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hello and welcome to technically speaking where scientists and Engineers come together to chat about a common interests share knowledge and satisfy some curiosity I'm Laura and I'm joined by Antonia to talk about science that astounds us why astounds us and share what we know about it so Antonio the idea for this episode like a lot of the episodes in this podcast came about because of something you saw recently so if you want to tell us about it yeah so I was at the Museum of
Science and Industry in Manchester recently and there was a exhibition about Stephen Hawking it was very interesting because it was sort of a scientist who I've sort of known about my whole life and it is so that he's not with us anymore but something I didn't realize was there's something that comes out of black holes and I always thought nothing comes out black holes straight up that was just fact Stephen Hawking theorized something that does come out black holes and it's now called Hawking
radiation I thought that was really interesting because never knew about radiation coming out of black holes and I did a little bit looking and actually it was theorized in 1974 and not properly proven with actual what's the word observations in space Oh okay so my undergrad degree now it was like 20 years ago when I studied this but I was taught a little bit about black holes and the one thing I remember is yeah pretty much what you say it was pretty much Thou shalt not have a naked
Singularity which means all black holes are surrounded by this event horizon which is the point at which light can't escape from it because everything sucked into it yeah but I also remember that some black holes can have Jets and I kind of thought that it was ejecting math in some way at some point but very hazy memory right so I looked it up and I was wrong it's not the black hole itself isn't ejecting anything it's the accretion disc around it and astronomers
think it's something to do with the fact that black hole's spinning and it creates this um like almost raps the gravity field or an electromagnetic field around itself and that causes stuff to fling off and that's what I was initially thinking about when you said stuff is given off by black holes so apparently I was wrong about that okay is the Event Horizon and is the accretion disc is that part of the black hole or is that just the things that we notice are
around black holes and only black holes already anywhere else because then does that Define a black hole oh I think a black hole is defined by how it bends space-time which is a phrase I've never really liked because I find it a bit meaningless unless you understand the physics I don't know for me who doesn't really understand the physics I feel like bending's face time yeah I can appreciate that I think that has a nice visual you can just see that just there's there's space and then
no space yeah it's usually visualized as like almost like a three a grid that starts off as flat and then you've got this sort of thing that sucks it all down into I guess it's like a gravity well I think it is I think it's it's an everything well isn't it yeah except for Hawking radiation I think you're asking is that a creation disc is that part of it I'm gonna say it's not but the accretion disc is caused by the effects of the black hole as it's sucking stuff
in that's the point at which it probably could Escape if you gave the math these particles some velocity because they eat galaxies and stars and all sorts don't they black holes or creation discs the black hole yeah and that's what the accretion disk is it's the that matter being broken up and moving around in like a blender like pretty much just kind of just kind of starts getting too close and then all the all of it just gets broken off into smaller pieces yeah
that's a good point that's quite a good analogy so I guess the black hole in that case is like the center of the blender with the blades whirling around yeah see I'm an engineer so you have to break things down a bit more simply there's an inherent double entender in that comment as well but the Hawking radiation I don't think I would talk anything about this in my undergrad it wasn't like but when I looked into it after you mentioned it the other day it sounds like it's a very
small amount of radiation anyway like a millionth of a degree celsius one degree Kelvin similar thing so it's not really possible to detect it in space because you've got so many other things going on so I guess I can see why no one's really
proven this Theory from 1974. and I suppose how close would you have to be before you could detect that kind of you know how sensitive an instrument would you need I had visions of someone flying up as close as they did to a black hole and like taking a picture there and running away but you're talking about like an earth-based sensitive detector or something surrounding our own Planet how far away are we from that technology I couldn't possibly say yeah how would you
build something to be that sensitive to detect a millionth of a degree change in most all this I guess you just call it noise if you don't want to detect it yeah I mean like what's the most precise temperature measurement we can currently take and then just imagine how like much of a distance we have to try and cover and detect that amongst yeah all the background noise as you were saying yeah see if someone could do that that would really blow my mind yeah I'd also read this gets even
weirder so you're quite surprised that black holes give off anything yeah apparently it's not just black holes that give off this Hawking radiation okay it's something to do with quantum physics so I think the Hawking radiation it's not even necessarily oh this is where it gets really weird the classical the normal description is that you've got these particles that kind of split apart you get a particular anti particle and yes one of those gets sucked into the black hole but I'd also read the
that is just a visual interpretation of the maths and the maths just creates these things that you can interpret as particles and it's just part of the equations is this where we start going into the Realms of where it could be a particle or it could be a wave yeah I believe so so it's not exclusive to black holes well I think Stephen Hawking came up with the idea from studying black holes that's my understanding of it yes I guess it's sort of related to Heisenberg's uncertainty principle I I
