Science
Researchers announce 62 new moons of Saturn
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The work of an international team of astronomers has resulted in the announcement of 62 new moons of Saturn, catapulting it back into first place of the “moon race” around the giant planets of our solar system.
The team is led by Edward Ashton (currently a postdoctoral fellow at Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics) and includes professor Brett Gladman (Department of Physics & Astronomy at the University of British Columbia), Mike Alexandersen (Harvard Smithsonian Center for Astrophysics), Jean-Marc Petit (Observatoire de Besancon), and Matthew Beaudoin (University of British Columbia).
Over the past two decades, Saturn’s surroundings have been repeatedly examined for moons with increasing sensitivity. In this latest study, Dr. Ashton’s team used a technique known as “shift and stack” in order to find fainter (and thus smaller) saturnian moons. This method has been used for moon searches around Neptune and Uranus, but never for Saturn.
Shifting a set of sequential images at the rate that the moon is moving across the sky results in enhancement of the moon’s signal when all the data is combined, allowing moons that were too faint to be seen in individual images to become visible in the “stacked” image. The team used data taken using the Canada-France-Hawaii Telescope (CFHT) on top of Mauna Kea, Hawaii between 2019 and 2021. By shifting and stacking many sequential images taken during 3 hour spans, they were able to detect moons of Saturn down to about 2.5 kilometers in diameter.
The original discovery search was done in 2019 when Ashton and Beaudoin were students at the University of British Columbia, uncovering the moons in a meticulous search of the deep CFHT imaging acquired that year. But just finding an object close to Saturn on the sky is insufficient to say for certain that it is a moon; it could in principle be an asteroid that just happened to be passing close to the planet (although this is unlikely).
To be absolutely sure, the object must be tracked for several years before one can establish that it is certainly orbiting the planet. After painstakingly matching objects detected on different nights over two years, the team has managed to track 63 objects, thus confirming them as new moons. One of the new moons, designated S/2019 S 1, was announced back in 2021, with the rest being announced over the last couple of weeks. Some of the team’s linked orbits were identified with past observations from many years ago that briefly glimpsed some of these moons (but were not tracked long enough to establish their orbit around Saturn).
“Tracking these moons makes me recall playing the kid’s game Dot-to-Dot, because we have to connect the various appearances of these moons in our data with a viable orbit,” explains Edward Ashton, “but with about 100 different games on the same page and you don’t know which dot belongs to which puzzle.”
All of the new moons are in the class of irregular moons, which are thought to be initially captured by their host planet long ago. Irregular moons are characterized by their large, elliptical, and inclined orbits compared to regular moons. The number of known saturnian irregular moons has more than doubled to 121, with 58 previously known before the search began.
Including the 24 regular moons, there is now a total of 145 recognized (by the International Astronomical Union) moons orbiting Saturn. The new discoveries have resulted in multiple milestones for the ringed planet. Saturn has not only regained its crown for having the most known moons (overtaking Jupiter with 95 recognized moons), it is also the first planet to have over 100 discovered moons in total.
The irregular moons tend to clump together into orbital groups based on the tilt of their orbits. In the saturnian system there are 3 such groups whose names are drawn from different mythologies: there is the Inuit group, the Gallic group, and the much more populated Norse group. For example, three new discoveries fall in the Inuit group: S/2019 S 1, S/2020 S 1 and S/2005 S 4 have very small orbits tilted similarly to that of the previously known larger irregulars Kiviuq and Ijiraq. All of the new moons fall into one of the three known groups, with the Norse group again being the most populated among the new moons. The groups are thought to be the result of collisions, where the current moons in a group are remnants of one or more collisions on the originally-captured moons.
A better understanding of the orbital distribution thus provides insight into the collisional history of the irregular moon system of Saturn. Based on their past studies of these moons, this team has suggested that the large number of small moons on retrograde orbits is the result of a relatively recent (in astronomical terms, being in the last 100 million years) disruption of a moderately sized irregular moon that is now broken into the many fragments that are being catalogued in the Norse group.
As professor Gladman explains, “as one pushes to the limit of modern telescopes, we are finding increasing evidence that a moderate-sized moon orbiting backwards around Saturn was blown apart something like 100 million years ago.”
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Science
'On every diver's bucket list': Video shows up-close encounter with shark in Alberni Inlet – CHEK News
A quartet of scuba divers on Vancouver Island were in for the plunge of a lifetime when coming across a shark in the depths of the Alberni Inlet.
In late May, Matteo Endrizzi and Garrett Clement got video of the encounter, calling it “incredibly rare” footage that even underwater filmmakers searching for the fish have difficulty capturing on camera.
Divemaster Endrizzi and environmental technologist Clement, both from Nanaimo, joined fellow divers Connor McTavish and Danton West when they spotted the bluntnose sixgill shark swimming in pirate movie-like atmosphere.
