Monthly Archives: July 2024

Omega Centauri is a spectacular collection of 10 million stars, visible as a smudge in the night sky from Southern latitudes. Through a small telescope, it looks no different from other so-called globular clusters; a spherical stellar collection so dense towards the center that it becomes impossible to distinguish individual stars. But a new study, led by researchers from the University of Utah and the Max Planck Institute for Astronomy, confirms what astronomers had argued about for over a decade: Omega Centauri contains a central black hole. The black hole appears to be the missing link between its stellar and supermassive kinstuck in an intermediate stage of evolution, it is considerably less massive than typical black holes in the centers of galaxies. Omega Centauri seems to be the core of a small, separate galaxy whose evolution was cut short when it was swallowed by the Milky Way.

This is a once-in-a-career kind of finding. Ive been excited about it for nine straight months. Every time I think about it, I have a hard time sleeping, said Anil Seth, associate professor of astronomy at the U and co-principal investigator (PI) of the study. I think that extraordinary claims require extraordinary evidence. This is really, truly extraordinary evidence.

A clear detection of this black hole had eluded astronomers until now. The overall motions of the stars in the cluster showed that there was likely some unseen mass near its center, but it was unclear if this was an intermediate-mass black hole or just a collection of the stellar black holes. Maybe there was no central black hole at all.

Previous studies had prompted critical questions of So where are the high-speed stars? We now have an answer to that, and the confirmation that Omega Centauri contains an intermediate-mass black hole. At about 18,000 light-years, this is the closest known example for a massive black hole, said Nadine Neumayer, a group leader at the Max Planck Institute and PI of the study. For comparison, the supermassive black hole in the center of the Milky Way is about 27,000 light-years away.

Thepaperwas published in the journal Nature on July 11, 2024. Watch the research come to life on August 8, 2024, at 7:00 p.m. when Anil Seth will present these once-in-a-lifetime findings at the Clarke Planetarium IMAX theater.

A range of black hole masses

In astronomy, black holes come in different mass ranges. Stellar black holes, between one and a few dozen solar masses, are well known, as are the supermassive black holes with masses of millions or even billions of suns. Our current picture of galaxy evolution suggests that the earliest galaxies should have had intermediate-sized central black holes that would have grown over time, gobbling up smaller galaxies done or merging with larger galaxies.

Such medium-sized black holes are notoriously hard to find. Although there are promising candidates,there has been no definite detection of such an intermediate-mass black holeuntil now.

There are black holes a little heavier than our sun that are like ants or spiderstheyre hard to spot, but kind of everywhere throughout the universe. Then youve got supermassive black holes that are like Godzilla in the centers of galaxies tearing things up, and we can see them easily, said Matthew Whittaker, an undergraduate student at the U and co-author of the study. Then these intermediate-mass black holes are kind of on the level of Bigfoot. Spotting them is like finding the first evidence for Bigfootpeople are going to freak out.

Needle in an archival haystack

When Seth and Neumayer designed a research project to better understand the formation history of Omega Centauri in 2019, they realized they could settle the question of the clusters central black hole once and for all. If they found fast-moving stars around its center, they would have the proverbial smoking gun, as well as a way of measuring the black holes mass.

The arduous search became the task ofMaximilian Hberle, a doctoral student at the Max Planck Institute. Hberle led the work of creating an enormous catalogue for the motions of stars in Omega Centauri, measuring the velocities for 1.4 million stars by studying over 500 Hubble images of the cluster. Most of these images had been produced for the purpose of calibrating Hubbles instruments rather than for scientific use. But with their ever-repeating views of Omega Centauri, they turned out to be the ideal data set for the teams research efforts.

Looking for high-speed stars and documenting their motion was the proverbial search for a needle in a haystack, Hberle said. In the end, Hberle not only had themost complete catalogof the motion of stars in Omega Centauri yet, he also found seven needles in his archival haystackseven tell-tale, fast-moving stars in a small region in the center of Omega Centauri.

Uncovering a black hole

The seven stars move fast because of the presence of a concentrated nearby mass. For a single star, it would be impossible to tell whether it is fast because the central mass is large or because the star is very close to the central massor if the star is merely flying straight, with no mass in sight. But seven such stars, with different speeds and directions of motion, allowed the team to separate the different effects and determine that thereisa central mass in Omega Centauri, with the mass of at least 8,200 suns. The images do not indicate any visible object at the inferred location of that central mass, as one would expect for a black hole.

The broader analysis also allowed the team to narrow down the location of Omega Centauris central region at 3 light-months in diameter (on images, 3 arc seconds). In addition, the analysis provided statistical reassurance: A single high-speed star in the image might not even belong to Omega Centauri. It could be a star outside the cluster that passes right behind or in front of Omega Centauris center by chance. The observations of seven such stars, on the other hand, cannot be pure coincidence, and leaves no room for explanations other than a black hole.

An intermediate-mass black hole at last

Given their findings, the team now plans to examine the center of Omega Centauri in even more detail. The Us Seth is leading a project has gained approval to use the James Webb Space Telescope for measuring the high-speed stars movement towards or away from Earth, and there are future instruments (GRAVITY+ at ESOs VLT, MICADO at the Extremely Large Telescope) that could pinpoint stellar positions even more accurately than Hubble. The long-term goal is to determine how the stars accelerate: how their orbits curve. Following those stars once around their whole orbit, as in the Nobel-prize-winning observations near the black hole in the center of the Milky Way, is a project for future generations of astronomers, though. The smaller black hole mass for Omega Centauri means ten times larger time scales than for the Milky Way: orbital periods of more than a hundred years.

Background information The work described here has been published as M. Hberle et al., Fast-moving stars around an intermediate-mass black hole in Centauri in the journal Nature. The star catalog on which the work is based has been accepted for publication as M. Hberle et al., oMEGACat IIPhotometry and proper motions for 1.4 million starsin Omega Centauri and its rotation in the plane of the sky in the Astrophysical Journal.

Other authors include the Max Plank Institute of Astronomy researchers Antoine Dumont, Callie Clontz (also University of Utah), Anja Feldmeier-Krause (also University of Vienna) and Maria Selina Nitschai in collaboration with Andrea Bellini (Space Telescope Science Institute), Mattia Libralato (ESA and INAF Padova), Holger Baumgardt (The University of Queensland), Mayte Alfaro Cuello (Universidad Central de Chile), Jay Anderson (Space Telescope Science Institute), Nikolay Kacharov (Leibniz Institute for Astrophysics Potsdam), Sebastian Kamann (Liverpool John Moores University), Antonino Milone (University of Padova), Renuka Pechetti (Liverpool John Moores University) and Glenn van de Ven (University of Vienna).

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Astronomers find missing link in massive black hole formation - ScienceBlog.com

Join in for a free event, Astronomy in the Park, on Saturday, July 13 at Shumway Oak Grove Regional Park, I-5 at Eight Mile Road, Stockton. The program is presented by The Stockton Astronomical Society, Oak Grove Docent Council, and San Joaquin County Parks.

View planets through giant telescopes after sunset. The July 13 program starts at 8:30 p.m. and features Mercury and M3, Star Cluster in Canes Venatici. There is no charge for the program but there is a $6 cash parking fee at the park.

