Tag: science

Spectacular 2,300-year-old wall mosaic found in archaeological dig in Rome

8:33 pm

Archaeologists have uncovered a 2,300-year-old wall mosaic in almost perfect condition in Rome that had been part of a banquet room overlooking a garden.

Estimated to be around 2,300 years old, the work is part of a larger aristocratic mansion, located near the Roman Forum, that has been under excavation since 2018. Almost five meters long (16.4 ft) and featuring depictions of vines, lotus leaves, tridents, trumpets, helmets and mythological marine creatures, the mosaic scene was painstakingly created using mother of pearl, shells, corals, shards of precious glass and flecks of marble. The piece is framed by polychrome crystals, spongy travertine, and exotic, ancient Egyptian blue tiles.

What makes this discovery “unmatched,” said archaeologist Alfonsina Russo, head of the Colosseum Archaeological Park in charge of the site, is not only the incredible conservation of the mosaic, but its decoration which also features celebratory scenes of naval and land battles likely funded — and won — by an extremely wealthy aristocratic patron who commemorated the victories on their walls.

Though it is believed such tiled mosaics were common in the homes of wealthy Roman aristocrats, most have not survived in good condition, making this discovery significant as well as beautiful. In addition, the location of the house and the details within the mosaic could make it possible to actually identify the Roman who lived here, which in itself would be a major historical find.

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A glacial lake on Mars?

12:40 pm

A glacial lake in a
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows what appears to be a glacial flow of ice, flowing downhill to the southwest and inside a wide canyon about three miles across. The canyon rims to the north and south are about 2,000 to 2,100 feet above the canyon’s lowest point, indicated by the string of “+” signs.

This close-up view immediately suggests a canyon whose glacier flows outward to the southwest into open lowland terrain, though the three craters, because they are undistorted, suggests that this flow is presently not active. That suggestion however would be wrong. It is always necessary to understand Martian geology to not only take close-in views at high resolution, but to zoom back and see the terrain in context.
» Read more

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New Hubble image of Saturn

10:04 am

Saturn and its rings, as seen by Hubble

The annotated image above was taken by the Hubble Space Telescope on October 22, 2023, showing Saturn, its glorious rings, and several of its dozens of moons from a distance of about 850 million miles. For the unannotated version, go here. Of all the features, the spokes in the rings are the most intriguing.

Saturn’s spokes are transient features that rotate along with the rings. Their ghostly appearance only persists for two or three rotations around Saturn. During active periods, freshly-formed spokes continuously add to the pattern. In 1981, NASA’s Voyager 2 first photographed the ring spokes. Hubble continues observing Saturn annually as the spokes come and go. This cycle has been captured by Hubble’s Outer Planets Atmospheres Legacy (OPAL) program that began nearly a decade ago to annually monitor weather changes on all four gas-giant outer planets.

Hubble’s crisp images show that the frequency of spoke apparitions is seasonally driven, first appearing in OPAL data in 2021 but only on the morning (left) side of the rings. Long-term monitoring shows that both the number and contrast of the spokes vary with Saturn’s seasons. Saturn is tilted on its axis like Earth and has seasons lasting approximately seven years.

This year, these ephemeral structures appear on both sides of the planet simultaneously as they spin around the giant world. Although they look small compared with Saturn, their length and width can stretch longer than Earth’s diameter!

Though the origin of the spokes remains unsolved, the leading theory proposes they are caused by interactions between Saturn’s magnetic field and the seasonal changes in solar radiation.

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Ingenuity’s engineers explain what they have learned flying the helicopter on Mars

9:49 am

Link here. The essay details carefully the problems they have faced, and how they have not only overcome them but used them to refine operations to squeeze far more capabilities out of the helicopter, beyond its initial design.

Saving flight time saves energy, reduces heating, and provides more freedom to use slower speeds to tiptoe around disruptive terrain that might otherwise endanger or significantly degrade the landing accuracy of the helicopter. Higher speeds and higher accelerations reduce the time needed to execute a given flight path. Higher altitudes permit higher speeds, as the wider field of view helps to keep ground features in view of Ingenuity’s navigation camera longer, counteracting the effect of increased speed. Expanding Ingenuity’s flight envelope had the potential to relax flight planning constraints and allow Ingenuity to operate more effectively alongside Perseverance.

As a result, beginning with flight 45 the team has made changes to increase flight speeds and acceleration at every point of every flight, thus allowing the helicopter to fly higher and farther with less strain.

