Tag Archives: hue

The boy’s body was preserved in a copper coffin, taking on a green hue.

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The mummified remains of a boy buried in a copper box between 1617 and 1814

Annamaria Arabiso

An adolescent boy, interred in a copper coffin almost three centuries ago in northern Italy, stands out as the only nearly fully preserved green mummy known to exist.

While other ancient remains have shown partial mummification or green coloration from burial alongside copper or bronze items, a green mummified hand of a newborn clutching a copper coin was discovered in medieval Hungary within pottery vessels.

In contrast, this Italian mummy is largely intact, save for its feet, showcasing an almost entirely green complexion from skin to bone, with the exception of its left leg.

The mummy emerged from the basement of an old villa in Bologna in 1987, where it underwent forensic analysis at the University of Bologna. Experts determined it belonged to a boy aged 12 to 14, and it has been preserved at the university since.

Annamaria Arabiso, a conservation scientist at the University of Rome Tor Vergata, took part in the examination alongside a myriad of specialists including geneticists, anthropologists, radiologists, mathematicians, physicists, and computer scientists. “It was an impressive interdisciplinary effort,” she remarks.

The researchers conducted an extensive series of chemical and physical analyses on the mummy. Radiocarbon dating assigned the boy’s death to between 1617 and 1814, with Arabiso noting that the remains exhibited no apparent signs of trauma or disease.

Copper played a crucial role in preserving both hard and soft tissues, owing to its known antimicrobial characteristics, Arabiso states. However, the copper box reacted with acid from the body, leading to corrosion that created copper byproducts interacting with the chemicals in the bone. Gradually, copper ions replaced calcium in the boy’s skeleton, imparting a green hue and simultaneously enhancing the structural integrity of his bones over time.

The skin developed a rough layer of copper corrosion products referred to as patina, a pale green film typical on bronze items. Arabiso explained that this patina formed as a result of copper’s reaction with water and carbon dioxide during decomposition.

“This fundamentally shifts our understanding of heavy metals, revealing a more intricate relationship regarding their effects on conservation than previously assumed,” she states.

Possibly due to acidic interactions, the bottom of the copper box eventually cracked, leading to liquid spillage that left the remains in a cool, arid environment with limited oxygen, which mitigated decomposition. Arabiso suggests the boy may have become disoriented and lost his footing during this process.

“Engaging with these extraordinary human remains was profoundly emotional for me,” she shares.

Julia Gallo, having seen images of mummies for the first time at the Collège de France in Paris, expressed her awe. “Oh, how beautiful!” she exclaims. “This entire case study is utterly captivating.”

Gallo offered praise for the researchers’ efforts in meticulously investigating the physical and chemical processes leading to the mummification and subsequent color changes. “The evidence robustly supports their conclusions regarding both the preservation of tissues and bones and the variations in coloration.”

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Source: www.newscientist.com

Iron-rich minerals containing water may be the primary reason for the red hue of Mars.

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This iron mineral, called ferihydrite, formed under oxidative conditions during cold, humid periods on early Mars, continuing its transition to the current overheating environment.

This image of Mars Express's high-resolution stereo camera shows Mars glove set on a dark background. The planet's disc has patches of yellow, orange, blue and green, all with a muted gray hue throughout, representing the various compositions of the surface. Image credits: ESA/DLR/FU BERLIN/G. MICHAEL/CC BY-SA 3.0 IGO.

Mars is easily identified in the night sky due to its prominent red tint.

Thanks to a fleet of spacecrafts that have been studying planets over the past decades, this red colour is known to be due to rusty iron minerals in the dust.

In other words, iron bound to the rocks of Mars reacted at one point with water and oxygen in the air, just as how rust on Earth formed.

For more than billions of years, this rusty material, iron oxide — has been broken down into dust around the planet by the wind, a process that continues today.

However, iron oxide has a lot of flavour and the precise chemistry of Mars' rust is heavily debated as it is a window into the environmental conditions of Earth at the time.

And what's closely linked to it is the question of whether Mars has been habitable to date.