Also, prior to the viewing, enjoy astronomy activities at the Nature Center until 8 p.m.

For more information, call 209-953-8814 or 209-953-8800.

Upcoming shows will feature: Aug. 10, 8 p.m., M8 and M20 (Lagoon Nebula, Trifid Nebula); Sept. 7, 7:25 p.m., Saturn, M13 (Star Cluster) and M57 (Ring Nebula). On Oct. 12, view Star Cluster in Hercules and the Dumbbell Nebula at 6:30 p.m.; Nov. 9 at 5 p.m., see Jupiter, Saturn, Venus and M31 (Andromeda Galaxy); Dec. 7, 4:45 p.m., see Saturn, Mars, M33 (Triangulum Galaxy).

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Astronomy Nights return to Oak Grove - Riverbank News

The SpaceX Crew Dragon Freedom splashed down with four astronauts on October 14, 2022. Credit: NASA/u003c/strongu003e

For about 15 minutes on July 21, 1961, American astronautGus Grissomfelt at the top of the world and indeed he was.

Grissom crewed theLiberty Bell 7 mission, a ballistic test flight that launched him through the atmosphere from a rocket. During the test, he sat inside a small capsule and reached a peak of over 100 miles up before splashing down in the Atlantic Ocean.

A Navy ship, the USS Randolph, watched the successful end of the mission from a safe distance. Everything had gone according to plan, the controllers at Cape Canaveral were exultant, and Grissom knew he had just entered a VIP club as the second American astronaut in history.

Grissom remained inside his capsule and swayed on the gentle ocean waves. While he waited for a helicopter to take him onto the USS Randolphs dry deck, he finished recording some flight data. But then, things took an unexpected turn. An incorrect command in the capsules explosives system causedthe hatch to pop out, which let water flow into the tiny space. Grissom had also forgotten to close a valve in his spacesuit, so water began to seep into his suit as he fought to stay afloat.

After a dramatic escape from the capsule, he struggled to keep his head above the surface while giving signals to the helicopter pilot that something had gone wrong. The helicopter managed to save him at the last instant. Grissoms near-death escape remains one of the most dramatic splashdowns in history. But splashing down into water remains one of the most common ways astronauts return to Earth. I am aprofessor of aerospace engineeringwho studies the mechanisms involved in these phenomena. Fortunately, most splashdowns are not quite that nerve-racking, at least on paper.

Before it can perform a safe landing, a spacecraft returning to Earthneeds to slow down. While it is careening back to Earth, a spacecraft has a lot of kinetic energy. Friction with the atmosphere introduces drag, which slows down the spacecraft. The friction converts the spacecrafts kinetic energy to thermal energy, or heat.

All this heat radiates out into the surrounding air, which gets really, really hot. Since reentry velocities can be several times the speed of sound, the force of the air pushing back against the vehicle turns the vehicles surroundings into a scorching flow thats about 2,700 degrees Fahrenheit (1,500 degrees Celsius). In the case ofSpaceXs massive Starship rocket, this temperature even reaches3,000 degrees Fahrenheit (nearly 1,700 degrees Celsius).

Unfortunately, no matter how quickly this transfer happens, theres still not enough time during reentry for the vehicle to slow down to a safe enough velocity not to crash. So, the engineers resort to other methods that can slow down a spacecraft during splashdown.

Parachutes are the first option. NASA typically uses designs with bright colors, such as orange, which make them easy to spot. Theyre also huge, with diameters of over 100 feet, and each reentry vehicle usually uses more than one for the best stability. The first parachutes deployed, called drag parachutes, eject when the vehicles velocity falls below about 2,300 feet per second (700 meters per second).

Even then, the rocket cant crash against a hard surface. It needs to land somewhere that will cushion the impact. Researchers figured out early on that water makes an excellent shock absorber. Thus, splashdown was born.

Water has a relatively low viscosity that is, it deforms fast under stress and it has a density much lower than hard rock. These two qualities make it ideal for landing spacecraft. But the other main reason water works so well is because it covers 70% of the planets surface, so the chances of hitting it are high when youre falling from space.

The science behind splashdown is complex, asa long history proves.

In 1961, the U.S. conducted the first crewed splashdowns in history. These usedMercury reentry capsules.

These capsules had a roughly conical shape and fell with the base toward the water. The astronaut inside sat facing upward. The base absorbed most of the heat, so researchers designed a heat shield that boiled away as the capsule shot through the atmosphere.

As the capsule slowed and the friction reduced, the air got cooler, which made it able to absorb the excess heat on the vehicle, thereby cooling it down as well. At a sufficiently low speed, the parachutes would deploy.

Splashdown occurs at a velocity of about80 feet per second (24 meters per second). Its not exactly a smooth impact, but thats slow enough for the capsule to thwack into the ocean and absorb shock from the impact without damaging its structure, its payload or any astronauts inside.

Followingthe Challenger loss in 1986, when the space shuttle Challenger broke apart shortly after liftoff, engineers started focusing their vehicle designs on whats called thecrashworthiness phenomena or the degree of damage a craft takes after it hits a surface.

Now, all vehicles need to prove that they can offer a chance of survival on water after returning from space. Researchers build complex models, then test them with laboratory experiments to prove that the structure is sturdy enough to meet this requirement.

Between 2021 and June 2024, sevenof SpaceXs Dragon capsules performed flawless splashdowns on their return from the International Space Station.

On June 6, the most powerful rocket to date,SpaceXs Starship, made a phenomenal vertical splashdown into the Indian Ocean. Its rocket boosters kept firing while approaching the surface, creating an extraordinary cloud of hissing steam surrounding the nozzles.

SpaceX has been using splashdowns to recover the Dragon capsulesafter launch, with no significant damage to their critical parts, so that it can recycle them for future missions. Unlocking this reusability will allow private companies to save millions of dollars in infrastructure and reduce mission costs.

Splashdown continues to be the most common spacecraft reentry tactic, and with more space agencies and private companies shooting for the stars, were likely to see plenty more take place in the future.

This article is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.

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Heres how astronauts splash back to Earth - Astronomy Magazine

For generations, skywatchers and hobbyists around the world have admired the beauty of the cosmos.

The Astronomy Photographer of the Year contest channels that wonder into dazzling images, taken by amateur and professional astrophotographers as they vie for a 10,000 ($12,750) grand prize. The contest, arguably the biggest astrophotography competition in the world, is run by the Royal Observatory Greenwich in England and is in its 16th year.

This time around, photographers from 58 different countries submitted more than 3,500 awe-inspiring entries, in categories featuring our sun and moon, planets and comets, skyscapes, galaxies, stars and nebulas and other extraterrestrial sights. The 2024 Astronomy Photographer of the Year shortlist, unveiled on Tuesday, includes an aurora shaped like a dragon, a total solar eclipse and a breathtaking shot of the Milky Way in a desert sky.

A panel of art and astronomy experts judges the contest. The overall winners will be announced on September 12. Along with the cash prize, winning images will be displayed in an exhibition at the National Maritime Museum in London, which will go on view September 14.

Below is a selection of ten shortlisted photos that have stood out to the judges so far in this years competition.

