Finally another sighting of those rare nacreous clouds. More on flickr .
Is this related to the northern light effect?
No, not linked at all. Northern lights are caused by particles from the Sun, while this type of clouds is still unclear what it actually is. NASA just launched a mission to found out more about it (http://en.wikipedia.org/wiki/Aeronomy_of_Ice_in_the_Mesosphere).
Nacreous clouds or mother of pearl clouds will only be seen just after sunset or before sunrise, they form in the stratosphere at heights of between 6-18 miles when the temperature there falls below -80°C and are ‘probably’ composed of ice particles with a liquid coating of nitric acid tri-hydrate. They appear bright because they are high enough to be illuminated by the sun long after local sunset and the pastel colours arise through diffraction or interference effects in much the same way that colours appear in a film of oil on a puddle of water. Aurora borealis (northern lights) & aurora australis is the emissions of photons in the Earth's upper atmosphere & not connected to these clouds formations.
Rob Benedict (UK)
Updated a building
Hadn't realised this was a Lib Dem policy! Khan taking credit again huh... https://t.co/VXq2JVejE1
Looks like I'll be giving two talks at #dpc17 this year!
Help! I need reproducing this Travis failure in a (Ubuntu 12.04) VM: https://t.co/Pw1uQgsx6F I'm having no luck reproducing this myself.
I am having no luck reproducing the failures on Travis (https://t.co/Pw1uQgsx6F) for the https://t.co/xssqDkDB9s PR — any help much welcome!
Drinking an Imperial Saison by @InboundBrewCo - https://t.co/rsAWlG68tq
For people joining the taproom crawl, be in the upper lobby near the down escalator at 16:05 *sharp* (train is at 16:23) #mwphp17 #mwphptc
Paths and sidewalks from my walk
Slides for today's "Storing Non-Scalar Data" talk (with reading list) are up through joind.in: https://t.co/sHImdY9HKx #mwphp17
Slides for yesterday's "MongoDB Schema Design" talk are up through joind.in: https://t.co/YHB2ucQs1k #mwphp17
I have a reading list to go with the talk that I gave: https://t.co/v7aoLuLJSS Slides will be up soon #mwphp17
I walked 14.0km in 2h18m48s
On the way to Minneapolis for @midwestphp See y'all in 9 hours. #mwphp17
One for you @ramsey https://t.co/TgdHwZb5MF
I walked 2.9km in 26m18s
Yay. @D66 seems to have done well in the Dutch elections with ~19 seats.
If they can't raise NICs due to the manifesto, why can they leave the single market? /cc @faisalislam https://t.co/yrt8TNERtP
I ran 8.2km in 49m58s @ 6m03s/km
Which driver/library do (PHP) users use to talk to CouchDB?