Over a Cup of Coffee
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How Penguin Poop Influences cloud formation

How Penguin Poop Influences cloud formation

Genetics of orange cats explained

Coffee Table Science
May 25, 2025

Welcome to this edition of Over a Cup of Coffee!

In this newsletter

Webb telescope spots frozen water around another s …
The genetics of orange cats explained
New 'super-vision' contact lenses enable users to …
How Penguin Waste Influences Cloud Development
- More interesting reads this week

Webb telescope spots frozen water around another star

Astronomers have used NASA's James Webb Space Telescope to confirm water ice in the debris disk surrounding a young, Sun-like star located 155 light-years away. We often link water to life, but ice is key to giant planet formation, influencing planetary structure. Icy bodies can form planets and deliver water, potentially explaining Earth's water origin. Icy clumps can initiate planet formation and could be how Earth got its water.

Compared to our 4.6-billion-year-old Sun, the 23-million-year-old star HD 181327 is slightly more massive and hotter, with a larger surrounding system. Webb's observations showed a large gap between the star and its "dirty snowball"-like, icy debris disk. The outer debris disk is over 20% water ice while the middle has only 8% due to near-equal vaporization and production.

Astronomers found little to no ice near the star, likely due to UV vaporization, with any remaining ice potentially inside planetesimals. Remarkably, the debris disk is very similar to our Kuiper Belt, an icy ring beyond Neptune. This similarity to our Kuiper Belt could suggest a common pattern in planetary system evolution, but only future Webb observations will confirm.

The insights were published in the journal Nature.

The genetics of orange cats explained

From Tama to Garfield, the beloved orange cat's color is tied to an unusual genetic pattern favoring males in tabbies. Scientists have long searched for the "orange gene" on the X chromosome, which is hinted at by this pattern. Researchers in Japan pinpointed an X-linked deletion mutation as the cause of orange cat fur, also discovering a new pathway for orange coloring in animals.

The X chromosome is thought to carry the "orange gene," determining orange fur in males with that single X. Females require two "orange genes" to be fully orange, explaining their scarcity compared to males; one "orange" and one "black" lead to calico/tortoiseshell coats. The team's DNA analysis of 18 cats revealed a specific ARHGAP36 deletion in all orange ones, a finding supported by data from 49 additional cats.

Supporting the long-held hypothesis, researchers found that the ARHGAP36 gene is chemically silenced during X chromosome inactivation in mice, cats, and humans. Examining calico skin tissue, the team found ARHGAP36 more active in melanocytes from orange patches than black or white ones.

The team found that high ARHGAP36 activity is associated with decreased activity in pigment genes, suggesting it might switch pigment production from dark to orange via an unknown mechanism. Given the gene's presence in humans and links to skin cancer/hair loss, the findings could be medically significant.

The findings were published in Current Biology.

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New 'super-vision' contact lenses enable users to see in total darkness

Scientists have developed "super-vision" night-vision contact lenses that let wearers see infrared light, which is normally invisible. Unlike traditional night-vision goggles, these lenses are power-free, using nanoparticles to convert low-frequency light into visible light. Traditional night-vision goggles, first used in WWII, convert visible light or near-infrared photons into electrons via an image-intensifier tube, which then glows green on a screen.

These goggles are often bulky due to their power requirements and struggle to distinguish light across the full infrared range, especially at longer wavelengths. Scientists created the new lenses by embedding nanoparticles (made of sodium gadolinium fluoride with ytterbium, erbium, and gold) into flexible, non-toxic polymers found in soft contacts. These nanoparticles absorb near-infrared photons (800-1,600 nm) and emit them as visible light (380-750 nm).

Researchers initially tested the new lenses on mice; those with the lenses preferred dark environments and showed pupil constriction and brain activity when exposed to infrared light, unlike their unlensed counterparts. Subsequently, human trials demonstrated that participants could perceive and orient themselves to flickering infrared light, with this vision improving when their eyes were closed.

By modifying the nanoparticles in the lenses to map specific near-infrared wavelengths to blue, green, and red, scientists suggest this could aid people with color blindness. More development is needed before the lenses are ready. Currently, they only detect bright LED light, so their sensitivity must be increased for lower intensities. Also, due to their closeness to the retina, a separate wearable glass system is being developed for higher-resolution viewing.

The insights were published in the journal Cell.

How Penguin Waste Influences Cloud Development

A recent study suggests that ammonia released from penguin droppings triggers cloud formation through a series of chemical reactions. This process might be altering temperatures in the Antarctic, with possible implications for the global climate. From January to March 2023, University of Helsinki researchers measured ammonia concentrations from a 60,000-strong Adelie penguin colony at Antarctica's Marambio Base.

When winds carried colony air, ammonia levels surged up to 1,000 times normal. Even after the penguins migrated in February, their lingering guano sustained ammonia levels 100 times higher for over a month. Penguin waste, rich in nitrogen from their diet of fish and krill, breaks down into ammonia gas. This ammonia then reacts with sulfur gas from marine microbes (like phytoplankton) to create aerosol particles, which ultimately form clouds with water droplets.

Antarctica's 20 million penguins produce massive amounts of poop, which in turn leads to significant cloud formation. Computer models suggest these clouds reflect sunlight, causing notable ground cooling. Researchers note that if these "poo clouds" are less reflective than ice, they could trap heat, raising temperatures. Understanding these local Antarctic and Arctic changes is crucial due to their global impact, particularly on sea level rise.

The findings were published in Communications Earth and Environment.

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