Neil deGrasse Tyson talks about Death By Black Hole And Other Cosmic Quandaries
Ever wondered what would happen to your body should you accidentally fall into a black hole? The man who first suggested Pluto was not a planet - setting off scientific soul-searching about our solar system - now leads an exciting journey through the extremes of the universe, from the excruciatingly hot, to the unbearably cold, to the ultra-gravitational.
Neil deGrasse Tyson
Neil deGrasse Tyson was born and raised in New York City where he was educated in the public schools clear through his graduation from the Bronx High School of Science. Tyson went on to earn his BA in Physics from Harvard and his PhD in Astrophysics from Columbia.
Tyson's professional research interests are broad, but include star formation, exploding stars, dwarf galaxies, and the structure of our Milky Way. Tyson obtains his data from the Hubble Space Telescope, as well as from telescopes in California, New Mexico, Arizona, and in the Andes Mountains of Chile.
In 2001, Tyson was appointed by President Bush to serve on a 12-member commission that studied the Future of the US Aerospace Industry. The final report was published in 2002 and contained recommendations (for Congress and for the major agencies of the government) that would promote a thriving future of transportation, space exploration, and national security.
In 2004, Tyson was once again appointed by President Bush to serve on a 9-member commission on the Implementation of the United States Space Exploration Policy, dubbed the "Moon, Mars, and Beyond" commission. This group navigated a path by which the new space vision can become a successful part of the American agenda. And in 2006, the head of NASA appointed Tyson to serve on its prestigious Advisory Committee, which will help guide NASA through its perennial need to fit its ambitious vision into its restricted budget.
In addition to dozens of professional publications, Dr. Tyson has written, and continues to write for the public.
Cosmic body with gravity (seegravitation) so intense that nothing, not even light, can escape. It is suspected to form in the death and collapse of a star that has retained at least three times the Sun's mass. Stars with less mass evolve into white dwarf stars or neutron stars. Details of a black hole's structure are calculated from Albert Einstein's general theory of relativity: a singularity of zero volume and infinite density pulls in all matter and energy that comes within an event horizon, defined by the Schwarzschild radius, around it. Black holes cannot be observed directly because they are small and emit no light. However, their enormous gravitational fields affect nearby matter, which is drawn in and emits X rays as it collides at high speed outside the event horizon. Some black holes may have nonstellar origins. Astronomers speculate that supermassive black holes at the centres of quasars and many galaxies are the source of energetic activity that is observed. Stephen W. Hawking theorized the creation of numerous tiny black holes, possibly no more massive than an asteroid, during the big bang. These primordial mini black holes lose mass over time and disappear as a result of Hawking radiation. Although black holes remain theoretical, the case for their existence is supported by many observations of phenomena that match their predicted effects.
10:45 Being English, I remember the visible spectrum like this: Richard Of York Gave Battle In Vain.
If we didn't have Indigo, we'd need a different mnemonic aid
Another one, for mixing the three primary colours (RGB): Right Colour Gets Me BY.
How did the ‘single point ‘ create if the matter
can escape from any strong gravitational force?"
Answer: The cosmological solutions of Einstein's equations are different from the Black Hole solution. A black hole is a static solution which does not change in time. In a non-feeding black hole spacetime has come to "rest". The black hole metric decays (pretty much) exponentially to the static solution and is then (classically, at least) the same until disturbed. In contrast, the cosmological solution is dynamic. It either expands forever or first expands for a finite amount of time and then collapses back to the infinite density (again, only classically) that it came from.
If you want a classical analogy, the black hole is like a stone at rest on the ground. Once at rest, without external force, it will never move. In comparison, the cosmological solution is like a cannonball. It, too, was once on the ground, but then it was given a finite amount of kinetic energy by the exploding black powder in the cannon and is now following a parabolic (or, as in case of our cosmos) hyperbolic ballistic trajectory.
So the only real question is where did the cosmos acquire its initial energy that makes the cosmological solution qualitatively different from the black hole solution? The answer can not be found in Einstein's theory. It has to be looked for in quantum mechanics, which says that space and time can not be restricted to the infinitely small because that restriction alone causes the energy to diverge. Therefor, an initially small cosmos must have had some finite self-energy, which sets the rest of the machinery in motion. I believe the observed energy in the universe points to an initial size that is on the order few tenth's of an inch or so (that's speculative, anyway, because we need to understand quantum gravity before we can attempt to actually calculate a realistic, meaningful number).
