🪐 A Rare Meteorite May Preserve Evidence of a Lost World from the Dawn of the Solar System

Scientists at the University of Colorado Boulder have uncovered what may be the strongest evidence yet for a vanished protoplanet — a planetary embryo that once orbited the young Sun more than 4.5 billion years ago before being destroyed in a catastrophic collision.

The clue comes from an unusual meteorite known as Northwest Africa (NWA) 12774, discovered in the Sahara Desert. It belongs to the angrites, one of the rarest meteorite groups ever found. Out of more than 80,000 known meteorites, only a few dozen are classified as angrites. These rocks formed during the earliest stages of solar system history, just a few million years after the Sun was born.

What makes NWA 12774 remarkable is its mineral chemistry. Researchers found clinopyroxene crystals enriched in aluminum — a signature that indicates formation under enormous pressure. Their calculations suggest pressures exceeding 17.5 kilobars, more than 17 times greater than the pressure at the bottom of the Mariana Trench.

Such conditions could not have existed inside a small asteroid.

The results imply that the meteorite’s parent body had a radius of at least 1,000 km. Because the crystals preserve delicate structures that would likely not survive deep burial, the original world may have been much larger — potentially approaching the size of the Moon and perhaps even Mars.

🔹 Evidence points to a planetary embryo at least 1,000 km in radius
🔹 Formation pressures exceeded 17.5 kilobars
🔹 Its composition differs significantly from Earth and Mars
🔹 It may represent a previously unknown pathway of planetary evolution
🔹 Fragments of similar lost worlds could still be hiding in meteorite collections

The study suggests that the early solar system was far more diverse than previously thought. Many planetary embryos likely formed, collided, merged, or were destroyed before the planets we know today emerged.

How many lost worlds helped build the solar system we live in?

📄 Original paper (Earth and Planetary Science Letters) · ScienceDaily

#astronomy #space #meteorite #planetaryscience #solarsystem

🪐 A Wobbling “Peanut” Asteroid May Still Carry Traces of Ancient Water

NASA’s Lucy mission has revealed one of the strangest small worlds ever seen up close: asteroid Donaldjohanson — a young, peanut-shaped rock in the main asteroid belt that tumbles through space and still preserves chemical hints of liquid water from its distant past.

Lucy flew past Donaldjohanson on April 20, 2025, at about 30,000 mph, coming within just 650 miles of the asteroid. The encounter was meant partly as a rehearsal before Lucy reaches Jupiter’s Trojan asteroids in 2027. Instead, it became a science story of its own.

Donaldjohanson does not rotate like a simple spinning rock. Data from Lucy show that it tumbles end-over-end once every 10.5 Earth days, while also wobbling around its long axis every 26.5 days — more like an unstable top than a normal asteroid.

Its shape is just as unusual. Donaldjohanson is a contact binary: two lobes joined by a narrow neck, giving it a cosmic peanut-like form. Scientists think it formed about 155 million years ago, when fragments from a violent collision gently came back together under their own gravity.

Since then, sunlight has been slowly reshaping it. Through the YORP effect — a tiny torque caused when sun-warmed surfaces radiate heat back into space — Donaldjohanson’s spin appears to have slowed by at least a factor of 10 over the last 20–60 million years. As the rotation changed, loose material likely slid down its slopes, softening craters and reshaping the surface.

But the most intriguing clue came from Lucy’s infrared data: iron-rich clay minerals on the surface. These minerals form in the presence of liquid water, meaning Donaldjohanson’s parent body once experienced aqueous alteration. But unlike Bennu and Ryugu, which contain magnesium-rich clays suggesting longer exposure to water, Donaldjohanson’s chemistry points to a much shorter episode.

🔹 Donaldjohanson is a bilobed “contact binary” asteroid
🔹 It tumbles on two axes, with rotation periods of 10.5 and 26.5 days
🔹 Its current body likely formed around 155 million years ago
🔹 Sunlight gradually slowed its spin through the YORP effect
🔹 Iron-rich clays suggest liquid water was present — but only briefly
🔹 The flyby was also a successful rehearsal for Lucy’s Trojan asteroid encounters, beginning with Eurybates in August 2027

Important caveat: this was a fast flyby, not an orbital mission or a sample return. Lucy measured the surface remotely; the asteroid’s interior remains unknown.

Still, Donaldjohanson matters because it gives scientists a rare comparison point. Bennu and Ryugu are near-Earth asteroids with long migration histories. Donaldjohanson is a much younger main-belt object that stayed closer to its birthplace. Its strange shape, unstable spin, and brief water history offer a fresh clue to how small bodies evolved — and how water-rich material may have moved through the early Solar System.

📄 Sources: https://www.science.org/doi/10.1126/science.aec0503

#NASA #LucyMission #Asteroid #PlanetaryScience #SolarSystem

🔴 A Rock From Mars Just Filled a 2-Billion-Year Hole in the Planet’s History

Scientists have dated an unusual Martian meteorite to 1.273 billion years old — placing it almost exactly inside a huge missing chapter in our geological record of Mars.

The meteorite, called NWA 13441, was discovered in Algeria in 2019. Most Martian volcanic meteorites of its type are either younger than about 600 million years or around 2.4 billion years old. Until now, researchers had essentially no samples from the enormous interval between them.

But its age may not even be the strangest part. The rock’s neodymium isotopes suggest that the magma it formed from came from a portion of the Martian mantle that had remained remarkably untouched since the earliest days of the Solar System. Mars formed very quickly and, unlike Earth, has no active plate tectonics constantly remixing its interior — potentially allowing ancient chemical reservoirs to survive for billions of years.

In other words, a small rock blasted off Mars by an impact and eventually found in the Sahara may contain a chemical fingerprint preserved from almost the beginning of the planet itself.

How much of Mars’s earliest history could still be locked inside rocks already lying somewhere on Earth?

#Mars #Space #Meteorite #PlanetaryScience #Geology #Science

https://doi.org/10.1016/j.gca.2026.06.035

🪐 Saturn Has Grown a Giant 10-Sided Storm Pattern

Saturn has been famous for decades for the enormous hexagon circling its north pole.

Now Hubble has discovered something even stranger at the opposite end of the planet: a vast decagon — a 10-sided atmospheric wave — surrounding Saturn’s south pole.

The structure sits roughly between 58° and 63° south latitude inside a jet stream moving at about 400 km/h. The decagon itself drifts much more slowly around the planet, at about 10 km/h, while its corners oscillate back and forth over periods of roughly a month. Multiwavelength Hubble observations show that the pattern extends through several atmospheric levels rather than existing as a superficial cloud shape.

What makes the discovery particularly intriguing is that it seems to be new. Cassini saw no comparable structure before its mission ended in 2017. Hubble data reveal faint hints beginning in 2023, with the ten-sided shape becoming increasingly distinct in 2024 and 2025. Astronomers may therefore be watching a giant planetary wave form almost in real time.

Scientists do not yet know why Saturn produces geometric atmospheric structures at all. Models suggest the decagon may be a huge wave trapped inside the jet stream, possibly triggered by an instability or a nearby vortex. But why the north settled on six sides and the south apparently chose ten remains unexplained.

Earth gets hurricanes.

Saturn apparently prefers geometry.

#Saturn #Hubble #Astronomy #PlanetaryScience #Space #Science

https://www.science.org/doi/10.1126/sciadv.aee4251