Quantum Cosmos @quantamastral

Almost exactly 100 years ago, a remarkable event occurred: a total solar eclipse. This eclipse was special in more ways than one. Firstly, at just under seven minutes in duration, it was the longest such eclipse in over 500 years. Secondly, it was used by astronomers to explore the then-new theory of general relativity — with successful and groundbreaking results. Einstein published his general theory of relativity in 1915. The total solar eclipse of 1919 offered the perfect opportunity to test it experimentally, by exploring whether — and how — the immense gravity of the Sun bends and distorts incoming light from more distant stars, as predicted by Einstein’s theory. For a brief moment during the eclipse, the Moon would block the Sun’s light in the sky and make visible some of the stars that lie close to the line of sight of the Sun, not normally visible during the daytime. By measuring the positions of these stars during the eclipse and comparing them to their positions at night, when the sun is not in the field of view, it would be possible to determine whether their light rays bends while passing close to the Sun. Three astronomers — Arthur Eddington, Frank Watson Dyson, and Andrew Crommelin — played key roles in this 1919 experiment. Eddington and Crommelin travelled to locations at which the eclipse would be total — Eddington to the West African island of Príncipe, Crommelin to the Brazilian town of Sobral — while Dyson coordinated the attempt from England. Eddington and Crommelin imaged the eclipse using the technology of the time: photographic plates made of glass. Sadly, the original plates from the 1919 expedition (one of which was reproduced in Dyson’s original paper) have been lost — but, luckily, copies of one of the plates were made and sent to observatories around the world to allow scientists everywhere to see the evidence in support of relativity with their own eyes. One copy of a plate from Sobral went to Landessternwarte Heidelberg-Königstuhl, who recently scanned theirs as part of the Heidelberg Digitized Astronomical Plates (HDAP) project [1]. The image shown here is arguably the highest resolution image of the 1919 eclipse, and is the result of applying modern image processing techniques — including image restoration, noise reduction, and removal of artifacts — to that plate copy (un-annotated version here). It unveils stunning details in the solar corona, a giant prominence emerging from the upper right part of the Sun, and stars in the constellation of Taurus (The Bull) that were used to confirm general relativity’s predictions [2].

The first evening of the new year was beckoned in by a spectacular supermoon, rising up from behind the majestic Cerro Armazones mountain in Chile. A supermoon like this is a magnificent, albeit relatively frequent, occurrence which takes place when a full moon coincides with the point in the lunar orbit that is closest to Earth, its diameter appearing about 14% larger in the sky. The road zigzagging up Cerro Armazones appears to lead directly to the Moon itself — truly making it a road to the stars. By 2024, the “world’s biggest eye on the sky” will rest on top of this mountain, as its peak will be home to the Extremely Large Telescope. At an altitude of 3046 metres, Cerro Armazones provides a spectacular environment for astronomical observations, in particular because it receives 320 clear nights per year. This photo was captured by ESO Photo Ambassador Gerhard Hüdepohl. He walked two kilometres from ESO’s nearby Paranal Observatory into the Atacama Desert to find the right position to take this photo. Beforehand, he had calculated the path the Moon would take to know the right time and place for this extraordinary shot. Credit: G.Hüdepohl

One of the winning artworks from the 'Catch a Star' astronomical competition. This is the winning piece in the 14-15 years age group. 'Catch a Star' was an international astronomical competition run by ESO and the European Association for Astronomy Education (EAAE). Credit: ESO

Trumpler 16 Hubble captures a dramatic corner of the Carina Nebula, where the massive open cluster Trumpler 16 blazes with some of the Galaxy’s most extreme stars. On the left, Tr16-36 shines brightly amid the surrounding gas and dust, while on the right WR 25 glows as one of the cluster’s powerhouse members—a rare Wolf-Rayet star whose intense radiation and powerful stellar winds are reshaping the nearby nebula. Embedded in this turbulent star-forming region roughly 7,500 light-years away, these colossal stars illuminate and sculpt the cosmic clouds around them, offering a vivid glimpse of the violent environments where the Milky Way’s most massive stars are born. Credit: NASA, ESA and Jesús Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)