Now, if you want to speculate in religious terms about it, I would suggest something like this:
"In the beginning God held the universe between his thumb and index finger. And the universe was very small and very hot and very dense. And God saw that it was good. And God smiled (Why wouldn't he? Isn't crating a universe a happy occasion?). And he let the universe go. And the universe inflated greatly. And God saw that it was almost homogeneous, with faint ripples that echoed his fingerprints. And God saw matter forming from the brightness that illuminated the universe and for a moment it went opaque. And then the hot matter condensed and became translucent again. Where his fingerprints had created ripples in the radiation, the now cooling matter began to form wispy strings of primordial galaxies and the stars lit up the universe, once more. This time the light would last for a trillion years and illuminate the days of countless inhabitants of his new creation. And God kept smiling."
Black hole and Big bang.
A black hole is a theoretical region of space in which the
gravitational field is so powerful that nothing can escape.
Hawking Radiation theorizes that black holes do not,
in fact, absorb all matter absolutely; they give off some
Once upon a time, 20 billions of years ago, all matter
(all elementary particles and all quarks and their
girlfriends- antiparticles and antiquarks, all kinds of
waves: electromagnetic, gravitational, muons…
gluons field ….. etc.) – was assembled in a ‘single point ‘
The reason of this unity is gravitational force.
How did the ‘single point ‘ create if the matter
can escape from any strong gravitational force?
Israel Sadovnik. Socratus.
@ JEAN D:
We better not label Ceres as the 5th planet. That would piss Jupiter off... and I do not think we should upset it. After all, see what it did to poor Europa (as a side note, life on Europa being called Europeans... ha ha ha, funny! Europeans always seemed a little 'otherworldly' to me)
I think what makes Neil deGrasse Tyson so entertaining to watch is not just his ability to explain technical topics in layman's terms, but also in his animated and rather comedic style in which presents them. If he wasn't an astro-physicist, he would probably do well as a comedian or comedic actor. An informative and quite entertaining video clip worth watching!
Good afternoon everyone and welcome again to the Commonwealth Club located in SanFrancisco. It's my pleasure today to be your moderator for today's event featuring Dr.Neil deGrasse Tyson, a name well known to anyone who enjoys reading about ouruniverse and thinking about questions about from when it's came and where is it going?Dr. Tyson's education actually relates to a physics degree from Harvard and a PhD inastrophysics from Columbia. His professional research in cosmology and astrophysicsincluding very broad subjects including star formation, exploring stars, dwarf galaxiesand the structure of the Milky Way. In 2001 Dr. Tyson was appointed to a 12 membercommission to study the future of the US aerospace industry in which he published a finalreport in 2002.Again in 2004 Dr. Tyson was again appointed to serve on a 9 member commission on theimplementation of the United States Space Exploration policy. Following upon that Dr.Tyson was appointed by NASA to help them deal with the very difficult question of howthe ambitious programs of NASA can be reconciled with a very restricted budget for theirgoal and mission.We are, of course, blessed not only with his technical expertise as it informs the scientificcommunity but he is a very important member of that community of scientists who helpinform the public to a greater understanding of scientific issues, a topic which is more andmore important as we as a public are decided to have opinions about and vote for peopleto represent us who might have a lay understanding and hopefully even an enlightenedunderstanding of the critical scientific issues facing us today. In this regard Dr. Tyson haspublished 7 books, that are directed towards people like us and is the host of course of theNova ScienceNow program with which you may be very familiar with him. I would liketo, at this moment, introduce Dr. Tyson and please give him a rousing welcome.Thank you for that warm welcome. It's good to back in this visit to San Francisco. I amtold the Sun was out a couple of days ago, is that right? The rain is plants need rainmore than we do. Thanks for coming out for this. I am just here to just kind of talk aboutthe universe, but through the lens I am restricted to the universe in my subject matterin Death by Black Hole, at first I couldn't resist that title. There is a chapter in here withthat title and that chapter bares that title because it's a complete discussion of how youdie when you fall into a black hole. And when I think of black holes I think of sort of theadult counterpart to what as a kid would be T-rex, because every kid loves T-rex but whydo they love T-rex, it's because T-rex can eat the kid.All right, and you tend to have a deep respect for things that can eat you. So black holes,when you come too close to them weird things happen to your body. And I will get backto that in just a few minutes. I am not going to read from the book because you can justget the book and read the book yourself. So presumably you came to hear me saysomething differently enlightening or even relatedly enlightening to what's in the book.And so