Name That Iceball
Galileo detected an induced magnetic signature around this Jovian moon, strongly suggesting a global electrically conducting ocean beneath its crust.
What is Europa?
Asteroids orbiting mainly between Mars and Jupiter occupy this region of the Solar System.
What is the main asteroid belt?
Water reacting with ultramafic rock during serpentinisation can generate this simple molecule, an excellent fuel for chemotrophic life.
What is molecular hydrogen, H₂?
The coexistence of strong oxidants and reductants can provide this thermodynamic resource for metabolism.
What is chemical free energy or redox disequilibrium?
When volatile ice sublimates from a cometary nucleus, it creates this diffuse envelope around the nucleus.
What is the coma?
Its south-polar “tiger stripes” spray water vapour, salts, ice grains and organics directly into space.
What is Enceladus?
Unlike a monolithic rock, many small asteroids are loosely bound collections of fragments described by this term.
What is a rubble pile?
On Europa, energetic particles can split surface water ice and produce oxidants through this process.
What is radiolysis?
A measurable preference for one molecular handedness over the other is called this.
What is enantiomeric excess?
These two processes primarily shape a comet’s ion tail and dust tail, respectively.
What are the solar wind and radiation pressure?
This is the largest moon in the Solar System and the only moon known to possess its own intrinsic magnetic field.
What is Ganymede?
Samples returned from the carbonaceous asteroids Ryugu and Bennu contain hydrated minerals and a rich variety of these carbon-based compounds relevant to prebiotic chemistry.
What are organic molecules?
These cage-like water-ice structures can trap methane, carbon dioxide and other gases within an icy crust.
What are clathrate hydrates?
Earth organisms accidentally carried to another world represent this category of planetary-protection problem.
What is forward contamination?
Rosetta spent more than two years studying this rubber-duck-shaped comet.
What is 67P/Churyumov–Gerasimenko?
The bright deposits in Occator Crater indicate that sodium-carbonate-rich brines once reached the surface of this dwarf planet.
What is Ceres?
Sunlight absorbed and thermally re-emitted by a rotating asteroid produces this subtle force, gradually altering its orbit.
What is the Yarkovsky effect?
Detection of sodium phosphates in Enceladus plume grains suggested that this bioessential element may be relatively abundant in its ocean.
What is phosphorus?
Biological carbon fixation often favours ¹²C, producing more negative values in this isotope notation.
What is δ¹³C?
Far from the Sun, where water ice barely sublimates, cometary activity can instead be powered by these more volatile carbon-bearing ices.
What are CO and CO₂?
This retrograde moon of Neptune is probably a captured Kuiper Belt object and was observed producing nitrogen-rich geyser-like plumes.
What is Triton?
When an asteroid spins faster because of uneven absorption and re-emission of radiation, this delightfully acronymed effect may eventually reshape or disrupt it.
What is the YORP effect?
At low temperatures, reactions involving H₃⁺ and HD can enrich molecules in this heavy isotope of hydrogen.
What is deuterium?
To compare quantitatively whether data favour a biological model over an abiotic model, researchers may calculate this Bayesian evidence ratio.
What is the Bayes factor?
Uneven outgassing can alter a comet’s rotation and trajectory through this mechanical effect.
What is an outgassing torque or non-gravitational acceleration?