Good Morning! 🌞

It seems like quite a lot of you all enjoyed the song we included in the intro yesterday. The singer, Haley Reinhart, was one of the most popular participants in the 10th season of American Idol which happened in 2011 when she was just 20 years old.

Innovation

The North Star Cannibalism

Polaris, the North Star, is one of the most famous stars in the sky, yet it remains an enigma. Recent reassessments of its fundamental properties, such as mass and distance from Earth, suggest that Polaris appears paradoxically youthful.

This strangeness might lead one to think astronomers have miscalculated its age. However, the truth might be even stranger: stars can sometimes rejuvenate themselves, turning back the cosmic clock.

Polaris is actually a multistar system where several stars orbit one another. Even a small backyard telescope will reveal Polaris as two stars: the bright Polaris A and the fainter Polaris B. Further observations show that Polaris A is actually a very tight binary system, consisting of two stars (Aa and Ab) orbiting closely together.

Polaris Aa, the giant and brightest of the trio, is usually what astronomers refer to when they mention Polaris. It is a special type of star known as a Cepheid variable, which periodically brightens and dims. Polaris Aa's brightness changes by about 4% over roughly four days. Cepheid variables are crucial for astronomy because the duration of their brightness cycle correlates with their intrinsic luminosity. This relationship allows astronomers to measure cosmic distances by comparing intrinsic brightness with observed brightness.

Polaris is the closest Cepheid variable to Earth, making its distance measurement critical. Accurate distance measurements to Polaris help calibrate distances to more distant Cepheids and galaxies. However, measuring the distance to Polaris has proven difficult due to its brightness, which saturates most modern telescopes. Estimates have varied widely, from 300 to 450 light-years, which is a significant uncertainty for such an important star.

In 2018, astronomers used a clever method to refine Polaris's distance. They assumed that Polaris B is physically associated with Polaris A and used the Hubble Space Telescope to measure Polaris B's distance via parallax. The result, 521 light-years, was a surprising but significant finding.

Astronomer Richard I. Anderson analyzed observations of Polaris Aa and used physical models to understand its characteristics. His findings suggest that Polaris Aa, with seven times the mass of the sun at 521 light-years away, aligns with the new distance measurement. However, this creates a paradox: Polaris Aa appears to be only about 54 million years old, while its companion, Polaris B, seems to be over two billion years old. This discrepancy challenges the notion that both stars formed simultaneously from the same gas cloud.

The possible explanation is that Polaris Aa underwent a stellar merger. A third star might have collided and merged with one of the existing stars, rejuvenating Polaris Aa. This merger would mix the star's gas, giving it a youthful appearance. Such mergers, while rare, are known to occur. Evidence of material ejected into space supports this hypothesis.

Without the merger, Polaris Aa would be a lower-mass star that looks its true age of around two billion years. Instead, the merger increased its mass, causing it to age faster. This explains why Polaris Aa, despite appearing young, is nearing the end of its life as a red supergiant.

If this "stellar merger" theory holds, we can confidently use Polaris to calibrate distances to other Cepheid variables and galaxies. This calibration is fundamental to measuring the vast distances in the universe.

Polaris has long guided explorers on Earth, and it continues to guide astronomers in mapping the cosmos.

Culture

The Window to the Soul

It is commonly said that eyes are the windows to the soul. This is not surprising, because there is something captivating about eyes.

Out of this fascination of eyes has come a new form of photography which takes an amazingly detail image of your iris. The images are absolutely stunning. IrisPhoto is one of the companies that do this type of photography. Here is their Instagram if you want to view more of their work!

Environment

Mushrooms Transform Toxic Brownfields into Blooming Meadows

Danielle Stevenson, an environmental toxicologist in California, is using fungi and native plants to clean up areas contaminated with heavy metals and other pollutants. Her work has transformed toxic industrial lots into flourishing meadows frequented by birds and pollinators.

Stevenson, the founder of DIY Fungi and a UC Riverside ecologist, recently discussed her efforts with Yale Press. She focuses on restoring "brownfields"—contaminated sites abandoned by industrial, extraction, or transportation operations. Examples include old railway yards and abandoned oil refineries, often laden with petrochemicals, heavy metals, or other toxins.

Inspired by studies on mushrooms around the Chernobyl nuclear plant, Stevenson learned that fungi are resilient organisms that consume carbon. While petroleum products are toxic to plants, mushrooms can break down these substances using the same enzymes they use to decompose dead trees. They can also digest plastic and agrochemicals.

At a Los Angeles railyard, Stevenson and her team planted native grasses and flowers alongside dead wood to cultivate arbuscular mycorrhizal fungi, which help plants extract heavy metals like lead and arsenic from the soil. This approach yielded impressive results, reducing pollutants by over 50% in three months and making them almost undetectable in 12 months.

Traditional soil decontamination involves costly and hazardous methods like bulldozing and transporting contaminated soil to landfills. Stevenson's bioremediation technique, on the other hand, involves harvesting and incinerating plants that draw out toxic metals, reducing the material to a small pile of ash for easier and safer disposal.

While bioremediation has some scaling and regulatory challenges, Stevenson has successfully applied it to various situations, including breaking down lubricant-soaked rags from bicycle repair shops. She emphasizes the importance of involving local communities in pollution cleanup efforts and providing them with the necessary tools to make informed decisions about their neighborhoods.

Mind Stretchers

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Yesterday’s Mind Stretchers:
We may die a thousand deaths and we may break a thousand hearts,
But it isn't cause for worry, for we live our lives in parts.
- Actors

Gerry Moore got the correct answer first!

Be the first to send us the correct answer for today’s mind stretcher for a shout-out with the answer tomorrow. Just send us the answer and your name to [email protected]

If you have any uplifting stories and experience you might want to share, send those over to [email protected] for the chance to be featured.