want to say that the interpretation of having these two physical particles is more if we have a mass or something a particle an electron whatever and we don't know exactly where it is so it could be on one side of the vent horizon or it could not be and then something interacts with it to cause that this is what I'm really trying to not use just standard physics terminology I really don't want to say the wave function the wave function collapses yeah there's a reason why we came up
with words it's the shorthand of the really long explanation of what a waveform is which I might need a reminder of what the waveform is oh I can say the wait for Mr smarts okay so one of the episodes that we did with uh Emma a while ago was talking about this sort of thing and she was like it's literally just a mathematical representation of the particle and it's just a series of like sine waves or cosines or whatever okay I'll accept that as the limit of my understanding
okay so that's that's interesting because I did hear about antimatter and Mata but we could never find any evidence of anti-masser because it would have been annihilated by Mata but then why did we end up in a world where we have matter whereas if it was even we should have nothing this is my understanding of the Big Bang the Amazon resident physicist it would really help issues they're asking me questions that I don't have if any of answers to you but if I had to guess
like in the episode without it was about um the Multiverse and does it really exist and can we find any evidence for it and if it's something that we don't understand the physics of well enough we can't interact with it I guess so the antimatter could just be something that's so radically different that we have no way of detecting it the same as we can't see inside a black hole because it sucks in all light and therefore all information so the physics in there
could be completely different and we have no way of figuring that out but something that that could be explained is I think Hawking radiation that formula incorporates a lot of uh theories and it's a nice tidy formula that physicists liked and they thought hey this this actually puts together a lot of theories and the fact that yeah you can see it in other places kind of shows we live in that classic physics world I want to say classic physics because it's what we uh sort of experience of
the world and that's how we understand physics right yeah the classical physics is sort of like macro scale stuff and the quantum physics is like the really tiny stuff that we can't quite see properly yeah I think one thing I find weird at all the physics is it's pretty much just really good understanding of maths in knowing the math well enough to say oh yeah that that clearly makes sense and that describes the universe and therefore can predict things that we can't interact with I guess that's
probably like a really powerful thing for physicists mathematicians that know their trade really well um there's a fundamental about the Hawking radiation we've not discussed which is it doesn't actually come from the black hole itself but it comes from just outside the Event Horizon so that's why I'm sort of asking what makes black hole is it just the absence of nothing or the other effects that it has around in space there's also the idea that black holes are very slowly evaporating though
aren't they like they're gradually losing mass and getting smaller and I didn't quite get how that matched up with the idea that they're giving off this radiation because as you say the radiation is outside of the black hole if you're asking the question where does the black hole start and end yeah then if they're saying this radiation is somehow linked to the fact that they're losing mass on a time scale of like billions of years how does that fit in question for the physicist maybe Emma
can tell us in a future episode but also if it's disappearing where is the mask going if like all the energy all the mass is condensed into a black hole what happens if it's going away that means something is leaving or it literally isn't there anymore like how is that possible yeah I assume the idea was it's putting it back into the universe that we can measure which made me think it must be the Hawking radiation it's converting some of its massages Hawking radiation giving it back to our known
universe but then if the Hawking radiation isn't coming from in the black hole there must be something else going on there something that people haven't quite figured out yet or that I just don't quite understand because it's quite nuanced maybe there are theories and we just haven't read them yet they're just too difficult to get your head around without being like a highly competent mathematician which I'm definitely not yeah count me out as well but I was
amazed to find that someone has kind of proven it on an artificial black hole so there's like two things that is amazing there a that they've sort of proven it and B they've made an artificial black hole that does sound weird so on Earth there is something that is meant to be supermassive sorry not the right term there but massive enough that it can suck light into it and it can't leave no they didn't do it that way they instead sort of made it analogous to a black hole in
the sense that they have made it out of sound waves so much that sound waves can't escape oh like creating this sort of a sound barrier yeah it doesn't sound right either sound barrier or something because we know what a sound barrier is instead they've got rubidium particles or atoms sorry and they move faster than the speed of sound so sound waves can't reach their Event Horizon and therefore escape the black hole okay so yeah I guess I sort of using the
concept of a sound barrier combined with the vibration of atoms that is weird but I suppose it also illustrates a version of wave particle duality I guess imagine if you could have a black hole made of sound then never have any noisy neighbors again perfect that is very true I can see some definite applications of that I spend a lot of time on trains trying to work when there are people on their way for a night out but yeah noise canceling headphones just mini black holes
