Monthly Archives: August 2015

Episode 32 – “I mean, they still make rulers with inches too”

Classes are back in session, and we’re back to normal episodes. Join us to talk about Brunton pocket transits, argue about strike and dip, and discuss the zombie apocalypse.

What is a Brunton?

  • A compass, but a really expensive one with lots of features
  • Generally referring to the conventional pocket transit
  • About the size of a deck of cards, but worth $500
  • It’s a very accurate compass/clinometer combination that we use to take strike and dip measurements amongst others
  • Can also sight bearings to objections or angle from horizontal by using the sights and mirror
  • Can set the magnetic declination. Just don’t forget!

Strike and Dip

  • Two numbers that define the orientation of a plane in 3-dimensional space using an agreed upon handedness convention
  • Dip direction is the direction water would run if poured on the rock, angle is how steep that rock is inclined to horizontal.
  • Strike is 90 degrees to dip, but conventions are mixed and messy

Azimuth vs. Quadrant

  • Compasses are available in two formats.
  • This has started holy-wars

History of the Brunton

  • Pocket transit invented by David W. Brunton (1849–1927) and patented in 1894
  • He was a Canadian mining engineer that was tired of carrying heavy survey equipment… any of us can relate
  • Neat photo of early Brunton
  • A bunch of businessmen in WY bought it and started Brunton Inc. in Riverton. (1972)
  • Silva of Sweden
  • Fiskars (Finnish company)

Issues

  • Needs to have the needle weighted when at very high magnetic dip angles.
  • Cheap knock-off compasses are everywhere
  • Changed the way the needle is balanced, and oftentimes it comes unscrewed with no way to fix it. This was a change in manufacturing that many people are unhappy about.

Fun Paper Friday

Zombies! This week we learn about mathematical modeling of zombie disease spread an how it relates to real world problems… mainly politics.

Munz, P., Hudea, I., Imad, J., & Smith, R. J. (2009). When zombies attack!: mathematical modelling of an outbreak of zombie infection. Infectious Disease Modelling Research Progress, 4, 133–150.

Contact us:

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

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


New episode!

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Episode 31 – “Galveston just gets it” Pt.2

We continue our quest form last week to hit the most interesting mechanisms of catastrophic sedimentation, talk about a new notebook, and learn how to give cosmic CT scans.

Floods

Bolide Deposits

Weather Related Sedimentation

Fun Paper Friday

This week we learn how cosmic rays can be used to see through buildings, insulation, and concrete to provide easy scans without the need for expensive and complex radiation sources.

Durham, J. M., Guardincerri, E., Morris, C. L., Bacon, J., Fabritius, J., Fellows, S., et al. (2015). Tests of cosmic ray radiography for power industry applications. AIP Advances, 5(6), 067111–9. http://doi.org/10.1063/1.4922006

Book Block

Contact us:

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

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


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Episode 30 – “YouTube is rife with turbidite videos”

This week we start an accidental two-part show on catastrophic sedimentation, John’s drone experiments, and a revisit of some stories from the past. Don’t miss this not so short summer short!

Catastrophism

Uniformitarianism

Turbidites

Landslides et al.

Fun Paper Friday

This week we get ready for one of our future topics by talking about bolides and airblasts. Also good timing with the perseid meteor shower!

Kring, D. A. (1997). Air blast produced by the Meteor Crater impact event and a reconstruction of the affected environment. Meteoritics & Planetary Science, 32(4), 517–530.

Contact us:

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

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


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Episode 29 – “Dear NASA, these are a few of our favorite things”

Intro

The Orbital Mechanics highlighted how little we know about planetary formation, so let’s talk about Pluto and what we’ve learned from the New Horizons Mission.

Pluto Basics

  • Officially a dwarf planet in the Kuiper belt
  • About 0.18 the radius of Earth
  • Mass 0.178 of the moon’s
  • Very low density
  • Gravity 0.63 g
  • Neptune and Pluto were both predicted to exist from orbital perturbations of Uranus
  • Percival Lowell (founder of Lowell observatory) started the hunt for pluto in 1906.
  • Tombaugh found Pluto using a blink comparison technique
  • Moons of Pluto
  • Orbit is chaotic, we can predict forwards and backwards for several million years, but over the Lyapunov time we have no idea.

New Horizons

The Glitch

  • July 4, 2015 the software went into safe mode
  • Turned out to be a flaw in the timing of the commands in the fly-by prep software.
  • Full functionality restored July 7
  • 9 hour round trip radio delay

Glaciers/Geology

  • Bright heart shape observed on the side of the planet during approach is ice (Tombaugh Regio)
  • Nitrogen ice flows like glaciers on Earth. Water ice is very brittle at surface conditions –390 F (–234 C)
  • Active surface is exciting, it’s not a dead planet!
  • Glacier Like Flows News Article from Science

Atmosphere

  • As UV light from the sun strikes the thin atmosphere, eventually making tholins that color the surface of the planet
  • Some particles remain suspended, shouldn’t be over 30 km (20 mi) off the sfc.
  • Particles were found to be up to 130 km (81 mi) above the surface
  • Atmospheric pressure is dropping

Charon

  • Space.com Article
  • Just as geologically exciting as Pluto
  • Likely atmospheric in origin, but could still be geologic
  • Low gravity of Pluto means it won’t hold onto its atmosphere…and Charon is near its same size, so it can pick up gravitationally what Pluto is putting down.
  • Red coating could take less than a million years to form

Near loss of the image

  • Science Magazine Article
  • Team opened the image file, but it was of Charon. They momentarily freaked wondering if the spacecraft wasn’t in the right position.
  • Ended up that they were looking in the wrong directory on a FTP server.

Future

  • 2 months of particle and plasma instrument gathering
  • Will choose between two Kuiper belt objects and head that way to meet in 2019
  • Data transmission home for about 16 months

Getting the data back

  • Tops out about 1 kilobit per second on the 70 m dishes of the deep space network
  • Can double the rate using different polarization transmissions from the two amps “twittas”, but something else must be shut down to have enough power to run both at the same time

Links

Fun Paper Friday

This week’s fun paper sounds a little bit like Jurassic Park to us. What do you think? Blood vessels recovered from fossils.

Schweitzer, Mary H., et al. “Soft-tissue vessels and cellular preservation in Tyrannosaurus rex.” Science 307.5717 (2005): 1952–1955.

Contact us:

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

John Leemanwww.johnrleeman.com@geo_leeman

Shannon Dulin@ShannonDulin


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