Astronomy Picture Of the Day (APOD)APOD: 2023 January 30 Б Globular Star Cluster NGC 6355 from Hubble
Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are less than 200 left. Over the eons, many globular clusters were destroyed by repeated fateful encounters with each other or the Galactic center.
APOD: 2023 January 29 Б Barnard 68: Dark Molecular Cloud
Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars.
Comet ZTF over Mount Etna
Comet-like plumes are blowing over the volcanic peaks of Mount Etna in this wintry mountain-and-skyscape from planet Earth. The stacked and blended combination of individual exposures recorded during the cold night of January 23, also capture naked-eye Comet ZTF just above Etna's snowy slopes.
Comet ZTF: Orbital Plane Crossing
The current darling of the northern night, Comet C/2022 E3 ZTF is captured in this telescopic image from a dark sky location at June Lake, California. Of course Comet ZTF has been growing brighter in recent days, headed for its closest approach to Earth on February 1.
Active Galaxy NGC 1275
Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission.
APOD: 2023 January 25 Б LDN 1622: The Boogeyman Nebula
To some, the dark shape looks like a mythical boogeyman. Scientifically, Lynds' Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only visible in long telescopic exposures of the region.
APOD: 2023 January 24 Б LHS 475 b: Earth Sized Exoplanet
If you could stand on exoplanet LHS 475 b, what might you see? No one knows for sure but pictured here is an interesting guess made by an Earth-based artificial intelligence (AI) engine.
APOD: 2023 January 23 Б The Colliding Spiral Galaxies of Arp 274
Two galaxies are squaring off in Virgo and here are the latest pictures. When two galaxies collide, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small fraction of that space.
APOD: 2023 January 22 Б In Green Company: Aurora over Norway
Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.
Naked Eye Comet ZTF
Comet C/2022E3 (ZTF) is no longer too dim to require a telescope for viewing. By January 19, it could just be seen with the naked eye in this rural sky with little light pollution from a location about 20 kilometers from Salamanca, Spain.