Funny cast episode fifteen one day simmering thousand listener questions parents are. Welcome page trying to be caps are we could backspace turning through because most where we help you understand you know what how we know. When it first came in on the publisher of universe today and with me just doctor pamela ok a professor at university of southern illinois every two pamela. Okay fraser how's it going good good while i'm really excited this week because we got lots of course especially when we kinda holding what it's telling people would be answering questions we've been holding on to them for. The better part of three months you know so we've got a a bunch of good questions to to go through a t also got some great uh audio questions last week which was which was wonderful so we will play a couple of those. Um. And if any you know if if anyone else has questions from from here oh no we doing this question throws regularly so. Uh if you have questions either on an episode we do or you know you've got just a more general question about astronomy just send it in. And we're happy to give you a phone call and say you know recorder side of the of calls we can actually get your your voice on on recording to to do the show three already i think i'm ready alright ok. Um okay so we're free here the first one other question which was great this was from uh pole nelson and he wants a little more information on dark matter which recovered in episode for. Well for your unbearable this is pole your long term fans. Where court and it has to do with dark matter and is what we think that this minute or is a new coming to of yes what can it just be work neary matter that we just can't figure it isn't just. Okay power so why why is dark matter. Not just like regular matter what is it well we've we've been looking for it and that's the problem more we look for the more we don't find it and. It was normal visible matter we'd be able to see the socks we to either be able to see it radiating light and we don't see rating like. We'd be able to see it blocking my um for instance dust it all over the place and it grabs occasionally tracks man best ones for awhile up on the dark water intelligent you're not hasn't tactic. And we we find out is is one and so a rating eight. Very long wave length of lighten radio and it also blocks light so just like you can see dust mode scattering light and sunbeam go through dusty room i like them to think alex he's traveling to er get scattered by dial. So we don't see dark matter on that it might we don't see it locking life. And we also look for it to nine five right there are a couple of different teams that look for qualification online this is where the gravitates she won't pull up the high math object. Um then light that would otherwise shoot off towards another part of the universe out of here on her so we see more right than normally would from a distance object. If a lot of these compact objects route there would be a lot of these magnifying. And we don't. So we're not finding dark matter that is nice to sign like where not finding it that isn't anymore blocking my and these are all thank the normal mother would be due. So. It has to be something else now there are cases where we do see grab occasional mine didn't do too large amount those dark matter this. Form hey lows i wound large massive systems like down foster's but we're not finding small balls of it it numbers that would. And town for all the dark matter that has to be out there. So what and your name in all the things you know about it has to be something you don't know about it just returning back to charlotte so so click we can detect it's gravity shouldn't affect on. On the couch who's themselves but we don't see it as as a compact option right and we don't see it as small normal things like dust grains and we don't see it as. Stuff doesn't i think might um so it's sort of well that's what it can be. What's left it stuff we don't understand alright well but it just pulls question. Okay so question or two. Charles london after bunch of questions. But this this was one that i that i really like they picked us out of the out of the bunch so here's what he has to say because i'm amazed the scientist can discuss with such certain t about events that happened tend to the minus thirty seconds after the big banks. How do people figure out this stuff. And i think that's that's what that's really good good question because there's no where we can actually go to that moment in time and see it we can't see whether telescope how can we how can we don't well and the truth it we actually can't see anything that happens. More than about four hundred thousand years ago four hundred thousand years after the big banker demanding cousins migrate background whereas uh he minutes. So it's the whole first almost four hundred thousand years of the universe is beyond part building yours at all. But because was all totally legal paper in blue to paint the like couldn't travel to get out and be free and reach us in our tells go to your honor it was sort of like trying to look through fluorescent light bulb you can't do it. Let me have all these theories that as he said go back to ten negative thirtieth of the second after the big bang hands that means. It zero point thirties zeros and no one second after the big bang. Yeah we were able to don't series that. Tell us what we think what's happening way that the very beginning universe is lots of my. Um but it's now that conform cities or do you first. So really smart people smarter than i will ever be with computers sit down and they say okay. Here's what we said able to observe so far which we look at the stars meets look mostly at the structure of the galaxy is around us we look at the large scale structured numbers. And we look at how that football doesn't time and we look at the cost of me read background we look at the structure of it anything all of these constrain they don't see the that. Started times you know and work forward and have to knowledge of what we certain classes my grey background. They have to want you to what we observe. At the universe is ability usual versus side uhhuh. And so so a lot of how to grow with members. And. Some look really good ones are able to predict thing we haven't been able to observe yeah uhhuh. There