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NASA launches first ever asteroid deflection mission

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Scientists including Stephen Hawking have described impact events as among the greatest threats facing humanity – and even if the planetary defence mission proves successful, huge questions about our future readiness will remain.

A spacecraft has been launched from California this morning carrying with it humanity’s greatest hopes of being able to protect our planet from a cataclysmic asteroid impact.

Fortunately the DART (Double Asteroid Redirection Test) mission is only a test, and if anything goes wrong before it intercepts its target next September, then Earth won’t suffer as a result.

But the stakes are high. Scientists including Stephen Hawking have described impact events as among the greatest threats facing humanity – and even if the DART planetary defence mission proves successful, huge questions about our future readiness will remain.

The DART spacecraft's collision will be observed by the LICIACube satellite
Image:The DART spacecraft’s collision will be observed by the LICIACube satellite. Pic: NASA

DART launched on top of a SpaceX Falcon 9 rocket at the Vandenberg Space Force base in California.

Roughly the size of a small car, the spacecraft has been developed by NASA and the Johns Hopkins Applied Physics Laboratory to demonstrate for the first time the “kinetic impactor technology” using a direct hit on an asteroid to adjust its speed and path.Advertisement

A small LICIACube satellite developed by the Italian space agency will travel alongside it to observe the collision which will take place when DART and its target asteroid are within 11 million kilometres of Earth, enabling ground-based telescopes to measure the impact too.

DART is targeting a near-Earth double asteroid known as Didymos and Dimorphos, with the latter being a “moonlet” estimated to be about 160 metres in size – a good test object, but not one that is actually expected to collide with Earth.

It will hit Dimorphos at a speed of roughly 6.6 kilometres per second and, in doing so, shorten its orbit about Didymos – proving that a kinetic impact can change an asteroid’s trajectory.

This nudge technique is preferred to blowing asteroids apart in the style of the film Armageddon, because the fragments from such an explosion could continue to imperil the planet.

A study from researchers at Johns Hopkins University in the US published in 2019 warned that for objects large enough to be targeted it was likely the blasted away fragments would reform under gravity.

Illustration of the DART spacecraft with the Roll Out Solar Arrays extended. Image credit: NASA
Image:The DART spacecraft is just the size of a small car, not including its solar arrays. Pic: NASA

How important is the mission?

The good news is that scientists are completely confident that no asteroids larger than 1km will strike our planet within the next century – the maximum period we can map out their movements for due to the unpredictability of dynamic systems.

What’s also good is that even among much smaller asteroids, ones larger than just 140 metres, there are no known objects that have a significant chance of striking Earth within the next 100 years too.

The bad news is that only 40% of these asteroids have been found, and the worse news is that asteroids can be much smaller than 140m and still cause significant damage to regions or cities.

Humanity’s ability to detect asteroids before they impact the planet is still in its infancy, in part because of limits set by the laws of physics – our ability to survey asteroids in the dark of space in our solar system depends on them reflecting light towards us, and that depends on direction of their approach relative to the sun and the phase of the moon.

There have been more than 1,200 impacts of asteroids larger than a metre in size since 1988 and of those impacts humanity has only predicted five in advance – less than 0.42% – and even those predictions came with just hours to spare.

This timeline offers much less wriggle-room than the five years between the DART mission getting approval at NASA and its scheduled rendezvous with Dimorphos next year.

Never mind deflecting an asteroid off-course, hours wouldn’t even offer enough time to evacuate a town.

But astronomers hope and expect that new technologies and monitoring systems will improve our ability to make these predictions in the future – giving us more time – and the DART mission is just the first step in us proving that there is something we can do about it when we know something is coming.

This video grab from YouTube footage shows a meteor streaking across the sky in the Chelyabinsk region of central Russia.
Image:This video grab from YouTube footage shows the meteor streaking across the sky in the Chelyabinsk

What damage can impact events cause?

Impact events are believed to have radically reshaped our planet throughout history, from the formation of the moon through to several enormous extinction events.

The Chicxulub crater is believed to have been caused by a large asteroid approximately 10km in diameter striking the Earth just over 66 million years ago, leading a very sudden mass extinction of an estimated 75% of all animal and plant life on the planet – including the dinosaurs.

A similar scale impact is not expected for the next 100 years at least, but significant damage could be caused by smaller asteroids.

Back in 2013, a meteor exploded in the atmosphere near Chelyabinsk in Russia, causing an enormous fireball, shattering windows, and leading to potentially more than a thousand people to seek medical treatment for their indirect injuries.