what I am going to do is and look the book is organized into sections withmultiple chapters within. I am going to like pick one of the chapters within each sectionthat happen to be one of my favorites. And then I will just kind of give you somesummary points of those chapters.Okay and then so this will be a sampling of the science that titillates me, but also thiscollection is the science that has been most requested by the public. Even if I didn't thinkit was interesting the public thought it was interesting. I thought well let me find out whyand part of it was this black hole thing. Everybody wants to know about black holes. If Iam on the plane and someone sees I am reading some astrophysics literature so what doyou do? I do astrophysics. First question, tell me about black holes? Then may be searchfor life and Big Bang and I am trying to think well, suppose I said I was like you know,nuclear chemist or particle physicists. That would just end the conversation right there butthey find I I have studied the universe and it becomes this very engaged conversation.So, this is appetite for cosmic content that, for which I see myself as a servant of publicinterest, and so the material that's in here is the blending of aspects of Universe that Iwant to bring you to. And aspects of the Universe for which I know the public has a deepcuriosity to learn more about and so that's how that goes. And let me lead off by thewith the following datum. There is about 6500 astrophysicists in the world. It's not verymany actually, just you know, a few thousands and there is about six and a half billionpeople in the world.So if you divide those 2 numbers you get one in a million. So no, no what I mean, thepoint of that exercise the point of that exercise is if you ever find yourself in thecompany of an astrophysicist that's your chance to ask the question, because you neverknow when that's going to happen again. That's that's just advice. Okay and I thinkthat's why like I said I am on the airplane that the people just bust out with questions.Like they have got some question center within them and its building up and then they areready to explode and the whole of the rest - so, it's just so you know.Okay, here we go. What I try to do here is connect the reader to the Universe in a way thatallows you to become a participant in the machinery of the cosmos. So I would like tothink of this book as your way to go around the back door and lift the hatch and see thegears turning and the oil box and the pulleys and the levers and all the things that allowyou to understand not simply what's in the universe but how the Universe works. And inthat way you are empowered to have fresh thoughts about what's going on rather than justrepeat the factual information you would otherwise get. That's the goal of this book.Okay and I invite to sharing that goal if, in fact, you value that level of intellectualdiversions in what is otherwise your work day. So I have got a chapter called Coming ToOur Senses and I am told I have like half an hour or something, right? Is that about halfhour? Happy to do that. All I want, okay. I will give you a late pass when you go back towork, okay if you need Coming To Our Senses there is a whole chapter called ComingTo Our Senses and what that is, you know we have got five senses, right? The touch,taste, smell touch, taste, sight, hearing. Thank you. Thank you. That's it five senses.Then occasionally you get the person who comes up to you and says I have a sixth sense, okay.These are people who claim to know stuff that they wouldn't other wise know, typically.It turns out if you take those people and put them in the laboratory the sixth sense justsimply goes away, under controlled circumstances. So either the sixth sense is the shything that doesn't lend itself to to investigation or it just doesn't exist at all and we haveduped ourselves into believing you had this power.But what I want to share with you is the fact that modern science, beginning beginning20th century began to invent apparatus that would measure things that are completelyoutside of your five senses. No capacity to measure it whatsoever. So that in fact modernscience has multiple senses, dozens of senses. So you want to ask what you have a sixthsense. Here is some things that you can't measure, for example, the magnetic field in thisroom. The human body has no capacity to measure the strength of the magnetic field. Thehuman body has no strength to measure whether we are being bombarded by ionizingradiation. You would eventually figure that out as your limbs fell off, you know as youyou come to learn that this was the case but while it was happening you would have noidea. We don't have radiation, high energy radiation detectors built into our system. Wehave got detectors that can do it, so if there is something that admitting ionizing radiationanywhere around, we would be able to find it. I call that a sense, another kind of sense.Now not only can we go outside of our five senses, we can vastly improve the five senseswe have. And so what science is about of course, is advancing our capacity to intersectwith the cosmos. That's what science is. So that's what a microscope does. You seesmaller things that you never know. The telescope sees farther away. Particle acceleratorall of this are simply ways to enhance and extend and invent beyond our five senses. Thesimplest ones among these are you know, this visible light, ROYGBIV