all your high cirrus clouds are ice xtls not actual water vapor. When the exhaust comes out of a plane at those high altitudes it almost immediately forms ice xtls and then evaporates. You never have to worry about icing at those altitudes. The relative humidity may very well be 100% meaning the air won't hold the moisture but if the moisture is so low to begin with there ain't really enough of it to do much. Its one of the reasons if you go to the south pole the humidity (absolute) is very low and the relative is very high and contrary to popular belief antarctica is really a desert. They get small snow falls and it just builds up because of the cold. Once a little moisture builds up it just snows. The wind just wips it up to blizzard conditions.