Earth’s oldest crystals suggest an early start for plate tectonics

Chemical evidence from ancient crystals suggests that Earth’s tectonic plates had already started moving 3.3 billion years ago, relatively early in our planet’s history. By analysing zircon crystals recovered from Western Australia — the oldest-known fragments of Earth rocks — researchers also found that the ancient Earth could have contained more oxygen, and possibly more water, than suspected. The movement of tectonic plates and higher-than-expected oxygen levels suggest that conditions on Earth could have been more conducive to life during this period than previously thought.

Surprise meteorite debris uncovered on Moon’s far side

Fragments of a rare type of meteorite have been discovered in the first samples from the Moon’s far side, brought back by China’s Chang’e-6 mission last year. The debris resembles material from asteroids that carry dust pre-dating the Solar System, so analysing it could help to trace how asteroids seeded Earth with volatile compounds, including water.

Wind from Earth is rusting the Moon

Oxygen particles blown from Earth to the Moon can turn lunar minerals into haematite — otherwise known as rust. The particles are carried in ‘Earth wind’ — a gust of ions of elements such as hydrogen, nitrogen and the offending oxygen — which hits the Moon for around five days each month. Researchers simulated the process by pelting single crystals of iron-rich minerals known to exist on the Moon with ions of oxygen, which caused the crystals to transform into haematite.

Dinosaur-killing Chicxulub asteroid formed in Solar System’s outer reaches

The asteroid that wiped out the dinosaurs was formed beyond the orbit of Jupiter. When the object struck what is now Chicxulub, Mexico 66 million years ago, the enormous explosion left a layer of asteroid material all over Earth. Researchers looked at an element preserved in that layer, ruthenium, and found that it matched the make-up of the type of asteroid that formed in the outer Solar System, rather than the type that was produced in the inner region.

Stonehenge’s enigmatic centre stone was hauled 800 kilometres from Scotland

Chemical analysis of tiny crystals in Stonehenge’s central Altar Stone suggest that it came from Scotland — and not from Wales as previously thought. The fingerprint of zircon, rutile and apatite crystals in the stone allowed it to be traced to the Orcadian Basin, which includes parts of northeastern Scotland and the Orkney Islands. Whether the six-tonne monolith was transported by land or by sea is hotly debated.

Mystery oxygen source discovered on the sea floor — bewildering scientists

Something is pumping out large amounts of oxygen at the bottom of the Pacific Ocean, at depths where a lack of sunlight makes photosynthesis impossible. The find has surprised scientists and the source remains a mystery. The oxygen might be generated by metal-rich mineral deposits, or nodules. To researchers’ surprise, they measured voltages of up to 0.95 volts across the surface of the nodules. It is possible that the nodules catalyse the splitting of water into oxygen and hydrogen, but more experiments are needed.

The Moon could be 40 million years older

A lunar rock collected by Apollo 17 astronauts suggests that the Moon formed 40 million years earlier than thought. The Moon was born when a Mars-sized object slammed into Earth around 4.5 billion years ago, although the exact timeline of when the molten Moon solidified remains unclear. A re-analysis of one of these rock samples discovered what might be the oldest lunar material: 4.46-billion-year-old zircon crystals.

Asteroid sample ferried to Earth is rich in the building blocks of life

Samples of asteroid Bennu that were returned to Earth by the OSIRIS-REx mission contain some of the building blocks of life — carbon and water, trapped inside the crystal structure of clay minerals. And this is just what’s on the surface of the sample container — it hasn’t even been opened yet.

‘Breakthrough’ could explain why life molecules are left- or right-handed

Magnetic minerals that were common on ancient Earth might be why nature shows a preference for the ‘left handed’ or ‘right handed’ versions of certain molecules that are essential for life. Some molecules have two mirror-image ‘chiral’ forms, and biology chooses just one: DNA, RNA and their building blocks are all right-handed; amino acids and proteins are all left-handed. Researchers found that magnetic minerals could have created an early surfeit of one-handed versions by causing more of one type to settle on their surfaces, kicking off the biological bias towards a single chiral form.

