Nebula and Galaxies
The Trifid Nebula (M20) combines three nebula types in one object: the red region is an emission nebula, the blue area is a reflection nebula, and the dark lanes crossing both are dense dust clouds forming a dark nebula. Early photographic and spectroscopic studies in the late 19th and early 20th centuries established that these distinct nebulae arise from different physical processes within the same cloud.
The Andromeda Galaxy (M31) is the nearest large spiral galaxy to the Milky Way, located about 2.5 million light-years away. Its extragalactic nature was established in the 1920s when Edwin Hubble used Cepheid variable stars as distance markers, applying the period–luminosity relationship discovered earlier by Henrietta Leavitt. Measurements of Andromeda’s motion show that it and the Milky Way are on a slow collision course, expected to merge in roughly 4–5 billion years.
IC 410 (The Tadpoles Nebula) is an emission nebula in Auriga shaped by a young cluster of hot stars whose radiation and stellar winds carve the surrounding gas into complex forms. Dense dust clouds scatter through the region, blocking background starlight and giving the nebula its textured appearance. At lower left, two elongated structures known as the Tadpoles are visible, each spanning roughly 10 light years, making them among the largest features sculpted by the cluster’s energetic environment.
This close-up reveals the pair of Tadpoles inside IC 410, each stretching for about 10 light years from end to end. These long, curved pillars of gas and dust are being eroded by intense radiation from nearby massive stars, producing bright, compressed tips that may seed new stars. Seen up close, their scale and structure show how powerful stellar feedback can shape enormous features within an emission nebula.
The Pleiades (M45) is a prominent reflection nebula and young open star cluster located about 440 light-years away in the constellation Taurus. Easily visible to the naked eye, it has been recognition across cultures worldwide as a distinct grouping of stars. In Hawaiian tradition it is known as Makaliʻi, whose seasonal rising was used to mark the timing of the Makahiki season and the renewal of the year.
The Heart Nebula (IC 1805) is a large emission nebula located roughly 7,500 light-years away in the Perseus Arm of the Milky Way. It was cataloged in the late 19th century during early photographic surveys of diffuse nebulae, which helped establish that glowing hydrogen clouds are associated with regions of recent star formation. Ultraviolet radiation and stellar winds from young, massive stars ionize and sculpt the surrounding gas into filaments, cavities, and shock fronts.
This close view shows thin filaments and bright ridges of glowing hydrogen within the Heart Nebula. Darker lanes mark denser clouds of gas and dust silhouetted against the illuminated background.
The Bubble Nebula (NGC 7635) is shaped by a very hot, massive star whose intense energy pushes the nearby gas outward and creates the round bubble at its center. The bluish interior glows from energized oxygen, while the surrounding red cloud is mostly hydrogen. The entire structure is about 7 light-years wide and lies roughly 7,100 light-years away in Cassiopeia.
The West Veil Nebula (NGC 6960) is a small part of the larger Veil Nebula Supernova Remnant, the expanding shell of gas created when a massive star exploded about ten thousand years ago. The red filaments trace glowing hydrogen, while the blue and teal strands come from oxygen shaped by the passing shock wave. The bright star in the frame, 52 Cygni, lies in the foreground and is not connected to the remnant even though it appears embedded in the filaments. The Veil sits roughly 2,400 light years away in Cygnus and spans more than 100 light years.
The East Veil Nebula (NGC 6992 / NGC 6995) is another prominent section of the larger Veil Nebula Supernova Remnant, formed from the expanding shell of gas left behind when a massive star exploded about ten thousand years ago. The red filaments come from hydrogen, while the blue and teal strands trace glowing oxygen shaped by the advancing shock front. This region stretches more than 30 light years and lies roughly 2,400 light years away in Cygnus.
Pickering’s Triangle (NGC 6979) lies within the interior of the Veil Nebula Supernova Remnant, created by the same ancient stellar explosion that formed the rest of the Veil. The tangled red and blue structures reveal hydrogen and oxygen shaped into thin, web-like strands as the shock wave moves through uneven layers of interstellar gas. Like the other parts of the remnant, it sits about 2,400 light years away in Cygnus.
The Helix Nebula (NGC 7293) formed when a star reached the end of its life and expelled the gas that now surrounds it. At the center is a faint “white dwarf,” which is the remaining core of the star and the source of the teal oxygen glow and the larger red ring of hydrogen. The nebula lies about 650 light years away and spans roughly 2.5 light years.
The Crescent Nebula (NGC 6888) is created by a Wolf Rayet star, a rare and short stage in the life of a very massive star when it sheds its outer layers at extremely high speeds. This outflow is colliding with gas the star released earlier, forming the bright curved shell often described as “wind blown” because it is shaped by material streaming off the star. Although the star is massive enough to eventually explode, the Crescent itself is not a supernova remnant. The nebula lies about 5,000 light years away in Cygnus and spans roughly 25 light years.