In a phenomenon known as a coronal mass ejection (CME), the suns outer atmosphere launches magnetic fields and plasma mass into space. Sometimes, these charged particles collide with Earths magnetic field, producing intense auroras near the poles, visible from the ground. Geophysicists who study magnetic disturbances have created a nine-point scale that indicates how intense a disturbance is. This photo comes after a KP7-ranked storm, which is powerful enough to cause auroras and upset power systems.

That night, I think, was one of the most amazing that I have experienced in my nighttime photography outings, photographer Jose Miguel Picon Chimelis tells Royal Museums Greenwich (RMG) in a statement. There was a prediction of a KP7 storm, and I was excited as to what I might see. What I couldnt have imagined was seeing these colors in the sky; it was a spectacle that was difficult to describe.

A solar prominencea large, bright structure extending outward from the suns surfacelooks like a geyser in this close-up imagedemonstrating activity in the lower region of the suns atmosphere, known as chromospheric activity.

This giant stretches around thesuns limb for thousands of kilometers andis several times larger than Earth, photographer Miguel Claro notes to RMG. As comparison, its width is larger than the width of the rings of Saturn.

This capture is a still from a time-lapse of 248 images. Claro put these together into a 4k high-resolution solar movie comprising 1 hour and 20 minutes of spectacular photos. The image above is a selection from that movie.

Above an abandoned house and lone tree, the Milky Way lights up the sky during a Namib Desert night. The Namib Desert is one of the worlds best spots for stargazing, as it is sparsely populated and largely protected from light pollution, making it extremely dark.

Stefan Leibermann, who captured this image in Garub, Namibia, described to RMG the experience of getting the shot: In the middle of the Namib Desert, you can find an abandoned house, and right above it, the Milky Way rises. I put some lights in the house, set up my star tracker and seized the opportunity. Through a veil of clouds, halos around the stars created a dream-like effect.

Carina Letelier Baeza imaged this uniquely shaped aurora, which shined with intense red and green coloring throughout the night. The photographer tells RMG the lights look like a big dragon over rock pyramids.

Letelier Baeza snapped the photo at the Arctic Henge, located in one of Icelands most remote and northernmost villages. Designed like a huge sundial, the Arctic Henge casts shadows in precise locations between its arched gateways.

Capturing this image also took some luck with the weather. This site was the only place in Iceland with clear skies that night.

The Pleiades (also known as Messier 45 or the Seven Sisters) is an open star cluster that can be seen with the naked eye. Open clusters consist of similarly aged stars numbering from the tens to a few thousand, formed from the same molecular cloud. Mutual gravitational attraction holds the stars together.

At 444 light-years away, the Pleiades is one of the closest star clusters to Earth. The cluster, dominated by hot, blue, luminous stars formed over the last 100 million years, has only a few stars that can be seen without the aid of a telescopethough in total, it contains roughly 1,000.

Sndor Biliczki, who is newer to astrophotography, traveled to Spain to capture this image, to look for lower light pollution and better atmospheric conditions. The Pleiades is very popular among astrophotographers, but there are so many tiny details to be discovered in it that, for me, it was a tremendous experience to process, Biliczki tells RMG.

The picture above depicts the International Space Station (ISS) orbiting the Earth in the foreground, while the backdrop displays a 51 percent illuminated moon. The ISS is the largest space station ever built, maintaining an orbit with an average altitude of 250 miles. The ISS circles the Earth in roughly 90 minutes.

Kelvin Hennessy captured this photo from Gold Coast in Queensland, Australia, with the help of various apps to confirm the stations transit path across the moon.

Finding a suitable shooting location in a city was the most difficult part of the shoot, the photographer tells RMG. I used Google Earth and Google Street View to look for a suitable candidate with clear skies and parking along the very narrow transit corridor.

Located in the swan constellation Cygnus, the Pelican Nebula is a star-forming region roughly 30 light-years across, and its hydrogen gas actively emits light.

To capture this shot, Bence Toth used narrowband filters for image acquisition and created a color image with the Hubble Palette method. The Hubble Palette method is a recognizable coloring system for images, made famous by the Hubble Space Telescope, and it can often help viewers see more detail throughout space images.

The fine dust and gas structures really reminded me of mist on mountains hit by the rising sun, Toth tells RMG.

To astronomers, SNR stands for supernova remnant, which describes a lingering structure resulting from the explosion of a star. A supernova remnant consists of ejected materials and shock waves from the blast.

This object, called SNR G156.2+5.7, lies in the constellation Auriga, behind dark molecular clouds. This means we have to look at this supernova remnant through the dust clouds in deep space, photographer Bray Falls tells RMG.Luckily, there are enough breaks in the clouds to see an incredible structure.

Is this the cosmic sandworm of Arrakis from Dune or the terrifying Graboid from the film Tremors? Alessandro Ravagnin, one of the collaborators who captured this shot, says to RMG.

This image shows CG 4, a star-forming region in the southern Puppis constellation about 1,300 light-years from Earth. In it, dense molecular clouds can collapse to form stars. The galaxy in the top left corner is a spiral galaxy seen nearly edge-on. While it may look close, is actually 118 million light-years away.

A group of astrophotographerscalled the Shared Remote Astrophotography (ShaRA) teamtogether rented a telescope and took several images from El Sauce Observatory, Ro Hurtado, Chile. They voted on the best ones, then merged them into this image.

As many might remember, a total solar eclipse inspired fanfare and viewing parties across North America earlier this year. However, total solar eclipses, which happen when the moon passes directly between the sun and Earth, blocking the face of the sun completely, occur somewhere on our planet about every 18 months.

This shot was taken in Exmouth, Western Australia, which experienced 62 seconds of totality during a hybrid solar eclipse in April 2023. The image showcases the suns corona, its pink chromosphere and Bailys beads, which are narrow openings of sunlight that shine through due to the moons rugged landscape.

With this collage, I wanted to show the beauty of the corona, photographer Gwenal Blanck tells RMG. I superimposed seven pictures for the background and six others for the chromosphere and prominences.

A total solar eclipse is one of the most beautiful spectacles nature can offer. Everyone should experience it at least once in their lifetime, Blanck adds.[Totality] seems short, but it was worth every penny and effort to get there. Pictures dont do justice to this wonder.

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See Ten Awe-Inspiring Images From the Astronomy Photographer of the Year Contest - Smithsonian Magazine

All photos by Robert Reeves

For over 400 years, legions of lunar cartographers have been surveying the surface of the Moon first by telescope and then by spacecraft charting and naming its features.

The resulting lunar map is constantly evolving. Over time, new names are added while existing names are dropped or changed after research shows a feature to be of a different geological type. The International Astronomical Union (IAU) establishes guidelines for lunar names; their approval is required to make a name official. These efforts keep scientific order in how we identify features and navigate the face of the Moon.

But our relationship with the Moon is not all science and regulated order. It is human nature to create endearments for the things we love. Deep-sky observers bestow unofficial nicknames to many, like the Lagoon (M8), Rosette (NGC 22379/44), and California (NGC 1499) nebulae. Luna is no exception; it too has its share of fanciful unofficial names for its features.

Human whimsy often trumps science in these names, such as the Cobra Head at the volcanic source that once fed flowing lava into Schrters Valley. During the Apollo expeditions, many astronauts made their mark on the Moon by giving features unofficial names, such as Jim Lovells famous Mount Marilyn, which he named after his wife during Apollo 8. While some of these popular lunar names are eventually rubber-stamped by the IAU (including Mount Marilyn in 2017), others do not appear on a map, but persist by general acceptance.

