Dark Matter Dynamics, Solar Flare Trio, and Meteor Shower Wonders: S28E07

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[00:00:27] Das ist Spacetime, Serie 28, Episode 7, vollbroadcast auf 15 Januar 2025. Coming up on Spacetime, Could dark matter have shaped one of the Milky Way galaxy's stellar streams? Our Sun emits three more powerful solar flares all on the same day? And Planet Earth experiences a spectacular Quadrantids meteor shower. All that and more coming up on Spacetime.

[00:00:57] Welcome to Spacetime with Stuart Gary. Physicists have proposed a solution to a long-standing puzzle surrounding the GD1 stellar stream, one of the best studied streams of stars within the Milky Way's galactic halo.

[00:01:27] The new research reported in the Astrophysical Journal letters proposes that a core collapsing self-interacting dark matter subhalo, that's a smaller satellite halo within the galactic halo, could be responsible for the strange spur and gap features observed in the GD1 stellar stream. A stellar stream is a group of stars moving collectively along a shared trajectory. A gap refers to a localized under-density of stars along the stream,

[00:01:54] while a spur is an over-density of stars extending outwards from the main body of the stream. Since dark matter governs the motion of stellar streams, astronomers can use these streams to trace invisible dark matter in the galaxy. And this new research could have significant implications for understanding the properties of dark matter throughout the universe. The Milky Way's galactic halo, a roughly spherical region surrounding the galaxy, contains dark matter and extends all beyond the galaxy's visible edge.

[00:02:22] Astronomers discovered that the spur and gap features of the GD1 stellar stream can't easily be attributed to gravitational influences of known globular clusters or satellite galaxies. But these features might be explained by an unknown perturbing object, such as a subhalo. The thing is the object's density would need to be significantly higher than what's predicted by traditional cold dark matter subhalos. The study's lead author, Haibo Yu from the University of California, Riverside,

[00:02:50] says that these typically lack the sorts of densities needed to produce the distinctive features observed in the GD1 stream. However, the research demonstrates that a collapsing self-interacting dark matter subhalos could achieve the necessary density. Now, such a compact subhalo would need to be dense enough to exert the sorts of gravitational influence required to account for the observed perturbations in the GD1 stream. Mind you, scientists have no idea what dark matter is. It can't be directly seen.

[00:03:21] They know it exists because they can see its effect on regular matter. And current estimates suggest dark matter makes up to 85% of all the matter in the universe. Cold dark matter, the prevailing dark matter theory, assumes that dark matter particles are collisionless. Self-interacting dark matter, a theoretical form of dark matter, proposes that dark matter particles self-interact through a new dark force. In their study, Yu and colleagues used n-body numerical simulations

[00:03:49] to model the behaviour of a collapsing self-interacting dark matter subhalo. Their findings therefore offer a new explanation for the observed spur and gap features in the GD1 stream which have long been thought to indicate a close encounter with some sort of dense object. Yu says in this new scenario that Perturba is a self-interacting dark matter subhalo which is disrupting the spatial and velocity distributions of the stars in the stream and creates the distinctive features seen in the stream.

[00:04:17] Now if correct, the discovery also provides new insights into the very nature of this mysterious substance called dark matter. This is space-time. Still to come, the Sun emits three powerful solar flares all on the one day and we're in for a spectacular quadrants meteor shower. All that and more still to come on space-time.

[00:04:54] Our local star the Sun has shown its violent streak again unleashing three significant X-class solar flares all on the same day. The flares were categorised based on their intensity with the first and third classified as X1.1 flares while the second was a more powerful X1.5. X-class flares represent the highest intensity on the solar flare scale with a logarithmic numeric value further detailing their specific strength.

[00:05:21] The three flares were detected by the solar ultraviolet imager operated by NOAA, the National Oceanographic and Atmospheric Administration, America's Weather Bureau. Solar flares are powerful eruptions of energy blasted out by the Sun. They're triggered by snapping magnetic field lines emanating from sunspots on the solar surface. Because the Sun's not a solid body but a fluid, different latitudes of the Sun rotate at different rates.