does it say it's a trap all sound or just a certain sounds like I imagine it would only trap something with a frequency similar to those vibrations it stopped it just straight up stopped sound waves yeah all sound yeah I quite like the idea of having a sound barrier that just cancels out all sound or even better yet selects different sounds so I can hear some of what's going on and just block out the sounds I don't like but um there's something from my undergrad degree it's not physics you'll
be happy to know that really astounded me when I heard it I see the half of my degree was geology and I did some paleontology modules as part of the degree one of my lecturers happened to say that the event that wiped out the dinosaurs was only really discovered in the 1980s before then no one really considered that an asteroid striking Earth is what wiped the dinosaurs out and I was born in the 1980s and I thought well this is a really recent discovery in that case it's a really
recent finding science is still evolving we still don't yet know everything by the universe clearly because we don't know how black holes work but they're really far away dinosaurs were on Earth so there is that but far away in time yeah that's true as well time and space very difficult when it's far away in time or space you know this is the thing that books and films are made out of Jurassic Park and the original Jurassic Park book was
written like like it was 1990. so I guess it was inspired by all this um conjecture from geologists and paleontologists about what wiped out the dinosaurs Oh Yeah from my point of view it's always been dinosaurs were wiped out by meteorite so the fact that it's brand new is is yeah quite I say brand new new in terms of science you know the physics we were talking about before is even even older isn't it that's it right a lot of the fundamental physics Concepts that we still use today and a
lot of like fundamental chemistry came from like early 1900s yeah and this is something from much later on I just thought wow what was it that they'd actually discovered there were some geologists that had noticed that in the Rock record that relates to about that time frame there was a lot of particular chemical element that isn't all right there's not a lot of it on earth right and there's a lot more comes from outer space and it was sort of almost like a blanket
surrounding all of the earth continents from the sound of it and they thought oh this is odd stuff where is what's how is this thing come from space and gotten all over Earth so they published their a theory in 1980 that it must have been an asteroid that was sufficiently large enough to deposit all this material around the Earth by hitting the Earth it's such an impact that the asteroid sort of spewed all of its matter up into the atmosphere and then ringed back down
and I think from what I'd read There were some people working for an oil company that had found what they thought could have been a giant impact crater in Mexico but because they were working for an oil company it didn't really get out into the scientific domain so it wasn't that well known about and it was only much later on in like in the 19 90s the this huge crater was linked to this idea that something large must have come from out with space to spread I think it was
it Indian or something all around the globe so the thing that really put it together was that finding this crater that matched what could possibly be a big enough thing that could kill all the dinosaurs I think so and yeah I did do a bit of thinking like how do they know that that crater was made in that time period and how do they know it was definitely caused by an impact from something coming from outer space and it sounds like there are various things you can look for like certain
changes in the Rock a little like glassy spheres that are only caused by the sort of high pressure high temperature event and um so a particular type of quartz I can't remember the exact phrase I know if you've read anything about quartz generated by asteroid impacts no I didn't actually read about that but from my understanding of of geography and how like mountains and and those kind of like formations on Earth you could kind of tell from like which way up the materials came so I suppose they
could take a slice and sort of see like it's it kind of is a is an abnormal sort of a deposit of material whereas you know it might come from the bottom up you might expect more of the similar type Rock but suddenly to have that cause it would kind of seem like a sudden bit of um change happened yeah and there are calculations you can do based on what type of rock is above it and how thick that type of rock is to work out how far back in time that rock comes from so these weird QWERTY things
they could figure out when they were formed um I I think I kind of understand how they figured out how big the asteroid was and how big a part it played I feel like I can probably just about explain it I mean have a go I mean it sounds like more reading than I've done on this so yeah I'd love to hear what you you'd figured out so I think the the Creator itself is 150 kilometers in diameter 110 miles um and it's about 20 kilometers deep oh 12 miles but the asteroid was
probably much smaller and they figured out how small it is and they figured out where that sort of asteroid might be in the asteroid belt that's between sort of us in Mars and Jupiter how fast that was likely to be moving and it's quite a slow one apparent um quite a fast one apparently and that sort of gave them an idea of how fast it would be moving so it was kind of like this almost like a jigsaw of putting together bits of information and then filling in the gaps
and then sort of reiterating that process to arrive at information that all matched together now that's surprising because what I did read was I think someone more recently thought that it wasn't as close by a rock as we thought but actually might come from the art cloud which extends Beyond Pluto okay so I still think it was an asteroid what do they think it was some other type of space debris like a comet no that is a good question what's the difference what's the
difference between a comet and asteroid I think I know what a comet is it kind of has a repeated pattern in space doesn't it it kind of follows almost its own um orbit although it can be swayed by other fields so it might change slightly that's a comet right so I normally defined as whether they're Rocky or icy so comments are generally icy but yeah they do orbit the sun on a fairly defined path and come quite close to it so when you can see a comment in the sky it's um some of the vapor