The selection of unofficial names presented here include some modestly proposed by the author. Whether they stick in lunar lexicon depends on the whims of Moon lovers everywhere.

Lunar nicknames bring life and familiarity to a stark and unforgiving landscape that is nonetheless appealing because of its alien strangeness. For the avid astronomer, the names here should become as familiar as the terms of endearment that we apply to the gems of the Milky Way and beyond.

Named by: Robert Reeves

Official name: Cleomedes, Burckhardt, Geminus, and Messala craters

Size: 81 miles (131 km), 34 miles (54 km), 51 miles (82 km), 76 miles (122 km)

Coordinates: centered at 33.5 N, 57.8 E

Feature named after: Appearance of sequential steppingstones

The linear string of four large craters extending north from Mare Crisium (at far lower right in this image) is reminiscent of steppingstones leading off to an adventuresome place. Each step is a leap through time, as none of these craters are the same age. The southernmost is flat-floored Cleomedes, an 81-mile-wide (131 kilometers) Nectarian-epoch crater that dates back 3.85 billion to 3.95 billion years ago. The smaller and slightly younger Imbrian-epoch crater Burckhardt follows. Farther north the sharper form of Geminus is even younger, dating to the Eratosthenian epoch. The final steppingstone, massive, ruined, pre-Nectarian-epoch Messala, is the oldest.

Named by: Unknown

Official name: Furnerius A, Stevinus A

Size: 7 miles (11 km), 5 miles (8 km)

Coordinates: 33.0 S, 54.7 E

Feature named after: Appearance of oncoming car headlights

Satellite craters usually do not draw the casual observers attention, but the brilliant, similar-sized Furnerius A and Stevinus A are an exception. Both young Copernican-epoch craters display disproportionately bright ray systems. The brilliant craters bracket the 45-mile-wide (72 km) Stevinus on the Moons southeast quadrant, creating the illusion of approaching car headlights.

Named by: Robert Reeves

Official name: Meton, Meton C, D, E

Size: 124 miles (200 km)

Coordinates: 72.6 N, 20.0 E

Feature named after: Appearance of a four-leaf clover

The merged forms of craters Meton C, D, and E overlaying Meton Crater on the northern polar landscape create a four-leaf clover shape representing a lunar good-luck charm. The interiors and rims of all four pre-Nectarian-epoch craters were buried by the wave of ejecta thrown from the Imbrium Basin impact 3.85 billion years ago, forming a common floor lying 5,000 feet (1,500 meters) below the surrounding territory.

Named by: Unknown

Official name: Rupes Liebig

Size: 90 miles (145 km)

Coordinates: 45.9 W, 25.1 S

Feature named after: Scarp with the same name

Lengthy Rupes Liebig arcs along the western shore of Mare Humorum and descends 2,300 feet (700 m) to the mare floor. The 6-mile-wide (9 km), 5,600-foot-deep (1,700 m) crater Liebig F lies atop the scarp and inspires the unofficial designation of the Liebig Wall.

Named by: Robert Reeves

Official name: None

Size: 6 miles (10 km)

Coordinates: 22.0 N, 55.5 E

Feature named after: Resembles a waterfall cascading down a mountainside

A bright splash of light-colored material ejected from a 0.8-mile-wide (1.3 km) craterlet on a mountainside on the northern rim of Mare Crisium looks almost as if it were a waterfall cascading down to the plain below. This bright, white spot can be found by following the northward arc of the craters Picard, Pierce, and Swift on the western side of Crisium. The spot has been reported to be a transient lunar event, as its reflectivity is variable and dependent on the Sun illumination angle, as seen in a comparison of these two images. The physical feature, however, is permanent. While the spot has no official name, Rik Hill, now retired from the University of Arizona, published an analysis of it thus, it is referred to as Hills Waterfall.

Named by: Robert Reeves

Official name: Lamont

Size: 52 miles (83 km)

Coordinates: 5.1 N, 23.3 E

Feature named after: Spiderlike appearance

First charted as a ghost crater on western Mare Tranquillitatis, Lamont is now regarded as a small ghost basin due to the 84-mile-wide (135 km) outer ring surrounding it. Lamont contains a spiderlike structure consisting of a system of lengthy radial wrinkle ridges that rise between 330 and 1,000 feet (100 and 300 m) above their surroundings. These form the legs of the spider.

Named by: Robert Reeves

Size: 44 miles (70 km)

Coordinates: 50.2 N, 20.1 E

Feature named after: Appearance of the letter S under sunset illumination

The apparition of the letter S appears for several hours at sundown on the eastern flank of Aristoteles Crater. The S is a combination of the northern rim of 19-mile-wide (30 km) Mitchell Crater, protruding from under Aristoteles eastern rim, and the swirl of topography north of Mitchell.

Named by: Unknown

Official name: Linn A 1

Size: 22 miles (35 km)

Coordinates: 30.4 N, 10.1 E

Feature named after: Appearance of a Valentines heart

The volcanic dome Linn A 1, just right of center in this image, rises 1,000 feet (300 m) above western Mare Serenitatis and is topped by half a dozen smaller volcanic domes, some capped with a small caldera. The rounded pancake-shaped dome resembles a classic Valentines heart.

Named by: Robert Reeves

Official name: None

Size: 93 miles (150 km)

Coordinates: 10.5 N, 6.8 E

Feature named after: Heart-shaped appearance

Some 370 miles (600 km) south of Valentine Dome lies another heart-shaped feature: the dark volcanic-ash-dusted mountains north of Rima Hyginus on Mare Vaporum, which reach 3,300 feet (1,000 m) in elevation. The mountains have no official name, but the overall appearance of the rugged region prompts the unofficial designation of the Heart of the Moon.

Named by: Unknown

Official name: None

Size: 68 miles (110 km)

Coordinates: 25.4 S, 1.0 E

Feature named after: Appearance of the letter X

As the First Quarter sunrise terminator crosses the merged rims of the adjacent craters Purbach, La Caille, and Blanchinus, they protrude in an X-shaped pattern that catches the first rays of sunrise and remains visible for about four hours.

Named by: Unknown

Official name: Hills: none; Tadpole: Reiner Gamma

Size: Hills: 171 miles (275 km); Tadpole: 124 miles (200 km)

Coordinates: Hills: 12.6 N, 53.9 W; Tadpole: 7.6 N, 58.6 W

Feature named after: Hills: nearby crater Marius; Tadpole: resemblance to a frog tadpole

The Marius Hills are the unofficial name for the 262 individual mounds on a 27,000-square-mile (70,000 square km) region of Oceanus Procellarum west of the crater Marius. Although casually called hills, the features are volcanic domes and cinder cones. Reiner Gamma, located west of the Marius Hills and affectionately known as the Tadpole, gets its nickname from its resemblance to this stage in a frogs life cycle. This feature possesses no vertical relief, does not cast a shadow, and is officially classified as an albedo feature.