Diamond delivers long-sought mineral from the deep Earth

Small black specks in a diamond mined decades ago in Botswana have turned out to be a vital ingredient of the deep Earth. This is the first time the mineral has been identified in nature, after decades of searching.

Prospects for life on Venus fade — but aren’t dead yet

Signs of the gas phosphine in Venus’s atmosphere — which offered the tantalising suggestion of life — have faded, but they’re not gone completely. A new data analysis from the team that made the original exciting announcement confirms the phosphine signal, but it’s fainter than before. Astronomer Jane Greaves said she and her team redid the work because they learnt that some of the original data contained a spurious signal that could have affected the results. A separate analysis of old data from the NASA Pioneer mission also found evidence that could point to phosphine.

‘Unexplained’ molecule on Venus hints at life

Phosphine has been detected in Venus’s atmosphere, raising the thrilling question of whether the molecule might be a sign of life on the planet. On rocky planets, life is the only known source of the compound — although it forms without a helping hand near the energetic cores of the gas giants. Life seems impossible on the surface of the Solar System’s hottest world, but the middle of its cloud layer offers a more promising environment in terms of temperature, pressure and presence of water and organic molecules. Even if it’s not a sign of life on Venus, the unexpected observation is exciting.

The asteroid Ceres seems to have liquid water

The dwarf planet Ceres seemingly has a salty ocean of water beneath its surface. The ocean is the source of mysterious bright areas spotted on the distant world’s surface. Images from NASA's Dawn spacecraft, which dipped to less than 35 kilometres above Ceres’s surface on its 2018 mission, reveal the areas are deposits of mostly sodium carbonate. These were formed as briny water percolated up to the surface and then evaporated.

Scientists crack mystery of the origin of Stonehenge's giant stones

Scientists have solved an enduring mystery about Stonehenge, determining the place of origin of many of the megaliths that make up the famed monument in Wiltshire, England, thanks to a core sample that had been kept in the United States for decades.

Geochemical testing indicates that 50 of Stonehenge's 52 pale-grey sandstone megaliths, known as sarsens, share a common origin about 25 kilometres away at a site called West Woods on the edge of Wiltshire's Marlborough Downs.

NASA drone will explore Titan's atmosphere and hydrocarbon lakes

NASA will send a dual-quadcopter drone to hop across the surface of Titan, Saturn’s largest moon. Named Dragonfly, the mission will launch in 2026 and arrive at Titan in 2034. Dragonfly will study the atmosphere as it flies around, and touch down for extended stays on the moon's surface. The drone will explore areas where methane- and ethane-rich lakes recently dried up — and in the process, might have left behind residue rich with organic compounds like those that may have existed on early Earth before life arose.

Mars rover detects ‘excitingly huge’ methane spike

NASA’s Curiosity rover has measured the highest level of methane gas ever found in the atmosphere at Mars’s surface. The reading taken last week at Gale Crater — 21 parts per billion — is three times greater than the previous record, which Curiosity detected back in 2013. Various spacecraft and telescopes have spotted methane on Mars over the past 16 years, but the gas doesn’t appear in any predictable pattern — deepening the mystery of its origin.

Mars Express confirms methane spike and narrows down location of its source

Fleeting spikes of methane have been detected in the Martian atmosphere several times over more than a decade, but none had been independently confirmed — until now.

Mars Curiosity rover detects seasonal changes in methane levels

The latest data shows huge swings in the level of methane in the atmosphere as the seasons change, and new types of organic molecules capable of preserving life just beneath its surface.

Mars rover finds organic matter in ancient lake bed

NASA’s veteran Curiosity rover has found complex organic matter buried and preserved in ancient sediments that formed a vast lake bed on Mars more than 3 billion years ago.

The discovery is the most compelling evidence yet that long before the planet became the parched world it is today, Martian lakes were a rich soup of carbon-based compounds that are necessary for life, at least as we know it.

Pluto's dunes made of frozen methane

The icy world has dunes, but unlike Earth's sandy versions, Pluto's seem to be composed of flecks of methane ice.