Young Star Cluster NGC 346
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The most massive young star cluster in the Small Magellanic Cloud is NGC 346, embedded in our small satellite galaxy's largest star forming region some 210,000 light-years distant. Of course the massive stars of NGC 346 are short lived, but very energetic. Their winds and radiation sculpt the edges of the region's dusty molecular cloud triggering star-formation within. The star forming region also appears to contain a large population of infant stars. A mere 3 to 5 million years old and not yet burning hydrogen in their cores, the infant stars are strewn about the embedded star cluster. This spectacular infrared view of NGC 346 is from the James Webb Space Telescope's NIRcam. Emission from atomic hydrogen ionized by the massive stars' energetic radiation as well as molecular hydrogen and dust in the star-forming molecular cloud is detailed in pink and orange hues. Webb's sharp image of the young star-forming region spans 240 light-years at the distance of the Small Magellanic Cloud.
2025-05-02
Too Close to a Black Hole
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What would you see if you went right up to a black hole? Above are two computer generated pictures highlighting how strange things would look. On the left is a normal star field containing the constellation Orion. Notice the three stars of nearly equal brightness that make up Orion's Belt. On the right is the same star field but this time with a black hole superposed in the center of the frame. The black hole has such strong gravity that light is noticeably bent towards it - causing some very unusual visual distortion. In the distorted frame, every star in the normal frame has at least two bright images - one on each side of the black hole. In fact, near the black hole, you can see the whole sky - light from every direction is bent around and comes back to you. Black holes are thought to be the densest state of matter, and there is indirect evidence for their presence in stellar binary systems and the centers of globular clusters, galaxies, and quasars.
1997-01-05 Robert Nemiroff (MTU)
NGC 6888: A Tricolor Starfield
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NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. Near the center of this intriguing widefield view of interstellar gas clouds and rich star fields of the constellation Cygnus, NGC 6888 is about 5,000 light-years away. The three color composite image was created by stacking exposures through narrow band filters that transmit the light from atoms in the clouds. Hydrogen is shown as green, sulfur as red, and oxygen as blue. NGC 6888's central star is classified as a Wolf-Rayet star (WR 136) and is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of our Sun's mass every 10,000 years. Burning fuel at a prodigious rate and near the end of its stellar life, this star should ultimately go out with a bang in a spectacular supernova explosion.
2006-07-06
What are Comet Tails Made Of?
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The tail of comet Hyakutake, visible in this recent color image, is composed of dust and gas driven off the icy comet nucleus by the Sun's heat and blown away by the solar wind. Bathed in solar ultraviolet light, the gas molecules break down and are excited, producing a characteristic glow. This glow is responsible for visible light from the tail and astronomers using spectroscopes can identify the compounds involved. The close passage of Hyakutake presents an excellent chance to use this technique to explore the composition of its tail. Typical comet gas tail constituents are simple combinations of hydrogen, carbon, nitrogen, and oxygen - for example, H20 (water), CO (carbon monoxide), and CN (cyanogen) are common. In fact, the poisonous CO and CN compounds were seen in the spectrum of Halley's comet during its 1910 apparition. This caused some public concern at the time as the Earth was expected to pass through Halley's tail! However, stretching for millions of miles, comet tails are extremely thin and tenuous and don't pose a danger to the Earth's atmosphere. Latest Comet Hyakutake images: JPL, Crni Vrh Observatory, Slovenia, Fayetteville Observer-Times, NASA's Night of the Comet
1996-03-26
The Long Jet of the Lighthouse Nebula
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The Lighthouse nebula was formed by the wind of a pulsar, a rapidly rotating, magnetized neutron star, as it speeds through the interstellar medium at over 1,000 kilometers per second. Some 23,000 light-years distant toward the southern constellation Carina, pulsar and wind nebula (cataloged as IGR J1104-6103) are indicated at the lower right in this remarkable image from the Chandra X-ray Observatory. Energetic particles generated by the pulsar are swept back into the wind's comet-like tail trailing up and to the left, along the direction of the pulsar's motion away from its parent supernova remnant. Both runaway pulsar and expanding remnant debris field are the aftermath of the core-collapse-explosion of a massive star, with the pulsar kicked out by the supernova explosion. Adding to the scene of exotic cosmic extremes is a long, spiraling jet extending for almost 37 light-years, but nearly at a right angle to the pulsar's motion. The high-energy particle jet is the longest known for any object in our Milky Way galaxy.
