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Explanation: The Rosette Nebula, NGC 2237, is not the only cosmic cloud of gas and dust to evoke the imagery of flowers, but it is probably the most famous. At the edge of a large molecular cloud in Monoceros some 5,000 light years away, the petals of this cosmic rose are actually a stellar nursery. The lovely, symmetric shape is sculpted by the winds and radiation from its central cluster of hot young, O-type stars. Stars in the energetic cluster, cataloged as NGC 2244, are only a few million years young, while the central cavity in the Rosette Nebula, is...

Explanation: Riding high in the constellation of Auriga, beautiful, blue VdB 31 is the 31st object in Sidney van den Bergh's 1966 catalog of reflection nebulae. It shares this well-composed celestial still life with dark, obscuring clouds B26, B27, and B28, recorded in Edward E. Barnard's 1919 catalog of dark markings in the sky. All are these nebulae are interstellar dust clouds. Barnard's dark nebulae block the light from background stars. For VdB 31 the dust preferentially reflects bluish starlight from embedded, hot, variable star AB Aurigae. Exploring the environs of AB Aurigae with the Hubble Space Telescope has revealed...

Explanation: What can a space rock tell us about life on Earth? NASA's OSIRIS-REx spacecraft made a careful approach to the near-Earth asteroid 101955 Bennu in October of 2020 to collect surface samples. In September 2023, the robotic spaceship returned these samples to Earth. A recent analysis has shown, surprisingly, that the samples contained 14 out of the 20 known amino acids that are the essential building blocks of life. The presence of the amino acids re-introduces a big question: Could life have originated in space? However, the protein building blocks themselves held another surprise -- they contained an even...

Explanation: Will the spider ever catch the fly? Not if both are large emission nebulas toward the constellation of the Charioteer (Auriga). The spider-shaped gas cloud in the image center is actually an emission nebula labelled IC 417, while the smaller fly-shaped cloud on the left is dubbed NGC 1931 and is both an emission nebula and a reflection nebula. About 10,000 light-years distant, both nebulas harbor young star clusters. For scale, the more compact NGC 1931 (Fly) is about 10 light-years across. The featured deep image, captured over 20 hours during late January in Berkshire UK, also shows more...

Explanation: Is this the largest hummingbird ever? Although it may look like a popular fluttering nectarivore, what is pictured is actually a beautifully detailed and colorful aurora, complete with rays reminiscent of feathers. This aurora was so bright that it was visible to the unaided eye during blue hour -- just after sunset when the sky appears a darkening blue. However, the aurora only looked like a hummingbird through a sensitive camera able to pick up faint glows. As reds typically occurring higher in the Earth's atmosphere than the greens, the real 3D shape of this aurora would likely appear...

Explanation: What strange world is this? Earth. In the foreground of the featured image are the Pinnacles, unusual rock spires in Nambung National Park in Western Australia. Made of ancient sea shells (limestone), how these human-sized picturesque spires formed remains unknown. In the background, just past the end of the central Pinnacle, is a bright crescent Moon. The eerie glow around the Moon is mostly zodiacal light, sunlight reflected by dust grains orbiting between the planets in the Solar System. Arching across the top is the central band of our Milky Way Galaxy. Many famous stars and nebulas are also...

Explanation: A waxing crescent Moon and a waning crescent Venus are found at opposite corners of this twilight telephoto field of view. The close conjunction of the two brightest celestial beacons in planet Earth's western evening sky was captured on February 1 from Rosario, Argentina. On that date, the slender crescent Moon was about 3 days old. But the Moon's visible sunlit crescent will grow to a bright Full Moon by February 14. Like the Moon, Venus cycles through phases as it orbits the Sun. And while its visible sunlit crescent narrows, the inner planet's apparent size increases as it...

Explanation: The giant galaxy cataloged as LEDA 1313424 is about two and a half times the size of our own Milky Way. Its remarkable appearance in this recently released Hubble Space Telescope image strongly suggests its nickname "The Bullseye Galaxy". Known as a collisional ring galaxy it has nine rings confirmed by telescopic observations, rippling from its center like waves from a pebble dropped into a pond. Of course, the pebble dropped into the Bullseye galaxy was a galaxy itself. Telescopic observations identify the blue dwarf galaxy at center-left as the likely collider, passing through the giant galaxy's center and...

Explanation: Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small, irregular galaxies form stars too. In fact dwarf galaxy IC 2574 shows clear evidence of intense star forming activity in its telltale reddish regions of glowing hydrogen gas. Just as in spiral galaxies, the turbulent star-forming regions in IC 2574 are churned by stellar winds and supernova explosions spewing material into the galaxy's interstellar medium and triggering further star formation. A mere 12 million light-years distant, IC 2574 is part of the M81 group of...

Explanation: Where is Comet ATLAS going? In the featured time-lapse video, the comet is not itself moving very much, but the Earth's rotation makes it appear to be setting over a hill. The Comet C/2024 G3 (ATLAS) sequence was captured with an ordinary camera on January 22 from the Araucanía Region in central Chile. Comet ATLAS has been an impressive site in the evening skies of Earth's Southern Hemisphere over the past few weeks, so bright and awe-inspiring that it may eventually become known as the Great Comet of 2025. Unfortunately, Comet G3 ATLAS is not going anywhere anymore because...

