A mind-expanding tour of the cosmos with Neil deGrasse Tyson and Robert Krulwich

find them in the vicinity of large galaxies, but you know what happens, you know that they orbit around the large galaxy, but their orbits are not stable and they go into a death spiral and they get devoured by the larger galaxy and we have a term for that : It's called galactic cannibalism, in fact, there are stars, there are streams of stars that we see in our own galaxy that have the same trajectory with each other through the star system that is the Milky Way, so they are Rel and you follow them and it comes back . it comes out and comes back in, so this is evidence that it was once a fleshy but dwarf galaxy that we ate torn apart and now the stars are just trying to hold on to some of the last bastions of a memory of what they once were because They are separating by what we call the tidal forces of our galaxy.

Does the Milky Way have dwarfs? Yes, I only have the well. So the first scientific essay I wrote was called The Galaxy and the Seven Dwarfs because at that time the Milky Way had seven dwarf galaxies orbiting around it and then, but dwarf galaxies are very small, they are difficult to detect and since then we've discovered, you know, a couple dozen more, so we could be above 20, two dozen dwarf galaxies in our neighborhood is basically close, so the point of going back into the void is you look into the void and say no. there's nothing there well, what are you invoking to declare it's a void? are your eyes?

Well, let's bring a telescope. are you using visible light? is that a visible light telescope brings an X-ray telescope. An infrared telescope brings the avalanche of senses that science has developed that transcend the five native senses we have through our human physiology and that power allows us to decode the universe as our senses receive them but as our detectors. There is a surprising chapter. or kod s in the back where you discover how human beings finally felt what they couldn't see, that there is a rainbow of colors that we can all see, that they are waves of different lengths, they take you from uh, whatever it is , GB vibbo Roy.

B Viv so what, yes Roy Biv Roy red to repeat after me Roy red G Biv red orange yellow green Biv blue indigo indigo V violet Violet you got it, but it's weird just a quick thing um um roses are red violets are violets , TRUE? I mean, who came up with purple or blue. Where do we have a name for that color? You know, Mark Twain's edict that I love it, what is it? First, get the facts straight and then distort them to your liking. Well, let me finish this thought and then I have ordered to ask a question.

At the end there is this moment where someone has to realize that there could be something redder than red or somehow more than violet now we only have eyes but this particular person used a thermometer what was bright was bright bright is OK, so Isaac Newton is the first to understand that white light is made up of colors, so he takes white light, passes it through a prism and gets Roy G Biv, actually indigo, he had a mystical fascination with it. number seven so I wanted to set seven colors oh but indigo it's actually blue violet okay but anyway we're going to give you indigo because he did all those things before he turned 26 so if you make up the calculation just for a challenge, we'll give it to you.

We will give you indigo if you need to have indigo for him to have the colors. and then he took those colors, fused them again and got white light on the other side, that's kind of weird, it's just weird, yeah, that red, orange, yellow, green, blue, violet equals white, okay, like this that we're okay, William Hersel is coming later and and I'm wondering if I even ask this question. I wonder if different colors of light have different temperatures. So he set up the spectrum with a prism of sunlight and put a thermometer in each color and then he had an eighth thermometer.

I do not know if. He used one and did the experiment seven times, but he had another thermometer that he used as a control thermometer. He put it on the side where there are no colors and that would probably just measure the ambient temperature, mhm, so it tastes enough to even out. I think this is an interesting exercise and you have a control thermometer and you just put it on the red side out of sight and then you look at the thermometers and the control thermometer goes off. Yes, he does and he's watching. He looks at it and says that something must be passing through this prism that I cannot see and describes it as light unfit for vision.

Yes, he discovers infrared light with that experiment and then another type that the human eye cannot see if he Go to the hardware store and get an infrared bulb, turn it on and it looks red. You are seeing the red light that this infrared bulb also emits and the heat that you feel that your eyes cannot see, that is all the infrared that you see. you're buying when you pay money for that light bulb and then another guy put a piece of paper on the other purple side and it turned dark and he did a test with photo paper and found that it responded the way you would normally respond by putting photo paper in front of the visible light, so he concludes that it was someone else later, someone else, yes, of course, and he says that there is something beyond light, there is something less than red infrared, something beyond violet and that is how light was discovered ultraviolet and so posing the question in the first place was a stroke of brilliance to then rely on your measurements to a level where you then declare that you have made Discovery something completely different, it's a yes, it's yes, this is what happens with this book, simply because That story is told in the book just so that people have an idea of ​​the story of the story of bewilderment and the story of Discovery summarized in one.