right. You know,ROYGBIV remember him, red, orange, yellow, green, blue, indigo, violet.There is really only six colors there but Isaac Newton who first labeled these, he had afascination with the number seven and he came up with six colors, I got to put in aseventh one, so he slipped in Indigo there, didn't belong there at all. But he slipped it in,if you are going to put in Indigo you might have like, put in seven other colors, have 14colors in the spectrum. If you are going to be that specific, Indigo is a narrow segmentbetween the blue and the violet. It doesn't - that scheme deserve it's own color name.Unless you are going to have way more than seven to label. But that's neither here, northere. So - so those are the colors.We define that as visible light, but light goes far beyond each side of that spectrum. Yougo beyond violet you get ultra violet, you go the other side of red you get infra red andyou keep going in each direction so, violet - ultraviolet, x-rays - gamma rays, red -infrared, micro waves - radio waves. All this is light, it all travels at the speed of light andwe had no telescopes capable of observing outside of the visible spectrum until 1920 andthat was a very crude telescope itself and we didn't start really getting data on this untilthe 1950s and 60s.So we were practically blind to the universe. Before 50 years ago, thinking that our eyeswere somehow the true measure of what's out there. So all of our detectors and telescopeswere extensions of our eyes and not probes into whole other branches of what we call theelectromagnetic spectrum. And so your senses are really these, you know, they are goodfor you know, getting around the house but they are not good for decoding the Universe.And here is how they get in the way.There is something called common sense, right what is common sense. Common sense, isif I let go of this gavel it will drop. So let's try that. Okay, it dropped, now so, soimportant is that fact to our senses that when you tell me to drop it, that's an instructionfor me to let go of it. What you really should be telling me to do is let go, that's yourinstructions to me, then it drops. Okay.Suppose we lived in a world where 30 percent of the time I let go this would float up toceiling. Then you wouldn't say just drop it, you just say let go and 30 percent of the timeit would go up. Now this would - it would sound like you are making this up to be funnybut no, there are parts of the universe for which the laws of physics, as we experiencethem, no longer apply. One of them for example, is the branch of physics called quantummechanics where matter behaves in ways that defy common sense. Particles exist here,disappear out of existence and pop into existence over here without any visible means ofgetting from here to there.A particle sits there minds it's own business and then transforms into another particle of awhole, completely different identity, a split second later. This is matter behaving, notbadly, matter behaving normally under those conditions. So if I am here and I and thiscup of water disappears and shows up over here, we would say that doesn't make sense.But if that's all you had known as a particle you say, hey, that makes sense. So, what youthink makes sense has nothing to do with reality, it just has to do with your lifeexperience. And your life experience may only be a small smidgeon of reality. Possiblyeven a distorted account of reality at that.So, what this means is beginning in the 20th century as our means of decoding naturebecame more and more and more powerful we started realizing, our common sense is nolonger a tool to pass judgment on whether or not a scientific theory is correct. And thuswas born quantum mechanics, relativity, curved space, expanding Universe. So when Itell you that the entire Universe, it's been around and expanding for 14 billion years. Yougo back 14 billion years ago the entire universe fit on the head of a pin, you are going tosay that doesn't make sense. And I am going to say I don't care that it doesn't makessense, the Universe doesn't care that it makes sense to you.That's not its that's not its goal in life, to make sense to you. It issues forth from awhole other investigation of the behavior of matter of the large. Einstein's general theoryof relativity, and then its the shot gun wedding of the general theory of relativity, thetheory of the large, with quantum mechanics. This is the physics of the small. The earlyUniverse the large was small and there is general relativity and quantum mechanicsintersected in a shot gun marriage. They are not otherwise compatible descriptions of theuniverse. This works there and this works there, now they got to work together.We have no understanding of how they work together we got top people working on it.They call string theorists, okay and they are still not there yet. They are still not therethey are working on it. Every time I ask they would say, oh we are couple of years away.They have been saying that for 20 years, I have been asking them since the early 80s butthis is the only game in town and they are very inexpensive to support. You give them apencil, you say, here you go and some paper and we will throw in a computer, then they are done, okay.So, I am okay with that. They are not going to bankrupt the science budget. And so in theexposition of Coming To Your Senses, its basically a celebration of what it is to have fivesenses but then the