This week we discuss the geologic time scale, meteorites, and fitness trackers!

Pittsburgh Fireball Feb. 17, 2015

Geologic Time-it’s really big (and deep)

The geologic time scale
Despite all kinds of fun things to demo how vast it is…still hard to understand
Cosmic Calendar
Pneumonic 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 years
Example of things changing in days to hours
Time’s Arrow, Time’s Cycle

How 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 world

Age-dating rocks

Many techniques, and the actual dates between our epochs change all the time as our age-dating techniques evolve
Many periods/eras/epochs are marked by “catastrophic” occurrences, hence making them natural boundaries, but the dates change.
5 major extinction events

Time as an arrow v. time as a cycle

Catastrophism vs. uniformitarianism and gradualism
Constantly evolving and vastly interesting
Thinking about the definitions of time and how we as humans try to grasp the enormity of geologic time in particular is humbling.

Fun Paper Friday

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

Episode 5 - "We actually don't call it the Tertiary anymore"