I'm not going to ask you anything else because it's Q&A time, but I would have just so you know what else is here, uh, there's something, there's dark matter, which is this mysterious thing that's out there, that we, the Dark matter, it's everywhere, yeah, okay, Dark Energy, one of the questions you ask is why are there so many celestial bodies around, uh, is there anything in the universe that is perfectly round? what happens between the planets, why is debris still coming in when the Earth seems to have collected everything after 4.6 billion rotations? Something in the end is called the cernic principle.

This is really what it is, but it doesn't matter, just let us turn on the lights, this is what we're going to ask you, if you can, raise a hand, I'll choose you and then, wow, you're a hotheaded man. Choose yourself and then you just get up and ask and I will repeat the question so that people in the part of the world that they broadcast can hear this current paradigm, the billion universe, the question is: the universe is 14 billion years old that we have now. Stars, stars, galaxies, galaxies have been seen that are 13 billion years old and in some ways that could suggest that the universe is

expanding

and that there is more and more Universe all the time.

Well, first of all, the universe is

expanding

and there is more and more observable universe. the moment when the Universe at its edge is expanding at one light year per year, that's how it works, so in a billion years the edge will not be 14 billion light years away, but 15 thousand million light years, so we got it right. now galaxies 13 billion light years away we are seeing light emitted from that galaxy and that light has been traveling for 13 billion years okay yes that galaxy emitted its light when the universe was at 10% of its current age and was in fact much smaller than him. is today, now you said that the current paradigm is the age of the universe of 14 billion years, you said that with a bit of oh, you'll come up with something different later, the correct way to say it is current measurements of age. of the universe that's how it works well um The paradigm entered our lexicon um in a big way in the 1970s with a book written by the philosopher of science uh Thomas cun what's this about there's a dangerous woman here who is this Joe Barker who you talk about so dangerously, you remember what happened to the guy who put and didn't put cream in his coffee, so this book, the structure of scientific revolutions, introduced the paradigm as a way for scientists to come together in around a paradigm and everyone accepts it and even though then something different happens and better data appears, we all rally around a different paradigm, uh, that happened basically until the dawn of the era of modern science, dating back to Galileo and uh and um bacon.

Francis Bacon where when you experimentally measure that something is true and it's verified to be a truth that then doesn't turn out to be false, period, that's not how science works, it's not like, oh, this is now, that's going to be false, Now, let's all get together. This would leave you with that impression that you read that book, but the book was very wrong for the previous modern science era, surely because people just thought about things and then they called themselves scientists and those were philosophers and you turn out be deeply wrong when someone else thought something better and then everyone is wrong when we finally start taking data, it's all about the data, okay, everything you described is perfectly fine, yes, find galaxies, the next telescope, the Telescope Space James Web, is tuned to live. in that regime to find galaxies that are born in the early Universe, so there will be a lot more data coming from the early Universe when that telescope is launched, lands at its observation point and turns on, so there is nothing that you have said that whether strange or strange, that's the universe we live in no, you don't get two, you don't get two, there's a lot of people, no, he, no, he, he's checking that I let him go with the universe, he has no obligation to make sense to you, yes.

Yeah, uh, how about upstairs? Is there anyone up there? I can't, well, you're not up there, but I will. Mr. Cap will ask you. Yeah, he's fine, well, in a second, he'll just scream next time. He green cap first. Yes I believe. you have a green cap a foldable cap whatever first i want to thank you for being so kind to humanity for making this so simple for everyone and i think i speak for everyone we want to say thank you oh wow thank you I don't think simple is the word is just uh, It's clear that maybe it's the word um that my question relates to.

