[It is amazing how many little moons exist around Saturn. But Saturn is really a planet that is surrounded by the results of massive violence. That's where its rings come from. But all these little moons are an amazing discovery. Jan]

Jupiter’s brief but glorious reign as the planet with the most moons in our solar system came crashing down this week as scientists confirmed the discovery of 62 new moons orbiting Saturn — bringing the ringed planet’s total to a whopping 145 moons.

That’s a decisive leap ahead of Jupiter’s 95 confirmed moons – a total that eclipsed Saturn’s moon count for several months after 12 new moons were officially recognized orbiting Jupiter in late December. Saturn is now the first and only planet in the solar system with more than 100 known moons, according to researchers at the University of British Columbia(opens in new tab) (UBC), who aided in the new discoveries.

The team of international researchers made their detections using data from the Canada-France-Hawaii Telescope on top of Mauna Kea, Hawaii between 2019 and 2021. By analyzing a trove of sequential images taken over 3-hour observation windows, the team identified 62 moons that were previously either too small or too dim to detect. Some of the smaller moons measured just 1.6 miles (2.5 kilometers) wide — a distance smaller than the length of the National Mall in Washington, D.C.

All of the 62 newly detected moons are "irregular moons," meaning they follow distant, elliptical orbits around their host planet and often move in retrograde — or in the opposite direction of Saturn’s rotation. Many of these tiny, oddball moons clump together in similar retrograde orbits, suggesting they may have originated from a larger parent moon that broke apart millions of years ago, according to the researchers.

"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," Brett Gladman(opens in new tab), a professor of astronomy and astrophysics at UBC, said in a statement.

The new moons are expected to be recognized later this month by the International Astronomical Union — a group of more than 12,000 scientists responsible for designating celestial bodies, among other things.

Jupiter could not be reached for comment.

Source: https://www.livescience.com/space/saturn/scientists-discover-62-new-moons-around-saturn-raising-total-to-145-the-most-in-the-solar-system

[This issue of oceans on other distant moons is very fascinating. Jan]

A reanalysis of Voyager data suggests that four of Uranus moons may have oceans tucked between their cores and icy crusts.

Hidden oceans may lurk under the icy crusts of four of Uranus’ moons.

Scientists recently reanalyzed data from the Voyager spacecraft that flew by Uranus in the 1980s and found that four of Uranus’ largest moons — Ariel, Umbriel, Titania and Oberon — may be warm enough to host liquid oceans. In Titania and Oberon, these oceans might even be warm enough to potentially support life, according to a recent study in the Journal of Geophysical Research(opens in new tab).

"When it comes to small bodies — dwarf planets and moons — planetary scientists previously have found evidence of oceans in several unlikely places, including the dwarf planets Ceres and Pluto, and Saturn’s moon Mimas," study lead author Julie Castillo-Rogez(opens in new tab) of NASA’s Jet Propulsion Laboratory in Southern California said in a statement(opens in new tab). "So there are mechanisms at play that we don’t fully understand."

The new study integrated 1980s Voyager 2 data with information on other icy moons such as Pluto’s Charon and Saturn’s Enceladus drawn from more recent NASA missions such as Galileo, Cassini, Dawn, and New Horizons. Uranus has 27 moons, but the researchers focused on the five largest, which are Ariel, Umbriel, Titania, Oberon and Miranda. Of these, Ariel is the smallest at 720 miles (1,160 kilometers) across, while Titania is the largest at 980 miles (1,580 km) across.

Previously, scientists thought only Tatiana was likely to generate any internal heat via radioactive decay — the process by which unstable atoms lose energy through radiation — believing the other moons to be too small. However, modeling the other moons’ porosity suggested that all but Miranda are insulated enough to retain internal heat created by radioactive decay. The researchers also found that any potential oceans beneath the icy crusts of these moons would be rich in chlorides, ammonia and salts, both of which would lower the freezing point of the water. The combination of a low freezing point and enough internal heat could mean that Ariel, Umbrial, Titania and Oberon all have oceans dozens of miles deep within their interiors, the researchers reported.

In 2020, scientists detected some evidence of recent geological activity on Ariel, suggesting the possible movement of a potential inner ocean. Miranda also has surface features that look relatively fresh, according to the researchers, but their modeling suggests that if the moon did have a liquid ocean at some point, it is likely frozen by now.