reality check on the fact that our senses are not only feeble, they areinadequate to properly decode all that's going on in the natural universe. And so aprevailing theme here is an attempt to give a reality check to the urge that we have, theurge understandable but inexcusable urge that we have to think more highly ofourselves than we actually deserve.This is a theme that's repeated through the history of human assessment of our place inthe universe. And in a little bit, in a little ways it continues that way today. But I someof some are sort of have enough foresight and hindsight to say I am not going to makethat mistake again. But here we are in earth and earth is special because its earth and restof that's just the sky and then we find we are one of the planets and then, oh ours truly,our Sun is special. No that's one of a 100 billion other suns in our galaxy. Well, theMilky Way, yeah that's the universe that's no Milky Way is one among the 100billion galaxies in the universe.Well for in the galaxy we have to be in the center of the galaxy. No we are outsomewhere in nowheresville. Okay, leading completely undistinguished existence in anundistinguished quadrant of an undistinguished galaxy. Get over it, okay. Find some otherways to measure your importance in life, don't reference the Universe. Why not helpsomeone? That'll measure your importance. Okay that's how to be important, helpsomebody else. Lead a better life. And so that's a running theme by the way. I justyou know I say that, yeah but every one of these chapter has some reference to it.And so let me move on and pluck another one from the how much time have I madeup all the time just talking about that. Yeah, I got a chapter called the planet,Vagabonds of the Solar System. That ones fun. I am not going to dwell on that, too much because inthere we are talk about Pluto. Pluto, you know has been on hard times, Pluto. And I amand its interesting because my I had a little something to do with that. In the year 2000our exhibits at the American Museum of Natural History, I and two colleagues of minewere co-writers of all the exhibits.We decided, upon noticing, that Pluto there are other objects orbiting the sun aboutwhere Pluto orbits. About the same size of Pluto, made of the same stuff as Pluto, samecockamamy orbits like Pluto has and so we said well, lets organize exhibits of Pluto withthe rest of these other newly discovered brethren in the Solar system. And then the giantthe gas giant planets, that put those together, they have more in common with each otherthan anyone has with any other object. The rocky smaller planets, I mean Mercury,Venus, Earth and Mars they had more in common with each other than any one of themhas with anything else. So we presented the Solar system as a collection of families.Well, page one story of the New York Times, Pluto not a planet, only in New York. Myphone was ringing off the hook, I was getting hate mails from 3rd graders and I said "Manpeople feel strongly about Pluto" and most of the Pluto lovers out there are there anyamong you in the audience? Pluto lovers, raise your hands if you are a Pluto we gotPluto lovers in the front row. Now I will bet you 10 to 1 that this will play out exactly as Iknow, okay. Pluto lovers please raise your hand once again, did you know that there are 6moons in the Solar system bigger than Pluto. Moons, he didn't know that Earth Moonamong them, didn't know that. That's because the Pluto lovers have elevated Pluto to agreater significance that it actually is. It has grown in your mind and in your soul,but not in the Universe.Okay, so Pluto, did you know, not meaning to be dissing you in the front row here but Ihad to get this, did you know, Sir, did you know that Pluto is more than half ice byvolume. Which means if you brought Pluto in, it if you put no you don't have to bring ittoo close, just bring it to like where earth is, the heat from the Sun would evaporate theice, turn it into gas and it would make this long plume of a tail. Now now what kind ofbehavior is that for a planet? We have words for things with tails. We call them Comets.Comets cross the orbits of other planets, so does Pluto. Pluto crosses Neptune's orbit.We just added all up. There is there is no way out of this you just just let and Ithink the reason why Americans liked it so much is because we have this otherassociation with Pluto, Pluto the Dog. Europeans don't care. I spoke to Europeans, theysaid, Oh we don't care whether its planet or not. Who cares! Because they don't have thisdog legacy. This this baggage. You know who Pluto is, the creature. Anyone doesn'tknow that Pluto is Mickey's dog.Now I don't know about you but that's disturbed me for a long time. Some thing's notright in the mammalian kingdom. If Pluto is Mickey's dog and Mickey is not Pluto'smouse, there is some wrong there. A mouse owning a dog, dogs eat mice, okay. So I wantto understand how is it that a mouse can own a dog? Then I learnt that actually I calledup Disney and apparently, this is important stuff you got to know. So apparently if youdon't wear clothes you can be owned by another creature who does. That's how you canhave animals owning animals, okay.So Pluto runs around butt naked and Mickey Mouse wears that bow-tie and so that's howyou get the social order of the characters. Well, meanwhile it turns out that Pluto, the dog,was first sketched the same year that Pluto the object was discovered. So it had