Giant black holes bigger than galaxies? Dark matter’s cosmic hide-and-seek just got a major clue—and the biggest black holes aren’t the answer. Imagine black holes so enormous they outweigh entire galaxies—objects with masses of 100 billion suns or more, casually called “stupendously large black holes.” For years, theorists wondered whether these monsters, if they formed in the early universe as primordial black holes, could account for a big chunk of the universe’s mysterious dark matter. A new study says no: they can’t be a major component. Dark matter makes up most of the matter in the cosmos, yet we only know it through its gravity. One long-running idea is that some of it could be primordial black holes—dense objects forged in the chaotic first moments after the Big Bang rather than from dying stars. Most mass ranges for these have already been tightly constrained. The last remaining loopholes were asteroid-sized black holes (still possible) and these stupendously large ones. These ultra-massive black holes are defined roughly as anything ≳ 10^{11} solar masses. They’re so big they couldn’t hide inside galaxies the way ordinary dark-matter particles or smaller black holes might. The biggest black hole actually observed so far weighs around 36 billion suns—impressive, but still short of the “stupendous” threshold. Because astronomers haven’t spotted even larger ones despite surveying many galaxies, these objects clearly can’t make up all the dark matter. The open question was whether they could still make up a significant fraction. Researchers tackled that question by looking at the cosmic microwave background—the afterglow of the Big Bang that we can still detect as faint microwave radiation across the sky. If the universe were sprinkled with these galaxy-scale black holes, their sheer discreteness would have created extra “isocurvature” clumpiness in the dark-matter density relative to the radiation. In plain terms, the cosmic microwave background would look grainier than it does. Planck satellite data shows no such graininess. The signal these stupendously large black holes would have produced exceeds the limits set by the observations. As one of the researchers put it, these black holes simply can’t be a significant part of the dark matter. The work carefully models how randomly distributed primordial black holes would generate these perturbations and how they evolve until the universe became transparent. Even under conservative assumptions, the predicted clumpiness is too large to match what we actually see for any substantial dark-matter fraction in this mass range. The window is effectively closed. Importantly, the result does not claim these stupendously large black holes are impossible. It only shows they cannot constitute a major share of dark matter. Smaller, asteroid-mass primordial black holes remain a viable (if still unconfirmed) candidate that could make up all of it. The dark-matter mystery continues—just with one dramatic, ultra-massive possibility largely ruled out. The universe still has its secrets. The biggest black holes we’ve imagined simply aren’t hiding most of the dark matter.

Payload deployment confirmed from Electron - all three HAWK satellites are now on orbit 🛰️🛰️🛰️

Gorgeous: The dark cloud Chamaeleon I holds pockets of starlight. Three reflection nebulae glow within its depths, reflecting light from new-born stars in one of Earth’s nearest stellar nurseries (Credit: CTIO/NOIRLab/DOE/NSF/AURA - T.A. Rector, M. Zamani & D. de Martin)

This very detailed simulation of large scale structure was created as part of the Illustris simulation. The distribution of dark matter is shown in blue and the gas distribution in orange. This simulation is for the current state of the Universe and is centered on a massive galaxy cluster. The region shown is about 300 million light-years across. Credit: Illustris Collaboration (not for commercial use

The gamma-ray burst GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye. Astronomers from around the world combined data from ground- and space-based telescopes to conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000. This 0.4 degree wide jet is contained within another slightly less energetic jet about 20 times wider. It also appears that the jets were aimed almost directly at the Earth. Credit: ESO

This artist’s impression shows two galaxies in the early Universe. The brilliant explosion on the left is a gamma-ray burst. The light from the burst travels through both galaxies on its way to Earth (outside the frame to the right). Analysis of observations of the light from this gamma-ray burst made using ESO’s Very Large Telescope have shown that these two galaxies are remarkably rich in heavier chemical elements. Credit: ESO/L. Calçada

This view shows a section of the widest deep view of the sky ever taken using infrared light, with a total effective exposure time of 55 hours. It was created by combining more than 6000 individual images from the VISTA survey telescope at ESO’s Paranal Observatory in Chile. This picture shows a region of the sky known as the COSMOS field in the constellation of Sextans (The Sextant). More than 200 000 galaxies have been identified in this picture. Credit: ESO/UltraVISTA team. Acknowledgement: TERAPIX/CNRS/INSU/CASU

This nebula-like formation is actually lightning illuminating the clouds during a storm off the coast of North Carolina in this photograph from the International Space Station as it orbited 260 miles above the Atlantic Ocean.