To find out if these hidden oceans really exist, scientists will have to get creative. Spectrometers that can detect wavelengths of light reflected by ammonia and chlorides could help prove the presence of these chemicals under the crusts. Scientists could also use instruments that can detect electrical currents carried by liquid water to probe beneath these moons’ surfaces. New modeling studies on how these moons formed could also help researchers plan what kind of observations they will need to make in the future, Castillo-Rogez said.

"We need to develop new models for different assumptions on the origin of the moons in order to guide planning for future observations," she said.

Source: https://www.livescience.com/space/uranus/4-of-uranus-biggest-moons-have-secret-underground-oceans-new-study-suggests

[The James Webb telescope is advancing astronomy at an insane pace. This is the first ever photo of an asteroid belt outside of our solar system. You can view the photo at the source link at the bottom. Jan]

The debris structures around the star Fomalhaut are more complex than comparable features in our own solar system.

NASA’s James Webb Space Telescope captured this image of the dusty debris disk surrounding the young star Fomalhaut using its Mid-Infrared Instrument. The image reveals three nested belts extending out to 14 billion miles (23 billion kilometers) from the star. The inner belts were revealed by Webb for the first time.

The first asteroid belt ever found outside the solar system is more complex than expected, new observations by the James Webb Space Telescope (JWST) reveal.

Astronomers used JWST to examine the dusty ring system around Fomalhaut, a young, hot star that lies about 25 light-years from Earth and is visible with the naked eye in the constellation Piscis Austrinu, the Southern Fish.

Fomalhaut’s ring system consists of three nested belts that extend out for around 14.3 billion miles (23 million kilometers) — about 150 times the distance between Earth and the sun. The rings are more complex than either the Kuiper Belt, a ring of frigid bodies beyond Neptune, or the main asteroid belt, which sits between Jupiter and Mars, the new JWST observations show.

Annotated version of an image captured by NASA’s James Webb Space Telescope showing the dusty debris disk surrounding the young star Fomalhaut, The image reveals three nested belts extending out to 14 billion miles (23 billion kilometers) from the star. The inner belts were revealed by Webb for the first time.

Astronomers discovered a dusty structure surrounding Fomalhaut in 1983 using NASA’s Infrared Astronomical Satellite. Yet the two inner belts of this system had never been sighted before this observation with the JWST.

The dust belts around the young star are thought to be debris from collisions between larger bodies like asteroids and comets, and are therefore referred to as "debris disks." These disks are different than protoplanetary disks, which hold material that later gloms together to form planets. Debris disks form later, after planets are in place.

"I would describe Fomalhaut as the archetype of debris disks found elsewhere in our galaxy, because it has components similar to those we have in our own planetary system," András Gáspár of the University of Arizona, the lead author of a study announcing the new results, said in a statement(opens in new tab).

"By looking at the patterns in these rings, we can actually start to make a little sketch of what a planetary system ought to look like —  if we could actually take a deep enough picture to see the suspected planets," Gáspár added.

Fomalhaut’s outermost belt, which is twice as large as the Kuiper Belt, has been imaged previously by the Hubble Space Telescope, the Herschel Space Observatory and the ground-based Atacama Large Millimeter/submillimeter Array (ALMA). None of those instruments were able to see the interior structure within the outer belt, however.

"Where the JWST really excels is that we’re able to physically resolve the thermal glow from dust in those inner regions. So you can see inner belts that we could never see before," study team member Schuyler Wolff, also of the University of Arizona, said in the same statement.

Going forward, astronomers hope to image debris disks like Fomalhaut’s around other stars using JWST.

"With Hubble and ALMA, we were able to image a bunch of Kuiper Belt analogs, and we’ve learned loads about how outer disks form and evolve," Wolff continued. "But we need the JWST to allow us to image a dozen or so asteroid belts elsewhere. We can learn just as much about the inner warm regions of these discs as Hubble and ALMA taught us about the colder outer regions."

Just like Jupiter dominates the main asteroid belt and Neptune sculpts the Kuiper Belt, astronomers believe that debris disks outside the solar system may be shaped by unseen planets. That means there may well be a planet or two lurking in the rings around Fomalhaut.

