Astronomy Picture of the Day: Astronomers have discovered the largest structure in the Universe!

 

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Black Hole Scientists have identified the "Kipu" superstructure, which spans more than 1.3 billion light-years. With a mass of 200 quadrillion solar masses, it ranks among the most massive cosmic structures known. The name "Kipu" alludes to the ancient Inca system of knotted-string records; the newly discovered structure also resembles a main strand with branching offshoots. The motion of galaxies within the structure influences measurements of the Hubble constant, which determines the rate of cosmic expansion. Despite its immense scale, the object aligns with the Lambda-CDM model, which predicts the existence of such formations. While Kipu may eventually disintegrate, it currently serves as a unique laboratory for studying dark matter and galaxy evolution.

Astronomy Picture of the Day: Exocomets around the young star PDS 70 may show how water reaches newborn planets!

 

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Black Hole PDS 70 is a T Tauri star about 370 light-years away and only 5.4–5.5 million years old — still a cosmic infant, slightly cooler than the Sun. Two giant planets have already been photographed in its disk, making the system a rare live snapshot of planet formation. JWST later found water vapor in the innermost part of that disk, right where rocky worlds could form. The puzzle was how the water got there. A new look at archival HARPS spectra revealed the clue: variable lines of neutral sodium. They appear and vanish over a few nights, only partly cover the star, and belong to gas moving faster than PDS 70 itself. That is a poor match for a steady disk wind, but a good match for icy bodies on stretched orbits heating up as they swing close to the star and shedding gas by sublimation — in other words, exocomets. Models suggest the system’s gas giants can fling those icy bodies inward from the cold outer disk, delivering water to the terrestrial zone. Something similar may have happened in the early Solar System. If the interpretation holds, PDS 70 is the youngest known example of this process around a star not far from the Sun in temperature: a still-forming planetary system already being watered by comets.

Astronomy Picture of the Day: Dust storm dances just off Mars’ South Pole!

 

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Black Hole

A swirling local dust storm dances just off Mars’ South Pole, frozen in a dramatic frame by ESA’s Mars Express. 🌪 As the southern hemisphere leans toward summer solstice, the winter’s thick blanket of frozen carbon dioxide starts to vanish in a rush of sublimation. The sudden burst of gas drives fierce winds that tear across the polar terrain, lifting rust-red dust into towering, restless clouds. These plumes stream mostly northward — a brief, violent ballet on a planet that never quite sits still.

Astronomy Picture of the Day: Voyager 1

 

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Black Hole

Today marks 49 years since the launch of Voyager 1—the spacecraft farthest from Earth. If you step outside on a clear night and shine a flashlight toward the constellation Ophiuchus, a couple of the photons you emit would, in theory, reach Earth's emissary. It would take them 23 hours and 47 minutes to get there.

Astronomy Picture of the Day: Comparison of Earth and Neptune's sizes!

 

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Black Hole

Neptune's diameter is 49,244 kilometers, making it the smallest gas giant in the Solar System.

Astronomy Picture of the Day: The final run at Mercury!

 

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Black Hole

After almost eight years and a 10-billion-kilometer slalom through the inner solar system, BepiColombo just kicked its cruise stage loose and started the final run at Mercury. Two spacecraft — one European, one Japanese — that have been riding piggyback since 2018 finally uncoupled from their transport module on Thursday. Controllers in Germany waited two tense hours for the radio confirmation to crawl back across 200 million kilometers. When it arrived, the room exhaled. The pair now have only about 3.3 million kilometers left before they slip into orbit in November and split into two independent probes in December. Getting this close to the Sun’s nearest neighbor is brutally hard. Mercury sits deep in the solar gravity well; you can’t just point and fire. BepiColombo needed nine planetary flybys — Earth, Venus, and Mercury itself — just to bleed off enough speed to be captured. The last swing-by in January 2025 already delivered crisp photos of cratered plains and strange, bright hollows. Those hollows are one of the planet’s many contradictions. Daytime temperatures can roast the surface at 427 °C, yet the poles hide permanently shadowed craters packed with water ice. A dense iron core generates a magnetic field no one fully expected from such a small world. Minerals appear to be boiling off the rocks, slowly eating pits into the landscape. Only two spacecraft have ever visited before; most of Mercury is still a mystery. The hardware has to survive what one engineer compared to “operating with a very hot pizza oven running right on your back.” Science operations begin next spring: dual orbits, dual instrument suites, and the first comprehensive look at the magnetic field, interior, and surface processes of the solar system’s smallest planet. The long, looping journey is almost over. The real work is about to start.