Named by: Straight Wall: Birt and Lee (1865); Ancient Thebit: Chuck Wood

Official name: Straight Wall: Rupes Recta; Ancient Thebit: none

Size: Straight Wall: 72 miles (116 km); Ancient Thebit: 105 miles (170 km)

Coordinates: 21.7 S, 7.7 W

Feature named after: Straight Wall: Linear appearance; Ancient Thebit: Proximity to Thebit Crater

Rupes Recta is a lengthy linear feature known by the beloved name of Straight Wall (a rough translation of its Latin name). It is also known as Huygens Sword in honor of 17th-century astronomer Christiaan Huygens, who studied the feature. The curved exposed crater rim at the southern end of Rupes Recta is also known as the Stags Horn. Straight Wall lies in an unnamed ghost crater marked by a horseshoe-shaped bay east of the Wall and the circular wrinkle ridges west of it. This crater was unofficially designated Ancient Thebit by Chuck Wood after the nearby, younger Thebit Crater.

Named by: Chuck Wood

Official name: None

Size: 13 miles (21 km)

Coordinates: 47.8 N, 0.3 W

Feature named after: Two mountains guarding a narrow gorge

The mouth at the western end of the Alpine Valley (Vallis Alpes) slashing through the lunar Alps (Montes Alpes) funnels from 13 miles (21 km) across down to a gorge just 660 feet (200 m) wide at the valleys entrance. The narrow channel is bounded by a northern massif that rises 6,500 feet (2,000 m), while the southern massif rises 8,200 feet (2,500 m) above the plains of Mare Imbrium. Chuck Wood unofficially named the twin mountains the Guardians.

Named by: Unknown

Official name: Tycho rays

Size: 447 miles (720 km)

Coordinates: 32.8 S, 19.5 W

Feature named after: Parallel placement, akin to railroad tracks

Tycho Craters two prominent northwestern ray streamers do not diverge from a point within Tycho, and each ray is tangential to the craters rim. This unusual parallel nature prompted the unofficial designation of the Railroad Tracks.

Named by: Robert Reeves

Official name: Flamsteed P, Wichmann R

Size: 62 miles (100 km), 40 miles (64 km)

Coordinates: 4.5 S, 40.7 W

Feature named after: Ghost crater locations

The Moons large basins were once dotted with craters, before volcanic flooding flooded many of them and created the maria. Some remain visible as ghost craters with their crowns protruding above the mare basalt. Those on southern Oceanus Procellarum are collectively known as the Ghosts of Procellarum.

Named by: Unknown

Official name: None

Size: 44 miles (70 km)

Coordinates: 16.8 S, 31.5 W

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20 things to see on the Moon: An observers guide to lunar names - Astronomy Magazine

For the first time, astronomers have spotted a middleweight black hole in the nearby universe. The discovery could help solve the riddle of how even heftier black holes form and grow up with their host galaxies.

The black hole, which sits about 16,000 light-years from Earth in the center of star cluster Omega Centauri, is at least 8,200 times as massive as the sun, putting it squarely in a rare category of intermediate-mass black holes, researchers report July 10 in Nature.

Most of the black holes astronomers have detected fall into one of two categories. Theyre either stellar-mass black holes, with masses up to about 100 times that of the sun, or supermassive black holes, which reside in the centers of galaxies and clock in at hundreds of thousands to billions of times the mass of the sun.

Black holes with masses in the middle could help span the gap between the two categories and explain how the supermassive ones got so big. But these black holes are a little like Bigfoot: There have been many claimed sightings, but most turn out not to be real (SN: 2/8/17).

Theres this rather wide mass range, between 100 and 100,000 solar masses, where there are only very few detections, says astronomer Maximilian Hberle of the Max Planck Institute for Astronomy in Heidelberg, Germany. Its interesting to find out whether they are there, and we just dont see them because they are hard to detect. Or maybe theres also a reason why they dont exist at all.

One reason to think midsized black holes should exist is because the supermassive black holes astronomers have spotted in the early universe didnt have time to grow so big if they were just eating gas and stars like black holes do today (SN: 1/18/21). If those black holes grew from mergers of intermediate-mass seeds, that could solve the puzzle (SN: 6/2/23).

Its like a missing link that is needed to explain the existence of the supermassive black holes, says Texas-based astronomer and data scientist Eva Noyola, who was not involved in the new work. If its proven that [intermediate-mass black holes] happen in dense stellar clusters, you have a solution there thats pretty elegant and simple.

So astronomers have been hunting for midsize black holes for decades, and searching Omega Centauri specifically since at least 2008. As the most massive cluster of stars in the Milky Way, its a relatively easy spot to search, and it may be the remnant core of another galaxy that merged with the Milky Way about 10 billion years ago (SN: 11/1/18).

Its basically a galactic nucleus frozen in time, says study coauthor Nadine Neumayer, also of the Max Planck Institute for Astronomy. Its black hole could be representative of all small galaxies black holes 10 billion years ago. It tells us immediately something about the seed mass for black holes.

But previous studies left it unclear whether Omega Centauri hosted a single medium-size black hole, or a bunch of smaller black holes close together.

Using 20 years of Hubble Space Telescope observations, Hberle and colleagues tracked the motions of 1.4 million individual stars in the cluster and searched for stars moving faster than expected.

The team found seven stars zipping around the innermost regions of the cluster at speeds between 66 and 113 kilometers per second speeds that should have rocketed the stars out of the cluster altogether. The only way those stars could remain in the cluster is if a single massive object is holding them close, the team concludes.

The observations of superfast stars, combined with other observations through the years, should resolve the debate about the black hole in Omega Centauri, says Noyola, who was on the team that first claimed to see the black hole in 2008 and faced skepticism when they reported the result.

It wasnt until over a decade later that astronomers nabbed undeniable evidence of an intermediate mass black hole. The first solid detection came from the LIGO gravitational wave observatory, which recorded ripples in spacetime shaken off after two smaller black holes merged to form a single black hole with about 142 solar masses (SN: 9/2/20). But that collision occurred about 17 billion light-years from Earth, making it challenging to study.

Omega Centauris black hole has two advantages over that one, from an astronomers perspective: Its in our galactic neighborhood, and astronomers can continue to observe it. Hberle and his colleagues are planning to use the James Webb Space Telescope, or JWST, to get more information on the orbiting stars speeds, which will let them put better limits on the black holes mass.

Another group, led by astrophysicist Oleg Kargaltsev at George Washington University in Washington, D.C., is using JWST to look for light emitted by super-hot gas flowing into the black hole.

It will be a completely independent, very different method of proving that there is an intermediate-mass black hole, Kargaltsev says.

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A middleweight black hole has been spotted for the first time in our galaxy - Science News Magazine

Friday, July 5 Earths orbit around the Sun is not perfectly circular, such that our planet sits marginally farther from the Sun in July and closer to it in January. Today, Earth reaches aphelion, that farthest point from the Sun, at 1 A.M. EDT. At that time, we are 94.5 million miles (151 million kilometers) from our star.

New Moon occurs this evening at 6:57 P.M. EDT, which is great news for those in the Northern Hemisphere hoping for a look at Comet 13P/Olbers, which is low but observable after sunset. An hour after sunset, the comet is 20 high in the northwest. It was recently recorded glowing at magnitude 6.7, great for larger binoculars or a small scope. For a signpost, you can use the magnitude 4 star 10 Ursae Majoris, which sits just less than 0.5 to the comets southwest.