[00:05:48] And consequently, magnetic field lines emanating from deep inside the Sun and travelling out through the Sun's visible surface, the photosphere, are twisted by this differential rotation. Eventually, the twisting causes them to snap, and when they snap, they release a solar flare. Now, if the solar flare is pointed towards the Earth, it can cause a lot of damage. It can even destroy satellites and other spacecraft. It can also shorten the life of orbiting spacecraft by causing Earth's atmosphere to expand.

[00:06:17] That increases atmospheric drag and consequently orbital decay, forcing a spacecraft to use more fuel in order to maintain its operational orbit. It can disrupt radio communications and navigation systems, impact power grids on the ground causing blackouts, and they can increase an astronaut's radiation exposure, posing a serious health hazard. In fact, even pilots, crew and passengers in high-flying aircraft can get increased radiation exposure when one of these space weather events occurs.

[00:06:46] This increase in solar activity is all part of the Sun's build-up to solar maximum, the peak of its current 11-year solar cycle, which began back in November 2019. Once the Sun reaches solar max, the crescendo of its violent outbursts, it will gradually start to come down again until it reaches solar minimum, at which point the Sun's polarity will flip, its North Pole will become South and South Pole North. This happens roughly every 11 years,

[00:07:14] although the exact timing is still not fully understood. This is Space Time. Still to come, the Quadrantids' meteor shower spectacular, and later in the science report, a new study warns that a quarter of the world's freshwater animals are now at risk of extinction. All that and more still to come on Space Time.

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[00:08:19] The Earth is currently experiencing one of its most spectacular meteor showers, the Quadrantids, which is lighting up the night sky with an array of dazzling so-called shooting stars. Shooting stars, more accurately meteors, are made up of dust and debris streams left behind by passing comets and occasionally by asteroids. When the Earth's orbit around the Sun happens to cross one of these streams, bits of dust and debris end up falling into the Earth's atmosphere, causing them to heat up due to friction with the air and eventually burn up,

[00:08:49] usually at altitudes of around 80km. And sometimes this can produce spectacular light shows. The Quadrantids themselves are generated by debris from the near-Earth asteroid 1962-56-2003 EH1, which may actually be an extinct comet first noted by Chinese astronomers in 1490. They're called the Quadrantids because they appear to originate from a point in the sky, called a radiant, named after the defunct constellation Quadrans Morales,

[00:09:17] which is now part of the constellation Bootes near the famous Plough Asterism. Observers enjoying dark skies should see around 50 or more meteors an hour as the Quadrantids reach their peak. The Royal Astronomical Society's Deputy Director, Robert Massey, says sky watchers on the west coast of the United States or in the Pacific could see as many as 70 or 80 meteors an hour, including some fireballs. Well, the Quadrantids meteor shower is an annual shower of meteors,

[00:09:44] and meteors are basically the result of small pieces of debris coming into the Earth's atmosphere at high speed. And by small I mean anything from grains of sand up to marble size. Not very big at all. But they come in so fast, up to 70 kilometres each second, many times the speed of the bullet, that they heat the atmosphere around them. And that hot air glows. And that's what we see as a shooting star or a meteor. And typically they only ask a fraction of a second.

[00:10:11] If you're very lucky you might see them lasting longer than that. But, you know, normally they're very, very fleeting. Showers happen because the Earth runs into a stream of debris rather than just random bits that are coming in all over the sky. And that's what the Quadrantids is. It's a shower that happens more or less at the same time every year. It's associated with a particular part in the sky, and that's because the Earth is running into a particular stream of debris. Now, the name comes from the fact that it's associated with the now defunct constellation

[00:10:40] Quadrans Moralis, which basically means a quadrant that was mounted on a wall. And this was a constellation that was created, as many were, in the 17th and 18th centuries. But it wasn't adopted in the present day. It's actually in the part of the sky between Ursa Major, which includes the Pleiol, you'll be familiar with that, the UK, and the constellation of Boötes, the Hertzman. So it's in that region of the sky, not far from the Popstar. The Quadrantids are unusual in that they appear to be associated not necessarily with a comet,

