Astronomy (General/Chat)
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Explanation: The tree is not in danger. That's because the comet pictured just above it, Comet C/2025 A6 (Lemmon), is far in the distance, well away from the Earth. Comet Lemmon now continues to brighten as it arcs through the inner Solar System, even though it has passed its nearest to the Sun -- because it is now approaching the Earth. The comet will likely appear brightest when it is at its closest to the Earth next week, then closing to about half the Earth-Sun distance. Comet Lemmon may then be visible to the unaided eye, but it is more...
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An incredible image captures the bizarre UFO–like ring floating above Possagno, a tiny town in the foothills of the Italian Alps. The photograph was taken by photographer Valter Binotto, who watched as the glowing structure flashed in the sky at 10:45 local time on November 17. A photographer has captured a baffling image of a red UFO–like halo floating over the small Italian town of Possagno This ring is likely a structure known as an 'emission of light and very low–frequency perturbations due to electromagnetic pulse sources', or ELVEs for short. These are rings of red or green light created...
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Explanation: Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way galaxy. The colorful, spiky stars decorating this cosmic portrait of NGC 1055 are in the foreground, well within the Milky Way. But telltale pinkish star forming regions and young blue star clusters are scattered through winding dust lanes along the distant galaxy's thin disk. With a smattering of even more distant background galaxies, the deep...
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Explanation: How much of Jupiter's moon Europa is made of water? No one is sure, but probably a lot. Based on the Galileo probe data acquired during its exploration of the Jovian system from 1995 to 2003, Europa possesses a deep, global ocean of liquid water beneath a layer of surface ice. The subsurface ocean plus ice layer could descend over 100 kilometers in average depth. Adopting a high-end estimate of 100 kilometers depth, if all the water on Europa were gathered into a ball, it would have a radius of over 800 kilometers. To scale, this intriguing illustration compares...
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Explanation: Stars, like bees, swarm around the center of bright globular cluster M15. The central ball of over 100,000 stars is a relic from the early years of our Galaxy, and continues to orbit the Milky Way's center. M15, one of about 150 globular clusters remaining, is noted for being easily visible with only binoculars, having at its center one of the densest concentrations of stars known, and containing a high abundance of variable stars and pulsars. The featured image of M15 was taken by combining very long exposures -- 122 hours in all -- and so brings up faint...
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Explanation: Orbiting 400 kilometers above Quebec, Canada, planet Earth, the International Space Station Expedition 59 crew captured this snapshot of the broad St. Lawrence River and curiously circular Lake Manicouagan on April 11, 2019. Right of center, the ring-shaped lake is a modern reservoir within the eroded remnant of an ancient 100 kilometer diameter impact crater. The ancient crater is very conspicuous from orbit, a visible reminder that Earth is vulnerable to rocks from space. Over 200 million years old, the Manicouagan crater was likely caused by the impact of a rocky body about 5 kilometers in diameter. Currently, there...
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The Bible tells us very clearly that there is coming in the future a “Deception” so great that even believers will be fooled by it. That’s not really up for debate. The only thing up for debate is (1) what is it, and (2) has it already started? I’m going to give you my opinion on both of those questions in this article and then I want to hear what YOU think! First I have to put this in context. Third years ago, if I would have tried to have a serious debate and discussion about whether “aliens” are real,...
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Artist’s impression of the collision between the early Earth and Theia. Since Theia originated in the inner Solar System, in this perspective the Sun can be seen in the background. (Credit: MPS / Mark A. Garlick) In A Nutshell * Inner Solar System origins: By measuring iron isotopes in Moon rocks and meteorites, researchers determined Theia probably formed closer to the Sun than Earth did, not in the distant outer Solar System. * Identical twins: Earth and the Moon have virtually identical chemical signatures, but both fall outside the range of any meteorites we’ve found—suggesting they incorporated exotic material from...
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Explanation: What did Comet Lemmon look like when it was at its best? One example is pictured here, featuring three celestial spectacles all at different distances. The closest spectacle is the snowcapped Meili Mountains, part of the Himalayas in China. The middle marvel is Comet Lemmon near its picturesque best early this month, showing not only a white dust tail trailing off to the right but its blue solar wind-distorted ion tail trailing off to the left. Far in the distance on the left is the magnificent central plane of our Milky Way Galaxy, featuring dark dust, red nebula, and...
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Explanation: It's only 50 light-years to 51 Pegasi. That star's position is indicated in this snapshot from August 2025, taken on a night with mostly brighter stars visible above the dome at Observatoire de Haute-Provence in France. Thirty years ago, in October of 1995, astronomers Michel Mayor and Didier Queloz announced a profound discovery made at the observatory. Using a precise spectrograph, they had detected a planet orbiting 51 Peg, the first known exoplanet orbiting a sun-like star. Mayor and Queloz had used the spectrograph to measure changes in the star's radial velocity, a regular wobble caused by the gravitational...