This report however does not provide any information on Ingenuity’s last two flights, especially its 68th, which did not go as planned. The helicopter appears to be in good shape (the team has already planned the 69th flight, which was supposed to happen two days ago), but a more detailed update would be appreciated.

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ULA’s Vulcan rocket fully stacked for the first time

9:39 am

Peregrine landing site
The landing site for Astrobotic’s Peregrine lunar lander

In preparation for its targeted January 8, 2024 launch, ULA’s Vulcan rocket has now been fully stacked for first time in its assembly building at Cape Canaveral.

ULA’s new rocket has rolled between its vertical hangar and the launch pad at Cape Canaveral Space Force Station several times for countdown rehearsals and fueling tests. But ULA only needed the Vulcan rocket’s first stage and upper stage to complete those tests. The addition of the payload shroud Wednesday marked the first time ULA has fully stacked a Vulcan rocket, standing some 202 feet (61.6 meters) tall, still surrounded by scaffolding and work platforms inside its assembly building.

It will next be rolled to the launchpad for some final checks prior to launch on January 8, 2023. Unlike most first launches, it carries a real payload, Astrobotic’s Peregrine lunar lander, which hopes to softly place several NASA and commercial payloads near the Gruithuisen Domes in the northwest quadrant of the Moon’s visible hemisphere, as shown on the map above.

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A movie of 14 years of gamma ray observations from space

8:49 am

Link here. I have also embedded the movie below. The movie was made from fourteen years of observations by the Fermi Gamma-Ray Telescope in orbit around the Earth. From the press release:

Gamma rays are the highest-energy form of light. The movie shows the intensity of gamma rays with energies above 200 million electron volts detected by Fermi’s Large Area Telescope (LAT) between August 2008 and August 2022. For comparison, visible light has energies between 2 and 3 electron volts. Brighter colors mark the locations of more intense gamma-ray sources.

“One of the first things to strike your eye in the movie is a source that steadily arcs across the screen. That’s our Sun, whose apparent movement reflects Earth’s yearly orbital motion around it,” said Fermi Deputy Project Scientist Judy Racusin, who narrates a tour of the movie, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Most of the time, the LAT detects the Sun faintly due to the impact of accelerated particles called cosmic rays – atomic nuclei traveling close to the speed of light. When they strike the Sun’s gas or even the light it emits, gamma rays result. At times, though, the Sun suddenly brightens with powerful eruptions called solar flares, which can briefly make our star one of the sky’s brightest gamma-ray sources.

The movie shows the sky in two different views. The rectangular view shows the entire sky with the center of our galaxy in the middle. This highlights the central plane of the Milky Way, which glows in gamma rays produced from cosmic rays striking interstellar gas and starlight. It’s also flecked with many other sources, including neutron stars and supernova remnants. Above and below this central band, we’re looking out of our galaxy and into the wider universe, peppered with bright, rapidly changing sources.

Most of these are actually distant galaxies, and they’re better seen in a different view centered on our galaxy’s north and south poles. Each of these galaxies, called blazars, hosts a central black hole with a mass of a million or more Suns.

Fermi is essentially mapping the high energy objects of the entire universe.
» Read more

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Ingenuity’s most recent flight, the 68th, a mystery

9:54 am

Overview map
Click for interactive map.

UPDATE: See this December 26, 2023 post for more accurate information.

Original post:
————————–
According to a recent update to the flight log of the Mars helicopter Ingenuity, it finally completed its 68th flight on December 15, 2023, not on December 9, 2023 as announced in the flight plan on December 8th.

More significantly, the flight only traveled 1,289 feet (393 meters), not the 2,716 feet (828 meters) intended. The flight was supposed to travel out to the northeast and then return to its take-off point, indicated by the green dot on the map above, completing a “flight test” as well as scouting the ground below. It appears it did not do this, but where the 68th flight actually went and landed has as yet not been released. According to the flight plan, Ingenuity likely landed somewhere in Neretva Vallis to the northeast, as indicated by the green line.

What we do know is that the engineering team knows enough about Ingenuity’s condition to release today the flight plan for the 69th flight, which was actually scheduled to occur yesterday. That flight plan calls for Ingenuity to travel about 2,300 feet to the east-northeast and then return to its take-off point.

Meanwhile, Perseverance (the blue dot) is working its way west back to its planned route, the red dotted line.

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A bubbly dwarf galaxy

9:09 am

A bubbly dwarf galaxy
Click for original image.

Cool image time! The picture to the right, cropped and reduced to post here, was released today by the science team of the Hubble Space Telescope, and shows an irregular dwarf galaxy that is about seven million light years away.

