Space
Biggest marsquake detected is record-breaker
Researchers released new details about the largest marsquake recorded so far. At magnitude 4.7, it was 5 times stronger than the previous largest known quake.
Human World
Spaceflight
SWOT mission to survey Earth’s water
NASA's Surface Water and Ocean Topography - SWOT - satellite launched on December 16. It's an international mission to observe water on Earth's surface.
Sun

Sun activity: Solar wind arrived, geomagnetic storm likely

Sun activity for December 20: High-speed solar wind from a coronal hole is impacting Earth. A G1 (minor) storm is expected tonight and early tomorrow.
Tonight

Moon near Crown of Scorpius December 21

A waning crescent moon - glowing beautifully with earthshine - joins the three stars that make up the Crown of Scorpius on the morning of December 21, 2022.
Tonight

Year’s shortest season starts at December solstice

The year's shortest season - between the December solstice and March equinox - is about 89 days. It's 5 days shorter than the longest season.
Astronomy Essentials

Meteor shower guide: Next up, the Ursids

Your meteor shower guide for the end of 2022. Plus look ahead to 2023. There are some good ones! Next up ... the Ursids followed by the January Quadrantids.
Astronomy Essentials

2022 December solstice: All you need to know

The 2022 December solstice will fall on December 21. Northern Hemisphere's shortest day. Southern Hemisphere's longest day. Happy solstice to all!
Astronomy Essentials

Comet C/2017 K2 is closest to the sun Dec 19

Comet C/2017 K2 (PanSTARRS) reaches its closest point to the sun - perihelion - on December 19, 2022. It's now a target for southern skies.
Constellations

Meet Pisces the Fish, 1st constellation of the zodiac

Pisces the Fish is a zodiac constellation that is high in the sky on December evenings. Look for it and its asterism, the Circlet of Pisces.
Tonight

Longest days accompany the December solstice

The longest days accompany the winter solstice. In December, a day - a whole cycle of day and night - is about half a minute longer than the average 24 hours.