The Southern Pinwheel Galaxy (M83) is a bright barred spiral galaxy about fifteen million light years away and one of the closest and most photogenic spirals in the southern sky. Its sweeping arms contain countless young blue stars and pink star forming regions that trace out its structure. M83 holds several hundred billion stars in total which makes it comparable in scale to our own Milky Way galaxy.
The Pinwheel Galaxy (M101) is a large face-on spiral galaxy in Ursa Major about twenty one million light years away. It contains roughly one hundred billion stars, comparable to the stellar population of our own Milky Way galaxy. M101 is nearly twice the Milky Way’s diameter and shows a subtly asymmetrical shape, likely influenced by past gravitational interactions with neighboring galaxies.
The Whirlpool Galaxy (M51) is a classic face on spiral galaxy about twenty three million light years away in Canes Venatici. It is interacting with its smaller companion galaxy, NGC 5195, whose close passage has pulled out long tidal streams and helped sculpt the Whirlpool’s prominent spiral arms. Together they show how galaxies can gravitationally influence each other over millions of years while still containing hundreds of billions of stars.
The Orion Nebula (M42) is a large emission nebula about fourteen hundred light years away and is one of the closest and brightest regions of active star formation. At its center is the Trapezium Cluster, a group of young stars that illuminate the surrounding gas and make the nebula visible even to the naked eye as the fuzzy middle “star” in Orion’s sword. The nebula also contains many small disks of gas and dust around young stars that represent early planetary systems in formation.
The Dumbbell Nebula (M27) is a planetary nebula about thirteen hundred light years away in Vulpecula and is the result of a Sun like star shedding its outer layers near the end of its life. At the center is the remaining stellar core, now a white dwarf, whose intense radiation lights up the expanding shell of gas. In M27 the visible structure is dominated by oxygen emission, which gives the nebula its characteristic blue green appearance, with hydrogen (in red) contributing less strongly.
The Eagle Nebula (M16) contains a mix of emission and dark nebula regions, including the famous Pillars of Creation (next image) shaped by ongoing star formation. It lies about 7,000 light-years away in Serpens and spans roughly 70 light-years across.
The Pillars of Creation are tall dark-nebula columns made of cold gas and dust, standing within the bright emission regions of the Eagle Nebula. Their surfaces are sculpted by radiation from nearby young stars, which reveals the dense cores where new stars are forming inside the pillars.
The Hercules Globular Cluster (M13) is a dense, spherical swarm of hundreds of thousands of stars located about twenty two thousand light years away. These stars are tightly packed together, especially toward the center, and are among the oldest in the Milky Way, with ages of around twelve billion years. M13 is one of the brightest and most easily observed globular clusters in the northern sky and is a key example of the ancient stellar populations that orbit the Milky Way’s halo.
The Lagoon Nebula (M8) is a large emission nebula about four thousand light years away in Sagittarius and is an active region of star formation within the Milky Way. Bright structures near the center are shaped by newly formed stars whose radiation is clearing out cavities in the surrounding gas. Dark lanes of dust cut through the glowing region, marking denser areas of material within the larger cloud.
The Rosette Nebula (NGC 2237) is a large emission nebula about five thousand light years away in Monoceros and is one of the Milky Way’s most active star forming regions. The young stars in its center are extremely hot and bright, and their radiation has pushed the surrounding gas outward to create the wide hollow cavity that defines the nebula’s core. This process compresses the remaining material into a ring around the edges, where new stars continue to form in dense pillars and clumps. The Rosette is a clear example of how one generation of stars can reshape the cloud that produces the next.
The Cocoon Nebula (IC 5146) is an emission and reflection nebula about twenty five hundred light years away in Cygnus. A young star near its center is illuminating the surrounding gas and dust, creating the bright red glow of hydrogen and the softer blue reflection component. Beyond the nebula, a long dark lane of dust extends outward, marking the dense filament from which the central star originally formed. IC 5146 is a compact but active star forming region that shows both newborn stars and the cloud that produced them.
The Running Man Nebula (NGC 1977) is a reflection nebula just north of the Orion Nebula, where dust is illuminated by the bright young stars embedded within it. The blue glow comes from starlight scattering off fine dust grains, while darker regions reveal thicker clouds that block the light behind them. The faint red structures in the central area come from a small amount of emission mixed in with the reflection component. Located about 1,500 light years away, NGC 1977 is part of the larger Orion star forming region.
