What happened in Science recently?

Being in both perfect physical and mental condition is crucial for an astronaut in order to withstand the forces of spaceflight. This two attributes were among the most important selection criteria for the USA and the Soviet Union at the beginning of the space era. In fact, little was known about the human body response to spaceflights. That’s why the first astronaut were recruited among military test pilots whereas cosmonaut were a bit younger.
Then, spaceflight evolved and so did the skills needed such as knowledge in scientific discipline. New mission, more complicated such as docking in orbit or going outside a spacecraft put more emphasis on engineering education. Buzz Aldrin, selected in the third group of NASA astronauts in 1963, was the first person to join the corps with a doctoral degree (in astronautics from the MIT).

However, the qualifications to be an astronaut remained the same through the Apollo program, only one astronaut who landed on the moon was a scientist : geologist Harrison “Jack” Schmitt in Apollo 17. But, with the Skylab program and then the Space Shuttle, profils begin to be more and more diverse, both in term ofqualification (physicist, electrical engineering, teacher) and diversity (women with Sally Ride in 1983 , minorities and citizens).
Finally, with the development of space station (Mir and then the ISS), spacemen were required to speak lots of different langage in order to communicate and live with their fellow comrades. To conclude, the qualififactions of astronauts will continue to evolve with the space goals. source

The first known fossilized feather has been an icon of palaeontology ever since it emerged from a German limestone quarry in 1861. That 150-million-year-old plume was the first fossil ever tied to Archaeopteryx lithographica—a name now given to a feathered dinosaur found in nearby rocks. About the size of a raven, that ancient animal’s mix of bird and dinosaur features showed an example of evolutionary transition, providing support for Charles Darwin’s theories.

But this feather is also among the most controversial. The question isn’t whether Archaeopteryx was feathered but whether this iconics feather actually belongs to Archaeopteryx.

Researchers led by National Geographic Explorer Ryan Carney are laying out what they say is the most comprehensive case to date that, yes, the feather belongs to Archaeopteryx. In 2012, he found that the feather most plausibly formed part of the upper surface of Archaeopteryx’s left wing, where it would have helped support a primary flight feather. The team also looked at the feather under high-powered microscopes and found fossilized pigments that suggested the feather was black.
But, since then, several studies have poked and prodded at the feather’s color and identity. The most shocking analysis came in 2019, when a team led by Thomas Kaye and Pittman cast doubt on the feather’s ties to Archaeopteryx.

Now, Carney and his colleagues have repeated the analysis done in 2019, and they’ve come to the opposite conclusion.Carney’s team expanded the 2019 study’s set of comparison bird feathers, to better account for the fact that feather shape varies widely across a given bird’s wing and from species to species. The researchers also retraced the fossil feather’s centerline and got a less curved one than the 2019 study did. The new centerline falls within the expanded set of feather shapes, supporting the idea that this feather could have fit within an Archaeopteryx’s wing. While Carney disagrees with the 2019 study’s calamus tracing, Pittman says that he disagrees with the new study’s tracing, and consequently all the analyses that follow. He likens the feather’s quill and shaft to a vaulting pole: Even tiny changes in the angle at its base will lead to major changes in its overall curvature, especially at its most distant tip.

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When searching for life beyond Earth, scientists commonly “follow the water.” One of the best places to do that could be the Martian south pole, where new research reveals that—beneath a mile of ice—multiple small ponds appear to surround a large lake.
More than a decade ago, Pettinelli and her colleagues turned their attention to a region on Mars called the South Pole Layered Deposits , where radar observations had uncovered bright, reflective areas beneath the frozen glaciers. To peer beneath the ice, the team aimed a radar called MARSIS .

Now, 105 additional observations, collected between 2015 and 2019 and covering a larger area, have reinforced the original detection.In addition to returning evidence that the reservoir was water, the data pointed to at least three smaller patches around it, separated by dry soil. While the team is confident that the larger reservoir is salt water, Pettinelli says those smaller patches could easily be soggy sediments—an environment where life could still exist.

Although liquid water is abundant on Earth and among the outer solar system’s icy moons, it’s been surprisingly tough to find on Mars. Its signatures are all over the planet’s surface, in the form of carved river beds, fanning deltas, and ancient shorelines, so scientists know that early Mars was a wetter world than the planet we see today—perhaps even temperate and hospitable. Now, scientists are asking: Where did all that water go?

Some of it is locked into ice caps that crown the planet’s poles—permanent icy deposits that seasonally shrink and expand. Shining brightly in telescope observations, the polar caps have been a subject of study for decades as scientists try to better understand the historical record that might be preserved in their accumulated layers. The bright reflections underneath the ice caps could hint at some of that history. But even so, some Mars experts still question the true nature of the material under the glaciers.

The interpretation is also inconsistent with MARSIS observations in nearby regions, where similarly bright patches extend to the very edge of the ice sheets. So far, Holt says, no one has explained what those bright patches are—but buried brines are not the answer, because if they were, brines in those areas would seep to the surface. source