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Explanation: What created this unusual space sculpture? Stars. This unusual system of swirls and shells, known as Apep, was observed in unprecedented detail by NASA’s James Webb Space Telescope in infrared light in 2024. Observations indicate that the unusual shape originates from two massive Wolf-Rayet stars orbiting each other every 190 years with each close passes causing a new shell of dust and gas to be expelled. Holes in these shells are thought to be caused by a third orbiting star. This stellar dust dance will likely continue for hundreds of thousands of years, possibly ending only when one of...
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Explanation: That big, bright, beautiful Full Moon you watched rise on the night of October 6 was the Harvest Moon. Famed in festival, story, and song, Harvest Moon is just the traditional name of the full moon nearest the time of the northern hemisphere's autumnal equinox. According to lore the name is a fitting one. Despite the diminishing daylight hours, as the growing season drew to a close in the north, farmers could harvest crops by the light of a full moon shining on from dusk to dawn. Later this year than usual, in 2025 October's Harvest Moon was also...
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Explanation: How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe. In light, the farthest we can see comes from the cosmic microwave background, a time 13.8 billion years ago when the universe was opaque like thick fog. Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them. The featured image illustrates the observable universe on an increasingly compact scale, with the Earth...
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Explanation: What powers are being wielded in the Wizard Nebula? Gravitation strong enough to form stars, and stellar winds and radiations powerful enough to create and dissolve towers of gas. Located only 8,000 light years away, the Wizard nebula, featured here, surrounds a developing open star cluster NGC 7380. Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional medieval sorcerer. The active star forming region spans about 100 light years, making it appear larger than the angular extent of the Moon. The Wizard Nebula can be located with a small...
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Explanation: Seen to the left of Saturn's banded planetary disk, small icy moons Dione and Rhea are caught passing in front of the gas giant's extensive ring system in this sharp telescopic snapshot. The remarkable image was recorded on November 20, when Saturn's rings were nearly edge-on when viewed from planet Earth. In fact, every 13 to 16 years the view from planet Earth aligns with Saturn's ring plane to produce a series of ring plane crossings. During a ring plane crossing, the interplanetary edge-on perspective makes the thin but otherwise bright rings seem to disappear. By November 23rd Saturn's...
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Explanation: Now a second supernova in this same galaxy is repeating. The cause is the gravitational lens effect of a massive foreground cluster of galaxies (MACS J0138) -- it creates multiple images of a perfectly aligned background galaxy (MRG-M0138). What's particularly interesting is that this background galaxy has young stars that keep blowing up. And images of each supernova explosion keep coming to us multiple times through different paths through the cluster. The original lensed supernova set, shown in the rollover, is called Requiem and was first seen by the Hubble Space Telescope in 2016. This second lensed supernova set...
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The incredible Apep system as seen in infrared by JWST. Image Credit: NASA, ESA, CSA, STScI; Science: Yinuo Han (Caltech), Ryan White (Macquarie University); Image Processing: Alyssa Pagan (STScI) DOWNLOAD PDF SHARE facebook-icon twitter-icon reddit-icon flipboard-icon bluesky-icon Google prefered source badge From the very first images, JWST showed that it was going to be a revolutionary instrument, and yet it continues to surprise us. New observations from the infrared space telescope have upended previous observations of a relatively close star system. It has revealed a complexity that had not been seen before in spectacularly crisp new images. The aging star...
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Explanation: Now outbound after its perihelion or closest approach to the Sun on October 29, Comet 3I/ATLAS is only the third known interstellar object to pass through our fair Solar System. Its greenish coma and faint tails are seen against a background of stars in the constellation Virgo in this view from planet Earth, recorded with a small telescope on November 14. But this interstellar interloper is the subject of an on-going, unprecedented Solar System-wide observing campaign involving spacecraft and space telescopes from Earth orbit to the surface of Mars and beyond. And while the comet from another star-system has...
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Explanation: How does a comet tail change? It depends on the comet. The ion tail of Comet C/2025 A6 (Lemmon) has been changing markedly, as detailed in the featured image sequenced over six days between September 25 and October 4 (left to right) from Texas, USA. On some days, the comet's ion tail was relatively more complex than other days. Reasons for tail changes include the rate of ejection of material from the comet's nucleus, the strength and complexity of the passing solar wind, and the rotation rate of the comet. Sometimes, over the course of a week, apparent differences...
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Explanation: Alnitak, Alnilam, and Mintaka are the bright bluish stars from east to west (upper right to lower left) along the diagonal in this cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie from 700 to 2,000 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the upper right. The famous Orion Nebula itself is off the right...
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