I really love this site and 
this is an awesome photo!
Kind of makes me realize how
small this planet Earth is....
Joe

Astronomy Picture of the Day

Explanation: Yes, but can your rainbow do this? After the remnants of Hurricane Florence passed over the Jersey Shore, New Jersey, USA in 2018, the Sun came out in one direction but something quite unusual appeared in the opposite direction: a hall of rainbows. Over the course of the next half hour, to the delight of the photographer and his daughter, vibrant supernumerary rainbows faded in and out, with at least five captured in this featured single shot. Supernumerary rainbows only form when falling water droplets are all nearly the same size and typically less than a millimeter across. Then, sunlight will not only reflect from inside the raindrops, but interfere, a wave phenomenon similar to ripples on a pond when a stone is thrown in. In fact, supernumerary rainbows can only be explained with waves, and their noted existence in the early 1800s was considered early evidence of light's wave nature.

Explanation: A deep image of the Sombrero galaxy reveals surprises. M104 is named the Sombrero galaxy because, on shorter exposures, it looks like a hat. A key defining feature of this huge galaxy is a dark brim of dust that circles the disk galaxy's center. A much longer exposure, however, brings up a hairy past where a bright, hazy halo is revealed that extends well past the central disk and contains many unresolved stars. Surprisingly, in this stellar haze, structures can be seen that include a diagonal ring. These structures and tidal streams provide fresh evidence that M104 had a violent past and is surely the result of collisions and mergers of smaller galaxies. Light takes about 30 million years to reach us from the Sombrero galaxy, which fully spans about 150 thousand light years across. The featured image was taken over seven days in mid-2026 from Namibia.

Explanation: Have you ever seen a complete auroral oval? You can't see one from the ground because it makes too large a circle around one of Earth's magnetic poles. But spacecraft high above the Earth can see them. The featured video from ESA and CAS's robotic SMILE spacecraft shows not only a full auroral oval, but using ultraviolet light, one that occurred during the day. The time-lapse covers about an hour in late July and shows visually how variable and turbulent auroras really are. The points of light on the sides are distant stars that appear to move only because SMILE's camera view shifts as the spacecraft orbits the Earth. A goal of SMILE is to better understand how the Sun's wind interacts with the Earth's magnetosphere -- and so better understand how to protect astronauts, spacecraft, and ground-based electrical grids from solar storms.

Explanation: "Happy New Year!" No, wait, this is not a fireworks display. This image shows Nebula Pa 30, observed with the Gemini North Telescope in Hawai'i. It is likely the remnant of an old supernova explosion: separate historical records by Chinese, Japanese and Arabic astronomers tell of a "guest star" that appeared in the sky for 185 days in the year 1181. It is believed that this bright new point of light came from the supernova that caused the fireworks in Pa 30. Astronomers don't know exactly what happened in this unusual explosion, classified as a Type Iax supernova, but it is thought to be caused by the merger of two white dwarfs. The mysterious central star in the image is extremely hot and produces a strong wind, possibly forming the radial filaments. Look closely at them: those pearl-like knots stringing the filaments are 4 light-days in diameter. Understanding how a supernova created this amazing nebula continues an 845-year old mystery (and counting).

Tomorrow's picture: smörgåsbord

Explanation: How was the Saturn system imaged so clearly? Astrophotographer Tom Williams captured such exquisite details due to one night of exceptional atmospheric conditions above the United Kingdom. This means more than a cloudless sky. Pockets of air at different temperatures and densities move around and bend light as it travels through Earth’s atmosphere, distorting astronomy images. This is called “seeing.” Less atmospheric turbulence means clearer images. The astrophotographer reduced the impact of seeing with the lucky imaging technique: thousands of short-exposure images are taken very quickly with a high-speed camera and the clearest images are added up. Which object in this smörgåsbord interests you? Perhaps Titan or the icy stripes of Enceladus? Maybe the gaps and spokes in Saturn’s rings? Saturn's opposition, when Earth passes in between the planet and the Sun, occurred on October 4th. Due to the planet's proximity and full illumination from the Sun, now is a great time of year to observe it!

Explanation: 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. Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon. This enhanced-color image of Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometers of Phobos in March of 2008. Even though the surface gravity of asteroid-like Phobos is less than 1/1000th Earth's gravity, streaks suggest loose material slid down inside the crater walls over time. Light bluish regions near the crater's rim could indicate a relatively freshly exposed surface. The origin of the curious grooves along the surface is mysterious but may be related to tidal stresses experienced by close-orbiting Phobos or the crater-forming impact itself.

Explanation: Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth. From lunar orbit, the Moon's farside can become familiar, though. In fact this sharp picture, a mosaic from the Lunar Reconnaissance Orbiter's wide angle camera, is centered on the lunar farside. Part of a global mosaic of over 15,000 images acquired between November 2009 and February 2011, the highest resolution version shows features at a scale of 100 meters per pixel. Surprisingly, the rough and battered surface of the farside looks very different from the nearside covered with smooth dark lunar maria. A likely explanation is that the farside crust is thicker, making it harder for molten material from the interior to flow to the surface and form dark, smooth maria.

