MFM Day 19: Autumn Soon

September 17th, 2009, Motor Free Month Day 19.




Mostly I notice the change in the morning, not in the evening. I think that because my routine is more consistent in the morning. I wake up, feed the dog, and head to my back room/office to write this blog every morning; at the beginning of the month it was light out when I woke up. Now it's just before the dawn as I write this. September is a beautiful month, but it is also a month that changes everything. At the beginning of September I'm riding around town in shorts and a t-shirt. Now, just over half way through, I'm wearing trousers, light-weight gloves and a light jacket in the morning. By the end, I'll likely be wearing a warm hat, heavier gloves and jackets.

Song de jour: The Church, Autumn Soon



If you think about it, it's totally natural, downright Newtonian why September (and it's mirrored-reflection March) would change so rapidly. As we know, the reason days are shorter and longer throughout the year is because of the angle at which the earth tilts in relation to its rotational axis, relative to the sun. If there were no tilt, every day would be like September 22nd (roughly) -- the Equinox. There would be an equal amount of night and day, every day. That just sounds unnatural to me! But in fact people living on the equator do have less variability in their seasonal daylight amounts. In large part that explains why they don't have seasons in the tropics like we do in more temperate latitudes. Typically they get a wet and dry season, not winter, spring, summer, and fall. And this also explains why people living in more northern climes get extreme winters and summers, and (I presume) not much Spring or Fall. But no matter where you live, the quickest path to Autumn and therefore Winter is through September. Its where the sun makes its most hasty retreat from the passage of days. This annual march and retreat of the sun can be graphed as a sine wave, as displayed here:
Note that the graph is counter-intuitive; the red line measures time of day when the sun rises, not amount of sun during the day. But the point is the same. Note also the slight difference between the downward and upward curve slopes. I'm guessing this has to do with the earth's elliptical orbit around the sun, but I'm not certain of that.


The greatest slope of the red curve represents the greatest change in the amount of daylight available on a given day. This graph looks different at different latitudes (this is for latitude 45, which is north of Fort Collins, probably closer to Chicago?), More compressed as one heads towards the equator, and more exaggerated as one travels towards the poles.






Point being, I can see it happening, living Motor Free! I feel more in tune with the daily sun rise and sunset. A part of me mourns the passing of Summer, as it does every year, but more so this year. Perhaps more so every year as I get older, but maybe I appreciate the sun a little more this year, as I'm more dependent upon it now.






We had big plans Thursday to attend the New Belgium "Bike-In" cinema, but we were feeling a bit like homebodies so we opted to stay home instead. If you've been following along, you know that Thursday is our day to ride down to the Fort Collins Brewery and pick up our weekly share of CSA vegetables. C_ rode her bike to work as well on Thursday, and since she works just down the street from me, we met up after work and rode home together, with a quick stop by the grocery store for some pizza dough. Our house is on the way to our CSA pick up location so we stopped home first, changed, and then went back out on bike to the brewery. We enjoyed a nice refreshing pint with the one employee left at the brewery, and then loaded up our bounty of the fields, and then rode home. By this time it was a little after 7. We could have gone to the bike-in movie. We probably should have gone to the bike-in movie! It would have been something to blog about, certainly! And it's Thursday, practically the weekend; get out there and do something! But alas we decided an evening at home would be better. So we made home-made pizza with our new vegetables (eggplant, onion, and spinach this time, with homemade sauce from CSA tomatoes), drank a beer, and watched a movie at home instead. I still feel a little bad about missing the bike-in movie since it was the last one, but my faithful readers will just have to use their own imaginations when thinking about hundreds of cyclists let loose on the streets of Fort Collins after watching "Superbad" and drinking Fat Tire.







The bailing out on the night's planned activity got me thinking that the days of the week follow a similar sine wave as does the amount of sunlight during the year. Except instead of "amount of sunlight", the weekly repeating variable is "amount of fun". Weekends are like a miniature Summer of Fun, with lots of fun available. Wednesday is therefore the Winter of Fun. A seasonal nadir of fun. Not much fun to be had on a Wednesday. Thursday is like the Spring of fun. It might be fun, it might not. It's unpredictable, but tacking towards another Summer regardless.







Note on graph: the y-axis is in IFU, or International Fun Units. Enjoy your weekend.