This week we discuss the geologic time scale, meteorites, and fitness trackers!
Pittsburgh Fireball Feb. 17, 2015
Video of meteorArticle with details of entryAnimation from meteor’s perspectiveNASA Fireball NetworkGeologic Time-it’s really big (and deep)
The geologic time scaleDespite all kinds of fun things to demo how vast it is…still hard to understandCosmic CalendarPneumonic devices for timescale-and why do we need to know it? (several examples)We make all kinds of assumptions about rocks that span millions of years, but an outcrop can change over the course of just a few years/ten yearsExample of things changing in days to hoursTime’s Arrow, Time’s CycleHow do we begin to define Geologic time?
International Commission on Stratigraphy: “ International Geologic Time Scale; thus setting global standards for the fundamental scale for expressing the history of the Earth”We have to have a baseline so that we can all talk about the “same” rocks across the worldMany techniques, and the actual dates between our epochs change all the time as our age-dating techniques evolveMany periods/eras/epochs are marked by “catastrophic” occurrences, hence making them natural boundaries, but the dates change.5 major extinction eventsTime as an arrow v. time as a cycle
Catastrophism vs. uniformitarianism and gradualismConstantly evolving and vastly interestingThinking about the definitions of time and how we as humans try to grasp the enormity of geologic time in particular is humbling.In an attempt to prolong our time on Earth, we’ll talk about accuracy of fitness apps. (John wears a Fitbit Flex and uses the Fitbit Aria scale.)“Accuracy of Smartphone Applications and Wearable Devices for Tracking Physical Activity Data”, Case et al., Feb 2015, Journal of the American Medical Association