Previous studies of the iron oxide components of Martian dust based solely on spacecraft observations found no evidence of water contained within it.

Therefore, planetary researchers say that this particular type of iron oxide is formed under hematite, which is formed under dry surface conditions through reaction with the Martian atmosphere for billions of years after an early wet period on Mars. I had concluded that it had to be.

However, new analysis of spacecraft observations combined with new laboratory techniques shows that Mars' red colour is better matched by iron oxides containing water known as ferihydrite.

Felihydrite usually forms quickly in the presence of cold water, so it must have been formed when Mars was still water on the surface.

The minerals hold a watery signature to this day, despite their spreading down to the ground.

Dr. Adomas Valantinas, a researcher at Brown University, said:

“Ferihydrite, mixed with volcanic rock basalt, has proven to be the most suitable for the minerals found in Martian spacecraft.”

“Mars is still a red planet. It's not only about understanding why Mars is red, but it also means that our understanding has changed.”

“The main meaning is that Mars was rusting faster than before, as ferrihydrite could only form when water was still on the surface.”

“In addition, under current conditions on Mars, ferrihydrite remains stable.”

Mars has acquired its iconic color from the combination of rust and erosion over its 4.6 billion years of history. Image credits: ESA/ATG Europe/Valantinas et al. , doi: 10.1038/s41467-025-56970-z.

Other studies have also suggested that ferrihydrite may be present in Mars' dust, but the current study has been the first comprehensive study through a unique combination of space mission data and new laboratory experiments. Provide evidence.

The authors used an advanced grinder machine to create replica Mars dust, achieving realistic dust grain sizes equivalent to 1/100th of human hair.

To make a direct comparison, the samples were then analyzed using the same technology as the spacecraft orbiting the spacecraft, and ultimately identified ferrihydrite as the best match.

“This study is the result of a complementary dataset from a fleet of international missions exploring Mars at orbital and ground levels,” says Dr. Colin Wilson, PhD, Trace Gas Orbiter (TGO) from ESA and Mars Express Project Scientist. said.

Mars Express's dust mineralogy analysis helped to show that even the highly dusty regions of the planet contain water-rich minerals.

Also, thanks to TGO's unique trajectory, you can see the same area at different lighting conditions and angles. Researchers can unravel the particle size and composition essential to replicate the correct dust size in the lab.

Data from NASA's Mars Reconnaissance Orbiter and ground-based measurements from NASA's Mars Rovers Curiosity, Pathfinder and opportunity also helped to assert ferrihydrite.

“We are eagerly awaiting the results of our upcoming missions, including ESA's Rosalind Franklin Rover and sample returns from NASA/ESA Mars.

“Some of the samples that have already been collected by NASA's Perseverance Rover and are waiting for their return to Earth contain dust. Putting these precious samples into the lab will result in dust. You can accurately measure the amount of ferihydrite contained and what this means to understand the history of water and the potential for life on Mars.”

“This research is an opening opportunity for the door,” said Dr. Jack Mustard, a planetary scientist at Brown University.

“It gives us a better opportunity to apply the principles of mineral formation and conditions and tap time.”

“More importantly, the return of samples from Mars, which are currently being collected through patience.”

Survey results It will be displayed in the journal Natural Communication.

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A. Valantinas et al. 2025. Detection of ferrihydrite in the red dust of Mars records ancient cold and wet conditions on Mars. Nut commune 16, 1712; doi:10.1038/s41467-025-56970-z

Source: www.sci.news

Newly color-corrected image shows that Uranus and Neptune have a greenish-blue hue

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The so-called ice giants Uranus and Neptune are the most distant giant planets in the solar system. Our knowledge of these worlds was revolutionized by his flybys of NASA’s Voyager 2 spacecraft on January 24, 1986 and August 25, 1989, respectively. Since these Voyager encounters, our knowledge of the visible appearance of these worlds has come primarily from images reconstructed from observations from Voyager 2 Imaging Science System (ISS), images were recorded with several separate filters ranging from ultraviolet to orange. In these images, Uranus appears pale green and Neptune appears dark blue, and the perception of the relative colors of these planets has become generally accepted. However, new research has revealed that the two ice giants are actually much closer in color.