I saw your interview on CBS related to God and wanted to know your opinion. There's been a lot of talk about people having near-death experiences and there have been experiments related to that and people come and you know they have experiences that are unexplained since you said the universe doesn't necessarily explain everything so I wanted to know your opinion about how this happens and how people have these experiences. Well, ask. It's, uh, PE, he heard something you talked about about God on CBS television and uh, he's had, he's thinking about near-death experiences and he's wondering if these deep mysteries are interesting to you.

Okay, so, one of the things we know from research and psychology. Aside from practical issues in conducting scientific experiments, is that one of the lowest forms of evidence that can be invoked is eyewitness testimony, which is strange because it is one of the highest forms of evidence in court, which disturbs me greatly. yes C if you come from a laboratory to a scientific conference and say this is true, we say how do you know this because I saw it well, that's really the end of your talk and you just leave and then we say come back when there is a chart recorder or You just have to give me something that doesn't have to flow through your senses because your senses are one of the worst data-gathering devices there is and science hasn't reached maturity.

Modern science did not reach maturity until we had instruments that expanded our senses or replaced them and Galileo it is no accident that we have modern science as I have described it uh experiment verification these tactics these methods and tools began with Galileo and Francis Bacon and Galileo It was around 1600 that was the invention in that period of the microscope and the telescope, so it's no accident that all of this came together at that time, so now we have people who are in the act of dying and come back from life and they report on mental experiences and that's intriguing, it's intriguing, um, but because it's in the realm of eyewitness testimony, maybe you can establish it as a personal truth, but it's going to take more than that to establish it as an objective truth and a Objective truth is the type of truths that science discovers. and it's the kind of truth that is true, whether you believe in it or not, that's okay, it exists outside of your culture, your religion, your political affiliation, personal truths, if I can consider it, that would be okay, Jesus is your savior, that's your personal truth, you can't convince someone.

Otherwise, that Jesus is their savior in an objective way, you have to persuade them, you have to persuade them in some cases, in some cases, through war. Look at the wars that have been fought between religions that couldn't agree on who their respective saviors were. so uh um sure if I walked on water I made you blind, we turned around, created loaves and fishes out of nothing, that would be amazing,reality, then you have to design an experiment that somehow touches your own world, yes, so you can invent something that you can't see if it has testable consequences in ways that you can see, that's perfectly allowed, it's not a problem, ah, and the way there are some people who say "you can't prove a negative" some people like to come after you, you usually won't hear a scientist say it's others like philosophers and people who like to criticize scientists but who They are not scientists like you can't prove it.

We do that all the time, okay, but we don't use the word proof, we prove without further discussion that the negative is true, okay, so here's an example, there's a cave, there's a bear in the cave. I don't know, I'm not going in there to find out, well, I'm going to set up cameras and see if a bear comes out, so I set up the cameras all summer, no bears come in and out, but then, okay, then I take. below the chamber maybe a bear went in there to hibernate, so this is what you do: put dust outside the cave, something that will record a footprint and just monitor this month after month after month after month, do it for 12 months If the period of time you waited is long enough for there to be no footprints, you conclude that there is no bear in that cave that I just demonstrated.

It's a negative enough of a negative that I don't want to ask that question anymore and move on to another problem, but if you're so distracted that it's not formal proof of a negative, then you might as well keep sitting there wondering while the rest of us decode the nature of the universe we have uh for the last bear in the cave well I guess let's see by the way maybe the cave isn't a closed cave it could have a back door it could have a back door yeah okay that's it Possible, I guess it's possible. so the assumption that there is no bear in the cave would be incorrect, but I or the cave could have a cave and that cave could have another cave.

You see, there's a lot to worry about, so you'll sit there. sit there um uh arrest Ed for your own ability to doubt an experimental reality yeah while like I said the rest of us go and keep making discoveries well we might need we have time for one more question and that person at the end under the exit sign with her hand raised prominently, not the one waving it, but the woman in the yellow shirt who still has her hand up and wonders if I'm looking at her, looking back and forth. Well, it's not a yellow shirt, it's not a yellow shirt, that's it, it's a horizontal striped shirt, oh, okay, really, oh oh, say it again, look, this was an art major or something.

