Samuel Crowe (UVA): "Massive stars are factories that produce heavy elements in their nuclear cores, so understanding them better is like learning the origin story of much of the universe." [Universe Today]

The year 2023 provided a lot of exciting astronomy stories. It wasn't easy to choose, but here are the ones I liked best.

Moons galore
February brought an announcement of the discovery of 12 new moons of Jupiter. It brought the overall number of Jovian moons to 112, overtaking the number of Saturn's moons. But only for a few months. In May, we learned that there were 65 new Saturnian moons, upping Saturn's total to 145.

First landing near the Lunar South Pole
The Moon's South Pole is of special interest because studies show there are large amounts of water ice there. However, it's a particularly difficult place to land and to explore. The successful first landing was made by India's Chandrayaan-3 mission.

Planetary defence
In September 2022, NASA crashed the DART (Double Asteroid Redirection Test) spacecraft into an asteroid. Why? It was to see if the trajectory of an asteroid threatening Earth could be deflected. Test results were published in March, and showed that there had been a successful deflection. It was the first time anyone had changed the motion of a natural object in space.

OSIRIS-REx brings it home
NASA's Osiris-Rex spacecraft was launched in 2016 and arrived at asteroid 101955 Bennu two years later. After two years of study, a sample collection was returned to Earth in 2023. Osiris-Rex released the return capsule for it to land in Utah's West Desert for retrieval. The spacecraft itself is continuing its voyage to another asteroid.

Lucy's double asteroid
NASA's Lucy spacecraft is a 12-year mission to study a few main belt asteroids and some Trojan asteroids that share Jupiter's orbit around the Sun. It's intended to expand our knowledge of planetary origins. Lucy's first target was asteroid Dinkinesh, which was a surprise. It turned out to be a contact binary, i.e., it's in two pieces that touch each other.

Three exciting missions launched
(1) Juice (ESA) will make detailed observations of gas giant Jupiter and its three moons with oceans – Ganymede, Callisto and Europa.
(2) Psyche (NASA) is an asteroid that looks like the exposed nickel-iron core of an early planet. It's an opportunity to observe the interior of a planet.
(3) Euclid (ESA) is designed to explore the evolution of the dark Universe. Astronomers hope for insight into dark matter and dark energy.

NASA's Juno mission has observed organic compounds on the moon Ganymede.
Scott Bolton, Juno's principal investigator, says that the greatest abundance of salts and organics was in the latitudes protected from Jupiter's dangerous magnetic field. "This suggests we are seeing the remnants of a deep ocean brine that reached the surface of this frozen world.” Compounds, probably coming from a subsurface ocean, might sustain life.

Kiladze cryovolcano?
There are folk still annoyed about Pluto's demotion to dwarf planet. They'll be cheering the planetary scientists that have reviewed data and images from the 2015 New Horizons flyby. They believe they've found the remains of a super cryovolcano on Pluto. (A cryovolcano erupts ice rather than lava.) The Kiladze crater, which is 27 miles wide, appears to be mostly water ice. Yet it's surrounded by a vast surface of methane ice. In addition, its distorted shape and faulted structures support the idea that it's the caldera of a supervolcano.

Venus isn't a dead planet.
Venus, hidden in clouds and very unwelcoming, hasn't seemed to suggest it was now nothing but a dead planet. However, making use of surface data, scientists have found volcanic structures that seem to have been fairly recently active. And probably still are. It doesn't make Venus inviting, but shows that it may well still be a tectonically dynamic planet.

JWST
The James Webb Space telescope has already shown us distant galaxies and exoplanet atmospheres. It has outdone old favorites of some of the nebulae that have wowed us with Hubble images. And the Solar System has been examined in ways we hadn't seen before. I can't choose from this amazing output. I can only agree with those who've said that the James Webb Space Telescope findings changed our understanding of the universe in 2023.