ENVIRONMENT

Earth’s innermost layer is a 400-mile-wide ball of iron, new study suggests

Feb 22, 2023, 5:00 AM

Earth's solid center has a hidden, innermost layer made of an iron-nickel alloy, according to a new...

Earth's solid center has a hidden, innermost layer made of an iron-nickel alloy, according to a new study. Photo credit: Drew Whitehouse/Son Phạm/Hrvoje Tkalčic.

 (CNN) — Scientists have long wondered what lies at the very center of the Earth, and the latest research is putting weight behind a theory that our planet has a distinct ball of iron within its metallic core.

Beneath the outermost crust, the mantle and the molten-liquid outer core lies the Earth’s solid metal center — which actually has a hidden layer, or an “innermost inner core” within, according to a new study published Tuesday in the journal Nature Communications.

The monumental finding suggests the Earth has five major layers instead of four, and offered new details scientists could use to help unlock some of the oldest mysteries about our planet and how it was formed.

Geoscientists first suggested that the Earth’s core might have an additional, imperceptible layer about 20 years ago, according to a news release. Now, using new data sets collected by measuring the seismic waves of earthquakes as they passed through the Earth’s center, researchers have finally detected that innermost core, the new study said.

Seismic waves are vibrations that run within or along the surface of the Earth and through its inner layers as a result of earthquakes, volcanoes or other means.

“In this study, for the first time, we report observations of seismic waves originating from powerful earthquakes traveling back and forth from one side of the globe to the other up to five times like a ricochet,” study coauthor Dr. Thanh-Son Phạm, a seismologist and postdoctoral fellow at the Research School of Earth Sciences at the Australian National University in Canberra, in an email.

Detection through quake activity

The reason this layer had not been previously observed in more detail is because its composition is so similar to what lies above it, Pham said. Both this newly detected center — which the study reports is likely a 400-mile-wide (644-kilometer-wide) ball of metal — and its outer shell are made of iron-nickel alloy, with trace amounts of other elements.

“Additionally, the transition from the innermost (solid) ball to the outer shell of the inner core (also solid shell) seems rather gradational than sharp,” Pham said. “That is why we cannot observe it via direct reflections of seismic waves from it.”

Using instruments that detect the vibrational waves, researchers found the innermost inner core has a distinct anisotropy, which is a property of a substance that allows it to take on different characteristics depending on the angle from which it’s approached. An example of an object that’s anisotropic is a piece of wood: It’s much easier to hack a piece of firewood apart by hitting it along the direction of its grain than against it.

It is that feature that distinguishes the innermost core.

When it came to assessing the Earth’s core, researchers looked at how fast seismic waves traveled through it in different directions, and they found the innermost inner core changed the speed of those waves in a different way than the layer above it, the center core’s outer shell.

Detecting the new layer more than 1,000 miles (1,600 kilometers) beneath our feet is significant. The presence of a distinct innermost core could give scientists a better understanding of Earth’s magnetic field and how it has evolved and will continue to do so.

The new finding also “gives us a glimpse of what might have happened with other planets,” Pham said. “Take Mars as an example. We don’t understand yet why (Mars’ magnetic field) ceased to exist in the past.”

We want to hear from you.

Have a story idea or tip? Send it to the KSL NewsRadio team here.

Environment

utah lake shown, a bill tackling a failed lake project has advanced...

Adam Small

A bill to undo law regarding controversial, failed Utah Lake project advances to the full House

The law that would be repealed through this bill is the same law that created the Utah Lake Restoration Act.

16 hours ago

People experiencing homelessness walk in the street near a winter overflow shelter at St. Vincent d...

Peter Johnston

Code blue bill would open emergency beds at 18 degrees

The legislature is considering whether to raise the temperature at which emergency beds open up during code blue alerts. 

20 hours ago

Rainy drive...

Adam Small

Rain and snow on its way to the Wasatch Front

Utah will be seeing rain and snow along the Wasatch Front over the next couple of days. Nice weather returns by week's end.

21 hours ago

Endangered Utah butterfly...

Ashley Imlay, KSL.com

Rare Utah butterfly lands on list of species at risk of extinction

A petition to list the Utah butterfly as threatened was submitted to the Fish and Wildlife Service more than 10 years ago.

23 hours ago

A lone American flag waves in the morning breeze Wednesday, Aug. 14, 2002, at the Bonneville Salt F...

Allessandra Harris

Water may be the solution to saving the salt flats

With the Bonneville Salt Flats eroding, newly discovered research may have found a way to save them.

3 days ago

There’s not a lot of options for dwarf fruit trees out there, but there’s enough in apples and ...

Michelle Lee

Growing dwarf fruit trees

One of the topics the KSL Greenhouse show has been covering a lot these past few weeks is gardening in small spaces. Last week, Hosts Taun and Maria decided to continue this discussion, with the focus on dwarf fruit trees.

4 days ago

Sponsored Articles

Mother and cute toddler child in a little fancy wooden cottage, reading a book, drinking tea and en...

Visit Bear Lake

How to find the best winter lodging in Bear Lake, Utah

Winter lodging in Bear Lake can be more limited than in the summer, but with some careful planning you can easily book your next winter trip.

Happy family in winter clothing at the ski resort, winter time, watching at mountains in front of t...

Visit Bear Lake

Ski more for less: Affordable ski resorts near Bear Lake, Utah

Plan your perfect ski getaway in Bear Lake this winter, with pristine slopes, affordable tickets, and breathtaking scenery.

front of the Butch Cassidy museum with a man in a cowboy hat standing in the doorway...

Bear Lake Convention and Visitors Bureau

Looking Back: The History of Bear Lake

The history of Bear Lake is full of fascinating stories. At over 250,000 years old, the lake has seen generations of people visit its shores.

silhouette of a family looking over a lake with a bird in the top corner flying...

Bear Lake Convention and Visitors Bureau

8 Fun Activities To Do in Bear Lake Without Getting in the Water

Bear Lake offers plenty of activities for the whole family to enjoy without having to get in the water. Catch 8 of our favorite activities.

Wellsville Mountains in the spring with a pond in the foreground...

Wasatch Property Management

Advantages of Renting Over Owning a Home

Renting allows you to enjoy luxury amenities and low maintenance without the long-term commitment and responsibilities of owning a home.

Clouds over a red rock vista in Hurricane, Utah...

Wasatch Property Management

Why Southern Utah is a Retirement Paradise

Retirement in southern Utah offers plenty of cultural and recreational opportunities. Find out all that this region has to offer.

Earth’s innermost layer is a 400-mile-wide ball of iron, new study suggests