“We went up to do a dive trip. A change of scenery, different dive sights,” said Endrizzi. “We did a dive in the morning, and then we decided to do a deeper dive on a shipwreck that was there. We went down about 100 feet.”
That’s when Clement says one of the divers, “the guy with the least amount of experience,” started signalling that he saw something unusual.
“I go over, and he gives me the classic signal for shark,” said Clement in an interview with CHEK News.
“I remember looking at him and going, ‘Really?’ We go over, and there’s nothing there, but he’s looking around like a madman. We don’t see anything. We can’t really talk when we’re scuba diving, so we just continue on our dive.”
Ten minutes later, their underwater dive in waters near Port Alberni turned into one they’ll never forget — one they’ve summed up as a big thrill.
“We just went along the side of the shipwreck. We were just looking down, and all of a sudden, someone’s light beam caught an outline of a shark swimming along the bottom of the shipwreck,” recalled Clement.
READ ALSO: Possibly pregnant bluntnose shark washes up on Hornby Island
While Endrizzi was excited by the sight, he’s most grateful he had his camera in hand to capture video proof of what they saw before their eyes.
“Usually, these sharks live in deep, deep water at 2,500 metres,” he said.
“It’s a deep-water shark, and no one knows why they come to the shallows. There are a lot of theories, but no one really knows.
“Garrett was pretty much right on the bottom at 80 feet, and I was a few feet higher, so we got different angles of video. I’m from above, and Garrett was down below. It’s nice to have both perspectives.”
Story continues below.
When spotting a shark, other divers may be urged to ‘dip’ or swim away to safety as quickly as possible, but this group had done its research.
“It’s a pretty docile shark,” said Endrizzi. “When we saw it, we knew exactly what it was. I think we were all a little bit excited, and I say that as an understatement. We all felt very lucky to witness what we did.”
According to Fisheries and Oceans Canada, the sixgill shark, or Hexanchus griseus, can grow up to 4.8 metres long and has two rows of teeth.
“The shark that we saw was a juvenile, but they can be quite big animals. The coast of B.C. is one of the only places in the world where divers can actually see these sharks,” said Endrizzi.
He says the group reached out to the DFO to notify them of the encounter, which in turn was “very grateful” to receive the information considering such sightings are seldom.
“If anyone does come across one, it’s a rare occurrence, and I definitely encourage them to reach out to DFO so that data can be recorded and we can get more information on these really cool creatures,” said Endrizzi.
The DFO has more information about sharks on its website, including ongoing research from the Canadian Pacific Shark Research Lab.
“I mean, they live at the bottom of the ocean, and it’s so hard to get any sort of data on them,” added Clement. “It’s on every diver’s bucket list to be able to see one of these things in the wild, but the reality is you could go on thousands and thousands of dives and never see one.”
-with files from CHEK’s Roger Collins
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This image of the barred spiral galaxy NGC 5068 is a composite from two of the James Webb Space Telescope’s instruments, MIRI and NIRCam. Credit: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST Team
<span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>NASA’s <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>James Webb Space Telescope has captured a detailed image of the barred spiral galaxy NGC 5068. Part of a project to record star formation in nearby galaxies, this initiative provides significant insights into various astronomical fields. The telescope’s ability to see through gas and dust, typically hiding star formation processes, offers unique views into this crucial aspect of galactic evolution.
A delicate tracery of dust and bright star clusters threads across this image from the James Webb Space Telescope. The bright tendrils of gas and stars belong to the barred spiral galaxy NGC 5068, whose bright central bar is visible in the upper left of this image – a composite from two of Webb’s instruments. NASA Administrator Bill Nelson revealed the image on June 2 during an event with students at the Copernicus Science Centre in Warsaw, Poland.
In this image of the barred spiral galaxy NGC 5068, from the James Webb Space Telescope’s MIRI instrument, the dusty structure of the spiral galaxy and glowing bubbles of gas containing newly-formed star clusters are particularly prominent. Three asteroid trails intrude into this image, represented as tiny blue-green-red dots. Asteroids appear in astronomical images such as these because they are much closer to the telescope than the distant target. As Webb captures several images of the astronomical object, the asteroid moves, so it shows up in a slightly different place in each frame. They are a little more noticeable in images such as this one from MIRI, because many stars are not as bright in mid-infrared wavelengths as they are in near-infrared or visible light, so asteroids are easier to see next to the stars. One trail lies just below the galaxy’s bar, and two more in the bottom-left corner. Credit: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST Team
NGC 5068 lies around 20 million light-years from Earth in the constellation Virgo. This image of the central, bright star-forming regions of the galaxy is part of a campaign to create an astronomical treasure trove, a repository of observations of star formation in nearby galaxies. Previous gems from this collection can be seen here (IC 5332) and here (M74). These observations are particularly valuable to astronomers for two reasons. The first is because star formation underpins so many fields in astronomy, from the physics of the tenuous <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>plasma that lies between stars to the evolution of entire galaxies. By observing the formation of stars in nearby galaxies, astronomers hope to kick-start major scientific advances with some of the first available data from Webb.