Voyager 2/ISS images of Uranus and Neptune, released shortly after the Voyager 2 flybys in 1986 and 1989, respectively, were used in this study to determine the best estimates of the true colors of these planets. The filtered image was compared with the reprocessed version.Image credit: Irwin other., doi: 10.1093/mnras/stad3761.

Professor Patrick Irwin of the University of Oxford said: “While the well-known Voyager 2 image of Uranus was released in close to ‘true’ color, the image of Neptune has actually been stretched and enhanced. As a result, it was artificially too blue.”

“Although artificially saturated colors were known to planetary scientists at the time and images were published with descriptive captions, over time that distinction has been lost. I lost it.”

“By applying our model to the original data, we were able to reconstruct the most accurate representation to date of the colors of both Neptune and Uranus.”

In the study, Professor Irwin and his colleagues space telescope imaging spectrometer On board the NASA/ESA Hubble Space Telescope (STIS) Multi-unit spectroscopic explorer (MUSE) ESO’s Very Large Telescope.

This means that the STIS and MUSE observations can be processed unambiguously to determine the actual apparent colors of Uranus and Neptune.

Astronomers used these data to rebalance the composite color images recorded by Voyager 2’s camera. Hubble’s Wide Field Camera 3 (WFC3).

This revealed that Uranus and Neptune are actually quite similar shades of greenish-blue.

The main difference is that Neptune has a slight hint of additional blue. Models revealed that this is due to Neptune’s thin haze layer.

The study also provides an answer to the long-standing mystery of why Uranus’ color changes slightly during the sun’s 84-year revolution.

The authors first reached their conclusion after comparing images of the ice giant with measurements of its brightness recorded in blue and green wavelengths from 1950 to 2016 by the Lowell Observatory in Arizona.

These measurements showed that Uranus appears slightly greener during the summer and winter solstices, when one of the planet’s poles points toward our star.

However, at the vernal equinox, when the sun is above the equator, the sun takes on a somewhat blue hue.

Part of the reason for this is known to be because Uranus has a very unusual rotation.

During its orbit, it effectively rotates almost sideways. This means that during the planet’s summer solstice, either the north or south pole points almost directly in the direction of the sun and Earth.

This is therefore important because changes in reflectivity in the polar regions have a large effect on Uranus’ overall brightness as seen from Earth.

Astronomers have not been very clear about how or why this reflectance differs.

This led the researchers to develop a model that compares the spectra of Uranus’ polar and equatorial regions.

They found that in polar regions, green and red wavelengths are more reflective than blue wavelengths. Part of the reason is that red-absorbing methane is about half as abundant near the poles as it is at the equator.

But this wasn’t enough to fully explain the color change, so the researchers looked at the gradually thickening icy surface of the planet’s sunlit pole during the summer. We added a new variable to the model in the form of a haze “hood”. We move from the vernal equinox to the summer solstice.

Astronomers believe it is likely made up of particles of methane ice.

When simulated in the model, the ice particles further increased reflection in green and red wavelengths at the poles, providing an explanation for why Uranus is green at the summer solstice.

“This is the first study to match quantitative models with image data to explain why Uranus’s color changes during its orbit,” Professor Irwin said.

“Thus, we prove that Uranus at the summer solstice is greener, not only because methane abundance is reduced in the polar regions, but also because the thickness of brightly scattering methane ice particles is increased. it was done.”

“The misperceptions of Neptune’s colors and the unusual color changes of Uranus have puzzled us for decades. This comprehensive study finally puts an end to both problems. ” said Dr. Heidi Hummel, a researcher at the Association of Universities for Astronomical Research (AURA).

of result will appear in Royal Astronomical Society Monthly Notices.

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Patrick G.J. Irwin other. 2024. Model the seasonal cycle of Uranus’ color and size and compare it to Neptune. MNRAS 527 (4): 11521-11538; doi: 10.1093/mnras/stad3761

Source: www.sci.news