Earth Archives

March 9, 2022March 9, 2022 by Evan Gough

How did Earth go From Molten Hellscape to Habitable Planet?

An artist's impression of the Hadean eon. Image Credit: By Tim Bertelink - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=48916334

Earth formed from the Sun’s protoplanetary disk about 4.6 billion years ago. In the beginning, it was a molten spheroid with scorching temperatures. Over time, it cooled, and a solid crust formed. Eventually, the atmosphere cooled, and life became a possibility.

But how did all of that happen? The atmosphere was rich in carbon, and that carbon had to be removed before the temperature could drop and Earth could become habitable.

Where did all the carbon go?

February 23, 2022February 23, 2022 by Evan Gough

Does the Entire Planet Have a Mind of its Own?

In a self-described "thought experiment," University of Rochester astrophysicist Adam Frank and colleagues David Grinspoon at the Planetary Science Institute and Sara Walker at Arizona State University use scientific theory and broader questions about how life alters a planet, to posit four stages to describe Earth's past and possible future. Image Credit: (University of Rochester illustration / Michael Osadciw)

What is humanity? Do our minds set us apart from the rest of nature and from the rest of Earth? Or does Earth have a collective mind of its own, and we’re simply part of that mind? On the literal face of it, that last question might sound ridiculous.

But a new thought experiment explores it more deeply, and while there’s no firm conclusion about humanity and a planetary mind, just thinking about it invites minds to reconsider their relationship with nature.

Overcoming our challenges requires a better understanding of ourselves and nature, and the same is true for any other civilizations that make it past the Great Filter.

February 8, 2022February 8, 2022 by Evan Gough

Massive Rocky Planets Probably Don’t Have big Moons

The Earth straddling the limb of the Moon, as seen from above Compton crater on the lunar farside, taken by the Lunar Reconnaissance Orbiter spacecraft. Credit: NASA/GSFC/Arizona State University.

The Moon has orbited Earth since the Solar System’s early days. Anyone who’s ever spent time at the ocean can’t fail to notice the Moon’s effect. The Moon drives the tides even in the world’s most remote inlets and bays. And tides may be vital to life’s emergence.

But if Earth were more massive, the Moon may never have become what it is now. Instead, it would be much smaller. Tides would be much weaker, and life may not have emerged the way it did.

February 2, 2022February 2, 2022 by Evan Gough

North Korea Releases Pictures of Earth They Say Were Taken From Space

This is an image taken with a camera onboard North Korea's Hwasong-12 missile during a test launch in January 2022. Image Credit: NKNews.org

North Korea released some pictures they say come from their recent missile test. The missile they tested—the intermediate-range Hwasong-12—can reach the U.S. territory of Guam. According to most North Korea observers, the country hopes the tests will bring the U.S. back to the negotiating table.

January 10, 2022January 10, 2022 by Evan Gough

The Early Earth was Really Horrible for Life

The Blue Marble image of Earth from Apollo 17. Credit: NASA

Earth has had a long and complex history since its formation roughly 4.5 billion years ago. Initially, it was a molten ball, but eventually, it cooled and became differentiated. The Moon formed from a collision between Earth and a protoplanet named Theia (probably), the oceans formed, and at some point in time, about 4 billion years ago, simple life appeared.

Those are the broad strokes, and scientists have worked hard to fill in a detailed timeline of Earth’s history. But there are a host of significant and poorly-understood periods in the timeline, lined up like targets for the scientific method. One of them concerns UV radiation and its effects on early life.

A new study probes the effects of UV radiation on Earth’s early life-forms and how it might have shaped our world.

December 14, 2021December 14, 2021 by Evan Gough

Life on Earth Needed Iron. Will it be the Same on Other Worlds?

Earth as seen by the JUNO spacecraft in 2013. Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

A lot has to go right for a planet to support life. Some of the circumstances that allow life to bloom on any given planet stem from the planet’s initial formation. Here on Earth, circumstances meant Earth’s crust contains about 5% iron by weight.

A new paper looks at how Earth’s iron diminished over time and how that shaped the development of complex life here on Earth. Is iron necessary for complex life to develop on other worlds?

December 7, 2021December 7, 2021 by Evan Gough

Asteroid Apophis’ 2029 Flyby Will Provide a Bonanza of Asteroid Science

The asteroid 99942 Apophis. Image Credit: NASA/Caltech/JPL

If NASA and other space agencies don’t want us to freak out about asteroids colliding with Earth, why do they give them names like Apophis? It sounds apocalyptic.

Apophis was the ancient Egyptian god of Chaos. He was an evil serpent that dwelled in endless darkness, the enemy of light and truth. So when they informed us that an asteroid named Apophis was due for a close encounter with Earth in 2029, people were understandably anxious. After all, Earth’s previous dominant inhabitants were evicted by an asteroid.

December 6, 2021December 6, 2021 by Evan Gough

Did the Earth’s Water Come From the Sun?

The sun, solar winds and asteroid Itokawa. Image Credit: Curtin University.

Where did Earth’s water come from? Comets may have brought some of it. Asteroids may have brought some. Icy planetesimals may have played a role by crashing into the young Earth and depositing their water. Hydrogen from inside the Earth may have contributed, too. Another hypothesis states the collision that formed the Moon gave Earth its water.

There’s evidence to back up all of these hypotheses.

But new research suggests that the Sun and its Solar Wind may have helped delivered some water, too.

November 24, 2021November 24, 2021 by Evan Gough

Did Cosmic Dust Deliver the Phosphorus Needed for Life?

Sunlight reflects off tiny, interplanetary dust particles, creating the faint column of glowing light seen against the stars in this image. New research suggests that cosmic dust might be an important source of phosphorus for life on Earth. Credit: Malcol, CC BY 3.0

Without phosphorus, there’s no life. It’s a necessary part of DNA, RNA, and other biological molecules like ATP, which helps cells transport energy. But any phosphorus that was present when Earth formed would’ve been sequestered in the center of the molten planet.

So where did phosphorus come from?

It might have come from cosmic dust.

November 19, 2021November 19, 2021 by Evan Gough

There’s So Much Pressure at the Earth’s Core, it Makes Iron Behave in a Strange Way

New observations of the atomic structure of iron reveal it undergoes "twinning" under extreme stress and pressure. Image Credit: SLAC National Accelerator Laboratory

It’s one of nature’s topsy-turvy tricks that the deep interior of the Earth is as hot as the Sun’s surface. The sphere of iron that resides there is also under extreme pressure: about 360 million times more pressure than we experience on the Earth’s surface. But how can scientists study what happens to the iron at the center of the Earth when it’s largely unobservable?

With a pair of lasers.