Explanation: Scientists are melting holes in the bottom of the world. In fact, almost 100 holes melted near the South Pole are now being used as an astronomical observatory. Astronomers with the IceCube Neutrino Observatory lowered a long string knotted with basketball-sized light detectors into each vertical lake. The water in each hole soon refreezes. The detectors attached to the strings are sensitive to blue light emitted in the surrounding clear ice. Such light results from fast-moving secondary particles liberated when high-energy neutrinos emitted by powerful processes out in the universe collide with ice molecules. IceCube has now detected many illuminating neutrinos. Pictured in 2010, one of the last of IceCube's detector strings is lowered into the freezing abyss, making IceCube the largest neutrino detector ever created. In recognition of unprecedented discoveries, it was announced earlier this week that a founding leader of the IceCube Collaboration will be awarded the Nobel Prize in Physics.

Explanation: How many moons can you see? The best answer is five: four orbiting Jupiter and Luna orbiting Earth. This multi-moon picture was possible because Earth's Moon moved directly in front of Jupiter last week. The featured image is a series of exposures near alignment taken from Westchester, New York, USA. The sunlit crescent of Earth's Moon, on the lower left, is overexposed, while the Moon's night side, on the upper right, is faintly illuminated by Earthshine. Lined up nearly vertically above our Moon, listed from bottom to top, are Jupiter's bright Galilean satellites: Ganymede, Io, Callisto, and Europa. Callisto, Ganymede, and Io are larger than Earth's Moon, while Europa is only slightly smaller. NASA's robotic spacecraft Juno is currently orbiting Jupiter and has made close passes near three of these moons.

Explanation: This stairway in Chile brings you only a little bit closer to heaven. But ooh, the sky above it makes you wonder. For example, you may wonder about the dark lane of our own Milky Way galaxy rising behind the expansive Atacama Desert in Chile, the band of zodiacal light on the upper left, the green and red airglow just above the horizon, the star Spica in the zodiacal light stripe, and, at the very top on the right, the Small Magellanic Cloud galaxy. The Desert Staircase sculpture is in the foreground, and this image was timed to catch the picturesque peering perch just in front of the near-vertical Milky Way band. Upon close inspection of the horizon you can find, left to right, some Andes Mountains, the Licancabur volcano, and the town lights of San Pedro de Atacama. The featured wide-angle composite was captured in July 2025.

Explanation: What a cosmic coincidence! In today’s image, Mars joins the Beehive cluster (M44 or Praesepe) below an auroral curtain and above a horizon of happy little trees near Lansjärv, Sweden. An eruption off the Sun reached Earth on October 10th, 2026 causing strong disturbances in Earth’s magnetic field. Energetic particles from the eruption collide with and energize the molecules in Earth’s atmosphere, which release that extra energy as the colorful aurora captured here. Auroras, or guovssahasat in North Sámi, is traditionally viewed with respect by the Sámi people indigenous to Sweden and other Arctic regions. Coincidentally, Mars appeared closest to the center of the Beehive cluster in the sky at the time. Although bees have been to space, the Beehive cluster is actually a swarm of young stars. Their rotation periods have helped humanity learn about how stars spin slower over time as they lose mass through their stellar winds.

Explanation: The city lights outshine the stars in the City That Never Sleeps. Who would have thought that the Milky Way could be visible in this sky? This image was taken with a filter that blocks most visible light, capturing instead only light in the near-infrared region of the electromagnetic spectrum (with lower energy than visible light). The astrophotographer's clever setup blocks most of the light pollution from the city: old incandescent light bulbs and some neon lights are still bright in the near-infrared, but fluorescent and LED light bulbs are not. Of course, stars are also bright in the near-infrared! This image is a reminder that we all live under the same sky, and astronomy allows all of us to learn more about humanity's place in the Cosmos.

Explanation: Blasting into the predawn sky on Tuesday, October 13, a Falcon 9 rocket and Dragon spacecraft are headed for low Earth orbit in this stunning timelapse video captured from Indian Harbour Beach, Florida. Starting with a launch from Space Launch Complex 40 at Cape Canaveral Space Force Station, Falcon and Dragon are chasing the International Space Station on NASA's 35th Commercial Resupply Services mission. On cue, the space station itself enters the frame from the top. Almost 8 seconds into the 30 second timelapse. the bright streak of the ISS appears heading "down" toward the horizon. The first and second stages of the Falcon 9 are separating as the spectacular exhaust plume jellyfish grows, already catching the light of the rising Sun. The visible sequence of first stage boost back, re-entry, and landing burns begins around 20 seconds into the video. With the second stage following the ISS toward the distant horizon, the jellyfish plume continues to drift in the predawn sky, even after the successful first stage landing at planet Earth's Landing Zone 40.