Anticrepuscular rays: How to see them

If you want to see anticrepuscular rays, look carefully opposite the direction of the sun. They are most often seen at sunrise or sunset.

Halloween is an astronomy holiday. It’s a cross-quarter day

A cross-quarter day falls between an equinox and a solstice. Halloween is the year's 4th cross-quarter day and the spookiest of the 4.

What was the Carrington Event, and why does it matter?

The Carrington Event of 1859 was a massive geomagnetic storm triggered by an active sun. People saw auroras at low latitudes bright enough to read by.

Solar eclipse photos keep coming, and they’re awesome

Solar eclipse photos from October 14, 2023, still haven't stopped coming in. Here are a few more great ones! Thanks to all who contributed.

New AI tool can help find alien life in the solar system

Researchers in the U.S. and Japan have developed a new AI technique that can determine if there is evidence for past or present life, or not, with 90% accuracy.

Happy Friday the 13th: It’s the 2nd one in 2023

When a year with 365 days starts on a Sunday, like 2023, it's inevitable Friday the 13th will occur twice. In 2023 Friday the 13th comes in January and October.

October birthstone: Colorful opal and tourmaline

Take your pick: the October birthstone is either the striking iridescent opal or the many-colored tourmaline. Learn the lore of these pretty gemstones here.

Bus-sized asteroid buzzed past Earth on Thursday

A bus-sized asteroid safely passed Earth less than 1/4 the distance to the moon at 12:52 UTC (7:52 am CDT) on October 12, 2023.

Biggest solar superstorm yet, glimpsed in ancient tree rings

Researchers analyzing tree rings discovered the biggest solar superstorm known so far. If it hit today, it would wreck some critical human infrastructure.

Argentina wildfire threatens city of Villa Carlos Paz

An Argentina wildfire was encroaching on the city of Villa Carlos Paz on October 11, 2023. Drone footage showed flames and a "wall of fire" near the city.