This view of the barred spiral galaxy NGC 5068, from the James Webb Space Telescope’s NIRCam instrument, is studded by the galaxy’s massive population of stars, most dense along its bright central bar, along with burning red clouds of gas illuminated by young stars within. This near-infrared image of the galaxy is filled by the enormous gathering of older stars which make up the core of NGC 5068. The keen vision of NIRCam allows astronomers to peer through the galaxy’s gas and dust to closely examine its stars. Dense and bright clouds of dust lie along the path of the spiral arms: These are H II regions, collections of hydrogen gas where new stars are forming. The young, energetic stars ionize the hydrogen around them, creating this glow represented in red. Credit: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST Team
The second reason is that Webb’s observations build on other studies using telescopes including the Hubble Space Telescope and ground-based observatories. Webb collected images of 19 nearby star-forming galaxies which astronomers could then combine with Hubble images of 10,000 star clusters, spectroscopic mapping of 20,000 star-forming emission nebulae from the <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>Very Large Telescope (VLT), and observations of 12,000 dark, dense molecular clouds identified by the Atacama Large Millimeter/submillimeter Array (ALMA). These observations span the electromagnetic spectrum and give astronomers an unprecedented opportunity to piece together the minutiae of star formation.
With its ability to peer through the gas and dust enshrouding newborn stars, Webb is particularly well-suited to explore the processes governing star formation. Stars and planetary systems are born amongst swirling clouds of gas and dust that are opaque to visible-light observatories like Hubble or the VLT. The keen vision at infrared wavelengths of two of Webb’s instruments — MIRI (Mid-Infrared Instrument) and NIRCam (Near-Infrared Camera) — allowed astronomers to see right through the gargantuan clouds of dust in NGC 5068 and capture the processes of star formation as they happened. This image combines the capabilities of these two instruments, providing a truly unique look at the composition of NGC 5068.
The James Webb Space Telescope stands as the apex of space science observatories worldwide. Tasked with demystifying enigmas within our own solar system, Webb will also extend its gaze beyond, seeking to observe distant worlds orbiting other stars. In addition to this, it aims to delve into the cryptic structures and the origins of our universe, thereby facilitating a deeper understanding of our position within the cosmic expanse. The Webb project is an international endeavor spearheaded by NASA, conducted in close partnership with the <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="
” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>European Space Agency (ESA) and the Canadian Space Agency.
Science
New image from the James Webb Space Telescope shows thousands upon thousands of stars in a galaxy 17 million light years away
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- The James Webb Space Telescope snapped a new image of a galaxy 17 million light-years away.
- Thousands upon thousands of stars are visible, many of which are concentrated in the galaxy’s heart.
- JWST is peering into the hearts of many galaxies to help scientists better understand star formation.
With the power of the James Webb Space Telescope, we can peer into the mysterious hearts of galaxies. And that’s exactly what you’re seeing here, in this new image from Webb of the galaxy NGC 5068.
NGC 5068 is located about 17 million light-years from Earth. For perspective, the Milky Way’s neighborhood of galaxies called the Local Group, is 5 million light-years away. So, this galaxy is beyond what we might consider close.
Each individual dot of white light you can see is a star, per Mashable. NASA said there are thousands upon thousands of stars in this image. And many of them are hanging out at the galaxy’s center, which you can see in the upper left as a bright bar of white light.
This region appears so bright because that’s where most of the stars are concentrated. That’s also where all the action is.
James Webb peers into the hearts of many galaxies to uncover their secrets
Most galaxies have an ultra-bright center due to warm dust that’s heated by massive bursts of star formation, according to the Harvard Smithsonian. And it’s this star formation that astronomers are interested in studying more with the help of JWST.
In fact, NGC 5068 is just one in a series of other galaxies Webb is observing for a project to help us better understand star formation. Webb has also taken images of the spiral galaxy IC 5332:
And the heart of galaxy M74, aka the “Phantom Galaxy”:
The James Webb Space Telescope has the advantage of seeing in the infrared.
Infrared wavelengths are too long for the human eye to detect. But they’re especially important for studying in space because they allow JWST to peer past obstructive visual light that would otherwise block our ability to see into the hearts of galaxies and their bustling environments of star formation.
“By observing the formation of stars in nearby galaxies, astronomers hope to kick-start major scientific advances with some of the first available data from Webb,” NASA said.
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