ERIK MARTIN WILLÈN: October 2024

Tuesday, October 1, 2024

NASA’s BioSentinel Studies Solar Radiation as Earth Watches Aurora - UNIVERSE

Illustration of NASA’s BioSentinel spacecraft as it enters a heliocentric orbit. BioSentinel collected data during the May 2024 geomagnetic storm that hit Earth to learn more about the impacts of radiation in deep space.

NASA/Daniel Rutter

In May 2024, a geomagnetic storm hit Earth, sending auroras across the planet’s skies in a once-in-a-generation light display. These dazzling sights are possible because of the interaction of coronal mass ejections – explosions of plasma and magnetic field from the Sun – with Earth’s magnetic field, which protects us from the radiation the Sun spits out during turbulent storms.

But what might happen to humans beyond the safety of Earth’s protection? This question is essential as NASA plans to send humans to the Moon and on to Mars. During the May storm, the small spacecraft BioSentinel was collecting data to learn more about the impacts of radiation in deep space.

“We wanted to take advantage of the unique stage of the solar cycle we’re in – the solar maximum, when the Sun is at its most active – so that we can continue to monitor the space radiation environment,” said Sergio Santa Maria, principal investigator for BioSentinel’s spaceflight mission at NASA’s Ames Research Center in California’s Silicon Valley. “These data are relevant not just to the heliophysics community but also to understand the radiation environment for future crewed missions into deep space.”

BioSentinel – a small satellite about the size of a cereal box – is currently over 30 million miles from Earth, orbiting the Sun, where it weathered May’s coronal mass ejection without protection from a planetary magnetic field. Preliminary analysis of the data collected indicates that even though this was an extreme geomagnetic storm, that is, a storm that disturbs Earth’s magnetic field, it was considered just a moderate solar radiation storm, meaning it did not produce a great increase in hazardous solar particles. Therefore, such a storm did not pose any major issue to terrestrial lifeforms, even if they were unprotected as BioSentinel was. These measurements provide useful information for scientists trying to understand how solar radiation storms move through space and where their effects – and potential impacts on life beyond Earth – are most intense.

NASA’s Solar Dynamics Observatory captured this image of a solar flare on May 11, 2024. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares.

NASA/SDO

The original mission of BioSentinel was to study samples of yeast in deep space. Though these yeast samples are no longer alive, BioSentinel has adapted and continues to be a novel platform for studying the potential impacts of deep space conditions on life beyond the protection of Earth’s atmosphere and magnetosphere. The spacecraft’s biosensor instrument collects data about the radiation in deep space. Over a year and a half after its launch in Nov. 2022, BioSentinel retreats farther away from Earth, providing data of increasing value to scientists.

“Even though the biological part of the BioSentinel mission was completed a few months after launch, we believe that there is significant scientific value in continuing with the mission,” said Santa Maria. “The fact that the CubeSat continues to operate and that we can communicate with it, highlights the potential use of the spacecraft and many of its subsystems and components for future long-term missions beyond low Earth orbit.”

When we see auroras in the sky, they can serve as a stunning reminder of all the forces we cannot see that govern our cosmic neighborhood. As NASA and its partners seek to understand more about space environments, platforms like BioSentinel are essential to learn more about the risks of surviving beyond Earth’s sphere of protection.

By: Frank Tavares

Source: NASA’s BioSentinel Studies Solar Radiation as Earth Watches Aurora - NASA

Brazilian fossils reveal early evolution of mammalian jaw and middle ear

Riograndia and Brasilodon. Credit: Jorge Blanco

Newly discovered fossils, belonging to the mammal-precursor species Brasilodon quadrangularis and Riograndia guaibensis, offer critical insights into the development of the mammalian jaw and middle ear, revealing evolutionary experiments that occurred millions of years earlier than previously thought.

Mammals stand out among vertebrates for their distinct jaw structure and the presence of three middle ear bones. This transition from earlier vertebrates, which had a single middle ear bone, has long fascinated scientists. The new study explores how mammal ancestors, known as cynodonts, evolved these features over time.

Using CT scanning, researchers were able to digitally reconstruct the jaw joint of these cynodonts for the first time. The researchers uncovered a 'mammalian-style' contact between the skull and the lower jaw in Riograndia guaibensis, a cynodont species that lived 17 million years before the previously oldest known example of this structure, but did not find one in Brasilodon quadrangularis, a species more closely related to mammals.

The work, published in Nature, indicates that the defining mammalian jaw feature evolved multiple times in different groups of cynodonts, earlier than expected.

These findings suggest that mammalian ancestors experimented with different jaw functions, leading to the evolution of 'mammalian' traits independently in various lineages. The early evolution of mammals, it turns out, was far more complex and varied than previously understood.

Riograndia. Credit: James Rawson

Lead author James Rawson, based in Bristol's School of Earth Sciences, explained, "The acquisition of the mammalian jaw contact was a key moment in mammal evolution.

"What these new Brazilian fossils have shown is that different cynodont groups were experimenting with various jaw joint types, and that some features once considered uniquely mammalian evolved numerous times in other lineages as well."

This discovery has broad implications for the understanding of the early stages of mammal evolution, illustrating that features such as the mammalian jaw joint and middle ear bones evolved in a patchwork, or mosaic, fashion across different cynodont groups.

Dr. Agustín Martinelli, from the Museo Argentino de Ciencias Natural of Buenos Aires, said, "Over the last years, these tiny fossil species from Brazil have brought marvelous information that enrich our knowledge about the origin and evolution of mammalian features. We are just in the beginning and our multi-national collaborations will bring more news soon."

Brasilodon. Credit: James Rawson

The research team is eager to further investigate the South American fossil record, which has proven to be a rich source of new information on mammalian evolution.

Professor Marina Soares of the Museu Nacional, Brazil, said, "Nowhere else in the world has such a diverse array of cynodont forms, closely related to the earliest mammals."

By integrating these findings with existing data, the scientists hope to deepen their understanding of how early jaw joints functioned and contributed to the development of the mammalian form.

James added, "The study opens new doors for paleontological research, as these fossils provide invaluable evidence of the complex and varied evolutionary experiments that ultimately gave rise to modern mammals."

by University of Bristol

Source: Brazilian fossils reveal early evolution of mammalian jaw and middle ear (phys.org)