y do somdays u see the jet streams and others u dont?

Question

On somedays you can see jet streams and others you dont I just don't get it I really need help PlZzzzzzzzzzzz!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

The jet streams you refer to are simply CONTRAILS, or condensation from the engine. A natural part of combustion is water. Since it is very cold where jets usually fly, the water almost instantly freezes and forms the trails. Depending on local weather conditions, these can last for many miles. They can also form from piston planes (ordinary internal-combustion engines); but you generally don't see them because they don't fly high enough. They generally begin around 28k-31k feet, but definitely can vary depending on weather conditions! Also, they can form on the wings from the drop in pressure lowing the freezing point.
An interesting study was done after the September 11th attacks and found a change in the average temperature do the lack of Contrails over the United States. It's estimated that they can cover 1% of the Earth's surface, an enormous amount!

Answer 2

A jet stream is simply the exhaust from a jet engine. When a jet is flying high in the air, it is in a very cold zone, and the jet stream shows up because the water in the exhaust freezes, so what you are actually seeing is a tiny little band of snow. It is very small particles, and they won't fall to earth (there aren't enough of them in any case) and they soon melt. You can tell that by watching a jet stream fade away. When the jet is flying closer to the ground, the temperature is warmer, and you can't see the jet exhaust, but it's still there.

Answer 3

All of the above three answers are correct.

Assuming you mean "contrails" (condensation trails) of a jet engine(s) flying at say over 30,000 feet, the amount of humidity in the atmoshere that the engine consumes during the combustion process has a direct impact on the formation of the contrails. One of the products of combustion of all fossil fuels is water, and since its always below freezing (0°C) above 30,000 feet, the water becomes ice and you can see the contrail.

However, if the relative humidity is very low, then the ice still forms but very quickly evaporates and you won't see the contrail. The process of ice becoming water vapor directly without going through the liquid state of water is called sublimation.

The amount of water vapour in the atmosphere is measured as the "dew point" in the aviation world.

lewkarg is correct on the study after the 9/11 attacks, but s/he forgot to mention the cause was the lack of aircraft in the air -they were all grounded - and not the attacks themselves.

Answer 4

Is true. Visibility of jet streams depends of temperature. The motor liberate water and gases and if the temperature is "low" the water Will get ice. small crystals of ice.
but I believe, the light are an influence of visibility of jet streams. for example: when the airplane fly in the same direction with soon the jet disappear. But I guess and I am sure, is the temperature. I has saw on TV : the temperature where the airplanes fly is arealy -50 Celsius grades mmmm.... very cold.

Answer 5

Sorry guys...
The jet stream is high altitude winds that shift.
They are caused by different temperature air masses that meet.
Airliners need to know where they are so flights can be adjusted accordingly.

Answer 6

To keep it simple..
It depends mostly upon the moisture content and temperature of the airmass that the aircraft is flying through.
More moisture + colder temps = more contrails.
To another extent....the size (fuel consumption) of the engines also plays a factor.

Answer 7

magic