Olbers is located in the constellation Lynx, just under the front feet of the Great Bear Ursa Major. As darkness falls, youll see the Big Dipper standing on its bowl with the handle pointing straight up appear higher in the northwest, well above the comets position. Much closer to the horizon and setting quickly is Cancer the Crab, carrying the famous open cluster M44. Swing your binoculars or scope down to see if you can catch the cluster in the 90 minutes or so after sunset, before it disappears below the horizon.

The dark, moonless skies will also allow observers to easily catch the dwarf planet 1 Ceres glowing at magnitude 7.3 as it reaches opposition in Sagittarius the Archer tonight at 8 P.M. EDT. Check out last Fridays entry for more details on how to spot it, or tune in later this week, when well stop back to take a look.

Sunrise: 5:38 A.M. Sunset: 8:32 P.M. Moonrise: 4:51 A.M. Moonset: 8:56 P.M. Moon Phase: New *Times for sunrise, sunset, moonrise, and moonset are given in local time from 40 N 90 W. The Moons illumination is given at 12 P.M. local time from the same location.

Saturday, July 6Early-morning observers can catch two of Jupiters moons crossing the giant planet with their shadows this morning, although what youll see depends on your location.

The gas giant rises in central Taurus around 3:15 A.M. local daylight time. Those on the East Coast and in the Midwest can catch the passage of Europas shadow across the disk, moving from east to west, visible as the planet is rising in these regions. Around 4:45 A.M. EDT, Europa itself moves onto the disk, again from the east moving west. Io (closer) and Callisto lie farther east, while Ganymede sits alone to the planets west.

Ios shadow slips onto the disk around 5:15 A.M. CDT after sunrise in the Eastern time zone and as twilight is brightening the sky in the Midwest. Europas shadow is now gone and Europa is approaching the western limb of the planet. Io follows its shadow just under an hour later, shortly after 5 A.M. MDT, and Europa slides off the disk just over 10 minutes later, at 5:12 A.M. MDT.

Sunrise: 5:38 A.M. Sunset: 8:31 P.M. Moonrise: 5:55 A.M. Moonset: 9:39 P.M. Moon Phase: Waxing crescent (1%)

Sunday, July 7The Moon passes 3 north of Mercury at 3 P.M. EDT. You can catch the pair, along with bright Venus, in the evening sky shortly after sunset though youll need to be quick.

Some 20 minutes after sunset, Venus is just 2 high in the west. Youll need a clear horizon to spot it; an observing location a bit higher than your surroundings will help as well. The planet glows a bright magnitude 3.9, which should help you spot it. Through a telescope, Venus appears fully lit (99 percent) and spans 10.

To the upper left of Venus are Mercury and the Moon; our satellite is a delicate 5-percent-lit crescent hanging 3 above Mercury. The tiny planet glows at magnitude 0.2 and should pop out of the growing twilight. Youll have longer to observe it, as it sits 10 high at this time. With the aid of a telescope, youll note that Mercury is only 67 percent lit and appears a little more than half the width of Venus, about 6 on the sky.

Mercury is roughly 1.5 east of M44 if you werent able to observe it on Friday, you might be able to catch the open cluster tonight, as its a bit higher above the horizon sooner after sunset though the sky is also brighter. Binoculars or a telescope will certainly bring it out long before the sky is dark enough to see much with the naked eye.

Sunrise: 5:39 A.M. Sunset: 8:31 P.M. Moonrise: 7:02 A.M. Moonset: 10:13 P.M. Moon Phase: Waxing crescent (3%)

Monday, July 8 Saturn is rising around local midnight and presents a stunning sight with its rings nearly edge-on. The planet is currently tilted just 2 with respect to our line of sight; this tilt will increase over the next few months before decreasing again for 2025s ring-plane crossing.

Located in Aquarius, Saturn glows at magnitude 0.9 and is easy to zero in on with a telescope. Thats exactly what youll want to do this morning to catch the planets largest moon, Titan, passing behind the disk and disappearing in an occultation. The event is visible in the eastern two-thirds of the U.S.; only those in the Pacific time zone wont be able to watch it.

Titan is approaching the planet from the west as it rises; the large moon draws closer to the limb, finally disappearing around 2:40 A.M. EDT. At the same time, those with large scopes (10 inches) and video-capture systems may notice the smaller moon Mimas transiting the planets disk with its shadow. Mimas is moving from east to west, led by the shadow, passing in front of Saturns south polar region. Additional moons Enceladus and Tethys are hanging out just east of the eastern edge of the rings, while Dione and Rhea are to the west. These moons are all 10th magnitude or fainter, so may not be easily picked up in smaller scopes.

Sunrise: 5:40 A.M. Sunset: 8:31 P.M. Moonrise: 8:08 A.M. Moonset: 10:40 P.M. Moon Phase: Waxing crescent (8%)

Tuesday, July 9 This evening, turn your eyes eastward as the constellation Aquila the Eagle climbs in the sky. The constellation is perhaps best known for its bright star Altair, which serves as one point in the famous Summer Triangle asterism. But Aquila is home to numerous deep-sky objects, including our target for tonight: NGC 6709, also known as the Flying Unicorn.

Located in the far western region of Aquila, near its border with Ophiuchus, this open cluster glows at magnitude 6.7 and spans about 15 (or ) on the sky. You can find it by skimming about 5 southwest of 3rd-magnitude Zeta () Aquilae.

NGC 6709 lies some 3,500 light-years away and contains a few hundred stars. Astronomers believe it is about 140 million years old. It is called the Flying Unicorn because some observers think its shape is akin to that of the mythological beast. What do you think? In the image above, the unicorn is facing to the right. Note that your telescope may flip or rotate the image you see compared to the one here.

Sunrise: 5:40 A.M. Sunset: 8:30 P.M. Moonrise: 9:13 A.M. Moonset: 11:04 P.M. Moon Phase: Waxing crescent (14%)

Wednesday, July 10 If youve got a larger scope (8 inches), tonights target should be on your list: the 9th-magnitude galaxy NGC 4631, also called the Whale Galaxy. Youll find the constellation Canes Venatici beneath (to the left of) the Big Dippers handle in the north tonight before midnight. NGC 4631 is located about halfway on a line drawn between Cor Caroli (Canes Venaticis alpha star) and Gamma () Comae Berenices to its southwest. The galaxy itself is 6.5 southwest of Cor Caroli.

Measuring about 15 along its longest side, the Whale Galaxy is an edge-on spiral with a bright center and mottled arms. Its shape has been distorted by a nearby satellite galaxy, NGC 4627, which itself has been heavily warped by the interaction. You may even be able to spot 12th-magnitude NGC 4627, some 2.5 northwest of the larger galaxy.

The celestial cetacean also has another companion: 10th-magnitude NGC 4656, also called the Hockey Stick Galaxy. This sits just 0.5 east-southeast of the Whale Galaxy and short-focal-length telescopes will show both in the same field of view. Its heavily distorted shape also speaks to interactions with the Whale.

Sunrise: 5:41 A.M. Sunset: 8:30 P.M. Moonrise: 10:14 A.M. Moonset: 11:25 P.M. Moon Phase: Waxing crescent (21%)

Thursday, July 11 Dwarf planet 1 Ceres is passing near the globular cluster M54 in Sagittarius the Archer. You can catch the pairing tonight in the south a few hours after sunset, as the Teapot asterism stands about 20 above the horizon (depending on your observing location, of course).