This image shows the Flame Nebula (NGC 2024), an emission nebula on the left, and the Horsehead Nebula (Barnard 33), a dark nebula silhouetted against the bright emission background of IC 434, on the right. The brilliant star Alnitak, the easternmost star in Orion’s Belt, lies just outside the Flame and is responsible for lighting both regions, energizing the Flame’s glowing gas and backlighting the dense dust pillar that forms the Horsehead’s profile. These nebulae lie about thirteen hundred light years away in one of the Milky Way’s most active star forming areas.
The Pacman Nebula (NGC 281) is an emission nebula in Cassiopeia that contains prominent dark dust lanes along with several Bok globules. These Bok globules are small, dense clumps of gas and dust that are much more compact than the larger dark nebulae surrounding them and they are places where new stars may eventually form. Their tight, rounded shapes appear as tiny dark knots against the brighter background. Located about 9,500 light years away, NGC 281 spans roughly 40 light years.
The Wizard Nebula (NGC 7380) is an emission nebula illuminated by a young cluster of stars forming within its central region. Dark dust lanes cut through the glowing hydrogen gas, creating the nebula’s distinctive shapes. The entire complex lies about 7,000 light-years away in the constellation Cepheus.
Solar System (Planets, Moon, Comets)
This image shows Jupiter, the largest planet in the solar system, with its banded cloud layers shaped by strong jet streams and long lived storms. Jupiter has more than ninety known moons, including its four largest moons Io, Europa, Ganymede, and Callisto, which were first identified by Galileo in the early seventeenth century.
This image shows Jupiter’s Great Red Spot, a massive storm system that has been active for at least several centuries. The storm is large enough to span more than the width of Earth and rotates counterclockwise within Jupiter’s turbulent southern hemisphere.
The small black spot above the Great Red Spot is Io’s shadow during one of its frequent transits across Jupiter. Although Io is in front of the planet at the same time, its tiny disk disappears against Jupiter’s bright atmosphere.
The small black spot above the Great Red Spot is Io’s shadow during one of its frequent transits across Jupiter, and Io itself is too small to be seen against the planet’s bright cloud tops. Coming in from the left is another of Jupiter’s moons, Europa, appearing as a small bright disk.
This image shows Saturn and its bright ring system, one of the most distinctive sights in the solar system. The rings are composed of countless icy particles, ranging from tiny grains to chunks several meters across, that orbit in thin, well-defined bands. Subtle shading across the planet’s disk comes from cloud layers in Saturn’s upper atmosphere, shaped by strong winds and rapid rotation.
This image of Saturn shows its largest moon, Titan, positioned above the planet. Titan is the second-largest moon in the solar system and orbits Saturn at a distance of about 1.2 million kilometers. Its hazy atmosphere makes Titan bright enough to show up clearly next to Saturn.
This image shows Mars during one of its close approaches to Earth, revealing its reddish surface and brighter polar region. The planet’s color is derived from iron-rich dust that covers much of its surface, while variations in brightness distinguish different terrains, including darker volcanic plains and lighter desert regions.
This image shows Venus, seen through its bright, reflective cloud layer that completely hides the surface from view. The planet’s thick atmosphere is made mostly of carbon dioxide and is covered by high altitude clouds of sulfuric acid, giving Venus its smooth appearance in visible light. Venus orbits closer to the Sun than Earth and shows phases similar to the Moon when viewed over time.
This is an image of a total lunar eclipse, when the Earth moves directly between the Sun and the Moon. Sunlight passing through Earth’s atmosphere filters out blue light and bends red light into Earth’s shadow, giving the Moon its deep reddish color.
This image shows the Moon with its mix of smooth, dark lunar maria and brighter, heavily cratered highlands. The maria are ancient lava plains that filled large impact basins billions of years ago, while the highlands preserve some of the oldest terrain on the Moon. Shadows along the terminator bring out the relief of craters, ridges, and mountains.
This is an image of the Plato Crater, a large, lava-flooded impact crater bordering the northern edge of Mare Imbrium. Plato is about 100 kilometers wide and is known for its unusually dark, flat floor, which contrasts sharply with the rugged terrain that surrounds it. Its location near several prominent mountain ranges makes it one of the most recognizable features on the Moon’s northern hemisphere.
This is an image of the Tycho Crater, one of the most prominent impact sites in the Moon’s southern highlands. The crater is about 85 kilometers wide and more than 4 kilometers deep, created by a large impact roughly one hundred million years ago. Its bright rays spread across much of the lunar surface, making Tycho easy to recognize in views of the full Moon.
Comet Lemmon (C/2025 A6) last passed through the inner solar system in the late 600s AD and won’t return for more than a thousand years. Its nucleus is made of frozen water, carbon dioxide, and dust, and as these ices warm, they release gas and particles that form the glowing coma and tail.