Neil deGrasse Tyson Explains How X-Rays Work

foreign [Music] Airport I don't know a couple weeks ago a few weeks ago maybe all right I want to give you things to notice on your next trip because otherwise it's just a drag to go through and TSA and everything just some things to notice and to think about you mean things like we've become a slovenly country that looks like we're going to the damn bathroom in the middle of the night when we travel put some clothes on people real clothes no they got their pajamas on because they want to sleep on the plane cut them some slack no no no so here you go so the first thing you know at the at the TSA you got the the X-ray machine right you got the X-ray machine okay I just want to alert you of something if there was a day and I'm old enough to remember before anything got x-rayed you know why because nobody had an x-ray machine to do it and in the 1960s there was a Spate of of hijackings many of them were to Cuba because we didn't we our diplomatic ties have been broken off uh and because the Cuba were like they were commies right they were sympathizers with the Soviet Union and they were in our Hemisphere and so we didn't have planes to Cuba so if someone wanted to get fly to Cuba they had to hijack a plane so I don't mean to laugh but the hijackings to Cuba were like common so Congress said we got to stop this the only way we can do it is maybe we can x-ray your luggage okay so does anyone have an x-ray machine that we can just drag in here and do this right that's not so large like you find in the hospital oh yeah astrophysicists of the early 1970s had just miniaturized x-ray detectors to put into satellites to observe the universe in the X-ray part of the spectrum because black holes and and matter swirling in down the throat of a black hole just before it goes to die radiates X-rays and we we calculated this and we knew this and we said we're going to find black holes in the universe we needed an x-ray telescope well the X-ray machines are huge we have then we got to make them smaller to fit into the into the the the order the orbiting satellite and so a company called American Science and Engineering based in Cambridge Massachusetts okay pioneered small x-ray detectors and then they got tapped by the government and say will you bring those into every airport in the country every International Airport and thus was born x-ray detectors at airports because of astrophysicists were any were any of these astrophysicists also hijacking planes because I can see a connection oh the conspiracy theories oh yes and one of the leaders of that was a guy named Ricardo giaconi and uh he was also a professor uh a scientist up at the Harvard College Observatory the Smithsonian astrophysical Observatory today it's just called the center for astrophysics and when I was an undergraduate there I worked in his group the X-ray group we did some things all right and he would later be given the Nobel Prize for pioneering x-ray opening up an entire new window on the universe x-ray astronomy so and another cool thing is I would later be tapped by the White House to serve on a committee to to give out the presidential medal of science okay and this is under the George W bush white house so I'm there and we get invited to the ceremony so I'm ready to enter the White House and he's oh we we awarded to him he'd already gotten the Nobel Prize dude give him the presidential medal of science okay right so exactly so he's coming into a little bit of a letdown right I know I know but so he comes in I and he's going through this there's this this house you have to walk through before you get to the White House and that's where all the security measures are so he's walking through and I can't help but notice the White House is using an American Science and Engineering x-ray detector which this guy invented it was his company it's his company we have come full circle here there it is that that's so funny is like the guy who made the thing that you're using for security is the Ultimate Security risk because he wouldn't know what because he knows all the back doors if there is any because he invented he knows what yeah exactly if you're using his machine he'll know how to buy his own around anything in his own inventions you know if if he had come to the White House and I was head of security I'd been like nah get that guy up against the wall full pat down cavity search that's right everything we got to make sure this guy knows how to hide stuff Lead Me So anyway so when you go through the not asne detectors anymore but that was the birth of that entire movement and it was astrophysicist serving our needs happened to also serve the needs of the government by the way I retell that story uh in my book um accessory to war the unspoken alliance between astrophysics and the military and more broadly it's between astrophysics and security hey I'm Adrienne solgard and I reinvented the suitcase I love to travel but I can never stay organized you know when you get to your hotel you open your suitcase and everything goes everywhere that's why we created the carry-on closet a revolutionary suitcase that keeps you organized on the go the carry-on closet has a patented built-in shelving system compression straps to save space and an even One Time Magazine best inventions of the Year oh and for every suitcase sold we saved 229 plastic bottles from going into our ocean learn more at soulguard.com so Chuck so the interesting thing about x-rays we think of them as penetrating through objects right special kind of light energy yes it's not as weird as you think okay okay you realize visible light penetrates glass okay that's why windows are made of glass uh okay I mean listen I know that that was a scientific stretch but uh okay but but wait a