I'm right, I guess so, if you had one last question to answer tonight. What would that question be? So you, you, you misunderstand me, um, oh, that wasn't your question, what can I at least answer? No, okay, go, oh, if you're in your career as a scientist, if there's a question you want to address. Before you go to the big cave with the bear or wait forever for the bear to come out and stay there, what would that science question be or did you like your previous question better? uh, yeah, okay, so I'm GNA, I give an answer, but then I want his permission to give him some sort of cop-out answer.

I'll give you a full answer and then a evasion answer. My full answer is: I wonder if, in fact, human intellect is sufficient to decode all the operations of this universe. in which we live, oh, and it is not specifically an astrophysical question, in fact, we are in an intelligent species because we define ourselves that way, we do not have the benefit of another species with which to compare ourselves, with which we could fail miserably and, Therefore, when we compare ourselves to chimpanzees, we sit up straight and say we have poetry and a Hubble telescope and philosophy and simply clipping Stacks ban Stacks boxes to reach a banana, but there is only a 1% difference in our DNA , but then you will say what a difference. 1% does and I would say that maybe that 1% difference in DNA corresponds to an equally small difference in intelligence between a chimpanzee and humans and you say: I can't believe that, no, no, well, imagine some other species that visits us, that is 1%.

On that same scale, the smartest of us consider the smartest chimpanzee to do what our little kids can do and there's no way you're going to explain to a chimpanzee I'll have dinner ready at 6:30, you'll pick up some juice on the way home that the The simplest human thoughts are inconceivable to a chimpanzee and his talents have to do with what our young children can do, so let's return to this 1% more intelligent alien that we have discovered corresponding to this analogy. Now we say how we would look to them. Well, they would roll. Steven Hawking advances after analyzing the human species and they would say that this one is a little more intelligent than the rest because he can do astrophysical calculations in his head like little Timmy who just came home from preschool oh Timmy, you just composed three sonnets.

It's not that cute, let's put it on the refrigerator door. Oh, you just derived the fundamental law of calculus. Isn't it so cute? Put it in the refrigerator. The simplest thoughts of him would transcend our deepest thoughts and perhaps to them it is obvious. Dark matter and dark energy perhaps for them particles appearing and disappearing are a trivial exercise in their understanding of the multidimensional space-time continuum and here we are feeling the sides of a wall without knowing how high, wide or deep it is. . because we have the limits of human physiology that evolved on the plains of Africa just to try to understand the entire universe, so I lose sleep over that question every night, so that's my wait, but did you almost say at the beginning of that answer are you? wondering, well, maybe something of a mystery, me, you, you, you, you're not sure, I'm not sure the world is like this, the universe is so complicated that it may be more complicated than we can imagine, No, that's the arrogant way of saying it.

That's not how I said it, okay, how did you say it again? We may not be smart enough. Okay, arrogant, if you're arrogant, you'd say we're smart, but the universe is really complicated. That's not what I said. I said maybe we're not. smart enough to discover a universe that might be trivial to the brain of a more intelligent species, okay, so leave your arrogance at the door, otherwise you won't be able to enjoy the cosmic perspective that much of this brings us. discussion. Now I give you my complete answer. My full answer is: I often think about the questions we don't know how to ask yet because the discoveries are yet to come, but when they arrive they will place us in a New View, a new place to be that will allow us to see questions not imagined before we got there. , so when I lie awake at night I again reflect on what kind of questions are beyond our reach because the questions that we even know how to ask are there and are not even interesting to me anymore. because we knew how to ask the question I want to know the question that is out of everyone's reach and by definition I can't because we haven't gotten there yet but that doesn't mean I shouldn't dream about that Frontier and and That sounded very strange to me.

I must say that I could hear the orchestra playing. Can I offer you a better Koda? Yes, and then we will let you go, but this, we took a long time, I'm sorry, it took a long time, try to never forget that the story of this exercise this beautiful exercise where we discover where we fit into this great development of cosmic events and phenomena that the bigger the larger area of ​​knowledge grows that area grows just remember that our perimeter of ignorance also grows it may be that as much as we think we know as much as we know, we know as much as the more things we finally learn for everything we know, we could be immersed in the center of infinite ignorance that then provides job security forever for scientists, right?

Robert CLT Neil Tyson