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Why human speech will sound garbled on Mars & lettuce to help astronauts retain bone mass

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: Analysing sounds captured by the Perseverance rover has helped scientists determine the speed of sound on Mars, revealing that human speech would sound garbled on the red planet.

The Perseverance rover, which landed on Mars over a year ago, is outfitted with a microphone, allowing the rover to beam back the first sounds ever heard from another planet.

Researchers, including those from Cornell University, calculated the speed of sound by measuring the amount of time it took for sounds from laser blasts from Perseverance to return to the rover’s microphone. The team found sound to be traveling on Mars at approximately 240 metre per second (m/s).

Moreover, different frequencies of sound travel at different speeds on Mars. The speed increases by approximately 10 m/s above 400 Hz. This finding suggests that communication would be extremely difficult on Mars, with different parts of speech arriving to listeners at different times, making conversations sound garbled. Read more.

Also read: South Pole warmer by 40°C, North Pole by 30°C. Simultaneous highs alarm scientists

Machu Picchu known by the wrong name

Machu Picchu — an Inca archaeological site that attracts hundreds of thousands of tourists every year — may have been known by the wrong name since its rediscovery.

According to a archaeologists, the UNESCO world heritage site was actually known as Huayna Picchu — the name of a peak overlooking the ruins — or simply Picchu.

The team from Peru’s ministry of culture and the University of Illinois Chicago said that analysing 19th-century maps, information in 17th-century documents and the original field notes of the US explorer Hiram Bingham, have revealed that not one of the sources refers to the site as Machu Picchu.

Machu Picchu was rediscovered by Bingham in 1911. At the time, the ruins were little known.

The researchers found that the ruins of an Inca town called Huayna Picchu are mentioned in a 1904 atlas that was published seven years before Bingham arrived in Peru. Read more.

Male dolphins use whistles to stay connected

While male bottlenose dolphins are known to use physical contact such as gentle petting to connect with their closest friends, a new study reveals that they also maintain their friendships with some of their acquaintances using whistles.

Researchers from the University of Bristol have shown that vocal exchanges — which take less time than a physical one — are used by dolphins to remain connected with their weaker allies.

The scientists used nine years of acoustic and behavioural data from a dolphin population in Shark Bay in Western Australia, to assess how male dolphins reinforced and maintained their valuable alliances.

Many animals use touch to strengthen and reaffirm important relationships. But as the number of close social relationships increases, the demands on time and space to maintain such relationship also increases.

Now, this research team has been able to identify the different ways that these male dolphins bonded with each other.

Vocalisations and language evolved as a form of ‘vocal grooming’ to replace physical grooming, as increasingly large group sizes placed impossible demands on the time available for physical contact behaviours. Read more.

New space lettuce can restore astronaut’s bone health

Scientists from University of California Davis have reported creating a new variety of transgenic lettuce that produces a bone-generating hormone, an advance that can help astronauts grow food aboard the international space station, helping guard against bone loss.

NASA is preparing to send humans to Mars by the 2030s. However, spending a long period of time in microgravity will cause astonauts to lose bone mass.

The new variety of lettuce could be grown in space to help guard against bone loss — simply by eating a big bowl of salad. In addition, the lettuce may also help stave off osteoporosis in resource-limited areas here on Earth, the researchers say.

Astronauts can carry transgenic seeds, which are very tiny and grow them just like regular lettuce. Read more.

Spinosaurus had dense bones to hunt underwater

Researchers have found that the Spinosaurus had dense bones that allowed this  dinosaur species to hunt underwater.

Spinosaurus is the biggest carnivorous dinosaur ever discovered — even bigger than T. rex— but the way it hunted has been a subject of debate for decades. Based on its skeleton, some scientists have proposed that Spinosaurus could swim, but others believe that it waded in the water.

Palaeontologists from the Universities of Cambridge and Oxford, and the Field Museum in Chicago, examined the density of their bones and compared them to animals like penguins, hippos and alligators. The team found that Spinosaurus, and its close relative Baryonyx, had dense bones that likely would have allowed them to submerge themselves underwater to hunt.

Meanwhile, another related dinosaur called Suchomimus, had lighter bones that would have made swimming more difficult, so it likely waded instead or spent more time on land like other dinosaurs.

The researchers put together a dataset of femur and rib bone cross-sections from 250 species of extinct and living animals, from seals, whales, elephants, mice and hummingbirds, to dinosaurs of different sizes, to extinct marine reptiles like mosasaurs and plesiosaurs.

They compared these cross-sections to bone from Spinosaurus and its relatives Baryonyx and Suchomimus. The team had to show proof of concept among present-day animals that we know for sure are aquatic or not, and then apply it to extinct animals that we can’t observe.

The study revealed a clear link between bone density and aquatic foraging behaviour: animals that submerge themselves underwater to find food have bones that are almost completely solid throughout, whereas cross-sections of land-dwellers’ bones look more like doughnuts, with hollow centres. Read more.

(Edited by Poulomi Banerjee)

Also read: Anthrax ruled out as cause of deer death inside IIT-Madras campus


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