Monthly Archives: February 2015

Episode 6 – “What if you calibrated your candles differently?”

Time is a very complex subject that you can devote your entire life to. Today we’ll cover a few of the basics and enough to get your interest up! We’ll see that it’s difficult to know what a second is and how long relative times are, but absolute time is even messier! We also discuss dried coffee and tetris!

Importance of Time (and why it’s on a geology show)

  • It synchronizes the world and our human interactions (need minutes – hours accuracy generally)
  • It allows us to talk about events in a common coordinate system
  • Allows synchronization of scientific measurements and comparison of data sources. This is really important for seismometers for EQ location!
  • Let’s us use GPS! 1 billionth of a second (nano second) error in 1 GPS satellite, GPS receiver is +/- 1 ft to satellite, which is 2–3 feet on Earth.

Early Timekeeping

  • Burning candles in marked cases
  • Hourglass
  • Water powered clocks
  • Pendulum clocks Galileo and Huygens (fancy temperature compensation as well)
  • Video on Galileo

Modern Time Keeping (Atomic Clocks)

  • First clock was ammonia maser at National Bureau of Standards in 1949, but it really wasn’t all that accurate. It was more of a proof on concept device
  • First cesium clock was in 1955 at the National Physical Laboratory (UK)
  • Leads us to the definition of the SI second he duration of 9,192,631,770 cycles of radiation corresponding to the transition between two energy levels of the caesium–133 atom
  • The NIST-F2, a cesium atomic fountain clock, is good to one second in 300 million years. How F2 works is a combination of feedback control loops, lasers, and really cold atoms.
  • Remember, atomic clocks tick away seconds, they say nothing about the hours, minutes, seconds notation we use to write time. We just define a frequency

Leap seconds

  • Can’t predict them far into the future because of irregularities in Earth’s rotation
  • Announced ahead of time in a bulletin by the International Earth Rotation and Reference Systems Service
  • 25 leap seconds since 1972
  • Next leap second is this year! June 30, 2015
  • Real problem in computing, has caused software and GPS hardware crashes/issues before
  • Google smears the second out over a period prior to the leap

Time Standards

There are TONS of time standards, we’re only going to touch on a few. Most are known with highest precision in retrospect!

Solar time

  • Exactly what you would think, it’s about using the sun’s position as a time source. There is the sundial time (apparent solar time) that changes throughout the year, and the mean solar time which is like a clock time.
  • The equation of time represents the difference between the mean and apparent solar day
  • Star clock

International Atomic Time (TAI)

  • A measurement of proper time (it’s a relativity thing)
  • Weighted average of over 400 atomic clocks
  • If there is an error, it isn’t corrected. This makes it into terrestrial time.

Universal Time (UT)

  • This is what we used to call GMT!
  • Based on Earth’s rotation w.r.t different bodies (why there is UT0,UT1,UT1R,UT2,UTC)
  • UT1 is really mean solar time at the equator

Coordinated Universal Time (UTC)

  • Formalized in 1960
  • Adjustments were accommodated by leap seconds starting in 1972
  • Generally considered to be GMT, but GMT isn’t defined/recognized by the scientific community
  • This comes from TAI by accounting for leap seconds!

Epoch time (Unix Time)

  • Epoch time is the number of seconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970
  • No leap seconds by definition, but implementation is actually messy
  • Stored is an integer (32-bits) meaning that it will run out and roll over on Tuesday 2038–01–19 One second after 03:14:07 UTC, it’s the year 2038 problem.

The Timekeeper Video

Audio after the outro is David Allen

FunPaperFriday

Contact us:

Showwww.dontpanicgeocast.com@dontpanicgeo – show@dontpanicgeocast.com

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


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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

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

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


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Episode 4 – “Is that cumulonimbus cloud storage?” Data Backups

  • Technicians at the KGRK weather radar encountered a rattlesnake during an upgrade this week. The official NWS statement says “DUE TO COMPLICATIONS INVOLVING A RATTLESNAKE DURING TODAYS UPGRADE…THE KGRK RADAR WILL REAMIN DOWN THROUGH THE OVERNIGHT HOURS AND POSSIBLY INTO WEDNESDAY AFTERNOON.”

Why should you backup?

  • Not lose your data
  • Not waste money, effort
  • Legal obligation (taxes, grant data policy, etc)

What makes a good backup?

  • Local and offsite
  • Multiple backups
  • Harward and software independence
  • Copies of raw and processed data (if possible)
  • Archivable formats
  • Incremental snapshots and clones

It’s not okay to “backup” versions of files like this!

Backup Solutions

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Contact us:

Showwww.dontpanicgeocast.com@dontpanicgeo – show@dontpanicgeocast.com

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


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Episode 3 – “Computers don’t like -20 degree temperatures” with Nick Holschuh

Feedback

  • We received an article from listener Hannah about using tech in education. Thanks Hannah!

Interview with Nick Holschuh

Nick is a graduate student at Penn State. He tells us about his field experience, getting to Antarctica, and dealing with equipment malfunction in the field!

#Fun Paper Friday

  • Dread Risk, September 11, and Fatal Traffic Accidents
  • Economic theory is built on the idea that humans, in aggregate, behave rationally. But in individual instances, under specific conditions, we find that humans rarely exhibit rationality, and so the study of these individual instances of decision-making gave birth to its own field (Behavioral Economics). It is super interesting, and is relevant to the world of science policy and public education. Here’s a crazy example of what we, as humans, do, when we fail to be rational.

Contact us:

Showwww.dontpanicgeocast.com@dontpanicgeo – show@dontpanicgeocast.com

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of our employers or funding agencies.


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