"We definitely didn’t expect the more complex structure with the second intermediate belt and then the broader asteroid belt," Wolff said. "That structure is very exciting, because any time an astronomer sees a gap and rings in a disk, they say, ‘There could be an embedded planet shaping the rings!’"

One feature already spotted by JWST in the rings may indicate the presence of forming protoplanets. The team saw what Gáspár labeled "the great dust cloud," which may point to a collision in the outer ring of Fomalhaut between two "under construction" infant planets. This feature could therefore be an expanding cloud of very fine dust particles from two icy bodies that smashed into each other.

A similar feature was spotted in the same ring by Hubble back in 2008. It had dissipated by the time the space telescope reexamined the ring system in 2014, researchers said.

Deeper investigations of more systems like Fomalhaut with JWST could reveal how planets move through these pancake-flat disks. Observing the dust cloud itself, meanwhile, could reveal details about the structure of planetary systems other than our own. This includes discovering what their asteroids — which are much too small to see even with powerful instruments like JWST or Hubble — are like, and if they are similar to the space rocks that swirl around our star and its planets.

The team’s research was published online Monday (May 8) in the journal Nature Astronomy(opens in new tab).

Source: https://www.space.com/james-webb-space-telescope-fomalhaut-asteroid-belt-photo

[This is a fascinating little analysis. I used to think, long ago, that the pyramids were too big to easily have been built, but archaeologists have found the places where the workers lived and they even found the diary of someone who worked on the pyramids. It's actually fascinating. The pyramids were built by professionals and there are modern stone masons in Europe who use techniques that are similar to what had to be used on the pyramids. Much of what was done is not as mysterious as you might think once you understand what stonemasons can do. The estimates herein are relatively accurate. Jan]

GIVEN THAT SOME 4,600 years have elapsed since the completion of the Great Pyramid of Giza, the structure stands remarkably intact. It is a polyhedron with a regular polygon base, its volume is about 2.6 million cubic meters, and its original height was 146.6 meters, including the lost pyramidion, or capstone. We may never know exactly how the pyramid was built, but even so, we can say with some confidence how many people were required to build it.

We must start with the time constraint of roughly 20 years, the length of the reign of Khufu, the pharaoh who commissioned the construction (he died around 2530 B.C.E.). Herodotus, writing more than 21 centuries after the pyramid’s completion, was told that labor gangs totaling 100,000 men worked in three-month spells a year to finish the structure in 20 years. In 1974, Kurt Mendelssohn, a German-born British physicist, put the labor force at 70,000 seasonal workers and up to 10,000 permanent masons.

These are large overestimates; we can do better by appealing to simple physics. The potential energy of the pyramid—the energy needed to lift the mass above ground level—is simply the product of acceleration due to gravity, mass, and the center of mass, which in a pyramid is one-quarter of its height. The mass cannot be pinpointed because it depends on the specific densities of the Tura limestone and mortar that were used to build the structure; I am assuming a mean of 2.6 metric tons per cubic meter, hence a total mass of about 6.75 million metric tons. That means the pyramid’s potential energy is about 2.4 trillion joules.

To maintain his basal metabolic rate, a 70-kilogram (154-pound) man requires some 7.5 megajoules a day; steady exertion will raise that figure by at least 30 percent. About 20 percent of that increase will be converted into useful work, which amounts to about 450 kilojoules a day (different assumptions are possible, but they would make no fundamental difference). Dividing the potential energy of the pyramid by 450 kJ implies that it took 5.3 million man-days to raise the pyramid. If a work year consists of 300 days, that would mean almost 18,000 man-years, which, spread over 20 years, implies a workforce of about 900 men.

Sweat Equity

SHEER HUMAN MUSCLE CAN RAISE A GREAT PYRAMID BECAUSE MOST OF THE MASS IS NEAR THE BOTTOM AND THE WORK CAN BE DIVIDED AMONG THOUSANDS OF PEOPLE AND DISTRIBUTED OVER DECADES. IT WAS THUS NO GREAT DRAIN ON NATIONAL RESOURCES—AND THINK OF THE SPIN-OFF EFFECTS!

