Oldest rocks in the world are in Canada scientists say
Scientists think they have found the oldest rocks on Earth.The ancient rocks were found in the Nuvvuagittuq Greenstone Belt, in Quebec in Canada, and for the last two decades scientists have been studying them.But they hadn't been able to agree on an accurate age for the rocks, until recently.Previously teams using two different dating methods had produced different ages for the rocks: 4.3 billion and 3.8 billion years old.But the latest study says the rocks are actually 4.16 billion years old!
How did scientists test the old rocks?
The scientists used both the techniques from previous tests, but focussed in on just one type of rock that made up the stripy stones. This type of stone is called metagabbro and is a rock that formed under huge heat and pressure inside the planet's crust billions of years ago.Both tests brought back the same result this time - the rock was 4.16 billion years old.The rocks are from one of the earliest periods on Earth, known as the Hadeon eon.The Earth was formed around 4.5 billion years ago and rocks from this time are an incredibly rare, as the movement of the Earth's tectonic plates mean that many have been melted and recycled.Jonathan O'Neil, who led the study in the Science journal said the rocks give a "unique window into our planet's earliest time to better understand how the first crust formed on Earth".He added that because some were formed through ancient seawater, they shed light on the first oceans and "help established the environment where life could have begun on Earth."
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The Guardian
10 hours ago
- The Guardian
‘It's something that happens': are we doing enough to save Earth from a devastating asteroid strike?
It is a scenario beloved of Hollywood: a huge asteroid, several miles wide, is on a collision course with Earth. Scientists check and recheck their calculations but there is no mistake – civilisation is facing a cataclysmic end unless the space rock can be deflected. It may sound like science fiction, but it is a threat that is being taken seriously by scientists. Earlier this year, researchers estimated that asteroid YR4 2024 had a 3.1% chance of hitting Earth in 2032, before revising that likelihood down to 0.0017%. This week, new data suggested it was more likely to hit the moon, with a probability of 4.3%. If that happens, the 53- to 67-metre (174ft-220ft) asteroid previously called a 'city killer' will launch hundreds of tonnes of debris towards our planet, posing a risk to satellites, spacecraft and astronauts. Before that, in April 2029, 99942 Apophis – an asteroid larger than the Eiffel Tower – will be visible to the naked eye when it passes within 32,000km of Earth. This attention-grabbing close encounter has prompted the UN to designate 2029 as the international year of planetary defence. When it comes to apocalyptic asteroid strikes, there is precedent, of course. Most scientists believe such an event hastened the demise of non-avian dinosaurs 66m years ago. 'This is something that happens,' said Colin Snodgrass, a professor of planetary astronomy at the University of Edinburgh. 'Not very often, but it is something that happens. And it's something that we could potentially do something about.' As Chris Lintott, a professor of astrophysics at the University of Oxford, told the UK parliament's science, innovation and technology committee this week, the risk posed by an asteroid originating beyond our solar system is minimal. Instead, he said, the greater threat comes from those in our cosmic back yard. 'Most asteroids in the solar system exist in the asteroid belt, which is between Mars and Jupiter, but they become disrupted, usually by encounters with either of those planets, and they can move into orbits that cross the Earth,' said Lintott, who presents the long-running BBC astronomy series The Sky at Night. 'Then it's just a case of whether we're in the wrong place at the wrong time.' The chances of an enormous asteroid – the type that did for the dinosaurs – hitting Earth is admittedly low. 'We think there's one of these every 10m to 100m years, probably,' Lintott told the Guardian. 'So I think you'd be right to ignore that when you decide whether to get up on a Thursday morning or not.' Snodgrass said there were 'precisely four' asteroids big enough and close enough to Earth to be considered 'dino-killers', and added: 'We know where they are, and they're not coming anywhere near us.' But damage can also be done by smaller asteroids. According to Nasa, space rocks measuring about one to 20 metres across collided with Earth's atmosphere resulting in fireballs 556 times over 20 years. Many collisions have occurred over the oceans, but not all. 