Today, the redditor aquiliz noticed a very strange 5000 km long straight cloud.

https://i.redd.it/ypei8456wf241.png

Here is my explanation. Continent long straight clouds cannot be formed naturally due to Coriolis effect.You need something like an airplane with exhaust gasses to create straight clouds. Commercial aircraft are slow and their cloud vanish within half an hour at most. You need something extremely fast to create 5000 km straight trail. There are two available technologies. The first is intercontinental ballistic missiles which travel outside of the atmosphere. You cannot create trail with the exhaust plumes if you are outside the atmosphere. The second option is hypersonic missiles which can travel up to Mach 20 in atmosphere, so can create extremely long straight clouds. The one end of this cloud in the picture pinpoints the Urengoy and Yamburg gas fields in Russian of extreme importance. The other end pinpoints 819th Brigade headquarters is China. The cloud is fading away in Chinese end but strong in the Russian end. This implies that a hypersonic missile launched from China to Russia.

https://jamestown.org/wp-content/uploads/2016/04/Missile_Ranges-600x424.jpg

https://jamestown.org/program/updated-chinese-hypersonic-weapons-development/

http://www.euanmearns.com/wp-content/uploads/2014/03/mearns121307t.png