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

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

Pittsburgh Fireball Feb. 17, 2015

• Video of meteor
• Article with details of entry
• Animation from meteor’s perspective
• NASA Fireball Network

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