Ceres is near magnitude 2.6 Zeta Sagittarii, which links the base of the handle with the teapots body. With binoculars or a telescope, simply center on Zeta and then swing your view about 1 west of the star to spot the seventh-magnitude main-belt world.

M54 is just 1 southwest of Ceres, forming a triangle together with the dwarf planet and Zeta Sag. The globular cluster shines at magnitude 7.6 roughly the same brightness as Ceres, though the compact ball of stars spans about 12 in diameter. Located nearly 90,000 light-years away, M54 is likely not one of the Milky Ways globulars at all, but instead belongs to the Sagittarius Dwarf Elliptical Galaxy, or SagDEG. This small satellite galaxy of the Milky Way was not discovered until 1994.

Ceres will swing closer to M54 over the next few days; it will stand due north of the cluster on the evening of the 15th.

Sunrise: 5:42 A.M. Sunset: 8:29 P.M. Moonrise: 11:14 A.M. Moonset: 11:44 P.M. Moon Phase: Waxing crescent (29%)

Friday, July 12The Moon reaches apogee, the farthest point from Earth in its orbit, at 4:11 A.M. EDT, when it will sit 251,259 miles (404,362 km) away.

Mars and Uranus are drawing close together in the early-morning sky; they will pass within 0.6 of each other on the 15th. You can check their progress today in the two hours or so before sunrise, as the pair climbs in the eastern sky. Both are located in far western Taurus, to the right of the Pleiades star cluster. First-magnitude Mars is visible to the naked eye about 8 southwest of the cluster. The Red Planets disk spans some 6 on the sky, currently the same apparent size as Mercury.

Once youve found Mars, youll need binoculars or a telescope to readily spot magnitude 5.8 Uranus. The distant ice giant sits just over 2 northeast of Mars and will appears as a flat gray star. Over the next few days, Uranus will appear to stay put as Mars draws closer, passing due south of the ice giant next week on Monday. Well certainly highlight the event, so check back for details then!

Sunrise: 5:42 A.M. Sunset: 8:29 P.M. Moonrise: 12:13 P.M. Moonset: Moon Phase: Waxing crescent (38%)

Sky This Week is brought to you in part by Celestron.

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The Sky This Week from July 5 to 12: Saturn hides Titan from view - Astronomy Magazine

Researchers have detected fast-moving stars in a nearby star cluster within the Milky Way. The finding suggests the presence of an elusive black hole which may be the closest one to Earth.

The star cluster, Omega Centauri, is a collection of around 10 million stars, visible as a smudge in the night sky south of the Equator.

It looks no different to similar clusters through a small telescope, but the new study confirms what astronomers had been suspecting for some time it contains a central black hole.

The black hole, which is at a distance of about 18,000 light-years, appears to be stuck in an intermediate stage of evolution, and is considerably less massive than typical black holes in the centres of galaxies.

Researchers say the finding appears to be the missing link between stellar and supermassive black holes.

Black holes have been observed in various sizes, including stellar-mass black holes with masses around five to 150 times that of the Sun, to supermassive black holes which are more than 100,000 times the mass of the Sun.

The black hole appears to be stuck in an intermediate stage of evolution. Photo: AFP

However, only a few intermediate-mass black holes, between 150 and 100,000 times the mass of the Sun, have been discovered.

Omega Centauri seems to be the core of a small, separate galaxy whose evolution was cut short when the Milky Way swallowed it, the study suggests.

Dr Nadine Neumayer, a group leader at the Max Planck Institute for Astronomy in Germany, said: Previous studies had prompted critical questions of So where are the high-speed stars?

We now have an answer to that and the confirmation that Omega Centauri contains an intermediate-mass black hole.

At a distance of about 18,000 light-years, this is the closest known example of a massive black hole.

Nasas Ingenuity helicopter has sent final message from red planet to Earth

The supermassive black hole in the centre of the Milky Way is at a distance of about 27,000 light-years.

The study, led by Maximilian Haberle of the Max Planck Institute for Astronomy, is based on more than 20 years of Hubble Space Telescope observations, and published in the Nature journal.

Writing in an accompanying article, Daryl Haggard and Adrienne Cool said: These newly discovered stars offer the best evidence yet that Alpha Centauri harbours an intermediate-mass black hole.

The results could suggest that searching for intermediate-mass black holes in other globular clusters may be warranted.

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Astronomers find black hole closest to Earth 18,000 light-years away - YP

Credit: NASA/Carla Cioffi

Edward Stone was a pre-eminent space scientist with an exceptional record of leading space missions and building ground-based astronomical facilities. The public face of NASAs Voyager missions for the launch of the two probes in 1977, he served as project scientist for 50 years. Stone introduced the world to the wonders of the gas-giant planets (Jupiter, Saturn, Uranus and Neptune) in multiple press conferences, from Voyager 1s encounter with Jupiter in 1979 to Voyager 2s fly-by of Neptune in 1989. He also oversaw the probes entering interstellar space the first in 2012 and the second in 2018. They continue to transmit data to Earth today.

At the helm of the California Association for Research and Astronomy in the 1990s, Stone was involved in the development of the twin 10-metre Keck telescopes on Maunakea in Hawaii, two of the most productive ground-based astronomical facilities ever built. And as the executive director of the Thirty Meter Telescope, for eight years he oversaw the huge international collaboration that plans to build one of the worlds largest opticalinfrared telescopes on the same mountain land that is sacred to Native Hawaiians, leading to years-long protests and controversy. The telescope aims to capture light from the earliest galaxies in the Universe and search for habitable planets. Stones involvement was a service to the astronomy community, because his observational interests were focused on cosmic rays.

Stone was born in Knoxville and grew up in Burlington, both in Iowa. His father was a construction supervisor who communicated his curiosity about how things worked to his son. Stone studied physics at the University of Chicago, Illinois, for a masters degree and PhD. Soon after he started studying there, in 1957, the Soviet Union launched Sputnik 1 the first artificial Earth satellite starting the space race. Stone took notice, and was at a good place to get involved. His thesis adviser, cosmic-ray-research pioneer John Simpson, was deploying instruments attached to high-altitude balloons as well as using ground-based neutron monitors. Instruments on rockets soon followed. Stones thesis experiment was on a now-declassified US spy satellite, Discoverer 31, flown in 1961.

The Milky Way is less weird than we thought

After earning his doctorate in 1964, Stone joined Rochus Robbie Vogt, whom he studied alongside at Chicago, at the California Institute of Technology (Caltech) in Pasadena, as a research fellow. Together, they formed the Space Radiation Laboratory, where I work. They focused on observations of cosmic rays, with instruments first carried on balloons and later launched into space. Stone moved up the academic ranks at Caltech, becoming a professor of physics in 1976. In 1972, he was appointed project scientist for NASAs MJS77 mission, later renamed Voyager. Stone was also directly involved in developing an instrument for use aboard the Voyagers the Cosmic Ray Subsystem helping to design its cosmic-ray telescopes and draw up the calibration procedures.