minute but let's let's keep going here do you know that glass blocks x-rays and high energy light okay all right now we're doing something so not all substances are transparent to all bands of light that's all I'm trying to say I got you okay so microwaves which is what your phone use to communicate right they clearly pass through walls because when you go indoors you can still use your cell phone I mean unless of course you have Sprint I mean yeah exactly I'm roaming in the kitchen but not in the living room what okay so so microwaves past the walls that are otherwise opaque to you so the fact that x-rays go through like luggage and things and human flesh uh you know you know what x-rays don't really go through they don't really go through your bones I was about to say why don't you if you really want to fool an x-ray just make everything out of human bones no no no no no no no so it doesn't does not go through bones so Bones cast a shadow on what it is they're trying to view ah so really what you're you're not seeing the bones you're not seeing the bone you're seeing the fact that the X-ray went everywhere else except the bones exactly so it's like when you stand in front of the Sun and you do a puppet you know on the ground a shadow puppet yeah it's really just the you know the it's not the image of your hand it's the absence of your hand correct it is it it is it is you're giving meaning to the absence of sunlight right where your hands had blocked the photons in the sand right so that's what's happening okay yeah yeah yeah and so that's cool uh discovered x-rays and he put his hand in front of it and he saw that they're the he saw the bones he could barely see the flesh because it went right through his flesh okay when you're looking out a window you're not looking at the window you're looking at what's beyond the window okay so he's looking at he doesn't see the he sees the bones because the x-rays were absorbed by the bones and he also think I saw his wedding ring or something which absorbed even more X-rays and that was like pitch black rather than sort of grayish and please do not ask why his wedding ring was made out of human bone he's a weird kinky Manhattan luncheon in fact in all the rest of the world they call rotten generates rather than x-rays um but ah yeah yeah yeah so uh point is uh x-rays are useful for looking through your luggage and finding things that you might make a weapon out of typically out of metal but they will not find weapons made out of things that are not metal and are otherwise transparent to plastic like um a plastic gun right if you make a plastic gun it's not it's not going to find it in the same way it would reveal a a metal gun so here's what you can do now controversy on that too about printable guns correct correct so here's an interesting thing you can do uh like like you said like I noted um the bone does not completely block the x-rays it just blocks more x-rays than your flesh does so it casts its own mild shadow in the photograph okay if you have different frequencies of light and you interplay them you can see what the trend line is in the things attempt to absorb it or not and once you do that you're better at detecting what could be in the suitcase if you move the frequencies back and forth but what they also do is they attach color this is the literal use of false color whether you attach a color to the edges of signals that are shown up in the image in the X-ray image because your eye picks up color much better than it picks up tiny changes in in a grayscale shadings all right so if I say anything grayer than this level make it red and anything less gray than that make it blue your eye boom I see red and blue as two completely separate things rather than as the Continuum that it is so the folks back there the TSA they have a fascinating task ahead of them to identify objects and shapes and and and and highlight them in ways that it makes it easy for the person looking through your looking at your luggage rather than harder yeah yeah that's that's super cool and I wonder did they assign a special color uh to sex toys because they tend to somehow find them all the time I've never seen this ever happen is this you trying to pull sex stories through the security is this I'm just saying I don't know how every time you never heard that this happens that somehow they're just like gotta check that one and it's just like nope just another sex toy sorry everyone everything's great oh good no reason to be alarmed just another tech sex story girl you're free to go with your sex toy uh and by the way those the those flappy things at the entrance where your luggage into the machine yes they're like have heavy metal particles in them so the X-ray is no correct so don't reach in there because it's trying to Shield you from the x-rays that would otherwise uh leak out of that hole nice there you go well that is super oh I I have to tell you I will never look at the X-ray machine again the same and I want you to think of astrophysicist when you do I and I I will now which I have never done before it I can say that with x-rays are just another band of light that comes to us from the depths of space that humans on Earth with excellent engineering has exploited for all manner of social cultural geopolitical purposes look at that thank you Bill him okay all right Chuck that's all we had time for this explainer okay x-rays in the universe and x-rays at the airport Chuck always good to have you uh Neil deGrasse Tyson here finishing up yet another explainer before star talk as always keep looking up thank you

Channel: StarTalk

Views: 130,839

Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, x-ray, x-rays, x-ray vision

Id: mfcF_jrufig

Length: 13min 42sec (822 seconds)

Published: Tue Nov 29 2022