APOD: 2023 May 2 Б Flat Rock Hills on Mars
2.05.2023

Why are there so many flat rocks on Mars? Some views of plains and hills on Mars show many rocks that are unusually flat when compared to rocks on Earth. One reason for this is a process that is common to both Mars and Earth: erosion.

APOD: 2024 January 3 Б A SAR Arc from New Zealand
3.01.2024

What is that unusual red halo surrounding this aurora? It is a Stable Auroral Red (SAR) arc. SAR arcs are rare and have only been acknowledged and studied since 1954. The featured wide-angle photograph...

APOD: 2024 January 22 Б Shadows of Mountain and Moon
22.01.2024

Can the Moon and a mountain really cast similar shadows? Yes, but the division between light and dark does not have to be aligned. Pictured, a quarter moon was captured above the mountain Grivola in Italy in early October of 2022.

Blood Monster Moon
4.06.2021

On May 26, the Full Flower Moon was caught in this single exposure as it emerged from Earth's shadow and morning twilight began to wash over the western sky. Posing close...

Asteroid 1998 KY26
19.09.2002

A day is just under 11 minutes long on 1998 KY26, a 30 meter wide, fast-spinning, water-rich asteroid. This computer simulated view of its lumpy surface has a resolution of about 3 meters and is based on radar and optical observations (click on the image for a series of surface views).

Jupiter's Great Red Spot from Voyager 1
2.05.2011

It is a hurricane twice the size of the Earth. It has been raging at least as long as telescopes could see it, and shows no signs of slowing. It is Jupiter's Great Red Spot, the largest swirling storm system in the Solar System.

Tardigrade in Moss
26.03.2017

Is this an alien? Probably not, but of all the animals on Earth, the tardigrade might be the best candidate. That's because tardigrades are known to be able to go for decades without...

Lunar Eclipse over Cologne Cathedral
22.01.2019

Why would a bright full Moon suddenly become dark? Because it entered the shadow of the Earth. That's what happened Sunday night as the Moon underwent a total lunar eclipse. Dubbed by some...

Comet Hale Bopp Over Indian Cove
20.04.2004

Comet Hale-Bopp, the Great Comet of 1997, was quite a sight. No comets of comparable brightness have graced the skies of Earth since then. During this next month, however, even besides the fleeting Comet Bradfield, two comets have a slight chance of rivaling Hale-Bopp and a good chance of putting on a memorable sky show.

The Moon Eclipses Saturn
16.07.2014

What happened to half of Saturn? Nothing other than Earth's Moon getting in the way. As pictured above on the far right, Saturn is partly eclipsed by a dark edge of a Moon itself only partly illuminated by the Sun.