At 9:40 last night the International Space Station flew by while I was taking pictures of the aurora. Because it passed almost overhead, the station was especially bright, outdoing Jupiter for sure. Its orbit is currently about 250 miles high, so if you’re lucky enough to get an overhead pass, the ISS will be as close to you as it can – 250 miles away.
A pass off to the north or south or when the station is off in the eastern or western sky is generally not as bright. because you have to add in the extra “horizontal” distance plus the altitude.
The clouds gobbled up what was left of the northern sky and northern lights late last night from my town. Hopefully, you had clear skies. Judging by the index of magnetic activity (Kp), the aurora continued well into the night. Tonight space weather forecasters are calling for another chance of aurora. Quiet conditions return Saturday and Sunday. More aurora pix are included at the end of this article.
The trail the ISS made in the photo reminds me of an airplane condensation trail or contrail. It’s fatter than usual because sunlight reflecting from the spacecraft lit up a high, thin cloud layer at my location. Earlier Thursday I was witness to real contrails as four separate transcontinental jets crossed the sky within the span of 10 minutes.
Contrails are created when warm water vapor created during the burning of jet fuel condenses into strings of artificial clouds in the wake of a high-flying aircraft. Real clouds form in a similar way – water evaporated from land and lakes by sunlight rises upward; when it reaches colder air aloft, it condenses into the visible form of a cloud.
Both contrails and clouds require tiny nuclei – dust, soot, etc. – to serve as sites for water to condense upon. For contrails, the exhaust particles from fuel combustion are right at hand, which is why contrails form so quickly behind an airplane.
Sadly, there’s a massive hoax and disinformation campaign online and elsewhere characterizing contrails as “chemtrails”. Supposedly our government is enlisting pilots to “aerial spray” the U.S. with virus and strange chemicals to study their effects on humans. Really?
There’s no scientific evidence to support this idea, just mistaken impressions and the usual fear-mongering. Many contrails disappear quickly because the air at altitudes of 26,000 feet and up is extremely dry. Sometimes however temperature, higher humidity or an approaching weather front conspire to not only prolong the trails but cause them to balloon into large rafts of cirrus clouds. These are the ones a few people are calling “chemtrails”. We’ve all seen these, and they’re perfectly normal. No chemicals needed – just the right atmospheric conditions.
If you’re still looking to point the blame finger at contrails, there may be a real scientific reason to do so. They appear to contribute to global warming. When they fan into clouds, they act like real clouds and trap heat rising from the Earth causing surface temperatures to rise. Weather service data reveal that the temperature of the surface and lower atmosphere rose by almost 0.5°F per decade between 1975 and 1994 because of contrails. So yes, they may affect our climate in a small way, but that’s a far cry from the bogus claims of chemical spraying.