Supernovae: Witnessing Cosmic Explosions Firsthand – Yvette Cendes

[Applause] [Music] [Applause] Mars in the winter I really like it because we have a riot or riot very cool constellation input I think he actually looks like something unlike some other constellations so first here we have Orion's belt some of you guys might notice the three bright stars here make up a running belt part of the entire constellation Orion is the constellation here and Betelgeuse is bright star star up here Betelgeuse is very bright red star makes up the left shoulder of Orion Rigel is the star down here another bright star in Orion and cool thing also about Orion is if you follow the belt down you get to the star Sirius that's the brightest star in the night sky Orion's also cool is near Logan here at Betelgeuse this sort of reddish star the left shoulder star in Orion that is a star that genres think is at the end of its life and is going to go supernova someday so females remember about stars and just as we see them in the night sky doesn't mean they're all there you know some are closer some are further they're all vastly different sizes so if we're looking at the stars that I was just showing you in the night sky so here's our Sun it is a very tiny star compared to stars like Siri okay definitely bigger Rigel is huge Betelgeuse is the biggest of all the reason this happens is if your star like our Sun when you reach the end of your life some 99% of stars you kind of swell up and you poof out your outer layers and then that is the end of your stellar story if you are a star however big like Betelgeuse what is going to happen if you are going to swell up you're going to be huge absolutely giant and what is going to happen though at the end of your stellar like when you finally run out of fuel at the center of your core as you are going to end up in a supernova explosion so what a supernova explosion happens the stars basically run out of fuel at the center of its core and basically the outer layers come down a neutron star or black hole is born in the center and we have basically an explosion that is the biggest explosion we really know of in astronomy one supernova can be brighter than the light of the rest of the galaxy when you see a supernova occurs so these things you could see them from even billions of light-years away particularly bright one nobody is we actually know about them pretty well okay so supernova the reason we know about supernova is what they would actually look like for us is we've actually seen them we have them in the historic record chinese astronomers in particular we're very good about recording the guest stars in the sky that they saw so stars that suddenly showed up that were suddenly bright and you know see so of a 1054 ad is particularly famous one and the reason is it was a supernova the Chinese the Japanese the Arabic astronomers definitely saw it we also think the European and astronomers in Chaco Canyon so people all around the world saw this object the reason was it was so bright you could read by the light of the star it was so bright it was in the sky for two years at the guest star and no idea of course what was causing it but it turns out because the chinese astronomers very good at recording where these guest stars are we can go today and see where is that what exactly is in that location No so this is what you see at the point how about I just tell you next slide this is what you see that if you go at the Hubble telescope to see this something that's on the track every one so our next slide please so think about supernovae I know is unless at 10:54 II we don't actually see them that often and the reason is because I said only one person of these stars goes supernova so we end up having effectively one supernova in a galaxy our size from century so when that happens the last time we saw one in our own galaxy 1604 Galileo saw it he didn't have his telescope yet so he couldn't pointed but 1604 I just told you want every century well we have a lot of dust in our galaxy a lot of probably a few supernovae have happened but we just have not seen them because it doesn't we doesn't it so the closest supernova to us since the invention of the telescope is this object here called supernova 1987a and the reason I like supernova 1987a is it's actually one of the things I talked about in my PhD thesis first whatever you do my research on and it's also one that tells you like when I tell you what I love the information first it happened not in our own galaxy it happened in a galaxy it called the Large Magellanic Cloud which is a satellite to auro it's basically 170,000 light-years away but you can look out at the Galactic plane so that's why you can actually see a lot of cool things happen seeing the Large Magellanic Cloud and you could even though it's so far away and you're in the southern hemisphere really see it for a few weeks with your naked eyes so what I do if this a little bit fear works yes so I basically study this supernova when the shockwave happen the shockwave goes out and interacts with all the material that is surrounding this region of 1987 day that the start affected before it died so if you want to know what happens in supernova it's a bit more circular but normally but you can basically see that some region light up and you can see supernovae they really also interact with the surrounding galaxies around these systems a lot of star formation gets triggered as the supernova shockwaves go out and then you get you know and this stuff showing you that