Novel Coronavirus Attacks Humanity
1.06.2020

Humanity is under attack. The attack is not from large tentacle-flailing aliens, but from invaders so small they can barely be seen, and so strange they are not even clearly alive. All over planet Earth, the human home world, DNA-based humans are being invaded by the RNA-based SARS-CoV2.

Iron in the Butterfly Nebula
20.07.2020

Can stars, like caterpillars, transform themselves into butterflies? No, but in the case of the Butterfly Nebula -- it sure looks like it. Though its wingspan covers over 3 light-years and its estimated surface temperature...

Circular Sun Halo
13.10.2023

Want to see a ring around the Sun? It's easy to do in daytime skies around the world. Created by randomly oriented ice crystals in thin high cirrus clouds, circular 22 degree halos are visible much more often than rainbows.

APOD: 2024 March 12 Б A Galaxy Shaped Rocket Exhaust Spiral
11.03.2024

What's that over the horizon? What may look like a strangely nearby galaxy is actually a normal rocket's exhaust plume -- but unusually backlit. Although the SpaceX Falcon 9 rocket was launched from...

APOD: 2025 September 10 Б The Great Lacerta Nebula
9.09.2025

It is one of the largest nebulas on the sky -- why isn't it better known? Roughly the same angular size as the Andromeda Galaxy, the Great Lacerta Nebula can be found toward the constellation of the Lizard (Lacerta).

APOD: 2026 July 7 Б NGC 6188: Dragons of Ara
6.07.2026

Where can you find dragons fighting in the night sky? In the southern constellation of the Altar: Ara. The dragons are, of course, actually made of suggestively shaped gas and dust. The celestial home...

A Leonid Meteor Over Sweden
20.11.2006

This past weekend, small remnant bits of a distant comet lit up the skies over much of planet Earth. Incoming reports, however, have this year's Leonid meteor shower as less active than Leonid meteor showers a few years ago.

Light Deposits Indicate Water Flowing on Mars
11.12.2006

What's creating light-toned deposits on Mars? Quite possibly -- water! Images of the same parts of mid-latitude Mars taken over the years but released only last week have shown unexpected new light-toned deposits where there were none before.

Colorful Airglow Bands Surround Milky Way
5.03.2018

Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

The Case of the Backwards Orbiting Asteroid
29.05.2018

Why does asteroid 2015 BZ509 orbit the Sun the backwards? As shown in the featured animation, Jupiter's trojan asteroids orbit the Sun in two major groups -- one just ahead of Jupiter, and one just behind -- but all orbit the Sun in the same direction as Jupiter.