A rocky exoplanet with an atmosphere

Astronomers have spotted a rocky exoplanet that looks likely to have an atmosphere — and could be a host for life. The planet, LHS 1140b, appears to have a helium-rich upper atmosphere and sits in the habitable zone around a star, the area in which an orbiting planet could maintain liquid water on its surface. Researchers can’t say for sure whether there is water on the exoplanet, but the findings constitute an “amazing missing piece of the puzzle” as to whether rocky exoplanets can have atmospheres, says astrophysicist Sara Seager.

First ‘true sugar’ molecule found in space — offering hints to life’s origins

Astronomers have detected a four-carbon sugar molecule in a cloud of gas and dust near the centre of our galaxy. The molecule, erythrulose, is the most complex sugar detected outside of our Solar System, the team says. If erythrulose exists in these molecular clouds, it could be transferred to passing asteroids and comets as a star system forms. Such bodies could have brought sugars — the feedstock for early versions of DNA and RNA — to Earth during a period of heavy asteroid bombardment around four billion years ago, suggests astronomer and study co-author Izaskun Jiménez-Serra.

Spotted Martian rocks hint at microbial life

Dark-rimmed ‘leopard spots’ in a rock studied by NASA’s Perseverance rover last year could be the remains of microbial activity on Mars. The rings aren’t a sure sign that microbes once thrived on the Red Planet; the only way to know for certain is to analyse a sample of the leopard-spotted rock here on Earth. Perseverance has a sample awaiting a ride off Mars for precisely that purpose. For now, the rings are being treated as ‘an intriguing signal’ of ancient Martian life, but far from a sure thing, said researchers at a conference yesterday.

Asteroid fragments upend theory of how life on Earth bloomed

Fragments collected from the asteroid Bennu contain the building blocks for life — all five nucleobases that form DNA and RNA and 14 of the 20 amino acids needed to make known proteins. But there’s a twist: on Earth, amino acids in living organisms tend to have a ‘left-handed’ structure. Those on Bennu, however, contain nearly equal amounts of these structures and their ‘right-handed’, mirror-image forms. This calls into question a hypothesis favoured by many scientists that asteroids similar to this one might have seeded life on Earth.

Mars rover finds possible signs of ancient Red Planet life

These tiny ‘leopard spots’, discovered in a rock on Mars by NASA’s Perseverance rover, could be possible signs of microbes that once lived on the red planet. “On Earth, these types of features in rocks are often associated with the fossilised record of microbes living in the subsurface,” says astrobiologist and Perseverance team member David Flannery. Without returning a rock sample to Earth, it will be difficult to further investigate the spots’ origin. “We have zapped that rock with lasers and X-rays and imaged it literally day and night from just about every angle imaginable,” says the rover’s project scientist Ken Farley. “Scientifically, Perseverance has nothing more to give.”

The Solar System has a new ocean

Mimas, a small moon of Saturn, turns out to have an ocean beneath its icy surface — despite looking too geologically inert to have water sloshing inside. The fact that unexceptional Mimas has an ocean means that “you could have liquid water almost anywhere”, says astronomer Valéry Lainey. And that means a greater chance of extraterrestrial life somewhere: interactions between a buried ocean and a moon’s rocky core could generate enough chemical energy to sustain living organisms.

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.

JWST spots biggest water plume yet spewing from a moon of Saturn

The James Webb Space Telescope (JWST) has spotted Saturn’s moon Enceladus spraying out a huge plume of very cold water vapour, far bigger than any previously seen there. The enormous cloud could carry the chemical ingredients of life: the salty ocean that lies beneath Enceladus’s icy surface is a possible haven for organisms, which could be sustained by hydrothermal vents.

Best view yet of planet in hotly pursued star system

The exoplanet TRAPPIST-1b — one of seven roughly Earth-sized planets in the TRAPPIST-1 system — probably doesn’t have an atmosphere. It’s not surprising: TRAPPIST-1b is the closest to its star and is blasted by four times as much radiation as Earth receives from the Sun. But the work shows the transformational power of the James Webb Space Telescope (JWST) to observe the system, which offers a unique laboratory for studying planetary environments and how they might become suitable for life.

Underground microbes may have swarmed ancient Mars

Ancient Mars might have been capable of nurturing hydrogen-eating, methane-producing microbes. Although similar creatures helped to make the environment on Earth more conducive to life, they would have done the opposite on Mars. Computer models show that methane produced by Martian microbial life would have cooled the planet and made it uninhabitable.

Radioactivity May Fuel Life Deep Underground and Inside Other Worlds

Scientists have long puzzled over how microbes living deep underground feed themselves without sunlight or heat. Now, two studies suggest that these organisms could feed off the radioactive decay of hydrogen and other elements. The findings open up new possibilities for life on other worlds — and could shed some light on our planet’s own history.

Life on Venus claim faces strongest challenge yet

Two papers have dealt a fresh blow to the idea that Venus’s atmosphere might contain phosphine gas — a potential sign of life. In one study, researchers analysed data from one of the telescopes used to make the phosphine claim and could not detect the gas’s spectral signature. In the other, they calculated how gases would behave in Venus’s atmosphere and concluded that what the original team thought was phosphine is actually sulphur dioxide, a gas that is common on Venus and is not a sign of possible life. Still, the case isn’t closed yet. The new studies argue against the presence of phosphine, but can’t entirely rule it out.

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.

Hubble telescope spies water raining on distant exoplanet

Astronomers have spotted hints of water raining in the atmosphere of a planet beyond the Solar System. The discovery is a rare glimpse of water molecules around a distant world that is not much bigger than Earth. Named K2-18 b, the planet is 34 parsecs (110 light-years) from Earth in the constellation Leo. Notably, it lies in the ‘habitable zone’ around its star — the distance at which liquid water could exist, making extraterrestrial life possible in its hydrogen-rich atmosphere.

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 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.

Organic molecule found in Titan's atmosphere

A compound that may form cell wall-like structures has been detected in the dense atmosphere of Saturn's moon Titan.

The earliest-known life on land 3.5 billion years ago

Ancient red rocks in Western Australia's Pilbara contain traces of a hot spring that hosted the earliest-known life on land 3.5 billion years ago. A team of researchers discovered evidence of fossil stromatolites — structures formed by layers of cyanobacteria — in what appears to be an ancient freshwater hot spring.