[00:11:09] or maybe an extinct one, but with an asteroid called 2003 EH1, which means it was discovered in 2003. Now, it passes reasonably near the Earth. It's called a near-Earth object. And we appear to be running into a trail of debris associated with it. So the thinking is that might actually be an extinct comet. So no longer anything generating a tail. It doesn't look like a comet these days. It just looks like a dot on even images on the wall from the largest telescopes.

[00:11:36] But 500 years ago, there was a comet seen back in 1490, more than 500 years ago. It was a comet seen by the Chinese, and it may be connected with that. So it may be that this comet was once active, has left a lot of debris in orbit around the surfaces, which the Earth runs into once a year, and that leads to the Quadrantid Meteors. Well, the Quadrantids are not bad, as meteor showers go.

[00:12:00] They have a pretty strong intensity if you happen to be in the right place at the right time. So if you are on the west coast of the US and the Pacific region, you could see maybe 70 or 80 an hour. If you're in the UK, you're going to see somewhat fewer than that, or it's likely that's the case. But it's still a strong shower. The great advantage this year is that the moon isn't interfering with it. So you haven't got a full wind in the sky. It's a very thin crescent. That means the light from the moon will not be a big problem.

[00:12:28] And if you get out to the city into a dark place, away from sources of light pollution, then you have a chance maybe of seeing up to a few tens of meteors an hour, maybe realistically perhaps 20 to 25. There won't be the brightest meteors on the whole, but it does include a fair number of fireballs quite typically. A fireball is a dramatic sounding thing. What it really means is a really bright meteor. The Quadrantids is a meteor shower that produces that kind of vent.

[00:12:53] So for that reason alone, if you have the time to look out and the weather is good, then do take a look. The really nice thing about a meteor shower is that you don't need any special equipment. You just basically need to have half decent eyesight. If you have a telescope or a binoculars and you try to watch a meteor shower, you're going to make it harder because you'll only be seeing a tiny part of the sky. What you need to do is go out, be prepared to wait outside for a bit and just watch the sky. They could be anywhere in the sky.

[00:13:20] So the biggest piece of advice or offer that I would give is just to look up, look at the sky, get an uncluttered view, be away from the lights of towns and cities and see what you see. But do be patient. Don't go outside. And if you don't see one in the first five minutes, be disappointed. I think the thing to do is to give it maybe half an hour or so. You'd be very surprised if you didn't see any in that time. Photographing meteor showers requires patience. If you take your, say you might have a phone camera up and you just click at the sky,

[00:13:48] you're unlikely to capture anything because they're so beating. They only last perhaps a fraction of a second. Your reaction is not going to be good enough to photograph it. So what people tend to do that are used to photographing is they do what are called long exposures. So they open up the lens, the shutter or the electronic shutter, depending on how you define it, but say something like a phone and leave it running actually for as long, at least in total, as a period of minutes, anything up to half an hour. In some cases, people have all sky cameras that run at night.

[00:14:17] And you have to do that because you never know exactly when the meteor is coming. And so you need a long period of time to see them. So if you do it well, and I guess people with DSLRs that can run for hours are the best place to do this. That's another option, just a more sophisticated digital camera. What you'll see is star trails. These are the result of the Earth turning and then the stars appear to trail across the sky as they appear to move. And then superimposed on that, we'll see streaks of light, bright streaks.

[00:14:46] And those are the meteors. Those will be the quadrontids. So it's not as simple as, say, holding up your camera and taking a picture of the Northern Lights. My advice would be to read up on it beforehand. Don't try and do it on the night because I think it would be a struggle. But if you've got the right kind of setup, a decent tripod, an ability to open up your camera for a long period of time, then you should see something. That's the Deputy Director of the Royal Astronomical Society, Dr Robert Massey. And this is Space Time.

