Could this giant telescope help protect the Earth from asteroid threats?
A new telescope could transform our understanding of the universe, and help protect the Earth from asteroid threats by creating the largest map of the night sky, multiple times a night every night, for the next 10 years, according to astronomers. Alice Rizzo reports.
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The Guardian
a day 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. Armed with an array of infrared detectors, this is 'the first space telescope specifically designed to detect asteroids and comets that may be potential hazards to Earth', the agency says. Lintott said: 'Between those two, we should find everything down to about 140 metres.' He said such observations should give scientists up to 10 years' warning of a potential collision. The European Space Agency (Esa) is planning a near-Earth object mission in the infrared (Neomir) satellite. Slated for launch in the early 2030s, this will help detect asteroids heading towards Earth that are at least 20 metres in diameter and obscured by the sun. Assessing the emerging capabilities, Edward Baker, the planetary defence lead at the UK's National Space Operations Centre (NSpOC) at RAF High Wycombe, said: 'I think we're in a good place. I can't see a situation like [the film] Don't Look Up materialising at all – though I wouldn't mind being portrayed by Leonardo DiCaprio.' 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. In 2024, Esa launched a follow-up to Nasa's Dart mission, called Hera. This will reach Dimorphos in 2026 and carry out a close-up 'crash site investigation'. It will survey the Dart impact crater, probe how effectively momentum was transferred in the collision and record a host of other measurements. Esa hopes this will provide crucial insights that can be used to make deliberate Dart-style impacts a reliable technique for safeguarding Earth. 'Dart was much more effective than anyone expected it to be,' Lintott said. 'And presumably that's something to do with the structure of the asteroid. I think we need to know whether Dart just got lucky with its target, or whether all near-Earth asteroids are like this.' For the most part, scientists say the threat of an asteroid strike does not keep them up at night. 'We're safer than we've ever been and we're about to get a lot safer, because the more of these things we find, the more we can spot them on the way in,' Lintott said. As Esa has quipped on its merchandise: 'Dinosaurs didn't have a space agency.'
Daily Mail
a day ago
- Daily Mail
Is THIS how the world will end? The universe has a 'self-destruct button' that could WIPE OUT life in an instant, scientists warn
From the Big Crunch to the heat death of the universe, it seems that science is always finding new ways the cosmos might come to an end. But physicists have now revealed the most devastating doomsday scenario possible. Experts believe the universe may have a built-in 'self-destruct button' called false vacuum decay. If this was ever triggered, every planet, star, and galaxy would be wiped out and life as we know it would become impossible. The basic idea is that our universe isn't currently in its most stable state, meaning we are in what scientists call a 'false vacuum'. If any part of the universe is ever pushed into its stable state, a bubble of 'true vacuum' will expand through the universe, destroying everything it touches. Professor Ian Moss, a cosmologist at Newcastle University, told MailOnline that the universe is like 'a table-top with many dominoes standing on their side.' Professor Moss says: 'They can stay upright unless some small disturbance topples one, and triggers all of them to fall.' What is a false vacuum? All objects contain a certain amount of energy and the amount of energy it contains is called its 'energy state'. The lower the energy state, the more stable the object becomes. If you think about a lump of coal, it has a very high energy state because it contains lots of potential energy, which means it's unstable and could catch on fire. Once that coal has been burned and the energy released as heat, the remaining ash has a very low energy state and becomes stable. Everything in the universe, from lumps of coals to stars, wants to get to its most stable state and so always tends towards the lowest energy state possible. We call the lowest energy state an object can have its 'vacuum' state, but sometimes objects can get trapped in something called a 'false vacuum'. Dr Louise Hamaide, a postdoctoral fellow at the National Institute for Nuclear Physics in Naples, told MailOnline: 'A good analogy for a field in a false vacuum is a marble in a bowl on top of a stool. 'The marble cannot leave the bowl unless it is given some energy in the form of a push, and if it does it will fall all the way to the ground.' Being on the ground is what we would call the vacuum state, whereas the bowl is merely a false vacuum which prevents the marble from falling to the ground. What makes this idea worrying is the possibility that a fundamental part of the universe's structure could be stuck in one of these false vacuums. All it needs is a little push, and the structure of reality itself will come crashing down to the ground. The universe's self-destruct button The idea of a false vacuum gets really scary when we apply it to our current model of reality. The universe and everything in it is made of subatomic particles such as electrons, photons, and quarks. But according to quantum field theory, all of these particles are actually just disturbances in an underlying field. What is false vacuum decay? One of the fundamental concepts of the universe is that things are moving from a state of high energy to a more stable 'ground' state, of lower energy. This fundamental concept holds true even in the strange world of quantum mechanics, with particles trying to reach their ground, called their vacuum state. The concept takes a stranger turn when it comes to the Higgs field – the quantum field which gives particles throughout the universe their mass. It is thought that this field is in its lowest energy state, but one theory states it may not be as stable as it seems. With the right kick, the Higgs field could careen towards its true lower energy state, sparking a chain reaction which would spread in all directions. Dr Alessandro Zenesini, a scientist at the National Institute of Optics in Italy, told MailOnline: 'The basic idea of quantum field theory is to represent reality only with fields. 