Twelve camera filters were combined to produce this image, with light from the mid-ultraviolet through to the red end of the visible spectrum. The red patches are likely interstellar hydrogen molecules that are glowing because they have been excited by the light from hot, energetic stars. The other sparkles on show in this image are a mix of older stars. An array of distant, diverse galaxies appear in the background, captured by Hubble’s sharp view.

The data used in this image were taken by Hubble’s Wide Field Camera 3 and the Advanced Camera for Surveys from 2006 to 2021.

The picture was taken as part of a study of dwarf galaxies, their make-up, and how their mergers eventually create the larger galaxies like the Milky Way.

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A land of buttes on Mars

11:14 am

A land of buttes on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 4, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled a “terrain sample” by the science team, it was likely shot not as part of any specific research project but to fill a gap in the schedule so as to maintain the camera’s proper temperature. When the camera team has to do this they try to pick targets that are of some interest. Usually they succeed, considering the enormous gaps we presently have of Mars’ geological history.

This picture is no different. It shows a land of buttes and mesas, all ranging from 20 to 200 feet high, surrounded by canyons filled with ripple dunes of Martian dust. If you look at the floor of those canyons closely, you will notice that where there are no ripple dunes the ground is slightly higher and smooth. It is as if that ground was a kind of sandstone that was eroded away by wind into sand, which then formed the dunes.
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Laser communication tests with Psyche have now included a cat video

9:06 am

Following up on the first tests in mid-November, engineers on December 11, 2023 downloaded a 15-second cat video from the asteroid probe Psyche at a distance of 19 million miles, demonstrating fast download speeds 10 to 100 times faster than the best radio transmissions.

The demo transmitted the 15-second test video via a cutting-edge instrument called a flight laser transceiver. The video signal took 101 seconds to reach Earth, sent at the system’s maximum bit rate of 267 megabits per second (Mbps). Capable of sending and receiving near-infrared signals, the instrument beamed an encoded near-infrared laser to the Hale Telescope at Caltech’s Palomar Observatory in San Diego County, California, where it was downloaded. Each frame from the looping video was then sent “live” to NASA’s Jet Propulsion Laboratory in Southern California, where the video was played in real time.

I have embedded that video below. More details about the information in that video can be found here.
» Read more

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The nearest star-forming region, as seen in infrared by Webb

10:05 am

The nearest star-forming region, as seen by Webb
Click for original image.

Time for another cool image on this somewhat quiet Monday. The false-color infrared image to the right, reduced and sharpened to post here, was taken by the Webb Space Telescope, and shows the Rho Ophiuchi star-forming region, the nearest to our solar system at a distance of about 460 light years.

It is a relatively small, quiet stellar nursery, but you’d never know it from Webb’s chaotic close-up. Jets bursting from young stars crisscross the image, impacting the surrounding interstellar gas and lighting up molecular hydrogen, shown in red. Some stars display the telltale shadow of a circumstellar disc, the makings of future planetary systems.

The young stars at the centre of many of these discs are similar in mass to the Sun or smaller. The heftiest in this image is the star S1, which appears amid a glowing cave it is carving out with its stellar winds in the lower half of the image. The lighter-coloured gas surrounding S1 consists of polycyclic aromatic hydrocarbons, a family of carbon-based molecules that are among the most common compounds found in space.

There are two features that are most compelling to me in this image. First, the red hydrogen jet that cuts across the entire right half of the image from top to bottom. At the top you can see how that jet is pushing material before it. Second, we have the cave-like structure surround S1, the central star. The yellowish cloud is almost like a hand cupped around that star.

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A galaxy of violence

9:53 am

A galaxy of violence
Click for original image.

Time for another cool image! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope, and shows a well defined spiral galaxy face-on in optical wavelengths.

This whirling image features a bright spiral galaxy known as MCG-01-24-014, which is located about 275 million light-years from Earth. In addition to being a well-defined spiral galaxy, MCG-01-24-014 has an extremely energetic core, known as an active galactic nucleus (AGN), so it is referred to as an active galaxy. Even more specifically, it is categorised as a Type-2 Seyfert galaxy. Seyfert galaxies host one of the most common subclasses of AGN, alongside quasars. Whilst the precise categorisation of AGNs is nuanced, Seyfert galaxies tend to be relatively nearby ones where the host galaxy remains plainly detectable alongside its central AGN, while quasars are invariably very distant AGNs whose incredible luminosities outshine their host galaxies.

In contrast, the core of our own Milky Way galaxy is very quiet, which is likely a factor in why it was possible for life to form on Earth.

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