APOD: 2020 August 25 Б Visualization: A Black Hole Accretion Disk
24.08.2020

What would it look like to circle a black hole? If the black hole was surrounded by a swirling disk of glowing and accreting gas, then the great gravity of the black hole would deflect light emitted by the disk to make it look very unusual. The featured animated video gives a visualization.

APOD: 2025 June 29 Б Dark Sand Cascades on Mars
28.06.2025

Are these trees growing on Mars? No. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The featured image was taken in 2008 April near the North Pole of Mars.

620 Kilometers Above Rhea
12.12.2005

What does the surface of Saturn's moon Rhea look like? To help find out, the robot Cassini spacecraft currently orbiting Saturn was directed to fly right past the second largest moon of the gas giant planet late last month.

3D Mercury Transit
24.11.2006

Mercury is now visible shortly before dawn, the brightest "star" just above the eastern horizon. But almost two weeks ago Mercury actually crossed the face of the Sun for the second time in the 21st century.

Earthshine and Venus Over Sierra de Guadarrama
28.03.2012

What just above that ridge? The Moon. Specifically, the Earth's Moon was caught just above the horizon in a young crescent phase. The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth.

Golden Gate Sunset: Green Flash
1.12.2015

The setting is San Francisco Bay, the time is sunset, and the bridge is the Golden Gate. What you are about to see is an unexpected double sunset ending with a rare green flash.

Crescent Enceladus
8.03.2019

Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured during November 2016 as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent.

Daphnis and the Rings of Saturn
2.11.2019

What's happening to the rings of Saturn? A little moon making big waves. The moon is 8-kilometer Daphnis and it is making waves in the Keeler Gap of Saturn's rings using just its gravity -- as it bobs up and down, in and out.

The Einstein Cross Gravitational Lens
16.10.2021

Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar.

Tutulemma: Solar Eclipse Analemma
21.08.2016

If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun's position change? With great planning and effort, such a series of images can be taken. The figure-8 path the Sun follows over the course of a year is called an analemma.