APOD: 2023 June 29 Б A Message from the Gravitational Universe
29.06.2023

Monitoring 68 pulsars with very large radio telescopes, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has uncovered evidence for the gravitational wave (GW) background by carefully measuring slight shifts in the arrival times of pulses. These shifts are correlated between different pulsars in a way that indicates that they are caused by GWs.

APOD: 2024 March 6 Б M102: Edge on Disk Galaxy
6.03.2024

What kind of celestial object is this? A relatively normal galaxy -- but seen from its edge. Many disk galaxies are actually just as thin as NGC 5866, the Spindle galaxy, pictured here, but are not seen edge-on from our vantage point. A perhaps more familiar galaxy seen edge-on is our own Milky Way galaxy.

APOD: 2023 November 28 Б Ganymede from Juno
28.11.2023

What does the largest moon in the Solar System look like? Jupiter's moon Ganymede, larger than even Mercury and Pluto, has an icy surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges.

APOD: 2024 December 30 Б M27: The Dumbbell Nebula
30.12.2024

Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets.

APOD: 2025 November 23 Б The Observable Universe
23.11.2025

How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe. In light...

APOD: 2024 April 1 Б Swirling Magnetic Field around Our Galaxys Central Black Hole
1.04.2024

What's happening to the big black hole in the center of our galaxy? It is sucking in matter from a swirling disk -- a disk that is magnetized, it has now been confirmed. Specifically, the black hole's accretion disk has recently been seen to emit polarized light, radiation frequently associated with a magnetized source.

APOD: 2024 June 23 Б The Colors of Saturn from Cassini
23.06.2024

What creates Saturn's colors? The featured picture of Saturn only slightly exaggerates what a human would see if hovering close to the giant ringed world. The image was taken in 2005 by the robot Cassini spacecraft that orbited Saturn from 2004 to 2017.

APOD: 2025 March 25 Б A Blue Banded Blood Moon
25.03.2025

What causes a blue band to cross the Moon during a lunar eclipse? The blue band is real but usually quite hard to see. The featured HDR image of last week's lunar eclipse, however -- taken from Norman, Oklahoma (USA) -- has been digitally processed to exaggerate the colors.

APOD: 2024 May 15 Б AR 3664 at the Suns Edge
15.05.2024

What did the monster active region that created the recent auroras look like when at the Sun's edge? There, AR 3664 better showed its 3D structure. Pictured, a large multi-pronged solar prominence...

APOD: 2025 August 27 Б WISPIT 2b: Exoplanet Carves Gap in Birth Disk
27.08.2025

That yellow spot -- what is it? It's a young planet outside our Solar System. The featured image from the Very Large Telescope in Chile surprisingly captures a distant scene much like our own Solar System's birth, some 4.5 billion years ago.