New Study: Modern Humans Had Many Failed Attempts to Settle in Europe

Women from the Samburu tribe receive a food donation given due to an ongoing drought, in the town of Oldonyiro, Isiolo county, Kenya, October 8, 2021. (Reuters File Photo)
Women from the Samburu tribe receive a food donation given due to an ongoing drought, in the town of Oldonyiro, Isiolo county, Kenya, October 8, 2021. (Reuters File Photo)
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New Study: Modern Humans Had Many Failed Attempts to Settle in Europe

Women from the Samburu tribe receive a food donation given due to an ongoing drought, in the town of Oldonyiro, Isiolo county, Kenya, October 8, 2021. (Reuters File Photo)
Women from the Samburu tribe receive a food donation given due to an ongoing drought, in the town of Oldonyiro, Isiolo county, Kenya, October 8, 2021. (Reuters File Photo)

Modern humans made several failed attempts to settle in Europe before eventually taking over the continent. This is the stark conclusion of scientists who have been studying the course of Homo sapiens' exodus from Africa tens of thousands of years ago, according to a report by The Guardian.

Researchers have recently pinpointed sites in Bulgaria, Romania and the Czech Republic where our ancestors' remains have been dated as being between 40,000 to 50,000 years old. However, bone analyses have produced genetic profiles that have no match among modern Europeans.

"These early settlements appear to have been created by groups of early modern humans who did not survive to pass on their genes. They are our species' lost lineages. The crucial point is that the demise of these early modern human settlers meant Neanderthals still occupied Europe for a further few thousand years before Homo sapiens eventually took over the continent," said Professor Chris Stringer of the Natural History Museum, London.

Modern humans first appeared in Africa around 200,000 years ago and slowly evolved across the continent before moving into western Asia around 60,000 years ago. Our ancestors then spread across the globe until every other species of hominin on the planet had been rendered extinct, including the Denisovans of East Asia and Homo floresiensis, the "hobbit folk" of Indonesia.

Neanderthals in Europe were one of the last hominin species to succumb, dying out around 39,000 years ago. However, recent studies – outlined at a meeting of the European Society for the study of Human Evolution earlier this year – have shown that this takeover by Homo sapiens was not straightforward. On several occasions, groups of early settlers perished as they moved into the continent.

In one study, international researchers re-examined a partial skull and skeleton of a woman found in the Zlatý Kůň cave in the Czech Republic. Originally thought to have been 15,000 years old, this new analysis indicated it was probably at least 45,000 years old, making her one of the oldest members of Homo sapiens found in Europe. However, the study also found she shared no genetic continuity with modern Europeans.



What is Helium and Why is it Used in Rockets?

India's Geosynchronous Satellite Launch Vehicle Mk III-M1 blasts off carrying Chandrayaan-2, from the Satish Dhawan Space Centre at Sriharikota, India, July 22, 2019. REUTERS/P. Ravikumar/File Photo Purchase Licensing Rights
India's Geosynchronous Satellite Launch Vehicle Mk III-M1 blasts off carrying Chandrayaan-2, from the Satish Dhawan Space Centre at Sriharikota, India, July 22, 2019. REUTERS/P. Ravikumar/File Photo Purchase Licensing Rights
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What is Helium and Why is it Used in Rockets?

India's Geosynchronous Satellite Launch Vehicle Mk III-M1 blasts off carrying Chandrayaan-2, from the Satish Dhawan Space Centre at Sriharikota, India, July 22, 2019. REUTERS/P. Ravikumar/File Photo Purchase Licensing Rights
India's Geosynchronous Satellite Launch Vehicle Mk III-M1 blasts off carrying Chandrayaan-2, from the Satish Dhawan Space Centre at Sriharikota, India, July 22, 2019. REUTERS/P. Ravikumar/File Photo Purchase Licensing Rights

Two NASA astronauts aboard Boeing's (BA.N) Starliner will stay on the International Space Station for months, because of a faulty propulsion system whose problems included helium leaks. Back on Earth, SpaceX's Polaris Dawn mission has been delayed because of helium issues on ground equipment.

Boeing's Starliner spacecraft landed uncrewed in a New Mexico desert late on Friday.

Past missions have that have been affected by pesky helium leaks include ISRO's Chandrayaan 2 and ESA's Ariane 5. Why do spacecraft and rockets use helium, and what is so tricky about it?

WHY HELIUM?

Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen.

Rockets need to achieve specific speeds and altitude to reach and maintain orbit. A heavier rocket requires more energy, not only increasing fuel consumption but also needing more powerful engines, which are more expensive to develop, test, and maintain.

Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that temperature range.

The gas is non-toxic, but cannot be breathed on its own, because it displaces the oxygen humans need for respiration.

HOW IS IT USED?

Helium is used to pressurize fuel tanks, ensuring fuel flows to the rocket's engines without interruption; and for cooling systems.

As fuel and oxidiser are burned in the rocket's engines, helium fills the resulting empty space in the tanks, maintaining the overall pressure inside.

Because it is non-reactive, it can safely mingle with the tanks' residual contents.

IS IT PRONE TO LEAKS?

Helium’s small atomic size and low molecular weight mean its atoms can escape through small gaps or seals in storage tanks and fuel systems.

But because there is very little helium in the Earth's atmosphere, leaks can be easily detected - making the gas important for spotting potential faults in a rocket or spacecraft's fuel systems.

In May, hours before Boeing's Starliner spacecraft made an initial attempt to launch its first astronaut crew, tiny sensors inside the spacecraft detected a small helium leak on one of Starliner's thrusters that NASA spent several days analysing before deeming it low-risk, according to Reuters.

Additional leaks were detected in space after Starliner launched in June, contributing to NASA's decision to bring Starliner back to Earth without its crew.

The frequency of helium leaks across space-related systems, some engineers say, have highlighted an industry-wide need for innovation in valve design and more precise valve-tightening mechanisms.

ARE THERE ALTERNATIVES?

Some rocket launches have experimented with gases such as argon and nitrogen, which are also inert and can sometimes be cheaper. Helium, however, is much more prevalent in the industry.

Europe's new Ariane 6 rocket ditched the helium of its predecessor Ariane 5 for a novel pressurization system that converts a small portion of its primary liquid oxygen and hydrogen propellants to gas, which then pressurizes those fluids for the rocket engine.

That system failed in space during the final phase of Ariane 6's otherwise successful debut launch in July, adding to the global rocket industry's long list of pressurization challenges.