[00:15:29] And time now to take another brief look at some of the other stories making news in science this week, with a science report. A new study warns that a quarter of the world's freshwater animals are now at risk of extinction. The findings reported in the journal Nature are based on a study of more than 23,000 fish, crustaceans and insects. Scientists classified the species' extinction risks, finding 24% were vulnerable or worse,

[00:15:55] similar to the proportion of high-risk freshwater mammals, birds, amphibians and reptiles. However, the two groups have different habitats and face different threats, with those in this study most threatened by pollution, dams, water extraction, land use change and invasive species. The authors stress that the needs of this group of animals should also be considered when it comes to any forms of freshwater management.

[00:16:20] A new study has confirmed that eating a diet of plant-based foods could help increase your microbiome that favours human health. A report in the journal Nature Microbiology looked into the diets of over 21,500 people and investigated what microbiomes were present depending on their food intake. A microbiome simply refers to the gut microbes in your intestines. The authors then compared the diets of omnivores against vegetarians and against vegans.

[00:16:49] They suggested those who ate high amounts of healthy plant-based and fibre-rich foods had larger colonies of good microbes, those related to good health, compared to their peers. A new study has shown that all that scrolling and posting you're doing might well end up causing you to become far more irritable. A report in the Journal of the American Medical Association surveyed over 40,000 people about their social media habits and the potential effect it has on their emotions.

[00:17:17] They found that people who frequently use social media, especially those who post it frequently, scored significantly higher on an irritability test compared to their social media-free or infrequent user peers. Now this kind of study can't prove that your hours of doom scrolling are directly making you ticked off, but in the light of known associations of irritability and mental health issues, maybe you should put down your phones just a little more.

[00:17:43] Well there's been massive news in technology this week, with Facebook boss Mark Zuckerberg admitting what we've been telling you for years. Fact-checkers can't be trusted with the truth. They're dishonest and they lie to push a political agenda. From the corrupt and scientifically stupid fact-checkers of YouTube, through to the socialist fact-checkers of the RMIT Fact Lab. Never trust what they say, always do your own research and always go to the original source.

[00:18:09] The Babylon Bee probably put it best when they wrote that the guy who said Facebook was not suppressing free speech has now announced that Facebook will stop suppressing free speech. With the details, we're joined by technology editor Alex Saharov-Royt from TechAdvice.live. It was very surprising to see Mark Zuckerberg, with extremely curly hair, coming out and saying on video that he was getting rid of fact-checkers. Zuckerberg's admitted that his fact-checkers are phony. He was going to implement community notes in a system that's similar to X,

[00:18:39] which does appear to be the fairest system. The whole idea is that people are checking up on other people and you're not relying upon the single source of truth, be it the government or RMIT university, you know, socialist scumbag fact-checkers who are trying to shut down all sorts of views that don't align with their views. And Mark Zuckerberg is doing this because he's trying to save his political skin. Well, of course, Zuckerberg admitted that he was taking instructions from the White House. Well, in one sense, he would have probably not had much choice. He would have become a bit of an enemy himself.

[00:19:07] But the thing is, Mark Zuckerberg did not appear to fight back. And given the fact he's had a 20-year apology tour, I don't trust Mark Zuckerberg. And for him to come out, it's great to see that he's finally done it, but it's probably about 20 years too late. And of course, when it comes to trust, Apple have had to do a big about-face. $95 million in payouts after it was found that Siri really was listening in. Yes, now the problem here is that whether it's Google, whether it's Amazon Alexa or Siri,

[00:19:34] if you say, hey Siri or Siri or the wake word, then the system is listening. And the problem is that when the system thinks it has heard the word Siri because you said sorry or because you said some other word that sounded like that, it starts listening and starts recording. It must be terrible if you run an Indian clothing store. Well, what about Tom Cruise's daughter, Siri? Oh, and I've heard the same sort of story for young people called, you know, young girls called Alexa in school. All their friends are like, Alexa, do this and do that. And ha ha, it's very funny. But clearly the joke does wear off after a while.