Explanation: Yes, but can your rainbow do this? Late in the day, the Sun set as usual toward the west. However, on this day, the more interesting display was 180 degrees around -- toward the east. There, not only was a rainbow visible, but an impressive display of anticrepuscular rays from the rainbow's center. In the featured image from Lekeitio in northern Spain, the Sun is behind the camera. The rainbow resulted from sunlight reflecting back from falling rain. Anticrepuscular rays result from sunlight, blocked by some clouds, going all the way around the sky, overhead, and appearing to converge...

Explanation: Some stars explode in slow motion. Rare, massive Wolf-Rayet stars are so tumultuous and hot that they are slowly disintegrating right before our telescopes. Glowing gas globs each typically over 30 times more massive than the Earth are being expelled by violent stellar winds. Wolf-Rayet star WR 124, visible near the featured image center, is thus creating the surrounding nebula known as M1-67, which spans six light years across. Details of why this star has been slowly blowing itself apart over the past 20,000 years remains a topic of research. WR 124 lies 15,000 light-years away towards the constellation...

Explanation: What's happening to Comet G3 ATLAS? After passing near the Sun in mid-January, the head of the comet has become dimmer and dimmer. By late January, Comet C/2024 G3 (ATLAS) had become a headless wonder -- even though it continued to show impressive tails after sunset in the skies of Earth's Southern Hemisphere. Pictured are images of Comet G3 ATLAS on successive January nights taken from Río Hurtado, Chile. Clearly, the comet's head is brighter and more centrally condensed on the earlier days (left) than on later days (right). A key reason is likely that the comet's nucleus of...

Explanation: Vivid and lustrous, wafting iridescent waves of color wash across this skyscape from northern Sweden. Known as nacreous clouds or mother-of-pearl clouds, they are rare. But their unforgettable appearance was captured in this snapshot on January 12 with the Sun just below the local horizon. A type of polar stratospheric cloud, they form when unusually cold temperatures in the usually cloudless lower stratosphere form ice crystals. Still sunlit at altitudes of around 15 to 25 kilometers, the clouds diffract the sunlight even when the Sun itself is hidden from direct view.

Explanation: The interstellar cloud of dust and gas captured in this sharp telescopic snapshot is seen to change its appearance noticeably over periods as short as a few weeks. Discovered over 200 years ago and cataloged as NGC 2261, bright star R Monocerotis lies at the tip of the fan-shaped nebula. About one light-year across and 2500 light-years away, NGC 2261 was studied early last century by astronomer Edwin Hubble and the mysterious cosmic cloud is now more famous as Hubble's Variable Nebula. So what makes Hubble's nebula vary? NGC 2261 is composed of a dusty reflection nebula fanning out...

Explanation: 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. The galaxy's central 60,000 light-years or so are shown in this sharp galaxy portrait. The portrait features M33's reddish ionized hydrogen clouds or HII regions. Sprawling along loose spiral arms that wind toward the core, M33's giant HII regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars....

Explanation: What are those strange rings? Rich in dust, the rings are likely 3D shells -- but how they were created remains a topic of research. Where they were created is well known: in a binary star system that lies about 6,000 light years away toward the constellation of the Swan (Cygnus) -- a system dominated by the Wolf-Rayet star WR 140. Wolf-Rayet stars are massive, bright, and known for their tumultuous winds. They are also known for creating and dispersing heavy elements such as carbon, which is a building block of interstellar dust. The other star in the binary...

Explanation: Comets can be huge. When far from the Sun, a comet's size usually refers to its hard nucleus of ice and rock, which typically spans a few kilometers -- smaller than even a small moon. When nearing the Sun, however, this nucleus can eject dust and gas and leave a thin tail that can spread to an enormous length -- even greater than the distance between the Earth and the Sun. Pictured, C/2024 G3 (ATLAS) sports a tail of sunlight-reflecting dust and glowing gas that spans several times the apparent size of a full moon, appearing even larger on...

Explanation: Stars come in bunches. The most famous bunch of stars on the sky is the Pleiades, a bright cluster that can be easily seen with the unaided eye. The Pleiades lies only about 450 light years away, formed about 100 million years ago, and will likely last about another 250 million years. Our Sun was likely born in a star cluster, but now, being about 4.5 billion years old, its stellar birth companions have long since dispersed. The Pleiades star cluster is pictured over Half Dome, a famous rock structure in Yosemite National Park in California, USA. The featured...

Explanation: Why does this comet have so many tails? C/2024 G3 (ATLAS) has developed several long and intricate tails visible from Earth's southern hemisphere over the past two weeks. Many observers reported seeing the impressive comet without any optical aid above the western horizon just after sunset. At least six different tails appear in the featured image captured five days ago from the dark skies above Paranal Observatory in Chile. One possible cause for the multiple tails is dust and gas being expelled from the comet's rotating nucleus. The outward push of the Sun's complex solar wind may also play...