Discover and read the best of Twitter Threads about #wintersolstice2018

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It's #WinterSolstice, that is the shortest daytime in the Northern Hemisphere. Today's daytime in hours is given by this function
Daytime (Φ) = 24×cos⁻¹(tan(Φ)tan(23.5°))/180°,
where 0°<Φ<66.5° is the latitude measured in degrees.

#Maths #Trigonometry #WinterSolstice2018 Image
Try to derive the above formula by calculating the length of the sunny arc on any given circle of latitude.

And of course, assume that the Earth is a sphere. Image
By the way the #WinterSolstice daytime function
works in the Southern Hemisphere (i.e. for -66.5°<Φ<0) as well. Image
Read 3 tweets
2018 is the 61st year of long term ecological research in Burrishoole #BurrishooleLTER @MarineInst. I'm going to pin this tweet here and at the end of every month add some phenological happenings 🌿🐛📈🐟💦🦆🦉🦇🕷🍃🌼🌙🌝❄️, including our main jobs. Stay tuned 👇🏼
@MarineInst This will coincide with our monthly staff meetings (last wed of each month) so I can get everyone's observations @FishEcoEvo @elizabethtray3 @B2020project
JANUARY: first snowdrops #phenology #burrishooleLTER
Read 125 tweets

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