Earth Archives

October 23, 2020October 23, 2020 by Evan Gough

Geologists Have Found the Earth’s Missing Tectonic Plate

This image shows plate tectonic reconstruction of western North America 60 million years ago showing subduction of three key tectonic plates, Kula, Farallon and Resurrection. Image Credit: Wu and Fuston 2020.

Northern Canada has been keeping a secret from the rest of the world. It’s home to “Resurrection,” a tectonic plate that has been much theorized but never found until now. A team of researchers used what amounts to a CAT scan of northern Canada and the mantle underneath it to find the missing plate.

Finding it could lead to better hazard prediction and also to finding mineral and hydrocarbon deposits. But better than that, it’s helping scientists piece together Earth’s history.

October 17, 2020October 17, 2020 by Nancy Atkinson

Great Barrier Reef Has Lost Half of its Coral Over the Last 25 Years

Great Barrier Reef, Queensland, Australia August 1992

A new study found that warmer ocean temperatures driven by climate change have caused Australia’s Great Barrier Reef to lose more than half of its corals since 1995. The researchers say virtually all coral populations along the Great Barrier Reef have declined due to repeated “bleaching events” in the past 25 years. They said the devastation of the coral will continue unless action is taken to mitigate the causes of a warming climate.

October 2, 2020October 2, 2020 by Evan Gough

A Supernova Exploded Dangerously Close to Earth 2.5 Million Years Ago

Visible, infrared, and X-ray light image of Kepler's supernova remnant (SN 1604) located about 13,000 light-years away. Credit: NASA, ESA, R. Sankrit and W. Blair (Johns Hopkins University).

In its 4.5 billion year history, Earth has had to run the gauntlet. Numerous catastrophes have imperilled the planet, from massive impacts, to volcanic conflagrations, to frigid episodes of snowball Earth. Yet life persists.

Among all of the hazards that threaten a planet, the most potentially calamitous might be a nearby star exploding as a supernova.

September 24, 2020September 24, 2020 by Evan Gough

A New Mass Extinction has been Discovered, Wiping Out Life 233 Million Years Ago, and Leading to the Rise of the Dinosaurs

Earth Observation has come a long way. But if satellites could orbit closer to Earth, in VLEO, then our observations would be a lot better. Image Credit: NASA Earth Observatory.

Most everybody knows that the dinosaurs perished rapidly in a tumultuous extinction, caused by an asteroid strike about 66 million years ago. But it looks like another extinction prior to the appearance of the dinosaurs paved the way for their long reign. That extinction took place about 233 million years ago.

And scientists have only now discovered it.

September 22, 2020September 22, 2020 by Nancy Atkinson

This is the View You Get Staring out of the Space Station’s Cupola Module

Clouds trace out the islands of the Caribbean Sea in this photo taken by an astronaut from inside the Cupola on the International Space Station. Credit NASA/NASA Earth Observatory.

Those lucky few who have the incredible opportunity to see the Earth from space often report the view gives them a sense of awe, unity and clarity. This perspective-altering experience has come to be known as the Overview Effect, from a book by the same name published 1987 by space philosopher Frank White.

September 9, 2020September 9, 2020 by Evan Gough

Earth’s Oxygen Could be Making the Moon Rust

Enhanced map of hematite (red) on Moon using a spheric projection (nearside only). Credit: Shuai Li

It takes oxygen to make iron rust. So when scientists discovered hematite spread widely through lunar high latitudes, they were surprised. How did that happen?

A new study suggests that oxygen from Earth could be playing a role in rusting the Moon.

September 9, 2020September 9, 2020 by Nancy Atkinson

Can you tell the difference between California, Venus, Titan and Mars? Hint: California is the one with buildings.

Californians woke up to an alien-looking sky this morning, Wednesday, September 9, 2020.

August 14, 2020August 14, 2020 by Evan Gough

Did Snowball Earth Happen Because of a Sudden Drop in Sunlight?

This artist's illustration shows what an icy exo-Earth might look like. A new study says liquid water could persist under ice sheets on planets outside of their habitable zones. Image Credit: NASA

Hundreds of millions of years ago, Earth went through two episodes of severe glaciation. These two episodes—the Sturtian and the Marinoan glaciations—occured during the Earth’s Cryogenian Period. The Cryogenian lasted from about 720 million to 635 million years ago.

The phenomenon is called “Snowball Earth” and both instances of it happened in pretty quick succession. And while a planet encased in ice and snow sounds devastating, these episodes may have paved the way for the development of complex life.

The question is, what caused the Earth to freeze over like that?

August 4, 2020August 4, 2020 by Evan Gough

Microbes Were Dormant for Over 100 Million Years, But They Were Able to Spring Back to Life

Magnified image showing microbes revived from 101.5-million-year-old sediment. Image Credit:Japan Agency for Marine-Earth Science and Technology

At the bottom of the ocean in the South Pacific Gyre, there’s a sediment layer that is among the most nutrient-starved environments on Earth. Because of conditions in that area, there’s almost no “marine snow”—the shower of organic debris common in the ocean—that falls to the ocean floor. Without all that organic debris falling to the floor, there’s a severe lack of nutrients there, and that makes this one of the least hospitable places on Earth.

A team of researchers took sediment samples from that area, and extracted 101.5 million year old microbes. When they “fed” those microbes, they sprang back to life.

The results are expanding our knowledge of microbial life and how long it can be dormant when conditions force it to be.

July 24, 2020July 24, 2020 by Evan Gough

What Cracked the Earth’s Outer Shell and Started its Plate Tectonics?

A snapshot of a model from the new work, showing the late stages of growth and coalescence of a new global fracture network. Fractures are in black / shadow, and colors show stresses (pink color denotes tensile stress, blue color denotes compressive stress). Image Credit: Tang et al, 2020.

Earth’s lithosphere is made up of seven large tectonic plates and a number of smaller ones. The theory of plate tectonics that describes how these plates move is about 50 years old. But there’s never really been an understanding of how this system developed, and how the Earth’s shell split into separate plates and started moving.

Now a group of researchers have a possible explanation.