'Chelyabinsk is the best example,' Lintott said. In 2013, a house-sized space rock – thought to have been about 20 metres across – exploded in the air above the Russian city with a force of nearly 30 Hiroshima bombs, producing an airburst that caused significant damage and hundreds of injuries, mostly from broken glass. Less dramatically, in February 2021 a space rock thought to have been just tens of centimetres across broke up in Earth's atmosphere, with fragments landing in the Cotswold town of Winchcombe in the UK. Thankfully, the damage was confined to a splat mark on a driveway. The types of asteroids we should perhaps be most concerned about are those about 140 metres across. According to Nasa, asteroids around that size are thought to hit Earth about once every 20,000 years and have the potential to cause huge destruction and mass casualties. The space agency has a congressional mandate to detect and track near-Earth objects of this size and larger, and a suite of new technological advances are helping them do just that. On Monday, the first images from the Vera C Rubin observatory in Chile were released to the public. This telescope is expected to more than triple the number of known near-earth objects, from about 37,000 to 127,000, over a 10-year period. In just 10 hours of observations, it found seven previously unspotted asteroids that will pass close to the Earth – though none are expected to hit. Also in the offing, though not planned for launch before 2027, is Nasa's near-Earth object (Neo) surveyor. 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As our ability to spot near-Earth asteroids increases, Lintott said, we should get used to hearing about asteroids like YR4 2024, which initially seem more likely to hit Earth before the risk rapidly falls towards zero. He described the shifting probabilities as similar to when a footballer takes a free kick. 'The moment they kick it, [it looks like] it could go anywhere,' he said. 'And then as it moves, you get more information. So you're like: 'Oh, it might go in the goal,' and then it inevitably becomes really clear that it's going to miss.' Of course, scientists aren't just monitoring the risks to Earth. They are also making plans to protect it. In 2022, Nasa crashed a spacecraft into a small, harmless asteroid called Dimorphos that orbits a larger rock called Didymos to test whether it would be possible to shift its path. The Dart mission was a success, reducing Dimorphos's 12-hour orbit around Didymos by 32 minutes. 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As Esa has quipped on its merchandise: 'Dinosaurs didn't have a space agency.'
The Independent
a day ago
- The Independent
Rock discovery offers fresh insights into planet's earliest history
A new study has identified rocks in Canada's Nuvvuagittuq Greenstone Belt as approximately 4.16 billion years old, potentially making them the oldest rocks on Earth. This research resolves a long-standing scientific debate regarding the precise age of these streaked grey stones, bridging previous estimates of 4.3 billion and 3.8 billion years. Scientists employed two established dating techniques, which measure the decay of radioactive elements, to arrive at the refined age. The discovery significantly contributes to understanding Earth's earliest formation, offering insights into the planet's primordial state and the origins of life. The ancient rock formation is located on tribal Inukjuak lands, and the local Inuit community has restricted sampling due to past damage, seeking to collaborate on establishing a provincial park for protection and research.
BBC News
a day ago
- BBC News
Oldest rocks in the world are in Canada scientists say
Scientists think they have found the oldest rocks on ancient rocks were found in the Nuvvuagittuq Greenstone Belt, in Quebec in Canada, and for the last two decades scientists have been studying they hadn't been able to agree on an accurate age for the rocks, until teams using two different dating methods had produced different ages for the rocks: 4.3 billion and 3.8 billion years the latest study says the rocks are actually 4.16 billion years old! How did scientists test the old rocks? The scientists used both the techniques from previous tests, but focussed in on just one type of rock that made up the stripy stones. This type of stone is called metagabbro and is a rock that formed under huge heat and pressure inside the planet's crust billions of years tests brought back the same result this time - the rock was 4.16 billion years rocks are from one of the earliest periods on Earth, known as the Hadeon Earth was formed around 4.5 billion years ago and rocks from this time are an incredibly rare, as the movement of the Earth's tectonic plates mean that many have been melted and O'Neil, who led the study in the Science journal said the rocks give a "unique window into our planet's earliest time to better understand how the first crust formed on Earth".He added that because some were formed through ancient seawater, they shed light on the first oceans and "help established the environment where life could have begun on Earth."