A similar number of workers might be needed to place the stones in the rising structure and then to smooth the cladding blocks (many interior blocks were just rough-cut). And in order to cut 2.6 million cubic meters of stone in 20 years, the project would have required about 1,500 quarrymen working 300 days a year and producing 0.25 cubic meter of stone per capita. The grand total of the construction labor would then be some 3,300 workers. Even if we were to double that number to account for designers, organizers, and overseers and for labor needed for transport, tool repair, the building and maintenance of on-site housing, and cooking and laundry work, the total would be still less than 7,000 workers.

During the time of the pyramid’s construction, the total population of the late Old Kingdom was 1.5 million to 1.6 million people, and hence such a labor force would not have been an extraordinary imposition on the country’s economy. The challenge was to organize the labor, plan an uninterrupted supply of building stones, and provide housing, clothing, and food for labor gangs on the Giza site.

In the 1990s, archaeologists uncovered a cemetery for workers and the foundations of a settlement used to house the builders of the two later pyramids at the site, indicating that no more than 20,000 people lived there. That an additional two pyramids were built in rapid succession at the Giza site (for Khafre, Khufu’s son, starting at 2520 B.C.E., and for Menkaure, starting 2490 B.C.E.) shows how quickly early Egyptians mastered the building of pyramids: The erection of those massive structures became just another series of construction projects for the Old Kingdom’s designers, managers, and workers. If you build things, it becomes easier to build things—a useful lesson for those who worry about the sorry state of our infrastructure.

This article appears in the June 2020 print issue as “Building the Great Pyramid.”

Source: https://spectrum.ieee.org/how-many-people-did-it-take-to-build-the-great-pyramid

[This German woman scientist tackles a very important topic. Jan]

Here’s the video: https://www.youtube.com/watch?v=c6DP5lgzmTA&list=PLwgQsqtH9H5d63nlZWtEEVjBfJbydma2S&index=7

[Ancient life was very strange. But the weirdest was the Claw-faced sea monster. It just amazes me that such animals could live. Jan]

The fossil record is filled with strange marine animals that would look like sea monsters if they were alive today.

From the creepiest Cambrian critters to massive marine reptiles, wonderfully weird sea creatures have inhabited our oceans for over half a billion years. We’ve put together a list of 25 of the strangest ancient sea monsters ever to have lived, all of which went extinct long before humans came along.

The only reason we know that these evolutionary marvels existed is because some left behind fossilized remains in rocks. Modern researchers are still interpreting these fossils and making fresh discoveries all the time, so be sure to keep up with the latest Live Science fossil news.

You can view all the images and the rest of the story here: https://www.livescience.com/strangest-ancient-sea-monsters

[NASA has been slow and inept on these moon missions. Jan]

COLORADO SPRINGS, Colo. — NASA’s goal of returning astronauts to the moon by 2025 has long been part of a long-term plan to build a sustainable base on the lunar surface. But that plan may include more moon bases than you might expect.

Jim Free, NASA’s associate administrator for exploration systems development, said Monday (April 17) that the agency’s Artemis program may ultimately build several bases around the moon instead of a single Artemis Base Camp at the lunar south pole as unveiled in 2020.

"It’s really hard to say we’re going to have a single base camp," Free told reporters here in a briefing at the 38th Space Symposium. "Because if we miss a launch window, we might have to wait a month to go back to that place."

Instead, NASA may work with its international partners to establish a series of moon camps spread across the lunar surface to maximize science and exploration. The agency, Free said, is studying whether it is a better idea to have a distributed approach with multiple moon bases, including some potentially contributed by international partners like the European Space Agency, Canada or Japan, who have all signed on as Artemis program partners.

"So we can maybe have two or three sites to go to that help our science diversity, because the reason we’re doing Artemis in the first place is for science," Free said.

NASA’s Artemis program originally aimed to roll out a base camp on the moon in stages using an orbiting Gateway station, landers, rovers and habitats as seen in this timeline illustration. The plan may now include additional moon bases, an official said April 17. (Image credit: NASA)

NASA’s Artemis Base Camp called for a primary moon base at the lunar south pole, possibly at Shackleton Crater, which has long been on the agency’s candidate list to explore on an Artemis mission because it is known to harbor water ice in its shadowed regions. The base would serve as a hub for crewed Artemis moon landings and support a team of four astronauts for up to a week at a time.

