Earth Archives

July 24, 2020July 24, 2020 by Evan Gough

800 Million Years Ago, it Was Raining Asteroids on the Earth and Moon

An artist's illustration of an asteroid shower on the Earth-Moon system. Image Credit: Murayama/Osaka Univ.

Natural processes here on Earth continually re-shape the planet’s surface. Craters from ancient asteroid strikes are erased in a short period of time, in geological terms. So how can researchers understand Earth’s history, and how thoroughly it may have been pummeled by asteroid strikes?

Scientists can turn their attention to our ancient companion, the Moon.

July 22, 2020July 22, 2020 by Evan Gough

Organic Matter Could Have Delivered Earth’s Water

This view of Earth’s horizon was taken by an Expedition 7 crewmember onboard the International Space Station, using a wide-angle lens while the Station was over the Pacific Ocean. A new study suggests that Earth's water didn't all come from comets, but likely also came from water-rich planetesimals. Credit: NASA

The origin of Earth’s water is a big piece of the puzzle in Earth’s history. Did it come from comets and asteroids? From water-bearing space dust? The scientific debate is not settled.

Now a new study shows that water could have been delivered to Earth by organic matter.

July 13, 2020July 13, 2020 by Evan Gough

This Giant Iceberg Has Been Sailing the Southern Seas for Three Years Now

The iceberg A-68A floating in open waters about 1050 km from its birthplace. It's been floating for three years. Image Credit: contains modified Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO

An iceberg that calved off of from a larger ice formation has spent three years floating on the ocean near Antarctica. The iceberg broke off of the Larsen Ice Shelf in mid-July 2017. It’s been battered and split up into three pieces, but it’s still going.

July 10, 2020July 10, 2020 by Evan Gough

Even If We Cut Greenhouse Gas Emissions Tomorrow, it Would Take Decades for the Earth to Start Cooling Again

Our beautiful, precious, life-supporting Earth as seen on July 6, 2015 from a distance of one million miles by a NASA scientific camera aboard the Deep Space Climate Observatory spacecraft. Credits: NASA

If—or hopefully when—we cut our Greenhouse Gas (GHG) emissions, we won’t notice much difference in the climate. The Earth’s natural systems take time to absorb carbon from the atmosphere. We may have to wait decades for the temperatures to drop.

Of course, that doesn’t mean we shouldn’t do it. It’s just that we have to temper our expectations a little.

July 7, 2020July 7, 2020 by Evan Gough

The Moon Might Be More Metal-Rich Than We Thought

The Moon contains more metal than previously thought, according to a new study. Is it time to re-think the giant impact hypothesis? Image Credit: NASA / GSFC / Arizona State University

A new study shows that the Moon is more metal-rich than previously thought. That has some far-reaching implications for our understanding of the Moon’s formation. If their results are solid, it means that we may need to re-think the giant impact hypothesis for the formation of the Moon.

June 25, 2020June 25, 2020 by Evan Gough

Last Year’s Total Solar Eclipse on Earth, Seen From the Moon

The Moon casting its shadow on the Earth during an eclipse in 2018. Image Credit: MingChuan Wei (Harbin Institute of Technology, BG2BHC/BY2HIT), CAMRAS Dwingeloo Radio Telescope, Reinhard Kühn DK5LA. Image edit by Jason Major.

On July 2, 2019, the Moon cast its shadow on the surface of the Earth. This time, the shadow’s path travelled across the South Pacific Ocean. It also passed over some of Argentina and Chile. For surface dwellers in the path, the Moon briefly blocked the Sun, turning night into day.

But for one “eye” in orbit around the Moon, the view was different. A camera on a tiny satellite watched as the circular shadow of the Moon moved over the Earth’s surface.

June 11, 2020June 11, 2020 by Evan Gough

It Should Be Easiest to Search for Young Earth-like Planets When They’re Completely Covered in Magma

Artist's impression of magma ocean planet. Credit: Mark Garlick

How did Earth evolve from an ocean of magma to the vibrant, life-supporting, blue jewel it is now? In its early years, the Earth was a blistering hot ball of magma. Now, 4.5 billion years later, it’s barely recognizable.

Is it possible to find exoplanets out there in the vast expanse, which are young molten globes much like young Earth was? How many of them can we expect to find? Where will we find them?

June 9, 2020June 9, 2020 by Evan Gough

Astronomers Have Found the Star/Exoplanet Combo That’s the Best Twin to the Sun/Earth

An artist's illustration of TOI 700d, an Earth-size exoplanet that TESS found in its star's habitable zone. Image Credit: NASA

At times, it seems like there’s an indundation of announcements featuring discoveries of “Earth-like” planets. And while those announcements are exciting, and scientifically noteworthy, there’s always a little question picking away at them: exactly how Earth-like are they, really?

After all, Earth is defined by its relationship with the Sun.

May 22, 2020May 22, 2020 by Evan Gough

Ocean Circulation Might Be the Key to Finding Habitable Exoplanets

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

We’ve found thousands and thousands of exoplanets now. And spacecraft like TESS will likely find thousands and thousands more of them. But most exoplanets are gassy giants, molten hell-holes, or frozen wastes. How can we find those needles-in-the-haystack habitable worlds that may be out there? How can we narrow our search?

Well, first of all, we need to find water. Oceans, preferably, since that’s where life began on Earth. And according to a new study, those oceans need to circulate in particular ways to support life.

May 22, 2020May 22, 2020 by Paul M. Sutter

Magnetic north is migrating towards Siberia. Here’s why

This visualization depicts what a coronal mass ejection might look like like as it interacts with the interplanetary medium and magnetic forces. Credit: NASA / Steele Hill

The North Pole ain’t what it used to be. Well, the geographic North Pole stays fixed over time (mostly because we define it to stay fixed over time) but the magnetic north pole constantly moves. And over the past decade it’s been moving out of Canada towards Siberia four times faster than it has in the past couple centuries. Armed with data from the ESA’s Swarm satellite, scientists might finally know why: the shifting of our magnetic field north pole is caused by a titanic struggle between two competing massive magnetic plumes.