EarthSky | Updates on your cosmos and world

Mars’ southern hemisphere is unusually hot deep underground

September 4, 2026

Sun news: More action from returning sunspot region

Sun news September 4, 2026: Returning region AR4524 fired an M1.2 flare. Its last pass across the Earth-viewed sun was promising, so stronger flares may follow.

C. Alex Young

September 4, 2026

Constellations

Cassiopeia the Queen ascends in September and October

Cassiopeia the Queen is an easy-to-find constellation. It has the shape of a W or M. Look for it in the north-northeast sky on September and October evenings.

Editors of EarthSky

September 4, 2026

Space

Saturn’s south pole decagon confirmed! A mysterious 10-sided figure

Saturn’s south pole is now known to have a giant, evolving 10-sided wave, similar to the Saturn north pole hexagon. Read more about it here.

EarthSky Voices

September 3, 2026

Earth

Today's Image

Hurricane triplets spin across the Pacific Ocean

Rare hurricane triplets are currently spinning across the Pacific Ocean: Lowell, Karina and Marie. Did El Niño play a part? Find out here.

Kelly Kizer Whitt

September 3, 2026

Space

BepiColombo mission 1 step closer to Mercury today

The BepiColombo mission has been maneuvering its way into orbit around Mercury for 8 years. On September 3, it successfully released 2 orbiters.

Kelly Kizer Whitt

September 3, 2026

Space

Giant mega-Earth is 23 times more massive than Earth

Astronomers have discovered a new giant mega-Earth exoplanet that is a whopping 23 times as massive as Earth and 2.5 times its diameter.

Paul Scott Anderson

September 3, 2026

Astronomy Essentials

Tonight

Visible planets and night sky guide for September

Visible planets and night sky guide: Jupiter is back, and the waning gibbous moon hangs near the Pleiades. Watch a video about September's best sky sights.

September 3, 2026

Corona Australis is the sparkling Southern Crown

Corona Australis is a dim constellation lying below the Teapot asterism of Sagittarius. Its sparkling, curving shape befits its name.

Kelly Kizer Whitt

September 3, 2026

Space

Roman space telescope has launched! You can adopt a pixel

The Nancy Grace Roman Space Telescope launched on August 30 from the Kennedy Space Center. Want to add your name to a pixel? Find out how here!

Editors of EarthSky

September 2, 2026

Earth

Lake Powell hits record low, continues to drop

Lake Powell has hit its lowest level ever. Despite the monsoons, like the flash floods that hit Grand Canyon over the weekend, water levels continue to drop.

Kelly Kizer Whitt

September 2, 2026