[00:20:03] But the short version is that because these interactions normally are not direct where you're giving the assistant an instruction, what was happening is that the system would listen and it would then send these conversations off to humans to listen and try and figure out and try and train the system to do better. Now, sometimes people were being recorded making love or having arguments or getting beaten up or even murders and private business information was being unveiled. And that's why some people refuse to have any smart speakers in their homes. I turned Siri off.

[00:20:33] Yeah, well, it is also possible to have Siri only be activated by pushing the button on the side of your phone. I use Siri a lot. I use it to set appointments and make calls and set timers and remind me to do things and take notes. So it does have its uses. And you can tell your systems now, they've brought this in over the past couple of years, to not send your recordings, not share your recordings with Apple. So I never want my recordings to be shared or any of the diagnostic information. I always turn that off because I'm worried about it too.

[00:21:00] Anyway, this lawsuit saw Apple not admitting any liability and it's hard to know how they're going to avoid this in the future. I do know that if I say, hey Siri or Siri, that another iPhone I have lights up for a second, but instantly it turns off because it knows that I haven't given it a command and it was just sort of an accidental wake word. So this is a problem where we need to trust the companies to do what they say they're going to do. And if not, they'll get caught out by some enterprising hacker and find hundreds of millions of dollars. Trusting companies is like trusting governments, mate. They're famous last words.

[00:21:29] CES has wrapped up in Las Vegas. Once again, lots of gadgets. How many of them do we really need is the big question, but there've been some fantastic products as well, such as what Nvidia are doing. Yeah, they've launched a whole series of updates to their AI chips, the ones that we use when we talk to chat GPT, but they've also launched a $3,000 supercomputer that you can hold in your hand, a bit like an Apple Mac mini. That's meant to have 1,000 times the power of your existing laptop computer.

[00:21:57] And although most people are not using a computer powered by an Nvidia chip to do their computing, many people do have an Nvidia graphics card. And some of the graphics card capabilities, I mean, we will soon have movies that look photo realistically human that are completely designed on the computer. And that's going to put certain actors and actresses out of work. If you don't have to have humans, it can all be done by a computer. Why not? But that's just one of the many things there. BMW, who launched their iDrive 24 years ago, there's a little system on a screen.

[00:22:25] Now the entire windscreen, windshield can be a display. One giant heads up display, just like a fire jet. One, that's right. And that'll keep, they said, your eyes on the road and your hands on the wheel. There was a concept of a system that like a mirror that you stood on, it could weigh you, could look at your weight, your height, your heart, your metabolic health. I mean, like a giant tricorder, Roborock, one of the vacuum cleaner makers where the vacuum cleaner scurry around your house, finds a teddy bear or something in the way. Normally it stops or has to go around it.

[00:22:55] With this particular robot, an arm pops out of the top of the unit and it can physically lift items out of the way. Oh, like the Jensen's. Yeah, it rose to the robot. And like Jensen Huang did at one of his previous keynotes, where he had a whole stack of robots behind him that just rose out of the stage. Well, he did it again at CES. He had all these robots that just popped out from behind him. And these robots are incredibly advanced. There was even a robot that's sort of the size of a child that was filmed wandering around CES, walking quite naturally. So the age of the robots truly is upon us.

[00:23:25] And the trick will be to get them to the price of smartphones. You know, if you can afford to buy a robot that can mine the kids, wash the dishes, do various things around the home for you, and it's around the cost of a mobile phone, who wouldn't get one? Elon Musk sees a market for billions of them, at least one for every human in the future. There are plenty of core things, smart glasses that can have a little 3.5 inch monochrome display that you're looking at, but it can also have an AI agent that's listening to conversations, answering questions during meetings, doing live translations.

[00:23:54] That's technology editor Alex Saharov-Royt from TechAdvice.Life. And that's the show for now. Space Time is available every Monday, Wednesday and Friday through Apple Podcasts,

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