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Minerals that tell the Earth’s history, and India’s challenge to Australia’s ‘cosmic dawn’ claim

ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to their sources.

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New Delhi: Researchers from Australia’s Curtin University have devised a new metric, which determines the “age distribution fingerprint” of minerals — known as zircon — within sand, which can help give insights into the evolution of the Earth’s surface over the last few billion years.

Most of the original geological record has been lost in the past thousands of years due to erosion, making it difficult for scientists to recreate the history of the Earth’s surface.

Minerals like zircon are durable and form sediments that effectively gather information from these lost times to paint a picture of the planet’s history, including changing environments, the development of a habitable biosphere, the evolution of continents, and the accumulation of mineral resources at ancient plate boundaries.

According to the team this paves the way for a greater understanding of the nature of ancient geology in order to reconstruct the arrangement and movement of tectonic plates on Earth through time.

Zircons contain chemical elements that allow scientists to date and reconstruct the conditions of mineral formation. The new technique allows them to chart the evolution of continents by identifying the particular age distribution fingerprint of zircon grains in a sample. Read more.


Also read: India gets 1st preprint server back — ‘IndiaRxiv’ aims to be one-stop shop for domestic research


Indian researchers challenge Australia’s ‘cosmic dawn’ claim 

A team of researchers from the Raman Research Institute in India has refuted the results of an experiment conducted four years ago, where a team in Australia claimed to have found evidence of the cosmic dawn.

The Indian research published in the journal Nature Astronomy, outlines how they tried to replicate the Australian team’s experiment and why they believe their failure to achieve the same results casts doubt on the efforts by the EDGES team.

In 2018, a team of radio astronomers in Australia used an instrument they called the Experiment to Detect the Global Epoch of Reionization Signature (EDGES) to find evidence of the cosmic dawn — light from the oldest stars in the universe.

Their device was meant to detect changes to interstellar hydrogen due to ultraviolet light emitted from the first stars.

Such changes, theoretically, would involve hydrogen changing from a transparent state to slightly opaque. When their device recorded seeing the changes they were looking for, the team claimed they had found the first evidence of the cosmic dawn.

However, in four years, no other team has been able to replicate the results.

The team in Bengaluru tried by placing a device called the Shaped Antenna Measurement of the Background Radio Spectrum (SARAS) on the surface of water bodies in India.

The team deployed SARAS on two water bodies — Dandiganahalli Lake and Sharavati backwaters. These were chosen specifically as the reservoir had to be one with just the right salinity to shield the device from underground background radiation. After finding the right reservoir, the researchers set up their device and set about looking for evidence of  cosmic dawn, but found none.

The group claims that their failure shows that the results by the team in Australia were flawed. They suggest the earlier findings were likely due to faulty equipment.

But this study does not end the debate on whether or not the team from Australia saw signs of the cosmic dawn. Several other teams are still in the process of setting up their own experiments to see if they can find evidence of it. Read more.

Dinosaur tracks reveal sauropods walked with unique gait

A pair of researchers at Liverpool John Moores University, who used a new method of studying dinosaur tracks, found that Sauropods walked with a gait that was unlike anything seen in any creature alive today.

Previous research has shown that elephants walk by taking two steps on one side, then two steps on the other. Paleontologists had so far assumed that big dinosaurs also walked with a similar gait, because of their large size.

However, researchers have found that to be not the case.

In the new study, the team suggest that because of the massive size of sauropods, walking like an elephant would have required a lot of energy just to keep them from toppling over to one side.

They created a method to study dinosaur trackways that involves accounting for variations in tracks and timing as an animal moves forward. By analysing trackways for three sauropods, they found that a front foot touched down on the ground just before a hind foot on the opposite side was lifted. This gait suggests the giant creatures didn’t wobble as they walked, thereby preserving energy. Read more.

‘Closest blackhole’ to the Earth goes missing?

Scientists have found that a system that in 2020 was reported to be the closest black hole to Earth, actually has no blackhole in it.

A team led by European Southern Observatory (ESO) astronomers had reported a system designated as HR 6819 to be the closest black hole to Earth, located just 1,000 light-years away.

However, a team from KU Leuven Belgium has found that there is in fact no black hole in HR 6819. Instead they report that this is a two-star system in a rare and short-lived stage of its evolution.

The original study on HR 6819 received significant attention from both the press and scientists. The team that had led the original research said that they welcome the scrutiny of their research.

The team from ESO were convinced that the best explanation for the data they had, obtained with a 2.2-meter telescope, was that HR 6819 was a triple system, with one star orbiting a black hole every 40 days and a second star in a much wider orbit.

But the new study now proposes a different explanation for the same data: HR 6819 could also be a system with only two stars on a 40-day orbit and no black hole at all.

This alternative scenario would require one of the stars to be “stripped”, meaning that at an earlier time, it had lost a large fraction of its mass to the other star.

The two research groups will now collaborate to monitor HR 6819 more closely and conduct a joint study of the system over time, to better understand its evolution, constrain its properties, and use that knowledge to learn more about other binary systems. Read more.

Including insects in our diet could improve sustainable farming

Insects — which are a part of the cuisine in many cultures — are an excellent source of protein for humans. Now, researchers suggest that the insect waste can also help promote sustainable crops.

The team argues that farming insects for food could enhance plant growth, health, pollination, and resilience.

The leftovers from insect production come in two main forms. The first is exuviae, which are exoskeletons. The second is frass, named for the German word for eating. Frass is basically insect poop and unconsumed food.

When added to soil, the exuviae and frass promote both plant growth and health. Insect feces are rich in nitrogen, a nutrient that is pivotal to plant growth, but is scarce in most soils. Therefore, it is often added to crops in synthetic fertilizer. The insect exoskeletons are rich in chitin, a polymer that is difficult for most organisms to digest.

The team see the application of insect-rearing by-products to crops as a novel step towards a circular food system in which there is very little waste. The insects are fed waste streams from crop farming or food production, and the insects then provide humans with food. Using the leftovers from insect production to bolster crop growth could close this circle. Read more.


Also read: Russia’s attack on Ukraine halts rocket launches, Venus mission, casts doubt on ISS fate


 

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