bothhad the same tenure in the hearts and minds of the American public. And Pluto, theobject, was discovered by an American. So this this sort of importance of stuffAmericans do, getting into the thought equation about how you evaluate who and whatPluto is or should be.So, anyhow, there is a little bit of that in the vagabonds of this. Right now, it was much,we file this wide, that this month I am depositing a manuscript to my publisher calledthe Pluto Files. This is an exposition of all the hate mail and all the correspondence that Ihave had with people who are just pissed off about what we did with their favorite planet.I had to get that off my chest so I got that how am I doing on time? I mean I got somuch I want to do. The Universe is a big it's like here you got 30 minutes, give themthe whole Universe. It's like how am I going to do that.So I told them about the Asteroid that's coming. No, no, I know, if there is enough timewe will tell them about the Asteroid that's going to hit. Okay, good. If I forget, remind methen about the killer Asteroid. That's due to come on Friday the 13th in April of 2029.But, this only if I forget. Just remind me about that. It's headed for the Pacific Ocean bythe way. But look - I will fill in if we can, - that's just the test, I am going to wait till thevery end and see how badly you have to get back to work, all right. It will be, it will bethere is a chapter, excuse me, I am recovering from a chest cold.There is a chapter here called Goldilocks and the Three Planets. And this is simple, theidea is simple but the consequences are profound. If you want to look for life in theuniverse, beyond earth, how do you go about it? We have to kind of define life, but youonly have an example of one. Biologists celebrate the diversity of life, but behind closeddoors they lament the fact that they only have a sample of one, because all life on earthhas common DNA lineage. And so in fact there is no bio-diversity on earth comparedwith what the biology would be to a completely alien creature. Then you are talkingdiversity. Okay. So so that's just it's that.So, now one of the things that we are pretty sure life, as we know it, requires is liquidwater, carries nutrients around, its very common ingredient in the Universe, hydrogen andoxygen. So where would you have to put a planet so that it could sustain liquid water andits orbiting around a star. You don't want to be too close because the water wouldevaporate. You don't want to be too far away, the water freezes. So it's got to be justright. So that's why it's like the Goldilocks thing. Okay, you remember Goldilocks. Thatstory disturbed me too.If I were the bear I would just eat Goldilocks you know. Sleeping in your bed, eating yourfood, you just maul her, all right, but but that's not the story that they wrote. But surelythat's what would have happened in that under those conditions. So any way, so sothere is Goldilocks. We have a zone around every star for which these conditions hold.We call it the habitable zone. Too many syllables I know, forgive us for it, but wecouldn't figure out what else to call it. Some call it the green zone,but, you know, they are habitable zone.For our Solar system Earth is in the habitable zone, its right there. Of course, its there, wehave to liquid water on our surface. But how about if you go a little to the left, go a littlecloser to the sun, you get what's generally referred to as our sister planet. It's about thesame size, about the same density, same mass, it's the planet Venus, little closer to theSun. What's the temperature on Venus? What's its atmosphere made of? It's got a carbondioxide atmosphere 100 times the density of Earth's atmosphere and it has a roaringgreen house effect, a runaway, it is so hot on Venus it is 900F. I did the calculation, youcould take 16 inch Pizza, put it out on the window sill, it will cook in 9 seconds. Now ofcourse you would have vaporized along with it, so its its not an it's a thoughtexperiment. Its not we are not inviting you to try that.Something bad happened on Venus, something bad happened there to its climate. Someknob got turned. Lets let's look a little to the right. The next planet out from the SolarSystem from us. That would be Mars, Mars has evidence of once having running water onits surface, there are river beds that meander, all the visual cues that you see when you flyacross country on the airplane and you looked down you see the Mississippi Delta, yousee if there is flood, you see the the plane, all of these features are there. Yet there is nota single drop of water left. Something bad happened on Mars too, something changed there.I want to know what that was, because today we are turning knobs on Earth, big knobs,Carbon dioxide knobs, environmental knobs. It is all Earth will be fine - I don't knowthat. I got a neighbor to the left, a neighbor to the right. Mars is bone dry, 200 degreesbelow zero. Venus is 900 degrees. I want to understand what can go wrong in the cosmos.So that we can avoid that for Earth. And so Goldilocks and the three planets is anassessment of where conditions would give you liquid water and what would then driveyour capacity to search for life and that for me is one of the most fascinating of themodern frontiers of cosmic discovery.And briefly we have learnt that you don't have to be in the habitable zone to have liquidwater. One of Jupiter's moon, Europa is actually kept warm by gravitational