where the time before w ma went we did a really good half of the problem i quit background we had ok now um coby did a really good job. But they didn't get that's fine the detail so let me see if i if i understand shrimp. Those scientists will will make these kinds of predictions going back using the math and using their understanding of. A physics right back to the first moments of of the universe you know if you push matter this type together this is what it should do if you push it that type together this is what you do. And then. You can then run that process forward again would be expansion with different things happening at different times and you should be able to find things that you can didn't see in the real universe. And that's exactly what they're doing day. Made predictions about fine structures and d numbers in v structures in the causing my quick background and what was observed matched with a theory they predicted. How galaxy cluster should form over time how many there should be a different ages in the universe and he sounds that. So there are building gone current observations and predicting once he drops relationships hold. And they start there clock at mode zero and still forward it completely consistent why. Especially each step notes on the previous that still from the previous stop and have to match with what we've observed once they reach that's pointing times we been able to see so it's not just uh. I guess inventing numbers it sounds like is a very rigorous process that they have to demonstrates. You know in the real universe that we see to make those numbers match up that's really what's really misery is a very complicated process they build three dimensional models um one number should look like in a box and your computer it's. Really quite beautiful one alright so we've got into got another question here's another audio question about b speed of gravity from john the key are this is joan so clear there's a question for you. What is the speed of gravity. We've heard and reset broadcasts about how super there was a jerk all that matter of the universe with a massive object like a star business space around it gravity will prevent such as a super certainly have a graphic initial consequence. Did we detect that and if so how fast is effect travel is about by the because like like speed limit or does it a break that wall well in theory i like. See personal but when the exploding lester absolutely perfectly perfectly is metric which means there are the exact same number of lots of material flying out the exactly all dimension all the way around this year. Um that usually but. In every case except for those probably impossible smile trickle cases. There are ground anyway inundated with super let's let's sort of what's a gravity waves across anyways is a wrinkled created and space time continuum by gravity i'm sorry i asked. So. Gravity not if that's itself by then and see this means that you are sitting in that case of your own space time continuum because you have now. Your curving the space around you towards your body is a very tiny tiny effect and the. Grab occasional pull the earth makes ain't much bigger down so you are just basically and you see the little thing getting pulled that no we do we noticed he needs gravitates your whole of the er right but i'm spending space and time around down if you will. And you don't move the constant right in straight lines um the weight move is going to create wait. Through the space time continuum the same way you can create wasting water and would some one was very you know to good equipment you know i guess theoretically be able to detect my movements from before. I i think you'd need equipment that we are capable of creating on the planet earth no i mean you know what you know infidelity dear you in a mathematical model yeah sure and. More importantly it's possible that is. Too big enough objects our orbiting one other like two blackwell will be able to detect this crap anyway. Allen super mobile also crazy scratching me. Um and these weights propagate three space at the speed of light. This is one of the great thing about serious relatively is it talks about how it takes time for all changes to communicate that change through space. So when i try not like about like takes time to reach you um went in and. Eight star explode it gravitates you'll feel changes because this is star flying off in all directions. And it takes time through those changes in the presentation appeals to communicate themselves to other parts of states. And choose just use a an analogy like if we. You know if the moon first earth disappeared suddenly just just completely disappeared the moon would still think first was there. For. It's a couple of for a couple of seconds yeah i'm still going into orbit and then. You know whatever the speed of light is you know to reach the moon um was four seconds. Um then the move your off and then go straight into space but for that intervening time you go the movie just because it just disappeared. It wouldn't actually go straight into space it would continue going around the sun but it wouldn't let me do all the way it does seem to serve it around or right right. But it would act as if it was still be you still going around earth for a few seconds before it and beard often. When districts and one of the really neat and it gravity then light. So we can actually look for this and a white as a potential way to confirm that gravity person gave the speed of light and everything bugs and tried to do it you know and quite sure if their results are being turkish correctly. But in theory um it might be possible to look at the light some distant claes ours and how that light and it's position changes as on. Um there are some folks back in two thousand we tried to do that looking in jupiter and that was quite sure singers themselves correctly um or let me rephrase that there are people who are quite sure they didn't hear people who are quite sure they didn't interpret the results correctly. But. These results allow it to think of ways that we might in the future get a better handle on exactly what this gravity is which are quite certain he's like but he's always cool deal to prove you're right and exactly talking. And i think we're i i know we're gonna be planning to do a show on gravity