The SpaceX Falcon 9 rocket launches with the Double Asteroid Redirection Test, or DART, spacecraft onboard, Tuesday, Nov. 23, 2021, Pacific time (Nov. 24 Eastern time) from Space Launch Complex 4E at Vandenberg Space Force Base in California. DART is the world...s first full-scale planetary defense test, demonstrating one method of asteroid deflection technology. The mission was built and is managed by Johns Hopkins APL for NASA...s Planetary Defense Coordination Office. Photo Credit: (NASA/Bill Ingalls)
Image:NASA launches first ever asteroid deflection mission. Pic: NASA/AP

That asteroid is believed to have been roughly 20 metres in size and was completely undetected before it entered the atmosphere, in part because it approached Earth from the direction of the sun – meaning it reflected no light to telescopes on Earth revealing its approach.

When it burned up in the atmosphere and exploded it briefly outshone the sun and the heat from the blast inflicted severe burns on observers below, as well as smashing windows and rattling buildings.

According to Johns Hopkins Applied Physics Laboratory, the Chelyabinsk meteor created “an airburst and shockwave that struck six cities across the country - and [sent] a stark reminder that dangerous objects can enter Earth’s atmosphere at any time”.

“Astronomers estimate there are tens of thousands of near-Earth asteroids close to 500ft (150m) wide and larger, big enough to cause regional devastation if they actually hit Earth.

“The Chelyabinsk object was just about 60ft (18m) wide, demonstrating that even small asteroids can be of concern - and making real-world tests of space-based planetary defence systems all the more important,” the university added.

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Science & Tech

Meta: UK competition regulator tells Facebook owner to sell GIF library Giphy

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The investigation into the acquisition has been acrimonious, with Meta previously being fined £50m by the CMA for deliberately refusing to comply with the regulator’s inquiries.

Facebook’s owner Meta has been issued a legally binding order to sell the GIF library Giphy after an investigation found the takeover “could harm social media users and UK advertisers”.

The Competition and Markets Authority (CMA) launched an in-depth investigation into the deal in April after raising a number of concerns. It subsequently warned of the potential forced sale in August.

Giphy – a website for making and sharing animated images, known as GIFs – was acquired by Facebook (now Meta) in May last year to integrate the GIFs with Instagram, but the CMA has now ordered the acquisition to be unravelled.

Sky News understands Facebook intends to appeal the CMA’s decision. It has four weeks to do so and the appeal would go to a the Competition Appeal Tribunal, which is independent of the CMA.

Meta could potentially challenge that ruling in the UK courts, but only on points of law.Advertisement

Facebook has rebranded to Meta
Image:Facebook’s parent company was renamed Meta last month

Stuart McIntosh, who chaired the independent inquiry into the acquisition, said: “The tie-up between Facebook and Giphy has already removed a potential challenger in the display advertising market.

“Without action, it will also allow Facebook to increase its significant market power in social media even further, through controlling competitors’ access to Giphy GIFs.

“By requiring Facebook to sell Giphy, we are protecting millions of social media users and promoting competition and innovation in digital advertising,” Mr McIntosh explained.

The investigation into the acquisition has seen points of acrimony, with Meta being fined a record £50m by the CMA for deliberately refusing to comply with the regulator’s inquiries.

Meta argued that it has been in compliance with the competition watchdog’s primary orders at all times.

At the time of the fine, the company complained that the CMA delayed for seven months a request to amend these orders which was eventually agreed in what the company described as nearly an identical manner to what had been requested.

When Facebook first merged with Giphy it terminated the image library’s advertising services, “removing an important source of potential competition” according to the CMA.

This was considered “particularly concerning given that Facebook controls nearly half of the £7 billion display advertising market in the UK”.

However in Meta’s response to the preliminary findings, the social media giant described the acquisition as a simple vertical merger and said that Giphy was financially troubled and suggested that its attempts to monetise its GIF library for display advertising were unsuccessful.

“If GIF paid alignments were the promising business model that the CMA believes they are, then one would expect to encounter them in the real-world at scale… Yet that is not the case,” the response stated.

According to the regulator, the acquisition potentially also enabled the social media giant to change the terms of access to the GIF library for its competitors.

“For example, Facebook could require Giphy customers, such as TikTok, Twitter and Snapchat, to provide more user data in order to access Giphy GIFs.

“Such actions could increase Facebook’s market power, which is already significant,” the regulator said.

In its review of the merger, the CMA said it risked entrenching Meta’s market dominance, noting that its platforms (Facebook, Instagram, and WhatsApp) already accounted for 73% of all user time spent on social media in the UK.

A spokesperson for Meta said: “We disagree with this decision. We are reviewing the decision and considering all options, including appeal. Both consumers and Giphy are better off with the support of our infrastructure, talent, and resources.

“Together, Meta and Giphy would enhance Giphy’s product for the millions of people, businesses, developers and API partners in the UK and around the world who use Giphy every day, providing more choices for everyone.”

