Earth Archives

November 30, 2022November 30, 2022 by Evan Gough

Should We Build a Nature Reserve on Mars?

There are 8 billion of us now. The UN says when the population peaks around the year 2100, there’ll be 11 billion human souls. Our population growth is colliding with the natural world on a greater scale than ever, and we’re losing between 200 and 2,000 species each year, according to the World Wildlife Federation.

An Engineer from the UK says that one way to mitigate the damage from the clash between humanity and nature is to create more habitat. We could do that by building Terran ecosystem preserves on Mars.

November 28, 2022November 28, 2022 by Nancy Atkinson

OK, Artemis. Now You’re Just Showing Off. A Stunning View of the Moon Eclipsing Earth From the Orion Spacecraft

Screenshot of the Moon eclipsing Earth, via NASA's livestream from Orion.

Have you ever seen a lunar eclipse of the Earth from the far side of the Moon? Now we have.

On Monday (November 28, 2022) NASA’s Orion spacecraft streamed back live video showing the Earth and Moon right next to each other, followed by a stunning view of the Moon eclipsing the Earth.

What a time to be alive! Image editor Kevin Gill might have said it best:

November 24, 2022November 24, 2022 by Evan Gough

What’s the Best Mix of Oceans to Land for a Habitable Planet?

A new study asks what ratio of land to ocean is best for habitability? Image Credit: Reto Stöckli, Render by Robert Simmon. Based on data from the MODIS Science Team

Earth is about 29% land and 71% oceans. How significant is that mix for habitability? What does it tell us about exoplanet habitability?

November 22, 2022November 22, 2022 by Evan Gough

Volcanoes are the worst. They’ve caused extinctions on Earth, and probably killed Venus

This is a computer-generated, three-dimensional perspective of the surface of Venus showing Maat Mons. It's Venus's highest volcano and is 8 kilometres (5.0 mi) high. The viewpoint is located 634 kilometers (393 miles) north of Maat Mons at an elevation of 3 kilometers (2 miles) above the terrain. Lava flows extend for hundreds of kilometers across the fractured plains shown in the foreground, to the base of Maat Mons. The vertical scale in this perspective has been exaggerated 10 times. Credits: NASA/JPL

Is there anything good about volcanoes? They can be violent, dangerous, and unpredictable. For modern humans, volcanoes are mostly an inconvenience, sometimes an intriguing visual display, and occasionally deadly.

But when there’s enough of them, and when they’re powerful and prolonged, they can kill the planet that hosts them.

November 16, 2022November 16, 2022 by Brian Koberlein

Mapping the Interiors of Meteorites to Learn how Earth got its Water

A composite image of Earth as a watery world. Credit: Reto Stöckli, Robert Simmon, MODIS/NASA

Earth is a strange world. A warm, rocky planet covered with oceans of liquid water. This strangeness is central to life on Earth, but it has been a longstanding puzzle for astronomers. Just why is our planet wet while other terrestrial worlds are dry? Where did all of Earth’s water come from?

November 8, 2022November 8, 2022 by Evan Gough

Earth’s First Known Mass Extinction Event Starved Life of Oxygen

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

650 million years ago, Earth was completely or almost completely frozen, according to the Snowball Earth Hypothesis. As the atmosphere changed and Earth warmed up, it heralded the beginning of the Ediacaran Period. The Ediacaran Period marks the first time multicellular life was widespread on the planet. It predates the more well-known Cambrian Period, when more complex life emerged, diversified, and flourished.

Life during the Ediacaran Period faced a mass extinction, and it was Earth’s first one.

What happened?

November 4, 2022November 4, 2022 by Evan Gough

Three New Potentially Hazardous Asteroids Discovered, Including a big one That Measures 1.5 km Across

Sstronomers have spotted three near-Earth asteroids (NEAs) hiding in the glare of the Sun. These NEAs are part of an elusive population that lurks inside the orbits of Earth and Venus. One of the asteroids is the largest object that is potentially hazardous to Earth to be discovered in the last eight years. Image Credit: DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA/J. da Silva/Spaceengine

An asteroid 1.5 km across is no joke. Even a much smaller one, about the size of a house, can explode with more power than the first nuclear weapons. When an asteroid is greater than 1 km in diameter, astronomers call them “planet-killers.” The impact energy released from a planet-killer striking Earth would be devastating, so knowing where these asteroids are and where they’re headed is critically important.

Our defensive capability against asteroid strikes is in its infancy, so advance notice of asteroids that could cross Earth’s orbit is critical. We’ll need time to prepare.

October 31, 2022October 31, 2022 by Carolyn Collins Petersen

Good News! The Ozone Hole is Continuing to Shrink

earth's atmosphere has an ozone hole (not seen here) — Earth’s atmosphere seen from space. The top layer of the stratosphere is the ozone layer, which protects us from harmful solar UV. Scientists are tracking the ozone hole over the Antarctic. Credit: NASA

Most of us don’t think about ozone as we go about our daily lives. Yet, this pale blue gas plays a huge role in keeping our planet habitable. There’s a layer of it in Earth’s stratosphere, and it absorbs most of the ultraviolet radiation streaming from the Sun. Without the ozone layer, the UV would cause severe damage to most life on Earth. What would happen if we had an ozone hole?

October 28, 2022October 28, 2022 by Evan Gough

The Most Devastating Solar Storms in History are Scoured Into Tree Rings

Scientists study tree rings because they retain a record of climatic events and changes. They also record the Sun's activity. Image Credit: Rbreidbrown/Wikimedia Commons, CC BY-SA

Trees are like sentinels that preserve a record of shifting climates. Their growth rings hold that history and dendrochronology studies those rings. Scientists can determine the exact ages of trees and correlate their growth with climatic and environmental changes.

But they also record the effects of more distant changes, including the Sun’s activity.

October 27, 2022October 27, 2022 by Evan Gough

Earth’s Hardiest Bacteria Could Survive Hundreds of Millions of Years Just Under the Surface of Mars

A few years from now, a small capsule will enter Earth’s atmosphere and float to the surface under a parachute. The parachute will likely be radar-reflective so that it can be easily tracked. It may land in Australia’s outback, a popular spot for sample returns. Scientists will take it to a sterilized, secure lab and carefully open it. Inside, there’ll be rock samples from Mars collected by the Perseverance Rover.

If a new study is correct, scientists should look carefully for dormant life in those samples.