Earth Archives

October 27, 2021October 27, 2021 by Evan Gough

Researchers Use Ancient Literature to Track 3,000 Years of Auroras

EIELSON AIR FORCE BASE, Alaska -- The Aurora Borealis, or Northern Lights, shines above Bear Lake here Jan. 18. The lights are the result of solar particles colliding with gases in Earth's atmosphere. Early Eskimos and Indians believed different legends about the Northern Lights, such as they were the souls of animals dancing in the sky or the souls of fallen enemies trying to rise again. (U.S. Air Force photo by Senior Airman Joshua Strang)

Auroral activity on Earth varies over time. As the magnetic poles drift, auroras can appear at different latitudes around the globe. Solar activity also affects them, with powerful solar storms pushing the auroras further into mid-latitudes.

In an effort to better understand how auroras move around, how they’ll move in the future, and when powerful solar storms might pose a threat, a team of researchers have tracked auroral activity for the last 3,000 years.

October 13, 2021October 13, 2021 by Evan Gough

You Can Blow Up an Asteroid Just a few Months Before it Hits Earth and Prevent 99% of the Damage

An artist's impression of a Nearth-Earth Asteroid (NEA) breaking up. Credit: NASA/JPL-Caltech

So far, the battle between life on Earth and asteroids has been completely one-sided. But not for long. Soon, we’ll have the capability to deter asteroids from undesirable encounters with Earth. And while conventional thinking has said that the further away the better when it comes to intercepting one, we can’t assume we’ll always have enough advance warning.

A new study says we might be able to safely destroy potentially dangerous rocky interlopers, even when they get closer to Earth than we’d like.

September 28, 2021September 28, 2021 by Evan Gough

The Early Solar System was Messier and More Violent Than Previously Believed

This artwork shows a rocky planet being bombarded by comets. Image credit: NASA/JPL-Caltech

Our conventional models of planet formation may have to be updated, according to a pair of new papers.

Accretion is the keyword in current planet formation theory. The idea is that the planets formed out of the solar nebula, the material left over after the Sun formed. They did this through accretion, where small particles accumulate into more massive objects. These massive boulder-sized objects, called planetesimals, continued to merge together into larger entities, sometimes through collisions. Eventually, through repeated mergers and collisions, the inner Solar System was populated by four rocky planets.

But the new research suggests that the collisions played out much differently than thought and that objects collided with each other several times, in a series of hit and runs, before merging. This research fills some stubborn holes in our current understanding.

September 20, 2021September 20, 2021 by Evan Gough

The Moon was Pummeled Even Harder by Asteroids Than it Looks

We intend to explore the Moon, use its resources, and use it as a jumping-off point for missions deeper into the Solar System. For that we need a Lunar GPS. Image Credit: NASA

The Moon’s pitted surface tells a tale of repeated impacts over a long period of time. While Earth’s active geology erases most evidence of impacts, the Moon has no mechanism that can do the same. So there it sits, stark evidence of an impact-rich past.

The visible record of lunar cratering is used to understand Earth’s formation and history since periods of frequent impacts would affect both bodies similarly. But something’s wrong in our understanding of the Moon’s history. Impact crater dating, asteroid dynamics, lunar samples, impact basin-forming simulations, and lunar evolution modelling all suggest there’s some missing evidence from the Moon’s earliest impacts.

New research says that there were even more large, basin-forming impacts than we think. Scientists think that some of those impacts left crater imprints that are nearly invisible.

September 13, 2021September 13, 2021 by Evan Gough

A New Way to Search for Exomoons

Artist's impression of the view from a hypothetical moon around a exoplanet orbiting a triple star system. Credit: NASA

We’d love to find another planet like Earth. Not exactly like Earth; that’s kind of ridiculous and probably a little more science fiction than science. But what if we could find one similar enough to Earth to make us wonder?

How could we find it? We progress from one planet-finding mission to the next, compiling a list of planets that may be “Earth-like” or “potentially habitable.” Soon, we’ll have the James Webb Space Telescope and its ability to study exoplanet atmospheres for signs of life and habitability.

But one new study is focusing on exomoons and the role they play in a planet’s habitability. If we find a Moon-like exomoon in a stable orbit around its planet, could it be evidence that the planet itself is more Earth-like? Maybe, but we’re not there yet.

June 21, 2021June 21, 2021 by Nancy Atkinson

Juno Captured This Image of Earth on its Way Out to Jupiter Back in 2013

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

Since the Juno spacecraft has been in orbit around Jupiter for nearly five years — since July 4, 2016 — you may have forgotten about that time back in 2013 Juno flew past Earth. The spacecraft needed a little extra boost to reach Jupiter, so it used Earth for a gravity assist. Image editor Kevin Gill reminded us of that flyby with some stunning newly processed images of Earth, taken by the JunoCam, the “citizen science” camera on board. Pale blue dot indeed!

June 10, 2021March 9, 2022 by Evan Gough

Did Asteroid Impacts Provide Both the Heat and Raw Ingredients to Enable Life?

An artist's conception of an asteroid collision, which leads to how "families" of these space rocks are made in the belt between Mars and Jupiter. Credit: NASA/JPL-Caltech — An artist's conception of an asteroid collision, in the belt between Mars and Jupiter. Credit: NASA/JPL-Caltech

This is our Great Question: How did life begin on Earth? Anyone who says they have the answer is telling tall tales. We just don’t know yet.

While a definitive answer may be a long way off—or may never be found—there are some clever ways to nibble at the edges of that Great Question. A group of researchers at Kobe University in Japan are taking their own bites out of that compelling question with a question of their own: Did the heat from asteroid impacts help life get started?

May 24, 2021May 24, 2021 by Nancy Atkinson

This is Currently the World’s Largest Iceberg

An enormous iceberg has calved from the western side of the Ronne Ice Shelf, lying in the Weddell Sea, in Antarctica. Image by the Copernicus Sentinel-1 mission. Credit: ESA

A gigantic chunk of ice recently broke off from an ice shelf in Antarctica, and is currently the world’s largest iceberg. The iceberg, dubbed A-76, measures around 4,320 square km (1,670 square miles) in size. At 170 km (106 miles) in length and 25 km (15 miles) wide, the iceberg is slightly larger than the Spanish island of Majorca, and bigger than the state of Rhode Island in the US.

A-76 was captured in the above image by ESA’s Copernicus Sentinel-1 satellite. Below is an animation of the iceberg calving off the Ronne Ice Shelf.

March 11, 2021March 11, 2021 by Nancy Atkinson

The Galápagos Islands From Space

A satellite image from the Copernicus Sentinel-2 mission showing the Galápagos Islands – a volcanic archipelago situated some 1000 km west of Ecuador in the Pacific Ocean. Credit: Modified Copernicus Sentinel data (2020), processed by ESA.

The Galápagos Islands hold an honored place in science history. I often wonder, if Charles Darwin could have seen this volcanic archipelago from this vantage point – a satellite view – how might have that aided or changed his research on evolution?

February 19, 2021February 19, 2021 by Evan Gough

Did a Comet Wipe out the Dinosaurs?

Artist's rendering of a comet headed towards Earth. Public domain illustration.

About 66 million years ago a massive chunk of rock slammed into Earth in what is the modern-day Yucatan Peninsula. The impact extinguished about 75% of all life on Earth. Most famously, it was the event that wiped out the dinosaurs.

While mainstream scientific thought has pointed to an asteroid as the impactor, a new research letter says it could’ve, in fact, been a comet.