Top 10 Astronomy News Stories of 2023

This year, we heard the low hum of gravitational waves criss-crossing the cosmos, observed a "ring of fire" solar eclipse, and applauded the arrival of asteroid samples. And, even as the James Webb Space Telescope and several solar system explorers continue to shape the science of astronomy, amateur astronomers and their ever at-the-ready scopes are making significant contributions.

Here are Sky & Telescope's picks for the top news stories in astronomy this year.

1. Detection of the Gravitational-Wave Background

The top news story of the year might also be its most esoteric. In an ingenious technique developed over decades, astronomers used the signals from pulsars all across the Milky Way to look for the infinitesimal squeezing and stretching of space due to criss-crossing ripples in spacetime. And this year, they finally found it: A low and quiet hum of gravitational waves, probably coming from supermassive black hole binaries near and far.

2. October's Annular Solar Eclipse Dazzles Americas

Sky & Telescope editors and contributing editors reported on the annular solar eclipse of October 14th from locations across the U.S. and Mexico. Observers across Americas felt the temperature drop, heard birds grow restless, watched light turn an eerie silver, and then watched as the Moon briefly centered itself in the Sun's blazing disk. As Editor in Chief Peter Tyson put it: "Something awesome was taking place and we were gratefully there to witness it."

Now we're anticipating the next eclipse, this one the total solar eclipse on April 8, 2024.

3. JWST Turns Up Unexpected Results in Early Universe

At an astronomy conference that opened the year, astronomers announced a surprising find in James Webb Space Telescope data: The early universe seemed to host more and bigger galaxies than astronomers had expected, calling into question either our understanding of galaxy formation, of dust formation, or of cosmology itself. While some initially doubted the extreme distances of the galaxies involved, results published later in the summer backed them up. Understanding what it all means awaits another year . . .

4. Asteroid Sample Return, Plus Lucy's Double-Surprise Flyby

On September 24, 2023, a capsule from NASA's Osiris-REX mission returned pieces of the asteroid 101955 Bennu safely to Earth. NASA’s first collection of a pristine asteroid sample was so successful that at first scientists had some trouble even accessing the sample. But study is now well underway to understand the role of carbonaceous chondrite asteroids in Earth's formation.

That wasn't the only big asteroid news of the year. In a bonus on November 1st, NASA's Lucy flew by the first asteroid of its mission. Images downlinked to Earth turned up a double surprise — not only did 152830 Dinkinesh have a moon, its moon was itself a contact binary.

5. A Re-Forecast for the Sun's Activity

Observers and scientists alike have been noticing that the number of sunspots, solar eruptions, and aurorae are more numerous than expected from a 2019 forecast. In response to the unexpected activity, the Space Weather Prediction Center has issued a new, experimental forecast, which predicts an earlier, stronger peak in the Sun's activity — now roughly coinciding with the the April 8, 2024, total solar eclipse!

6. Attention on Light Pollution

A number of results on artificial light at night — both on the ground and in our skies — have gained the public's attention this year. Among them, a study found that light pollution is increasing even faster than we thought it was, while another study found that not even remote observatories are safe.

Satellites, too, are a growing problem for the Hubble Space Telescope, for radio observatories, and a particularly bright one known as BlueWalker 3 could severely affect even the most casual observers. It's not all bad news, though: SpaceX's Starlink company is making efforts to mitigate their satellites' brightness, and they're working. Larger policy changes may also help other companies follow suit.

7. Scientists Finally Find Active Volcanism on Venus

After decades of searching, scientists have finally found a clear sign of active volcanism on Venus. A new analysis of decades-old data from NASA's Magellan orbiter caught a change in the shape and depth of an apparently active caldera. We've long known that volcanism has completely resurfaced Venus in the recent past; now, we finally have evidence that it's still happening. The find will also inform future missions, which will know better what to look for when they arrive at our secretive sister planet.

8. Successful Launches and Moon Landings

Three nations attempted to land on the Moon this past year, and one succeeded: India's Chandrayaan 3 set down in the lunar south pole on August 23rd. Russia's Luna 25 lander and Japan's Hakuto R lander crashed, however.

Meanwhile, three successful launches marked a great year for planetary science and astronomy in space. NASA's Psyche mission is now on its way to a metallic asteroid, ESA's JUICE mission is en route to Jupiter, and another just-launched ESA mission, Euclid, is already returning spectacular first images.

9. No Atmosphere on Exoplanets Trappist-1b and c

The promising septuplet system of rocky planets around the nearby red dwarf star Trappist-1 disappointed this year, with two sets of JWST data turning up no air at all on Trappist-1b and only a small chance of atmosphere on Trappist-1c. However, even if both inner planets end up being airless, that doesn't spell doom for the system as a whole. Time will tell what Webb will find for the five more temperate outer planets.

10. Amateur Contributions to Astronomy

This was an especially active year for amateur astronomers contributing to science. In 2023 amateurs helped uncover a strange supernova, aided the tracking of asteroids Didymos and Dimorphos following the DART probe's crash, found another asteroid's moon, noticed new dwarf galaxies, provided insight into Venus's atmosphere, and even discovered a glowing green arc near Andromeda that still defies explanation.

Click through the links above to read about each of these incredible amateur contributions! Even more results are incoming, as amateur astronomers recently contributed to a rare occultation of Betelgeuse on December 12th — those observations await analysis.

Honorable Mentions

While big results become big news, sometimes it's the cosmic oddballs that garner attention. We thought these particular oddities (in no particular order) were worthy of note in this year's round-up. Click the links to learn more about what makes these objects odd, and important too.

• First Exo-Trojan
• Mysteriously Slow Pulsar
• Ghost-like Galaxy
• Jekyll-Hyde White Dwarf
• Sand-cloud Exoplanet
• Quaoar's Weird Rings (And while we're at it, those rings around Chiron are pretty strange, too)

What's your pick for top stories of the year? Tell us in the comments below.