Astronomy Picture Of the Day (APOD)APOD: 2023 October 15 Б An Eclipse Tree
Yes, but can your tree do this? If you look closely at the ground in the featured image, you will see many images of yesterday's solar eclipse -- created by a tree. Gaps between...
Circular Sun Halo
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.
Hydrogen Clouds of M33
Gorgeous spiral galaxy Messier 33 seems to have more than its fair share of glowing hydrogen gas. A prominent member of the local group of galaxies, M33 is also known as the Triangulum Galaxy and lies a mere 3 million light-years away.
Mu Cephei is a very large star. An M-class supergiant some 1500 times the size of the Sun, it is one of the largest stars visible to the unaided eye, and even one of the largest in the entire Galaxy.
APOD: 2023 October 11 Б NGC 1097: Spiral Galaxy with Supernova
What's happening in the lower arm of this spiral galaxy? A supernova. Last month, supernova SN 2023rve was discovered with UAE's Al-Khatim Observatory and later found to be consistent with the death explosion of a massive star, possibly leaving behind a black hole.
APOD: 2023 October 10 Б Hidden Orion from Webb
The Great Nebula in Orion has hidden stars. To the unaided eye in visible light, it appears as a small fuzzy patch in the constellation of Orion. But this image was taken by the Webb Space Telescope in a representative-color composite of red and very near infrared light.
APOD: 2023 October 9 Б A Distorted Sunrise Eclipse
Yes, but have you ever seen a sunrise like this? Here, after initial cloudiness, the Sun appeared to rise in two pieces and during a partial eclipse in 2019, causing the photographer to describe it as the most stunning sunrise of his life.
APOD: 2023 October 8 Б Plane, Clouds, Moon, Spots, Sun
What's that in front of the Sun? The closest object is an airplane, visible just below the Sun's center and caught purely by chance. Next out are numerous clouds in Earth's atmosphere, creating a series of darkened horizontal streaks.
The Once and Future Stars of Andromeda
This picture of Andromeda shows not only where stars are now, but where stars will be. The big, beautiful Andromeda Galaxy, M31, is a spiral galaxy a mere 2.5 million light-years away. Image data...
Edwin Hubble Discovers the Universe
How big is our universe? This question, among others, was debated by two leading astronomers in 1920 in what has since become known as astronomy's Great Debate. Many astronomers then believed that our Milky Way Galaxy was the entire universe. Many others, though, believed that our galaxy was just one of many.