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COVID-19: Mild and moderate cases during pregnancy doesn’t harm babies’ brains, finds study

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Parents should be reassured, there is “no evidence that a maternal SARS-CoV-2 infection has any effect on the brain development of the unborn child” say scientists.

Mild and moderate coronavirus infections in pregnant women appear to have no effect on the brain of the developing foetus according to a new study.

Two years into the COVID-19 pandemic “there is evidence that pregnant women are more vulnerable” to the coronavirus, according to a study presented to the Radiological Society of North America (RSNA).

The new study aims to identify what the possible consequences are for the unborn child if the mother is infected during pregnancy, and to study the likelihood of the virus being passed on to the foetus.

“Women infected with SARS-CoV-2 during pregnancy are concerned that the virus may affect the development of their unborn child, as is the case with some other viral infections,” said Dr Sophia Stoecklein, senior author of the study.Advertisement

“So far, although there are a few reports of vertical transmission to the foetus, the exact risk and impact remain largely unclear,” added Dr Stoecklein, from the department of radiology at Ludwig Maximilian University of Munich.

“The aim of our study was to fill this gap in knowledge regarding the impact of a maternal SARS-CoV-2 infection on foetal brain development,” she added.

MRI scans were used to study 33 pregnant women who were infected with COVID-19 during their pregnancy, with the women roughly 28 weeks into the pregnancies at the time of the scan.

The scans were evaluated by radiologists with years of experience in foetal MRIs who found that the brain development in the assessed areas was age-appropriate in all of the children, with no findings indicating any infection affected the brains.

“In our study, there was no evidence that a maternal SARS-CoV-2 infection has any effect on the brain development of the unborn child,” Dr Stoecklein said. “This fact should help to reassure affected parents.”

But she cautioned that only mothers with mild to moderate symptoms who were not hospitalised were included in the study, meaning the impact of “severe infection on brain development in the foetus has not been conclusively determined”.

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Earth’s water may have come from the Sun, new research finds

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Researchers at the University of Glasgow say there is evidence that particles emitted by the Sun created water on the surface of dust grains on asteroids which hit Earth.

The origin of Earth’s water continues to be debated by scientists – whether it was here when the planet formed or if it had an extraterrestrial source.

But new research points the finger at a previously uncounted point of origin: the Sun at the centre of our solar system.

According to astronomers, solar radiation may have created water on the surface of dust grains carried on asteroids that smashed in to our planet billions of years ago.

Alaska has been hit by an earthquake. File pic: iStock.
Image:Water covers 70% of the Earth’s surface – but scientists aren’t sure where it came from

Water covers more than 70% of our planet’s surface, but the exact source has puzzled scientists for decades if not longer.

A new study published in the journal Nature Astronomy suggests it has found a source which perfectly matches the isotopic signature of water on Earth.Advertisement

The research, led by scientists at the University of Glasgow, used a process called atom probe tomography to analyse different asteroid samples – some of which carry water and others which orbit too close to the Sun to do so.

Dr Luke Daly, from the University of Glasgow and the study’s lead author, said: “The solar winds are streams of mostly hydrogen and helium ions which flow constantly from the Sun out into space.

“When those hydrogen ions hit an airless surface like an asteroid or a space-borne dust particle, they penetrate a few tens of nanometres below the surface, where they can affect the chemical composition of the rock.

“Over time, the ‘space weathering’ effect of the hydrogen ions can eject enough oxygen atoms from materials in the rock to create H2O – water – trapped within minerals on the asteroid.

“Crucially, this solar wind-derived water produced by the early solar system is isotopically light.”

“That strongly suggests that fine-grained dust, buffeted by the solar wind and drawn into the forming Earth billions of years ago, could be the source of the missing reservoir of the planet’s water,” Dr Daly added.Thousands of people could still be killed by a completely unpredictable asteroid impact

Professor Bland at Curtin University explained that the existing theory that water was carried to Earth in the final stages of its formation by water-carrying asteroids didn’t hold up to examination.

“Previous testing of the isotopic ‘fingerprint’ of these asteroids found they, on average, didn’t match with the water found on Earth meaning there was at least one other unaccounted for source,” he said.

“Our research suggests the solar wind created water on the surface of tiny dust grains and this isotopically lighter water likely provided the remainder of the Earth’s water,” added the professor, who works at the Space Science and Technology Centre at Curtin University.

“This new solar wind theory is based on meticulous atom-by-atom analysis of miniscule fragments of an S-type near-Earth asteroid known as Itokawa, samples of which were collected by the Japanese space probe Hayabusa and returned to Earth in 2010.

“Our world-class atom probe tomography system here at Curtin University allowed us to take an incredibly detailed look inside the first 50 nanometres or so of the surface of Itokawa dust grains, which we found contained enough water that, if scaled up, would amount to about 20 litres for every cubic metre of rock,” added Professor Bland.

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