stress fromJupiter itself. It put stress on Europa and if you ever played racquet sports and you hit theball, you literally at the beginning say, lets warm up the ball. You are actually warmingup the ball every time you hit it. You compress it and it it has a recoiled force it bouncesback. But the energy that you pumped into has got to go somewhere. Some of it goes topop the ball back into shape, the rest goes into heat, the intermolecular vibrations of therubber of the ball.And so Jupiter is pumping heat into Europa. Europa's way and Jupiter is way outside thehabitable zone because you calculate the habitable zone based on Sunlight. But out thereyou got a heat source from Jupiter getting pumped into it. It is icy on the surface andliquid ocean beneath it. It has been liquid for billion years. I want to go to Europa to goice fishing, cut through the ice, lower submersible, look around see what's there. Seewhat swims up to the (indiscernible) and licks it, that would be kind of cool. Liquid waterfor billion years, imagine.Life on earth didn't require that much time to form. Life of earth is something you mighthave not have known, it's a recent thing. We all took biology at school, I think,presumably, okay. You took Biology and what did you learn? Well, when did when didthe Earth form? The Earth formed four and a half billion years ago. What's the earliestsign of fossil life? Back then when we took biology it might have been three billion yearsago, maybe 3.2. So then you say life, well, life had one and a half billion years to form onearth, okay. From the primitive chemistries of the early days to the complex chemistry oflife and that's pretty good because then we want another three billion years after that. Butas time went on, we found earlier fossil evidence, not 3.5, 3.7 billion years.As time went on what we found is that the early solar system was a shooting gallery ofleft over debris slamming into earth surface. If you are going to do that, it's not fair tostart the life clock because complex chemistry could not have begun if you are liquidmolten surface. So that's not fair to start the life clock then. Let that period of heavybombardment which is officially called the period of heavy bombardment - it is true. Ihave said this before we tell it like it is in Astrophysics, okay.Spots on the Sun what are they called, sunspots, thank you. Dark areas of space you fallin, you never come out again. Black Hole see, we are into one syllable one syllablelexicon. The origin of the entire universe space time and anything, Big Bang, okay. As abiologist what's the most important molecule deoxyribonucleic acid. 12 syllables or 10syllables later you get the molecule. So where was I, before I interrupted myself? Well,thank you, somebody was paying attention over here on the left aisle, the period of heavy bombardment.Once we could do the computer calculations of how long it would take to vacuum up theremaining debris of the solar system to become the planets, we realized that took upwardsof 600 million years. Earth didn't cool down until 600 million years after it formed. Soyou go from four and a half billion years ago to 3.9, 3.9. Now you start the life clock andwhen is the first sign of fossil evidence, 3.7, 200 million years to form life on Earth,that's nothing in the time of the earth and its least than nothing in the time of theuniverse. So you have complex chemistry enabled by the ingredients of life itself.Hydrogen, oxygen, carbon, nitrogen, other the famous element, other. Those are the topfive ingredients in life on earth.What's the top ingredients in the Universe? Hydrogen, and we have seen that on Earth.Our next one is helium, the helium is not chemically interesting. You can inhale it andyou know it sound like Mickey Mouse, but its it doesn't bind with anything, so it's notuseful to us chemically. Next in universe is Oxygen, that's what it was in the humanbody. Next is Carbon, that's what it was it. Next is Nitrogen, that's what it was with us.Next is other, just like it was with us. So if we if we were made of like some isotope ofBismuth, then you would have an argument to say that we are something rare in thecosmos. But we were made of the most common ingredients with a chemistry based onCarbon which is the most of fertile of all elements on the periodic table. You can makemore molecules out of carbon then you can with all other elements combined.So you got the right ingredients and you have the fertility of the carbon atom. You arethere and give Earth 200 million years you are there, you are there. And so when youwant to think about the search for life elsewhere these are factors that come in. Justbecause you hadn't figure out how to do it yet in the lab, it doesn't mean nature had ahard time doing it, that's the hubris again. Okay. Just because you can or can't dosomething therefore it is impossible that way in the whole universe. We got to be a littlemore humble about our ignorance and get top people working on it. And so I had a pointout of all of that, I forgot what the point was going to be.Europa. Thank you. So here with it, so here we got, lets say we find - you could see,people on the left side of the room are actually paying attention. You guys over here Idon't know what you are doing, okay. Left side of the room, yes. So, Europa, let's sayyou find life. Here is in unresolved question, okay. We have got top people working onthis without a solution yet. If you