wait. So that's a really interesting concept and uh so we'll cover that in a lotta due to exactly how they plan to detect them and so so so painted for that. Um okay so next question um richard chat blow is following on from episode for where we discussed one of the consequences of dark matter is how it causes eclectic disk to rotate so here's a question. On the dark matter part cast pamela explains that the dark matter amount increases with distance from the galaxy center and that explains to read you're walking of start philosophy then how to spiral arms forms and go to see if the dark matter have some walks moving. We've gotten a lot of p back on this and what can you can you cook soul up once and for all. Ok so if we had a night happy come chlorine desk where. All of the start act start i'm like this one on our solar system where the further you are away the slower your philosophy is because gravity home not. And we expect things to be moving apart so yes. I dropped my radius by ten percent i hopped off the earth move towards the sign and attentive away um from here to decide then i expect muscle and go up about five percent. No. What kind of dark matter. Yes i go out in the galaxy and i hop off of our solar system and at times of the way from our solar system aimed towards the center of the galaxy. I expect to see mine philosophies he's still. Go up that five percent but it doesn't my philosophy stays exactly the same because of the gravitates she'll pull it don't bother any other person galaxy. Now. Let me trying to explain it using a reference frame all kinds of on your let's imagine you and i go down to antarctica where it's really cold and have land and we start walking in perfect circle around pull. No if i'm closer to the polls and he wants and we're walking past the exact same right where are you the marching band steps when we go a certain number yards in every certain numbers that slow her short period of time. As well walking along because we're walking in the exact same region we're really big circle going around the pole we yourself walking side by side. But as time progresses differences user compass and two circles walking on well yeah so you can double walking the exact same taste. Overtime i'm i who won smaller circle will begin that. So yeah it's fun ten percent closer to the polls anymore. Ah date of the time it takes for you to go all believable i will come on one point one times around. No pieces normal because we're in motion where like you're getting closer to the full i'm moving faster we start off at times you're out at i b chugging along faster than you and he would instantly see who has. And at the end of the time that it takes you to go one time oh we around the pool outlook on seventeen percent further around the block on one point one seven times wrongful. So even short time yep using my walking it seems a lot people stay side by side. But i was a long period of time person closer to smoke and slowly further and further ahead. And this is what's happening galaxy. As the galaxy rotate stars there further from the center they have to going much bigger circle. So they're gonna slowly long further and further behind well stars that are closer to the center which um smaller circles with the exact same philosophy. Are slowly going to appear to create the head creating in some cases these files structures what if we didn't have the dark matter you rolls be completely twisted up because you be like er are. Solar system with us the planets role in of going around and run around number to reach goes around you know a dozen times. There it just goes around once it would twist itself up faster so it's all now there's tons of scale let's move on to the next one then. Oh so when episode fifteen we discuss super nova and i had a whole bunch of questions but it's coming up so fast i forgot to ask them all so uh fortunately any duncan remind me of the one that i was meaning to ask. Uh which was so here's a question. I'd like to know if when one of these massive stars goes into super nova how visible would it be us here on earth. So how bright would be super no well that to close the stars most likely to explode on it and go to the green. That was this is the closest to base it it's only four hundred and thirty like hm away and when he goes he's gonna appear to be about the same right now. Ah a hassle man definitely look up and and and we call it a quarter means um about half of them in the faces and is nothing. But the thing all of that like we can dead get content down to a single point so take all of that really bright light and focus it down to a star on scott. This is vincent amazingly bright it's going clearly this folder hm day can cast shadows it just uhhuh cool. And how long would it lasts for um it'll be visible for several months but it'll only be advised or a week. And and how quickly would it take to get right would it just writing up with college a couple of the he really growing who's looking to like curse agent right in straight out and slowly increased so that's brad right. Yep see it from the day with no question where it is nice. They let me show rhonda ryan the hunter poetic to think about okay what what did a creative and because it's a it's one of the wolf right sir it well it's not there yet but that's where it's headed is this joanne stars it. Hundred times the size of the phone huge. Doing weird stuff all the time we don't really we stand it. And luckily is about send uhhuh times further away building is located seven thousand five hundred like his last. And since it's so much further away um when it explodes if it gets to about the same right now as buildings does need to super nothing. That seventeen and a half time further translates into three hundred something. So it'll be the brightest thing this guy it will be giving off more like the means higher milky way galaxy. Um probably will during the day ah but just not waiting who was beaches so the so the most exciting super nova we've got to look for to is people choose exactly. So just keep in iowa hunter and watch out for him to get winded by because we got pollution fell revolution particular well i guess we could always you know get lucky as well and have a type warning with uh wait for school off call survived. Uhhuh depends on your definition of