Astronomy Picture of the Day: A visual demonstration of how much water and air there is on our planet!

 

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The Earth has approximately 1 billion 408 million 700 thousand cubic kilometers of water and about 5.14 quadrillion tons of air. And if you look closely, you'll see two smaller spheres hanging above the blue sphere of water. These are fresh water and atmospheric water vapor.

Astronomy Picture of the Day: Cosmic Belch, Then a Delayed Roar!

 

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Black Hole

Deep in the Perseus Cluster, the supermassive black hole at the heart of galaxy NGC 1275 just put on a show—and then made everyone wait for the encore. Astronomers pieced together nearly two decades of NASA Swift X-ray observations and radio monitoring to catch it in the act. In February 2023 the black hole suddenly flared in X-rays, doubling in brightness in the strongest outburst ever recorded from this galaxy. The episode lasted under 60 days and came in at least two sharp bursts, each only about five days long. Then, 296 days later, the radio jets lit up. That lag is the headline. It looks like the time it takes some disturbance—maybe extra material dumped onto the accretion disk, or a shock racing down the jet—to travel from the X-ray-bright region close to the black hole out to the radio-emitting zone farther along the jets. In other words, we may have watched the message travel from the engine to the exhaust pipes. NGC 1275 is already a messy, photogenic wreck: an ongoing merger, glowing gas filaments, and giant bubbles inflated by previous jet outbursts. That chaos makes it a perfect laboratory for “disk-jet coupling”—the still-murky link between how a black hole eats and how it launches those powerful jets that can heat cluster gas and throttle galaxy growth. The team ruled out a star being torn apart (a tidal disruption event). The flare faded too slowly for that. Instead the evidence—X-ray spectrum, rapid flickering, and a telltale iron line—points to a change in the feeding rate or a disturbance downstream in the jet itself. They’re not 100 percent sure every bit of the X-ray glow came from the corona right around the black hole; some of it could have been produced farther out. Still, this is a rare, clean look at the delay between an inner-disk event and the jet’s response. Coordinated X-ray and radio watching of similar galaxies could turn these delayed aftershocks into a regular way of studying how black holes actually launch their jets. The paper, led by Sarah Ketchum of the University of Michigan, was posted to arXiv in August 2026 and accepted by The Astrophysical Journal Letters. One more reminder that even the universe’s most extreme objects sometimes take their time to finish the sentence.

Astronomy Picture of the Day: Tthe star closest to the Sun is Proxima Centauri!

 

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As is well known, the star closest to the Sun is Proxima Centauri—a component of the Alpha Centauri system also known as Alpha Centauri C—located approximately 4.2 light-years away.

However, this will not always be the case. In about 10,000 years, due to stellar motion within the galaxy, Barnard's Star will become our nearest neighbor, situated at a distance of 3.8 light-years. And that is not all: in roughly 33,000 years, Ross 248 will become the closest star, approaching the Sun to within 3 light-years. Then, another 10,000 years later, the status of our nearest cosmic neighbor will revert to the Proxima Centauri system. All these stars are red dwarfs with masses approximately one-sixth that of the Sun. Consequently, this "rotation" of our nearest stellar neighbors is unlikely to cause any significant effects on Earth or within the Solar System at large. However, in about 1.3 million years, the orange dwarf Gliese 710 will approach Earth to within approximately 0.2 light-years—effectively entering the confines of the Solar System. Such a close encounter could perturb the orbits of small celestial bodies and, in particular, trigger an intense bombardment of the inner planets by asteroids and comets.