Taxonomy term


Glass shards reveal a fiery history in Ethiopia

Chains of volcanoes and a lava lake pepper the landscape of the Afar Triangle in northeastern Ethiopia, where eruptions and earthquakes are byproducts of the rifting that is literally ripping Africa apart, but recent eruptions have been docile. Now, scientists studying ash deposits from the last 40,000 years are showing that dangerous, explosive eruptions present an ongoing hazard, striking the region every 1,000 years on average.

18 Sep 2017

Magnesium part of Earth's magnetic field engine

Earth’s magnetic field, which arises from convective flows in the planet’s core, known as the geodynamo, has existed for at least 3.4 billion years, meaning that the field-generating processes must have existed for that long as well. But what exactly those processes have looked like throughout Earth’s history, particularly early on, has been poorly understood. In a new study, researchers suggest that magnesium mineral formation in the core is a previously unrecognized but important piece of the puzzle.

26 Apr 2016

Introducing Earth's inner inner core

A humongous hunk of iron — that’s how scientists have long thought of Earth’s solid inner core. But new research suggests there’s more to it than that: namely, that the inner part of the inner core may have different physical properties than the outer part. In addition to revealing a new feature in Earth’s layer-cake internal structure, the discovery may shed light on the planet’s formation, say the authors of the study, published in Nature Geoscience.
06 Jul 2015

March 29, 1936: Notes on Earth's Inner Core

On March 29, 1936, Danish seismologist Inge Lehmann wrote a letter to a colleague in which she argued that seismic waves — specifically P-waves — recorded from distant earthquakes showed some anomalous characteristics. “If you had seen so many records from these distances as I have,” she wrote, “I am sure you would not doubt that the amplitudes are abnormally small.” Within the year, Lehmann published a study based on those unusual amplitudes, work that first proposed that Earth has a solid inner core inside its liquid outer core.

29 Mar 2015

Ancient meteorites reveal early magnetic fields

Even before the birth of the planets, our solar system was hardly a lonely place. Small rocky bodies, called planetesimals, filled the inner solar system, eventually colliding together to form the planets. Now a new look at a group of ancient meteorites shows that at least some planetesimals generated their own magnetic fields — a feat many scientists thought extremely difficult for such small astronomical bodies. The work also has scientists rethinking how planets formed.

21 Jan 2009

Of molten iron and magnetism

Since 1999, the German satellite CHAMP (CHAllenging Mini-satellite Payload) has swirled around Earth, keeping watch as the planet’s magnetic field waxes and wanes over time. CHAMP’s continuous measurements of Earth’s field have created a finely detailed picture of how the field changes both in space and in time — and by extension, how the movement of the molten iron in Earth’s outer core ebbs and flows. And thanks to these data, researchers report, they can now track even small-scale, rapid fluctuations in the field’s strength around the planet.

28 Aug 2008