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When a comet hits a tidally locked exo-Earth

Comets that have hit Earth have been a mixed bag. Early in Earth’s history, during the solar system’s chaotic beginning, they were likely the source of our planet’s water, ultimately making up about 0.02% of the planet’s mass. (Mars and Venus received a similar fraction.)

Comets brought complex organic molecules and the biosphere, but later posed a threat to the same in cometary collisions. A (or asteroid) likely caused the Tunguska Event in 1908 in Russia, and a comet fragment likely triggered the rapid climate shift of the Younger Dryas 12,800 years ago, with its widespread extinctions.

If such collisions happen here, they likely take place in other solar systems as well. Now three scientists in the United Kingdom have modeled the impacts of an icy cometary collision with an Earth-like, tidally locked terrestrial planet. Such objects are prime candidates in the search for habitable exoplanets outside our solar system.

Snowball Earth: Drone mapping and isotopic dating suggest Marinoan glaciation spanned 4 million years

Scientists at the University of California, Berkeley, and Boise State University have found evidence suggesting that the Marinoan glaciation began approximately 639 million years ago and lasted for approximately 4 million years. In their study published in the Proceedings of the National Academy of Sciences, the group used drone and field imagery along with isotopic dating of glacial deposits to learn more about global glaciation events during the Neoproterozoic Era.

Prior research has shown that during the early days of the planet, during the Neoproterozoic Era, Earth underwent two ice ages. The first, known as the Sturtian glaciation, lasted approximately 56 million years and covered the entire planet with ice. Less is known about the second event, called the Marinoan glaciation. In this new effort, the research team set themselves the task of figuring out when it began and how long it lasted.

The work involved sending drones over a part of Namibia, where prior research has uncovered evidence of glacial activity during the Marinoan. This allowed the team to map that were stacked up in a way that showed little vertical shift had occurred, which meant the glaciers did not move much during the time they were there. Additional field imagery helped confirm what the team found in the images.

Atmospheric reaction between Criegee intermediates and water found to be unexpectedly fast

Criegee intermediates (CIs)—highly reactive species formed when ozone reacts with alkenes in the atmosphere—play a crucial role in generating hydroxyl radicals (the atmosphere’s “cleansing agents”) and aerosols that impact climate and air quality. The syn-CH3CHOO is particularly important among these intermediates, accounting for 25%–79% of all CIs depending on the season.

Until now, scientists have believed that syn-CH3CHOO primarily disappeared through self-decomposition. However, in a study published in Nature Chemistry, a team led by Profs. Yang Xueming, Zhang Donghui, Dong Wenrui and Fu Bina from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has uncovered a surprising new pathway: syn-CH3CHOO’s reaction with is approximately 100 times faster than previously predicted by theoretical models.

Using advanced laser techniques, the researchers experimentally measured the reaction rate between syn-CH3CHOO and water vapor, and discovered the faster reaction time. To uncover the reason behind this acceleration, they constructed a high-accuracy full-dimensional (27D) potential energy surface using the fundamental invariant-neural network approach and performed full-dimensional dynamical calculations.

Scientists find way to rewire the brain

The first genetically engineered synapses have been implanted in a mammal’s brain. Chemical brain signals have been bypassed in the brains of mice and replaced with electrical signals, changing their behaviour in incredible ways. Not only did they become more sociable, they were also less anxious and exhibited fewer OCD-like symptoms. This work has sparked hope that one day we could use this technology to help humans with mental health conditions. But would you want someone making permanent edits to your brain?

For the first time, climate scientists can now link specific fossil fuel companies to climate-related economic damages in particular places. A new method has been developed that can show the exact impact these companies are having on our environment — which the world’s top five emitters linked to trillions of dollars of economic losses. Find out how scientists have managed to piece this together — and whether these companies are about to face massive lawsuits.

As we reflect on the death of Pope Francis, we explore his legacy on scientific issues and his transformative stance on climate change. As the spiritual leader of 1.4 billion Catholics, he became an influential figure in advocating for better care to be taken of our planet. Will his legacy continue with the next Pope?

Chapters:
00:00 Intro.
00:28 First brain engineering in a mammal.
10:57 Landmark in fossil fuel lawsuits.
19:33 Climate legacy of Pope Francis.

Hosted by Rowan Hooper and Penny Sarchet, with guests Alexandra Thompson, James Dinneen, William Schafer, Chris Callahan, Justin Mankin and Miles Pattenden.

Learn more ➤ https://www.newscientist.com/podcasts.

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