Astronomy Picture Of the Day (APOD)Stickney Crater
Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877.
The Double Cluster in Perseus
This pretty starfield spans about three full moons (1.5 degrees) across the heroic northern constellation of Perseus. It holds the famous pair of open star clusters, h and Chi Persei. Also cataloged...
Fireworks vs Supermoon
On July 4, an almost Full Moon rose in planet Earth's evening skies. Also known as a Buck Moon, the full lunar phase (full on July 3 at 11:39 UTC) was near perigee, the closest point in the Moon's almost monthly orbit around planet Earth.
APOD: 2023 July 5 Б A Map of the Observable Universe
What if you could see out to the edge of the observable universe? You would see galaxies, galaxies, galaxies, and then, well, quasars, which are the bright centers of distant galaxies. To expand understanding...
APOD: 2023 July 4 Б Aurora over Icelandic Waterfall
It seemed like the sky exploded. The original idea was to photograph an aurora over a waterfall. After waiting for hours under opaque clouds, though, hope was running out. Others left. Then, unexpectedly, the clouds moved away.
APOD: 2023 July 3 Б Venus in Ultraviolet from Akatsuki
Why is Venus so different from Earth? To help find out, Japan launched the robotic Akatsuki spacecraft which entered orbit around Venus late in 2015 after an unplanned five-year adventure around the inner Solar System.
APOD: 2023 July 2 Б Milky Way and Aurora over Antarctica
It was one of the better skies of this long night. In parts of Antarctica, not only is it winter, but the Sun can spend weeks below the horizon. At China's Zhongshan Station, people sometimes venture out into the cold to photograph a spectacular night sky.
Three Galaxies in Draco
This tantalizing trio of galaxies sometimes called the Draco Group, is located in the northern constellation of (you guessed it) Draco, the Dragon. From left to right are face-on spiral NGC 5985, elliptical galaxy...
APOD: 2023 June 30 Б Orbits of Potentially Hazardous Asteroids
Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on Earth.
APOD: 2023 June 29 Б A Message from the Gravitational Universe
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.