picture the supernova this is all radio data by the way oh this is very strong so to start wrap up folks are like what would happen it was supernova though happened closer than the Large Magellanic Cloud you know like let's get rid of this for a second so first of all the first thing to emphasize is staying off them people worry about whatever you talk about Johnny explosion and we're not going to die if a supernova happens in our galaxy why do I say this so if the supernova is going to disrupt their atmosphere and things like that it has to be with it a few hundred light years of the mania thousand like your maximum these stars I mean Betelgeuse that was a huge star you know you can see that from very far away we're pretty sure we know about the immediate area around us and we don't see any stars that are about to go to explode that are going to really hurt us so that's cool so next slide please the next strike though is so okay what kind of alert will we get it for these supernovae some of you guys like save nothing those questions we miss being up late that's not a case of supernovae there's a little technicality here particles in the universe called neutrinos and neutrinos are fundamental particles or like electrons are in all their other favorite friends like that but they're a little different cuz there's just a bunch of them so this is an interactive astronomy on time everybody give me a thumbs up hey okay so when you do your homes up every single second about a billion neutrinos go into the tip of your thumb so these are particles they are just very weakly interacting they don't really interact with anything but when a supernova happens and the neutron star is created in the center of the supernova basically enough neutrinos come out it's about the number of atoms there are in the Sun and what happened for 1987 is detectors like this this is a neutrino detector just for comparison next slide please sort of if you look that that's two people in a pope for comparison and what this neutrino detectors like in size and the first time we ever detected neutrinos from outside of our own galaxy was expert from our own solar system forgive me was actually during 1987a I told you all these neutrinos get created and they saw them like 20 and 3 observatories around the world it was the coolest thing that ever happened so but the trick is also you get the neutrinos arrive a few hours before the light because I just told you they don't interact with anything the light has to travel through the layers of the star when the core of the star collapses so you actually get the alert from you the neutrinos treat several hours before the actual supernova Venice scene you can actually by the way go online online there's a supernova supernova alert Network neutrinos Network that you can sign up for alerts it's because suddenly all the neutrino detectors around the world go up you can sign up to say ok like I want to see what's gonna happen and you know you just got what we all received the alert tonight we're gonna run outside we're going to see this view here and so what's gonna happen you're gonna stand there maybe you're going to be the first person you know over 400 years to see light from the supernova in our own galaxy and you're gonna wait wait love astronomy is waiting and then look there we are and then that is what it will be like suddenly we'll have a guest star first time in hundreds of years in our a night sky [Applause] so the question was you all star supernova No so all only 1% of stars are massive enough to go supernova you have to be roughly 8 times the mass of our own Sun to go supernova so in the case of supernova 1987a basically because there was the supernova event and they knew from theory that that's what caused it and they literally never detected you to turn support that was the main reason for it but as I said it was also the fact that was the so the question was where is the picture of the neutrino lab that was actually in Japan so the deputies are very good at neutrino astronomy did you use the various neutrino detectors this kind of triangulation as a big telescope to point you at the supernovae so the question was being used in neutrino detectors at the telescope so the answer is people can now like I mean of the field said 30 years or so to evolve and the field is now at the point where yes you can they have actually within the past and associate in the 19 you know that would have it the question was that's a good question how do you evaluate data from a thousand ad I think the fact that if you go and then you see the supernova remnant there is very telling and also the fact that all of these records have been up there in the same period of time archeoastronomy is so supernova remnants is literally just the remnants of the star and the gas and everything surrounding sorry so supernova remnants on another clone field of astronomy and yes okay so the question was good question have we detected gravitational waves from supernovae the answer is no but my understanding is when the supernova goes off in our own galaxy like as would be expected I did actually ask at one point for whatever basic gravitational wave detectors there were in 1987 quite stupid detected or not apparently there is a [Music] [Applause] so that was a good question or what is better another star that might go supernova other than Betelgeuse actually the best candidate in my opinion at the star called eater Carina but it's in the southern hemisphere so the talk is not as good [Laughter] [Applause]