Under the Base Camp plan, the habitat would include power infrastructure, radiation shielding, facilities for waste disposal and a landing pad for visiting crews. It would also be home to a lunar rover that astronauts could drive around the moon and a "habitable mobility platform" that crews could use to visit other locales on the moon for up to 45 days at a time.

But having multiple, smaller Artemis bases on the moon may yield better science and access to the lunar surface, Free said Monday. However, NASA won’t be building those extra habitats anytime soon, he added.

NASA’s next Artemis mission is Artemis 2, which will launch four astronauts around the moon no earlier than November 2024. NASA unveiled the crew of Artemis 2 earlier this month. The first crewed Artemis moon landing, the Artemis 3 mission, is slated for sometime in 2025.

"Artemis 3 is get the crew down, let them stay for six and a half days and get them back," Free said. "And we’re slowly going to build the time that we will have the crew spend, and then the number of crew, on the surface."

As those longer and bigger missions develop, NASA hopes to send lunar rovers for Artemis astronauts to drive on the moon, starting with an unpressurized rover and leading to a truck-like pressurized vehicle. Japan’s space agency has teamed up with Toyota to build such a moon truck. A permanent habitat would then follow for rotating crews, Free said.

"So we’re probably looking at the later missions, like [Artemis] 7, 8 and 9, where we’re starting to look at adding permanent habitation on the surface," he added.

On Tuesday (April 18), NASA’s deputy administrator Pam Melroy will speak at the Space Symposium to "discuss progress toward a blueprint for sustained human exploration throughout the solar system," NASA has said(opens in new tab). You can watch that speech, called "Our Next Steps to the Moon and Beyond," on NASA TV (opens in new tab)and YouTube(opens in new tab).

It will detail NASA’s planned architecture for Artemis moon missions, plans for Mars and beyond, Free said.

Source: https://www.space.com/nasa-artemis-base-camp-more-moon-bases

[I find this amazing. And it has to do with their metabolism. Jan]

Scientists estimate the Greenland shark lives at least 250 years. They may live over 500 years.

Scientists have suspected for a while that Greenland sharks lived extremely long lives, but they didn’t have a way to determine how long. The age of other shark species can be estimated by counting growth bands on fin spines or on the shark’s vertebrae, much like rings on a tree. Greenland sharks, however, have no fin spines and no hard tissues in their bodies. Their vertebrae are too soft to form the growth bands seen in other sharks. Scientists could only guess that the sharks lived a long time based on what they knew — the sharks grow at a very slow rate (less than 1 cm per year) and they can reach over 6 meters in size.

But recent breakthroughs allowed scientists to use carbon dating to estimate the age of Greenland sharks. Inside the shark’s eyes, there are proteins that are formed before birth and do not degrade with age, like a fossil preserved in amber. Scientists discovered that they could determine the age of the sharks by carbon-dating these proteins. One study examined Greenland sharks that were bycatch in fishermen’s nets. The largest shark they found, a 5-meter female, was between 272 and 512 years old according to their estimates. Carbon dating can only provide estimates, not a definitive age. Scientists continue to refine this method and may provide more accurate measurements in the future. But even at the lower end of the estimates, a 272-year lifespan makes the Greenland shark the longest-lived vertebrate.

One theory to explain this long lifespan is that the Greenland shark has a very slow metabolism, an adaptation to the deep, cold waters it inhabits. A NOAA remotely operated vehicle doing a dive off New England encountered a Greenland shark at a depth of 783 meters, but these sharks are known to dive as deep as 2,200 meters. They’re also the only shark that can withstand the cold waters of the Arctic Ocean year-round.

The slow metabolism could explain the shark’s slow growth, slow aging, and sluggish movement — its top speed is under 2.9 kilometers per hour. Because the sharks grow so slowly, they aren’t thought to reach sexual maturity until they’re over a century old. That means removing mature Greenland sharks from the ocean affects the species and the ecosystem for many decades. Though the Greenland shark used to be hunted for its liver oil, the majority of Greenland sharks that end up in fishing nets and lines now are caught by accident. Reducing bycatch is critical in conserving this unique species.

Source: https://oceanservice.noaa.gov/facts/greenland-shark.html

[This is something I've wondered about myself many times. Jan]

Here’s the video: https://www.youtube.com/watch?v=ZHxoM9lvzVA

Here’s the video: https://www.youtube.com/watch?v=Pa_WH7kVcaE