2014-02-21
Explosions Discovered Near Galactic Center
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Tremendous explosions near the center of our Galaxy were discovered just this past December and are being announced today by a paper in Nature and a press conference at NASA. Bursts like these have never been seen before, and so the exact cause is unknown and will likely be the source of astronomical speculations and observations for years to come. Much more powerful than any explosions we humans can create, these eruptions likely involve the extreme conditions found only on the surface of a neutron star in a binary system, possibly similar to the X-ray binary system depicted in the above drawing. The new source, dubbed GRO J1744-28 for its discovery spacecraft and position, currently produces multiple pulsed bursts of energy per day, each of which last several seconds. The bursts are quite prominent in X-ray light. Discovery team leaders include Chryssa Kouveliotou (USRA) and Gerald Fishman (NASA /MSFC).
1996-02-28
Still Life with NGC 2170
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In this beautiful celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines at the upper left. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a compact red emission region, and streamers of obscuring dust against a backdrop of stars. Like the common household items still life painters often choose for their subjects, the clouds of gas, dust, and hot stars pictured here are also commonly found in this setting - a massive, star-forming molecular cloud in the constellation Monoceros. The giant molecular cloud, Mon R2, is impressively close, estimated to be only 2,400 light-years or so away. At that distance, this canvas would be about 15 light-years across.
2010-12-30 Adam Block
A Phoenix Aurora over Iceland
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All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet September night, much of that night's auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again. This time, surprisingly, pareidoliacally, the night lit up with an amazing shape reminiscent of a giant phoenix. With camera equipment at the ready, two quick sky images were taken, followed immediately by a third of the land. The mountain in the background is Helgafell, while the small foreground river is called Kaldá, both located about 30 kilometers north of Iceland's capital Reykjavík. Seasoned skywatchers will note that just above the mountain, toward the left, is the constellation of Orion, while the Pleiades star cluster is also visible just above the frame center. The 2016 aurora, which lasted only a minute and was soon gone forever -- would possibly be dismissed as a fanciful fable -- were it not captured in the featured, digitally-composed, image mosaic. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
2024-02-25 Hallgrimur P. Helgason; Rollover Annotation: Judy Schmidt
A Rorschach Aurora
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If you see this as a monster's face, don't panic. It's only pareidolia, often experienced as the tendency to see faces in patterns of light and shadow. In fact, the startling visual scene is actually a 180 degree panorama of Northern Lights, digitally mirrored like inkblots on a folded piece of paper. Frames used to construct it were captured on a September night from the middle of a waterfall-crossing suspension bridge in Jamtland, Sweden. With geomagnetic storms triggered by recent solar activity, auroral displays could be very active at planet Earth's high latitudes in the coming days. But if you see a monster's face in your own neighborhood tomorrow night, it might just be Halloween.
2021-10-30 Göran Strand
62 Kilometers above Comet Churyumov-Gerasimenko
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Spacecraft Rosetta continues to approach, circle, and map Comet Churyumov-Gerasimenko. Crossing the inner Solar System for ten years to reach the vicinity of the comet last month, the robotic spacecraft continues to image the unusual double-lobed comet nucleus. The reconstructed-color image featured, taken about 10 days ago, indicates how dark this comet nucleus is. On the average, the comet's surface reflects only about four percent of impinging visible light, making it as dark as coal. Comet 67P/Churyumov�Gerasimenko spans about four kilometers in length and has a surface gravity so low that an astronaut could jump off of it. In about two months, Rosetta is scheduled to release the first probe ever to attempt a controlled landing on a comet's nucleus. Astronomers: Has an APOD image ever helped your research?
2014-09-15 Elisabetta Bonora & Marco Faccin (Alive Universe Images)