Artist's impression of a telescopic view of a lunar occultation of Mars. Credit: ESO/Nico Bartmann/spaceengine.org. [Scientific American]

It's been another exciting year for astronomy and space – here are my choices for the top stories from 2022.

JWST
Christmas day 2021 saw the launch of NASA's James Webb Space Telescope, a project over three decades in the making. A big event, but this was just the beginning. In 2022, JWST made its way to the second Lagrange point where it was set up and put through its paces. One of its test targets was the “Pillars of Creation”, a star-forming region in the Eagle Nebula. The Hubble Space Telescope version of this region is well known, but have a look at the JWST version of the Pillars. Breathtaking.

Double Asteroid Redirection Test (DART)
NASA crashed a spacecraft into the asteroid Dimorphos. In the past, small asteroids have collided with Earth and caused notable destruction. But might it be possible that an asteroid headed our way could be nudged into a new trajectory bypassing Earth? A few weeks after DART, astronomers could see that the path of Dimorphos had been changed. It looks like this is a technology worth developing.

Lunar eclipse with occultation of Mars
In a total lunar eclipse, the Sun, Earth and Moon are aligned, blocking direct sunlight to the Moon. On December 7, a lunar eclipse was accompanied by an occultation of Mars. Not only were the Sun, Earth and Moon aligned, but Mars was at opposition. That means it was positioned directly between the Sun and the Earth. And since the Moon was also in the alignment for a time, it hid Mars. This is called an occultation.

Ingenuity
NASA's Perseverance rover didn't go alone to Mars in 2021. It carried the robotic helicopter Ingenuity with it. This was an experiment. Would the aircraft fly in the thin Martian atmosphere? It did, making the first ever flight of a robotic craft on another world. But the test flights weren't the end of the story. In 2022 Ingenuity set further distance and altitude records. And more importantly, it's been supporting Perseverance as the rover’s aerial scout. It has flown over areas deemed too dangerous for the rover, as well as surveying potential future destinations.

Back to the Moon
NASA's Artemis program aims to put humans on the Moon. It took three tries of the Space Launch System (SLS) to get a successful Moon launch. But on November 16 the Orion spacecraft was on its way. It made its way around the Moon and back to Earth, having tested the rocket and the crew capsule. Orion safely re-entered Earth's atmosphere on December 11, and the capsule splashed down off the coast of Mexico's Baja Peninsula. The next trip is expected to be crewed.

Tiangong
Tiangong means "heavenly palace," and its spacefarers are called taikonauts. In October, China added the final module to its space station Tiangong. Its low-Earth orbiting laboratory is now complete. It's intended to be a place where scientists will conduct research in microgravity, much like astronauts at the International Space Station.

Earendel
The most distant star ever observed was discovered by the Hubble Space Telescope, the results reported in March. It existed only 900 million years after the Big Bang, and its light has travelled nearly 28 billion years to reach us. Its host galaxy is called the Sunrise Arc because its light is distorted by gravity into a crescent arc. Gravitational lensing of the galaxy makes it possible to see the star at the edge of it. The star is at least 50 – and as much as 500 – times the mass of the Sun, and millions of times brighter. It's been named Earendel, old English for morning star or rising light. Fans of JRR Tolkien may also recognise the name in The Silmarillion. [Image processing: NASA/ESA/Alyssa Pagan (STScI)]

Sgr A* – the black hole
Sagittarius A* [Sgr A*] is the supermassive black hole at the center of the Milky Way. It's over four million times the mass of the Sun. The Event Horizon Telescope (EHT) is an array of eight combined radio observatories. It imaged Sgr A* in 2017, but the final image was released in 2022. The event horizon is the boundary of the black hole where light can't escape. So although we can't see the event horizon, we can see a dark central region surrounded by a bright ringlike structure.

5000 exoplanets
In 2022, NASA announced that over 5000 confirmed exoplanets had been discovered. The very first exoplanet discovered orbiting a main sequence star was in 1995. The planet was much bigger than Jupiter, but it was orbiting its Sun-like star eight times closer than Mercury is to the Sun.

With regard to the exoplanets since discovered, NASA's Jet Propulsion Laboratory said: "The 5,000-plus planets found so far include small, rocky worlds like Earth, gas giants many times larger than Jupiter, and ‘hot Jupiters’ in scorchingly close orbits around their stars. There are ‘super-Earths,’ which are possible rocky worlds bigger than our own, and ‘mini-Neptunes,’ smaller versions of our system’s Neptune."