ICYMI: If theories about this opaline silica are correct, this could be a huge discovery.

ICYMI: After years of unwarranted hype and dubious experimental claims, the EmDrive received its first peer-reviewed paper.

The change of seasons is bringing a change of stars, too — but there are still a few summer stragglers waiting for you tonight.

From the Archives: Go behind the scenes of The Martian.

ICYMI: This discovery could bring us a step closer to understanding how galaxies form.

ICYMI: The largest object in the asteroid belt is a crash course in weird dwarf planet behaviors.

ICYMI: Hunting for ET now involves Dyson spheres, infrared signals, and laser communications.

ICYMI: New Hidden Figures trailer shows what the women go through to achieve the impossible.

Algol will doom and brighten all through the night tonight.

ICYMI: Pluto may be the latest place in the solar system to show evidence of liquid water.

ICYMI: New research suggests an environment too dry beyond simple water vapor to exist.

This beginners guide to picking out your telescope could be a great gift for the new observer.

Save up to 50% on Astronomy back issues and special issues + doorbuster deals!

A quirk of perspective will make Callisto seem a little off track from Jupiter tonight.