The Voyager missions capitalized on a rare alignment of the four gas-giant planets a once-in-176-years opportunity that allowed a single spacecraft to visit all four. It required a launch between 1976 and 1980 to succeed. For budget reasons, only a two-spacecraft mission to Jupiter and Saturn was initially approved. Voyager 2 was later re-programmed to visit Uranus and Neptune as well.

Eleven experiments were planned. Stones role included developing a planetary fly-by programme that would be agreeable to all the participating principal investigators. To accomplish this, he learnt about the science of each experiment earning the respect of all involved. One of the researchers, Tom Krimigis, recalled: He was always knowledgeable, insightful and fair in his decisions, with the principal focus on the best science; he never deviated from that.

159 days of solitude: how loneliness haunts astronauts

The Voyager planetary fly-bys resulted in many discoveries, including moons, rings, a moon with volcanoes, moons with more water than there is on Earth and Triton a moon of Neptune that is one of the coldest places in the Solar System and yet has geysers. Textbooks on the outer planets of the Solar System were rewritten. But the culmination of Stones research career came when Voyager 1 crossed the heliopause the boundary between interplanetary and interstellar space, at 18.2 billion kilometres from the Sun. The Cosmic Ray Subsystem was at last able to measure something that cannot be quantified inside the heliopause because of the Suns outflowing solar wind: the intensity of low-energy cosmic rays in the Milky Way galaxy.

For his work on the Voyagers, Stone was awarded the National Medal of Science by then US president George Bush in 1991, and in 2019 he received the Shaw Prize in astronomy. A prolific administrator and multitasker, Stone chaired the physics, mathematics and astronomy division at Caltech for five years in the 1980s and was the director of NASAs Jet Propulsion Laboratory from 1991 to 2001. During his tenure there, he oversaw the first landing of a robot on another planet the Mars rover Sojourner. His work ethic was extraordinary. In total, he held a major role on 14 NASA missions and 2 US Department of Defense missions most of the time while running the Space Radiation Laboratory at Caltech.

In 2022, owing to declining health, Stone retired as Voyager project scientist and became emeritus professor at Caltech. He was always even-tempered in his dealing with colleagues and sought to reach a consensus on whatever debate was going on. He will be greatly missed in both the space-science and astronomical communities.

The author declares no competing interests.

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Edward C. Stone obituary: physicist who guided Voyager probes to interstellar space - Nature.com

Temperate exoplanet LHS 1140 b may be a world completely covered in ice (left) similar to Jupiters moon Europa or be an ice world with a liquid substellar ocean and a cloudy atmosphere (centre). LHS 1140 b is 1.7 times the size of our planet Earth (right) and is the most promising habitable zone exoplanet yet in our search for liquid water beyond the Solar System. Image credit: B. Gougeon/Universit de Montral

Study: Transmission spectroscopy of the habitable zone Exoplanet LHS 1140 b with JWST/NIRISS

A team that includes a University of Michigan astronomer has identified a temperate exoplanet as a promising super-Earth ice or water world.

The findings, led by Universit de Montral, show that the habitable zone exoplanet, LHS 1140 b, is not likely a mini-Neptune, a small so-called gas giantlarge planets composed mostly of gaswith a thick hydrogen-rich atmosphere. The planet, located about 48 light-years away in the constellation Cetus, emerges as one of the most promising habitable zone exoplanet candidates known, potentially harboring an atmosphere and even a liquid water ocean.

Data from the James Webb Space Telescope were collected in December 2023 and added to previous data from other space telescopes Spitzer, Hubble, and TESS to solidify this result, accepted for publication in The Astrophysical Journal Letters this week.

This is the first time we have ever seen a hint of an atmosphere on a habitable zone rocky or ice-rich exoplanet. Detecting atmospheres on small, rocky world is a major goal from JWST, but these signals are much harder to see than for giant planet atmospheres, said Ryan MacDonald, NASA Sagan Fellow in the U-M Department of Astronomy who was key in the analysis of LHS 1140 bs atmosphere. LHS 1140 b is one of the best small exoplanets in the habitable zone capable of supporting a thick atmosphere, and we might just have found evidence of air on this world.

LHS 1140 b, an exoplanet orbiting a low-mass red dwarf star roughly one-fifth the size of the sun, has captivated scientists due to it being one of the closest exoplanets to the solar system that lies within its stars habitable zone. Exoplanets found in this Goldilocks Zone have temperatures that would allow water to exist on them in liquid form, a crucial element for life as we know it on Earth.

One of the critical questions about LHS 1140 b was whether it is a mini-Neptune type exoplanet or a super-Eartha rocky or water-rich planet larger than Earth.

Of all currently known temperate exoplanets, LHS 1140 b could well be our best bet to one day indirectly confirm liquid water on the surface of an alien world beyond our solar system, said Charles Cadieux, lead author of the science paper and doctoral student at Universit de Montral. This would be a major milestone in the search for potentially habitable exoplanets.

Analysis of the teams observations strongly excluded the mini-Neptune scenario, with evidence suggesting the exoplanet LHS 1140 b is a super-Earth that may even have a nitrogen-rich atmosphere like that of Earths. However, the team cautions that additional observations with JWST observations will be necessary to confirm the signature of nitrogen gas.

Estimates based on all accumulated data reveal that LHS 1140 b is less dense than expected for a rocky planet with an Earth-like composition, suggesting that 10 to 20% of its mass may be composed of water. This discovery points to LHS 1140 b being a compelling candidate water world, likely resembling a snowball or ice planet with a potential liquid ocean at the sub-stellar point, or the area of the planets surface that would always be facing the systems host star due to the planets synchronous rotation (much like the Earths moon).

MacDonald conducted the atmospheric retrieval analysis that suggests LHS 1140 b has a nitrogen-rich atmosphere, potentially similar to the Earths atmosphere, which is 78% nitrogen. While it is still only a tentative result, the presence of a nitrogen-rich atmosphere would suggest the planet has retained a substantial atmosphere, creating conditions that might support liquid water.

This discovery favors the water world/snowball scenario as the most plausible. Current models indicate that if LHS 1140 b has an Earth-like atmosphere, it would be a snowball planet with a bulls-eye ocean about 4,000 kilometers in diameter, equivalent to half the surface area of the Atlantic Ocean. The surface temperature at the center of this alien ocean could even be a comfortable 20 degrees Celsius.

LHS 1140 bs potential atmosphere and favorable conditions for liquid water make it an exceptional candidate for future habitability studies. This planet provides a unique opportunity to study a world that could support life, given its position in the habitable zone and the likelihood of having an atmosphere that can retain heat and support a stable climate.

This is our first tantalizing glimpse of an atmosphere on a super Earth in the habitable zone. Compared to other known habitable zone exoplanets, such as those in the TRAPPIST-1 system, the star LHS 1140 appears to be calmer and less active, making it significantly less challenging to disentangle LHS 1140 bs atmosphere from stellar signals caused by starspots, MacDonald said.

Our initial reconnaissance of LHS 1140 b with JWST has revealed this to be perhaps the best habitable zone exoplanet currently known for atmospheric characterisation. While we need more JWST observations to confirm the nitrogen-rich atmosphere, and to search for other gases, this is a very promising start.

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Astronomers find surprising ice world in the habitable zone with JWST data - University of Michigan News