Podcaster: Richard Drumm
Title: Space Scoop: Using Magnets to Peer Deep Into the Earth
Organization:365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1621/
Description: Space scoop, news for children
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
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Transcript:
This is 365 Days of Astronomy. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Today’s story is: Using Magnets to Peer Deep Into the Earth
The Universe is a dangerous place, filled with scorching hot stars, deadly cosmic rays and giant rocks flying at 40,000 miles an hour!
But have no fear, Earth is the Fortress of the Solar System. It has a whole host of incredible natural defenses that protect life. One of the best is Earth’s magnetic field.
A magnetic field is an invisible force field that surrounds a magnet: in this case, the magnet is Earth’s iron core. This magnetic field shields Earth from those harmful cosmic rays that bombard us from the Sun and from the rest of the galaxy.
To help us understand our cosmic magnetic shield, and allow us to predict its behavior, a set of satellites called Swarm were launched into Space in 2013 by the ESA, the European Space Agency.
SWARM is made up of three satellites, named Alpha, Bravo & Charlie, that work together to study magnetic fields on Earth.
Within just a few years, Swarm has done some phenomenal science. For the first time ever, it measured the tiny magnetic fields created by our oceans!
As the salty ocean water flows through the Earth’s magnetic field, it generates its own, secondary magnetic field. But this isn’t the end of the discovery.
MRI scanners in hospitals use magnetic fields to probe beneath our skin to study the soft tissues inside of our bodies, tissues that X-rays can’t see.
In a similar way, Swarm used the oceans’ magnetic fields to probe beneath the Earth’s surface 250 kilometers below the ocean floor!
The 3 Swarm satellites and the earlier Champ satellite have allowed the scientists to distinguish between the rigid ocean ‘lithosphere’ and the more pliable ‘asthenosphere’ that lies underneath it.
The lithosphere is the rigid outer part of the Earth, consisting of the crust and upper mantle, while the asthenosphere lies just below the lithosphere and is hotter and more fluid than the lithosphere.
The lithosphere is the broken into tectonic plates, so these 3 plucky satellites have given us insights into the most important geologic process of all.
The lithosphere under the oceans is thinner, at 50-140 km thick, than that under the continents, which can be up to 280 km thick.
The continental lithosphere is less dense in addition to its being thicker, and the lower density helps it float on the asthenosphere. In some cases for billions of years!
We don’t have many ways of probing deep under the surface of our planet, but Swarm is finally helping reveal mysteries deep below Earth’s surface!
Hey, Here’s A Cool Fact:
This work shows that down even farther to about 350 km below the surface, the degree to which material conducts electric currents & distorts magnetic fields is related to its composition.
In addition, the Swarm analysis shows a clear dependence on the tectonic setting of the oceanic plates. These new results also indicate that, in the future, we could get a full 3D view of conductivity below the oceans.
The effect of Earth’s magnetic field extends almost 60,000 km out into space. That’s seriously far! It’s 1/6 of the way to the Moon!
Thank you for listening to the 365 Days of Astronomy Podcast!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!