let's see if it to close it could be very bad before through communication satellites that quick both of these drums right. Right so we if if one of those type wanting super nova was nearby cities closest people just how how bright would it be compared to be soldiers going off the super now. Those are about twice as bright so it yes a regular season because off other types sorry so the correct one he people have because on ah it's about twice as bright me and she is gonna be bothered by this for me. Compacted down to single point compacted them the points imagine focusing all of the lights moving down was single point yeah something pretty painful look at. Wow. Okay supposed one twelve last question then. And i'm gonna ask this question because actually come from a lot of people and this is this is quite a puzzle or so um i think we probably goes question four or five times and this sort of place also mentioned early on. With with the big bearing and soap you wanna know how was it possible that the expansion of the universe after the big bear with with with dark energy can go faster than the speed of light i i thought nothing single faster than this before it. Well it's not a lot of isn't on p c's moving at the speed of light its another at that this stuff between thing is growing in a normal reasonable rate but there's so much stuff between you and just an object. They is need that is not checked and things like. So let me see if i can make sense. Um astronomers has measured the expansion rink locally and right now at this moment as we sit here reporting. Um be one parsing one back up parts that of space around that is expanding at a rate about seventy climbed airs per second. Now one that could parts like the kind of weird number and it works out to being three million two years it's the one thousand six hundred and thirty six point two six light years. So that. Lots of light years expanding sending climbed airs for second so every second that make a perfect the space get something conversation. No that is that if something's kill clock to make a car sex away the space between us anything's going a hundred and forty columbus percent. If something is. Twenty five make a person what the space between continued is increasing at one thousand thousands fifty climbed airs for second this morning all sorts of second order those. So the further something is away. The faster it appears to be moving because the space between austin it is expanding and for for every one that could parts like the distance we accessing climate or some space every second. Know as you get greater and greater distances did guess means something so. Yes use i just laughed and said one thousand make a perfect the way for me. I would see new appeared to be losing and one two three the speed of light. Ah that's pretty fast another quarter the speed of light and it's not that you are losing had a cold in the speed of light it's that were shelley. Seventy thousand columbus ears the space between you and i every second so it's not setting a thousand extra kwong here's between you and i think his he appearing us moving. No it works out that someone has to be about four thousand two hundred at five eighty six made the first six away um the faster than device. So if i think you asked exactly four thousand two hundred and eighty five point seven meg of our sex. With a speed of light as three hundred thousand congress for second which there is around and um i'll see you moving has this been just line help how far across the universe is uh. That's actually for the universe and then around for me actually get to see that's thirteen point nine billion light years away and as you're researching point seven billion. Yours old things that are beyond the horizon of like even had time to reach us. Um they're moving so fast that we never actually get to see. Now this means that there is stuff relatives all of us appears to be moving faster than white. And also the their relative to other points and users we up here just like like it's all in relation brought on by the fact is and well. So what's gonna happen to us trying to see those things if it starts to move you know they'll be moving a certain speed and then suddenly they'll be moving faster than the speed of light away from us but when she. So this is here soldier she's like the last full tones that were able to make it and then everything else is just going. Well then most of your relatives because ah and start at like as something falls into a lot hold it appears to stop and hang out there. Um so things disappear over the edge of horizon. They'll just. Tivoli appeared stop away. So i just you know when you say that nothing could move faster than the speed of light it's kind of them is no one in fact you know relative to people everything in the universities moving faster than it's beautiful it's been somewhere you're looks. But we can't to go faster than the relative to think though i i sit here and he said here the space between can increase that task and things like but we can't move below that me and faster than before. You know i think we're gonna get more questions on that so it's one of those need mine been i don't kidding. Well that was great come on fix a lot i think we got uh we talk through our first question show we got some great questions um. And i hope that people will send this in some more so what's just er close it gives people more information about the show. Uh you can find more information about strongly cast in our website astronomy cast i'll call them because then it's comments questions are feedback. Info astronomy cost dot com and uh you can participate in the forums only beside every episode on our website. You can subscribe to the show supporting your part catching software out astronomy cash dot com slash part cast thought x. m. l. or subscribe to it from within i choose to search for astronomy cast. And if you wanna support astronomy cast. Uh we're will gladly accept your donations a link to the donations page from our website and all donations are tax deductible for u. s. citizens. She can help themselves and see if money on your taxes at the same time or come over for you next week. The next week this has been on it a week turn reason reminded about that all right
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