were largely ignored in the decades following.
Researchers are most interested in persistent contrails
because they create long-lasting, and sometimes extensive, clouds that would not normally form in the atmosphere, and are believed to be a factor in influencing Earth's environment.
Many long-lived contrails
were expected from the traffic in the North Atlantic flight corridor.
The theory first gained popularity in 1996 when the US Air Force was accused of spraying the population with mysterious substances from aircraft generating unusual contrail
Currently, the physics behind the formation of contrails
is relatively well understood.
If we can predict the regions where contrails
will form, it may be possible to mitigate their effect by routing aircraft to avoid them," Emma Irvine of the university's Department of Meteorology said.
Just like natural clouds, contrails
reflect some of the Sun's incoming energy, resulting in a cooling effect, but also trap some of the infrared energy that radiates from Earth into space, therefore having a warming effect.
BEIRUT: The straight horizontal white contrails
left by Israeli jets criss-crossing Lebanese skies on a near daily basis are a common sight.
The Allied bombing of WI represented an inadvertent environmental experiment on the ability of aircraft contrails
to affect the energy coming into and out of the Earth.
2] lingers for decades, the warming effect of contrails
dissipates immediately if flights are grounded, as happened after the September 11 attacks and last year's volcano eruption in Iceland.
form when the temperature is cold enough (below about -40[degrees]C) but the air is humid--in a similar way to when you breathe out on a cold day and can see your breath.
over the Mojave: The Golden Age of Jet Flight Testing at Edwards Air Force Base by George J.