Earth’s Magnetic Field Almost Completely Collapsed 550 Million Years Ago

Visual simulation of the Earth's magnetic field. Credit: NASA Goddard Space Flight Center

More than half a billion years ago, Earth experienced an almost-complete collapse of its magnetic field. It began in the early Cambrian period. Then, after a period of about 15 million years, the field began to grow again. The cause of that collapse and the bounceback of the field was a mystery. Then, a group of geologists studied rocks from Oklahoma that were created during that time. Magnetic markers in the rocks’ minerals pointed toward an event that began some 550 million years ago. That was before the introduction of multicellular life on our planet.

Continue reading “Earth’s Magnetic Field Almost Completely Collapsed 550 Million Years Ago”

Scientists Identify the Source of a Famous Meteorite as One Crater on Mars

Researchers have found the source crater for the Martian Black Beauty meteorite, aka NWA 7034. It came from the north-east of the Terra Cimeria—Sirenum region, inside the black circle to the west of the Tharsis region. Image Credit: NASA/MOLA/The Planetary Society.

If we think untangling Earth’s complex geological history is difficult, think of the challenge involved in doing the same for Mars. At such a great distance, we rely on a few orbiters, a handful of rovers and landers, and our powerful telescopes to gather evidence. But unlike Earth, Mars is, for the most part, geologically inactive. Much of the evidence for Mars’ long history is still visible on the surface.

That helped scientists identify the source of one of our most well-known meteorites.

Continue reading “Scientists Identify the Source of a Famous Meteorite as One Crater on Mars”

Mars' Carbon Dioxide Glaciers are on the Move

Mars’ south polar ice cap. Credit: ESA / DLR / FU Berlin /

In 1666, famed Italian astronomer and mathematician Giovanni Cassini (the man who discovered four of Saturn’s largest moons) observed the Martian polar ice caps for the first time. However, it was not until the late-18th century, when Sir William Herschel recorded his own observations, that the connection to Earth’s own ice caps was established. In his subsequent treatise, “On the remarkable appearances at the polar regions on the planet Mars” (1784), noted how the southern cap grew and shrunk due to seasonal changes.

With the development of modern telescopes and robotic explorers, scientists have learned a great deal more about these polar deposits. In 2011, they learned that unlike the northermost ice sheet, the southern cap is largely composed of frozen carbon dioxide (aka. “dry ice”). According to new research led by the Planetary Science Institute (PSI), glaciers of carbon dioxide ice have been moving and carving features in the southern polar region for more than 600,000 years – and are on the move right now!

Continue reading “Mars' Carbon Dioxide Glaciers are on the Move”

Jupiter’s Moon Io has Dunes. Dunes!?

Potential dunes on Jupiter’s moon Io. An analysis indicates that the dark material (lower left) is recently emplaced lava flows, while the repeated, line-like features dominating the image are potential dunes. The bright, white areas may be newly emplaced grains as the lava flows vaporize adjacent frost. Credit: NASA/JPL-Caltech/Rutgers

Within Jupiter’s massive system of satellites, four large moons really stand out. They’re known as the “Galilean Moons” in honor of Galileo Galilee, who made the first recorded observations of them in 1610. The innermost of these moons is the rocky moon Io, which is slightly larger than Earth’s Moon and slightly denser. With more than 400 active volcanoes on its surface, it is the most geologically active body in the Solar System.

Add to that the intense radiation it gets from Jupiter’s magnetic field, and it’s arguably one of the most hellish environments in the Solar System! Nevertheless, scientists have long been puzzled by the meandering ridges visible on the surface, which are as large as any seen here on Earth. Thanks to a recent study led by Rutgers University, there’s now an explanation for how these formations can exist on a surface as icy and volcanic as Io’s.

Continue reading “Jupiter’s Moon Io has Dunes. Dunes!?”

Marsquakes are Caused by Shifting Magma

Mars' interior as revealed by the NASA/DLR InSight lander. Image Credit: Cottar, Koelemeijer, Winterbourne, NASA

Before the InSight Lander arrived on Mars, scientists could only estimate what the planet’s internal structure might be. Its size, mass, and moment of inertia were their main clues. Meteorites, orbiters, and in-situ sampling by rovers provided other clues.

But when InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) arrived on Mars in November 2018 and deployed its seismometer, better data started streaming in.

Continue reading “Marsquakes are Caused by Shifting Magma”

Primordial Helium, Left Over From the Big Bang, is Leaking Out of the Earth

The center of Lagoon Nebula, captured by the Hubble Telescope. Nebulae are the primary sources of helium-3, and the amount of He-3 leaking from the Earth’s core suggests the planet formed inside the solar nebula, according to a new study in the AGU journal Geochemistry, Geophysics, Geosystems. Credit: NASA, ESA

Something ancient and primordial lurks in Earth’s core. Helium 3 (3He) was created in the first minutes after the Big Bang, and some of it found its way through time and space to take up residence in Earth’s deepest regions. How do we know this?

Scientists can measure it as it slowly escapes.

Continue reading “Primordial Helium, Left Over From the Big Bang, is Leaking Out of the Earth”

Pluto’s Surface was Shaped by Ice Volcanoes

New Horizons mission scientists have determined that cryovolcanic activity most likely created unique structures on Pluto not yet seen anywhere else in the solar system. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Isaac Herrera/Kelsi Singer

For all of Earth’s geological diversity and its long history, the planet has never had ice volcanoes. But Pluto has. And that cryovolcanism has shaped some of the ice dwarf’s surface features.

The resulting structures are unique in the Solar System.

Continue reading “Pluto’s Surface was Shaped by Ice Volcanoes”

These are Star Dunes on Mars, Formed When the Wind Comes From Many Different Directions

An amazing aspect of Mars that is captured in many HiRISE images is geologic diversity within a small area. This image, of a crater in the Tyrrhena Terra region, was targeted to look at the geologic aspects of possible clays detected with the CRISM instrument. Image Credit: NASA/JPL/UArizona

Missions to Mars are expensive, even orbiters. They’re there to do science, not take pretty pictures. But sometimes Mars’ beauty is captured inadvertently, usually with some science mixed in.

That’s the case with this picture of star dunes captured by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter.

Continue reading “These are Star Dunes on Mars, Formed When the Wind Comes From Many Different Directions”

The Strange Swirls on the Lunar Surface are Somehow Related to Topography

This is an image of the Reiner Gamma lunar swirl from NASA's Lunar Reconnaissance Orbiter. Credits: NASA LRO WAC science team

The Moon is the most studied object in space. But our nearest neighbour still holds a few mysteries. One of those mysteries is the lunar swirls. These strange serpentine features are brighter than their surroundings and are much younger. They’re not associated with any specific composition of lunar rock, and they appear to overlay other surface features like craters and ejecta.

Scientists have been puzzling over the swirls for decades, and with lunar outposts looming as a real possibility, understanding these swirls takes on new importance. Now a new study finds a link between lunar topography and the swirls.

Continue reading “The Strange Swirls on the Lunar Surface are Somehow Related to Topography”

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?

Continue reading “How did Earth go From Molten Hellscape to Habitable Planet?”