NASA’s Hubble Space Telescope has unveiled in stunning detail a small section of the expanding remains of a massive star that exploded about 8,000 years ago. Called the Veil Nebula, the debris is one of the best-known supernova remnants, deriving its name from its delicate, draped filamentary structures. The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus, the Swan. This 3-D visualization flies across a small portion of the Veil Nebula as photographed by the Hubble Space Telescope.

This is an artist concept, based on data from NASA Spitzer Space Telescope, of graphene, buckyballs and C70 superimposed on an image of the Helix planetary nebula, a puffed-out cloud of material expelled by a dying star.

Resembling a nightmarish beast rearing its head from a crimson sea, this monstrous object is actually an irnocuous pillar of gas and dust. Called the Cone Nebula (NGC 2264), this giant pillar resides in a turbulent star-forming region. This picture, taken by the newly installed Advanced Camera for Surveys (ACS) aboard Hubble Space Telescope (HST) during Space Shuttle STS-109 mission in March 2002, shows the upper 2.5 light-years of the nebula, a height that equals 23 million roundtrips to the Moon. The entire nebula is 7 light-years long. The Cone Nebula resides 2,500 light-years away in the constellation Monoceros. Radiation from hot, young stars (located beyond the top of the image) has slowly eroded the nebula over millions of years. Ultraviolet light heats the edges of the dark cloud, releasing gas into the relatively empty region of surrounding space. There, additional ultraviolet radiation causes the hydrogen gas to glow, which produces the red halo of light seen around the pillar. A similar process occurs on a much smaller scale to gas surrounding a single star, forming the bow-shaped arc seen near the upper left side of the Cone. This arc, seen previously with the HST, is 65 times larger than the diameter of our solar system. The blue-white light from surrounding stars is reflected by dust. Background stars can be seen peeking through the evaporating tendrils of gas, while the turbulent base is pockmarked with stars reddened by dust. Credit: NASA, H. Ford (JHU), G. Illingworth (USCS/LO), M. Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA.

Massive stars can wreak havoc on their surroundings, as can be seen in this new view of the Carina nebula from NASAs Spitzer Space Telescope.

After barely 2 months in space, the Chandra X-Ray Observatory (CXO) took this sturning image of the Crab Nebula, the spectacular remains of a stellar explosion, revealing something never seen before, a brilliant ring around the nebula's heart. The image shows the central pulsar surrounded by tilted rings of high-energy particles that appear to have been flung outward over a distance of more than a light-year from the pulsar. Perpendicular to the rings, jet-like structures produced by high-energy particles blast away from the pulsar. Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous x-ray images have shown the outer parts of the jet and hinted at the ring structure. With CXO's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with CXO's Advanced Charge-Coupled Device (CCD) Imaging Spectrometer (ACIS) and High Energy Transmission Grating. The Crab Nebula, easily the most intensively studied object beyond our solar system, has been observed using virtually every astronomical instrument that could see that part of the sky

Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it “Nasty 1,” a play on its catalog name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars. First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core. But Nasty 1 doesn’t look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, ...more Date Created:2015-03-21

A colony of hot, young stars is stirring up the cosmic scene in this new picture from NASA Spitzer Space Telescope. The image shows the Orion nebula, a happening place where stars are born. Date Created:2010-04-01 Center:JPL

art002e009301 (April 6, 2026) – Captured by the Artemis II crew during their lunar flyby on April 6, 2026, this image shows the Moon fully eclipsing the Sun. From the crew’s perspective, the Moon appears large enough to completely block the Sun, creating nearly 54 minutes of totality and extending the view far beyond what is possible from Earth. We see a glowing halo around the dark lunar disk. The science community is investigating whether this effect is due to the corona, zodiacal light, or a combination of the two. Also visible are stars, typically too faint to see when imaging the Moon, but with the Moon in darkness stars are readily imaged. This unique vantage point provides both a striking visual and a valuable opportunity for astronauts to document their observations during humanity’s return to deep space. The faint glow of the nearside of the Moon is visible in this image, having been illuminated by light reflected off the Earth.