some of the some of the ice vaporizing as it gets close the Sun and heats up and that's why you can see like comic tails in the sky whereas asteroids are mostly just rock see but I did read something that said like oh how did we end up striking this asteroid was there something some event that caused various asteroids to collide and change their paths they ended up in the path of the Earth or on a trajectory to Earth and no one's entirely sure the answer to that question no one knows how this
asteroid ended up hitting Earth it's also quite amazing considering how big the impact is from something seemingly relatively small as well six to nine miles in diameter it sounds pretty big to me but like a hundred times in in scale was it's like spread over the impact yeah so apparently they think it was traveling at 45 000 miles per hour okay I can't even imagine that no like how far away would it be before you could see it before it would have just killed you instantly
good question I guess it depends also where it is in space right because I assume you can't see it unless sunlight is reflecting off it yeah or until it gets into the Earth's atmosphere and starts um heating up the speed of light would also have to be enough or there would be enough time for the speed of light to travel to your eye as well before it hits you I think the speed of light's a bit faster than that though isn't it that is true yeah those I mean there's all these things that need to
line up fair enough uh well I'm just like trying to picture how does that how would I actually work that out but I need a flow diagram [Laughter] all these sort of things like Space and Science they always seem to be sort of the first hooks as children into what's so interesting about science for me the first thing I was interested was space and planets and learning about all that for some children it's dinosaurs I kind of know why I'm interested in space but I don't get why other people are so
interested in dinosaurs and why kids are so interested in dinosaurs I can't say I was ever hugely excited by dinosaurs either apart from the Jurassic Park films which I absolutely loved the first one when I saw it as a kid but yeah again I was also quite interested in space and at one point I didn't want to be an astronaut oh yeah I mean I think for me that's the idea of going out into the unknown and having an adventure right I don't know what what it was about planets that I think it was
because it was sort of mystical and the idea that there you know where we are on a sort of rocky earth-based planet there were there were icy planets the entire planets made of gas and that was what was interesting to me imagining like floating gas in space just blew my mind I guess for the dinosaur Fanatics it's kind of the opposite I mean you said there was something on on earth right so there's sort of this tangible link to home albeit when the dinosaurs were
around home looked very different I think yeah we we have a lot of like scaly toys for dinosaurs but actually they were feathery and that's also a new bit of science that we only found out about recently like in our lifetimes right I've heard this as well and I think because I'm so used to the the representation from childhood of dinosaurs being big lizards with just leathery skin that I can't imagine a feathery T-Rex say be a lot less scary exactly you don't
imagine well then again I say you don't imagine feathery things as being scary because they're kind of fluffy but birds of prey if you've ever been dive bombed by a buzzard in the Lake District which I have you run true I mean anything flying towards you of a reasonable size yeah it's time to run I do have a weird fear of being like spared in the eye by a black bird that doesn't get out of the way in time he's just flying along not really paying attention and I might like
riding my bike or something and we Collide uh I see I was I was thinking like at what speed would you have to be traveling at for Blackbird to just head on you know flying to you weird fear I know but it's there I mean it's not impossible is it just what are the chances exactly that bird is probably paying quite a lot of attention and then and then you know it's quite inherent to them as well to make sure when they fly they don't fly into things yeah I was going to make a
point about birds flying into windows but I think that's because they can't quite see them because they're they're transparent or reflective so I'm gonna show up yeah it's a bit of an abnormal phenomenon from their point of view they haven't learned it from thousands and millions of years be interesting when they have evolved to avoid glass if only they could I feel like I said entirely separate podcast episode how do birds see what spectrum do they see how often do people walk into windows
I'm like big plate glass doors doesn't even have to be see-through though like the amount of times like I feel like it was always when I was walking to school that someone will walk into a Lamppost hmm and they're not see-through whatsoever that is getting I feel like we're getting completely off topic here as well so yeah accident rate of uh lamp post that's that's another episode yeah something else that is down in this but possibly doesn't really fit into this one so I
feel like we're just deviating and talking about random things like people walking into lampposts maybe that's a good place to leave the episode so things that is down to us or the discovery of what really killed the dinosaurs and the black holes do seem to give off some sort of radiation although we don't quite understand the details of that so if you've got something about science that stands you please let us know we would love to hear about it and we might do it as a future episode until
next time thank you for listening the views expressed in this podcast belong entirely to the person that said them they do not represent any industry or organization if you enjoyed listening to these views it would really help us out if you could rate US leave a review and tell a friend this podcast was sponsored by no one but if you're interested in funding us to continue to have Frank discussions about science and engineering please get in touch [Music]