'Think of a water surface. When flat, it is an empty field. As soon you have a wave, this wave can be seen as a particle which can interact with another wave.' Just like everything else, these fields have energy states, and want to get to their lowest energy state possible like a body of water becoming flat and calm. In the first few seconds of the Big Bang, so much energy was released that it pushed all the fundamental fields down into their vacuum states. But scientists now think that one of the fields might have gotten stuck along the way. Some researchers believe that the Higgs field, the field which makes the elusive Higgs Boson, is stuck in a false vacuum state. This essentially means that the entire universe could be rigged to blow at any moment. What would happen if a false vacuum collapsed? If the Higgs field is ever pushed down to its true vacuum, the resulting 'phase shift' will release a vast amount of energy. This energy is so concentrated that it will force nearby areas of the field out of their false vacuum, dropping their energy level and releasing even more energy. The resulting chain reaction would spread through the universe like the flames from a match dropped into a lake of petrol. A bubble of true vacuum would then spread out in a sphere from the starting point until it consumes the entire cosmos. At its edge, between the true and false vacuum, the energy would collect into a thin wall of incredible power. Dr Hamaide says: 'That kinetic energy of the wall is so high, even though the Higgs carrying this energy is a very heavy particle, it would move at the speed of light. 'So we would never see the wall coming, because light couldn't reach us before the wall did.' If the wall hit the solar system, Dr Hamaide says it would have so much energy that 'it would instantaneously destroy any star or planet its path'. However, what would be left behind after the initial destruction is perhaps even more terrifying. The interaction between the fundamental fields is what gives particles their properties and determines how they interact. This, in turn, determines everything from the physics that holds planets together to the chemical reactions taking place inside our cells. If the Higgs field suddenly takes on a new energy level, none of the physics we are familiar with would be possible. Dr Dejan Stojkovic, a cosmologist from the University at Buffalo, told MailOnline: 'As a consequence, electrons, quarks and neutrinos would acquire masses different from their current values. 'Since the structures that we observe around us are made atoms, whose existence depends on the precise values of the parameters in the standard model, it is likely that all these structures would be destroyed, and perhaps new ones would be formed.' Scientists have no idea what the world left behind by false vacuum decay would be like. But we do know that it would be absolutely incompatible with life as we now know it. What could trigger the end of the world? To trigger false vacuum decay, you would need an extremely powerful force to pack a huge amount of Higgs particles into a tiny space. In the current universe, places with this much energy might not even be possible but the bad news is that the early universe might have been violent enough to do it. In particular, scientists think that dense regions of matter might have been crushed into tiny primordial black holes in the first few seconds of the Big Bang. These are ultra-dense points of matter no larger than a single hydrogen atom but containing the mass of an entire planet. As these black holes evaporate through Hawking radiation, some researchers believe they could trigger false vacuum decay. Professor Moss says: 'Condensation is a similar process to vacuum decay, the condensation of water vapour into clouds is triggered by tiny grains of dust or ice crystals. 'Tiny black holes seed vacuum decay in the same way.' Is the world already over? Perhaps one of the strangest implications of false vacuum decay is that it might have already started somewhere in the universe. Dr Hamaide says: 'Under some very specific assumptions, we showed these bubbles are 100 per cent likely to occur.' According to some calculations, one primordial black hole in the universe would be enough to trigger the universe's self-destruct process. Likewise, due to small fluctuations at the quantum level, known as quantum tunnelling, it is possible that the parts of the universe might randomly jump into the lower energy state at any time. That could mean that a bubble of true vacuum is already out there somewhere in the cosmos, racing towards us at the speed of light and annihilating everything it encounters. The comforting news is that, even at the speed of light, it could take billions of years for a true vacuum bubble to reach us. If the bubble starts far enough away, the expansion of the universe might even mean it never reaches us at all. Dr Hamaide and Professor Moss suggest that the fact we aren't already dead is evidence that there aren't any primordial black holes out there in the first place. We also don't know what effects dark matter and dark energy could have on the energy state of the universe. It might be possible that these mysterious substances reverse any bubble expansions as soon as they occur to keep the universe stable. However, until a bubble of true vacuum does tear our reality apart, there might not be any way to know who's right. The theories and discoveries of thousands of physicists since the 1930s have resulted in a remarkable insight into the fundamental structure of matter. Everything in the universe is found to be made from a few basic building blocks called fundamental particles, governed by four fundamental forces. Our best understanding of how these particles and three of the forces are related to each other is encapsulated in the Standard Model of particle physics. All matter around us is made of elementary particles, the building blocks of matter. These particles occur in two basic types called quarks and leptons. Each consists of six particles, which are related in pairs, or 'generations'. All stable matter in the universe is made from particles that belong to the first generation. Any heavier particles quickly decay to the next most stable level. There are also four fundamental forces at work in the universe: the strong force, the weak force, the electromagnetic force, and the gravitational force. They work over different ranges and have different strengths. Gravity is the weakest but it has an infinite range. The electromagnetic force also has infinite range but it is many times stronger than gravity. The weak and strong forces are effective only over a very short range and dominate only at the level of subatomic particles. The Standard Model includes the electromagnetic, strong and weak forces and all their carrier particles, and explains well how these forces act on all of the matter particles.
BBC News
2 days 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."
