Earth Archives

November 4, 2022November 4, 2022 by Evan Gough

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

Recently, Astronomers 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. Could we use space lasers to protect Earth from these hazards? 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 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 26, 2022October 26, 2022 by Evan Gough

How Dangerous are Nearby Supernovae to Life on Earth?

A composite image of SN 1987A from Hubble, Chandra, and ALMA. Image Credit: By ALMA (ESO/NAOJ/NRAO)/A. Angelich. Visible light image: the NASA/ESA Hubble Space Telescope. X-Ray image: The NASA Chandra X-Ray Observatory - http://www.eso.org/public/images/eso1401a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=30512379

Life and supernovae don’t mix.

From a distance, supernovae explosions are fascinating. A star more massive than our Sun runs out of hydrogen and becomes unstable. Eventually, it explodes and releases so much energy it can outshine its host galaxy for months.

But space is vast and largely empty, and supernovae are relatively rare. And most planets don’t support life, so most supernovae probably explode without affecting living things.

But a new study shows how one type of supernova has a more extended reach than thought. And it could have consequences for planets like ours.

October 25, 2022October 27, 2022 by Nancy Atkinson

Lucy Took This Picture of Earth as it was Making its Gravity Assist Maneuver

NASA’s Lucy spacecraft captured this image of the Earth on Oct 15, 2022 during the spacecraft's flyby of our planet for a gravitational assist on its way to explore the Jupiter Trojan asteroids. Credits: NASA/Goddard/SwRI

We may take it for granted, but every day we receive picture postcards from the robotic travelers we have sent out to explore our Solar System. Usually, we get to see faraway planets, moons, asteroids, or comets. But sometimes we get to see ourselves.

The Lucy spacecraft took a couple of amazing images of our home planet as the spacecraft was approaching Earth for the first of three slingshot gravity assists on its way out to explore the Trojan asteroids along Jupiter’s orbit.

October 18, 2022October 18, 2022 by Evan Gough

Scientists Discover a New Way Exoplanets Could Make Oxygen; Unfortunately, it Doesn’t Require Life

Oxygen is a valuable biosignature because Earth is oxygen-rich, and because life made all that oxygen. But if we find oxygen in an exoplanet atmosphere does that mean life made it? Or is there an abiotic source of oxygen? Image Credit: NASA

Finding oxygen in an exoplanet’s atmosphere is a clue that life may be at work. On Earth, photosynthetic organisms absorb carbon dioxide, sunlight, and water and produce sugars and starches for energy. Oxygen is the byproduct of that process, so if we can detect oxygen elsewhere, it’ll generate excitement. But researchers have also put pressure on the idea that oxygen in an exoplanet’s atmosphere indicates life. It’s only evidence of life if we can rule out other pathways that created the oxygen.

But scientists can’t rule them out.

October 14, 2022October 16, 2022 by Evan Gough

If Earth Were an Exoplanet, it Would Still be Tricky to Figure Out if There’s Life Here

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

How would Earth appear to alien astronomers? What would their observations tell them about Earth if they searched the heavens for signs of habitability like we are? It’s a fun thought experiment.

But the experiment is more than just fun: it’s scientifically instructive. In many ways, it’s easier to study our planet and how it appears and then extrapolate those results as far as they go.

A new study shows that finding evidence of life on Earth may depend on the season alien astronomers are observing.

October 8, 2022October 8, 2022 by Nancy Atkinson

The Methane Released From the Damaged Nord Stream Pipeline is Visible From Space

On September 20, 2022 a GHGSat satellite observed the area of the Nordstream pipeline break, and saw an estimated emission rate of methane of 79,000 kg per hour – making it the largest methane leak ever detected by GHGSat from a single point-source. Credit: GHGSat and ESA.

On September 26, 2022, leaks were discovered in the underwater Nord Stream 1 and 2 gas pipelines, located near Denmark and Sweden. Both pipelines are owned by Russia and were built to transport natural gas from Russia to Germany through the Baltic Sea. Officials have said the leaks were caused by deliberate action, not accidents, and were likely intentional sabotage. While accusations have abounded, the motives behind the damage are not yet known.

Seismic disturbances in the Baltic Sea were detected, and officials said that while neither pipeline was transporting gas at the time of the blasts, they still contained pressurized methane, which is the main component of natural gas. The methane has now spewed out, producing a wide stream of bubbles on the sea surface which are visible from various satellites in Earth orbit.

October 7, 2022October 7, 2022 by Laurence Tognetti

The Moon is the Perfect Spot for Humanity’s Offsite Backup

In a recent study, a collaborative team of researchers discuss the potential for future lunar settlers to establish a backup data storage system of human activity in the event of a global catastrophe on Earth that could be used to recover human civilization on a post-catastrophe planet. This comes as NASA’s Artemis missions plan to send people back to the Moon for the first time since 1972, coupled with current global events such as the ongoing coronavirus pandemic and the War in Ukraine, with Russian President Vladimir Putin recently threatening nuclear war. Given the current state of world affairs, how important is it to establish a type of off-world data backup?

October 3, 2022October 3, 2022 by Evan Gough

Scientists Have Been Underestimating the Asteroid That Created the Biggest Known Crater on Earth

South Africa's Vredefort Crater is Earth's largest impact crater. New Research clarifies the power of the impact and its catastrophic effects. Image Credit: NASA Earth Observatory image by Lauren Dauphin / University of Rochester illustration by Julia Joshpe

Ancient impacts played a powerful role in Earth’s complex history. On other Solar System bodies like the Moon or Mercury, the impact history is preserved on their surfaces because there’s nothing to erase it. But Earth’s geologic activity has erased the evidence of impact craters over time, with some help from erosion.

Earth’s complex history has elevated its status among its Solar System siblings and created a world that’s rippling with life. Ancient giant impacts have played a role in that history, bringing catastrophe and disruption and irrevocably changing the course of events. Deciphering the role these giant impacts played is difficult since the evidence is missing or severely degraded. So how do scientists approach this problem?

One crater at a time.

September 14, 2022September 14, 2022 by Matt Williams

Mars did Have Moving Glaciers, but They Behaved Differently in the Planet's Lower Gravity

Glacial landscapes on Axel Heiberg Island (Canadian Arctic Archipelago) showing typical (glaciers) and atypical (subglacial channels, bottom right) glacial landscapes. Credit: A. Grau Galofre

On Earth, shifts in our climate have caused glaciers to advance and recede throughout our geological history (known as glacial and inter-glacial periods). The movement of these glaciers has carved features on the surface, including U-shaped valleys, hanging valleys, and fjords. These features are missing on Mars, leading scientists to conclude that any glaciers on its surface in the distant past were stationary. However, new research by a team of U.S. and French planetary scientists suggests that Martian glaciers did move more slowly than those on Earth.