We can't directly measure the Earth's core, so we study its magnetic field. What about the early core? That data is stored in ancient rocks.
The Earth Magnetism Lab is where Aleksey Smirnov, an associate professor of geophysics, peels back the layers of old data in rocks and meteorites. The lab is in the very bottom of the Dow Building on campus and Smirnov's basement is way cooler than ours. We politely call our University Marketing and Communications floor the "garden level."
A lot of creativity happens in our garden-level basement. But we don't always get to see where the magic happens—or rather, The Science. So every once in a while, we set up lab tours; this time, we found out why they don't allow any hammers on the floor of the Earth Magnetism Lab. (You'll have to read all the way through to find out why.)
Tour the Earth Magnetism Lab
What happens when the Michigan Tech writers and print folk and webmasters escape their garden level offices in the Admin building? Lab tours. We toured the Earth Magnetism Lab, where some of the oldest rocks in the world reveal their iron-locked secrets.
Welcome to our next lab tour @mtugeomining with Aleksey Smirnoff and his students Katie Bristol and Marine Foucher #mtulive #geoscience pic.twitter.com/poSdVD0TRz
— MTU Research (@mturesearch) February 16, 2017
Specifically, we're talking about how the Earth's inner core and magnetic field developed #mtulive #geoscience #paleointensity pic.twitter.com/gHG9OrzU0P
— MTU Research (@mturesearch) February 16, 2017
Old Rocks and Meteorites
Aleksey Smirnov directs the Earth Magnetism Lab. His PhD student Marine Foucher and undergrad assistant Katie Bristol gave us a tour, showing everyone the sample prep room and the magnetically shielded room that houses two magnetometers.
The lab equipment do two things: understand the strength and alignment of magnetic signatures in rocks #mtulive
— MTU Research (@mturesearch) February 16, 2017
Some of the rocks in the Earth Magnetism Lab are old. Like billions of years old. So how do we analyze them? #mtulive #geoscience pic.twitter.com/mujDJfb2nf
— MTU Research (@mturesearch) February 16, 2017
As well as some of earth's oldest rocks, the lab analyzes meteorite magnetism. We touched a rock older than our planet. #mtulive #geoscience pic.twitter.com/1Q5meYxjzX
— MTU Research (@mturesearch) February 16, 2017
Marine says some old rocks are like thumb drives: they store data about the earth's magnetic field. #mtulive #paleointensity
— MTU Research (@mturesearch) February 16, 2017
To get the best data, the team has to remove some magnetic info. It's like cake. Why does that matter for a compass? #mtulive #geocience pic.twitter.com/hcrFV2cPBA
— MTU Research (@mturesearch) February 16, 2017
Because once you're inside the "sauna" (or rather the magnetically shielded room) your compass won't work #mtulive #geoscience pic.twitter.com/9UjjIhqkuP
— MTU Research (@mturesearch) February 16, 2017
Meet the Magnetometers
In order to analyze the magnetic strength and alignment of rock samples--which reveal details about the Earth's ancient magnetic field--Smirnov, Foucher, and Bristol have to run tests using a magnetometer. Theses are no ordinary magnetometers; they are specially designed to extract magnetic signatures out of rock samples, which require a special temperature treatment so the data locked in the rock's iron-rich minerals doesn't become distorted.
In the shielded room, only about 5% of the Earth's magnetic field is getting through. It allows the magnetometer to work. #mtulive pic.twitter.com/zKGzFeQQbT
— MTU Research (@mturesearch) February 16, 2017
The machine is a super-conducting magnetometer that measures bulk rock samples. Marine named it Big Bob. #mtulive
— MTU Research (@mturesearch) February 16, 2017
There's also Little Bob--and a large difference in sample size requirements for magnetometer Big Bob. #mtulive pic.twitter.com/J3xqwCyMjI
— MTU Research (@mturesearch) February 16, 2017
Since researchers cannot visit the core, they use rocks at the surface as a proxy. Specifically, volcanic rocks record the intensity and changes in Earth's magnetic field and the record extends back billions of years to the early days of the planet's young core and the development of the geodynamo.
Clues to the Earth's Ancient Core
And when it's time to clean up, don't forget to sweep. (It demagnetizes the lab.) #mtulive #paleointensity pic.twitter.com/oRq3sYdCNy
— MTU Research (@mturesearch) February 16, 2017
The hammer thing: think about it. In a magnetically shielded room, where precision equipment rules with an iron fist, would you want any metal about that could warp the low-magnetic environment? No. So, don't leave your hammers on the floor.
Michigan Technological University is a public research university founded in 1885 in Houghton, Michigan, and is home to nearly 7,500 students from more than 60 countries around the world. Consistently ranked among the best universities in the country for return on investment, Michigan’s flagship technological university offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, computing, forestry, business, health professions, humanities, mathematics, social sciences, and the arts. The rural campus is situated just miles from Lake Superior in Michigan's Upper Peninsula, offering year-round opportunities for outdoor adventure.
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