find life on Jupiter's moon, Europa, do you call itEuropean? You see we don't have an answer to that yet. We don't know what to do aboutthat, okay, I don't know, just okay.By the way these are not just idle thoughts. For example, because you want to like get theanswer before it happens, so you are not caught having to make something up on the fly.If you are from Mars, you are a Martian, right. You are from Earth, you are earthling. Youknow, we have heard it. If you are from Venus, you are Venutian. But it turns out, theastronomers got there too late. We got to Venus too late. And we were we haveregretted it ever since.Okay, Mars is the God of War, remember from Roman mythology. Venus is the Goddessof Love and Beauty. They called that planet Venus before they knew that you wouldinstantly vaporize on Venus's surface. Okay, because it is beautiful in the sky eventhough it's seething gases of carbon dioxide and sulfuric acid, beautiful Venus, anyhow.So we got there too late. We were beaten - we got beat. Why? Because the medicalcommunity started looking around, they got the microscope. They look and say hey, thereis this particular disease that only, class of disease that only shows up as a product of lovemaking. We must name that disease after one who is accountable for this. That would beVenus, won't it. Let us name these diseases venereal diseases. To be a Venus is to bevenereal. And then damn we could - so at that point we can't now call life forms fromVenus, venereals, right.Imagine the space traveler, hi, we are venereals. It's like oops, excuse me. If somebodyelse had shake that hand, you know, so we had to then invent a new thing that is notderivable from the latin and so we just invented Venutian. But it really they should bevenereals, okay. So this is stuff that - I have 30 seconds left here before we go to Q&A.Where - but I am not done yet. I said only after I am done.I notice against the left side of the room asking about the asteroid. They don't even carewhen they die, alright. They don't know over here on the right. I should first describe toyou how you die falling into a black hole, you're ready? Its quick, I get this done like that.You're ready? I got a whole chapter on it but I wouldn't tell you because it's kind ofbecause, you should know this. All right, you are standing up on Earth. Your feet areclose to the center of the earth than your head is. You can calculate that the force ofgravity at your feet is stronger than the force of gravity at your head because the closeryou are to the center of the gravity of an object the stronger its gravity is. It's that simple.Not more complicated than that. But don't blame your light headed on this fact becausethat difference is very small, because your height is small compared with the size of the Earth.But imagine you are falling towards an object where your height becomes significantcompared to the size of the object. Under those conditions the difference in gravitybecomes ever so great, like as you descent to the center of a black hole. So you take a feetfirst dive, you begin to stretch. It will kind of feel good at first, right? We all stretch,wake up in the morning the first thing you do, stretch. And then you realize its notstopping, okay and you begin to stretch more and more and more and you can calculatewhen the force the difference in the force of gravity becomes greater than the molecularbonding forces of human flesh. At that moment your body will snap into two pieces, mostlikely at the base of your spine.Now you will be able to watch this, okay because not because all your vital organs areabove your waist. You have important organs below your waist but they are not vital.Okay so your so you just watch that, you watch your legs toward a descent, then theupper part will feel the same effect as you get closer, so will lower part. So they will thensnap into 2 pieces. Now you are 4 and then 8 and then 16 and then you bifurcate your waydown to the abyss. Now, it gets worse! Not only did you become the stream of particlesyou are getting funneled through the fabric of space, because Einstein's general relativitytells us that gravity curve space. And in the vicinity of a black hole you are funneled down to a point.So you are not only stretched, you are extruded through this structure. Like tooth pastethrough a tube. And we have a word for this, it's called spaghettification. It's a real word,I am telling you and we are good at inventing words about how to kill people. Whenelectricity was discovered and used in the late 1800s 1900s they said, hey you canwould kill somebody with electricity. Let's invent a word for that, Electrocute! Okay sowe are good at inventing death words. Spaghettify. You become Spaghettified and theDeath by Black Hole chapter talks about not only how you will die but how Black Holesdine upon stars and gas clouds that wander too close, as they get flayed of their outer surfaces.And I will leave you with, I guess, you want to know about the Asteroid. Okay I wouldtake two minutes and we go Q&A beginning quarter two, how about that Sir? You arecool with that. He is cool, okay. He is the coolest guy around, he just chilling here. And Igot to give this side of the room a chance to redeem themselves, okay. So December 2004an Asteroid was discovered. By the way Asteroids are discovered all the time. This is nota new thing. Hundreds of asteroids are discovered each year and some years thousandsget logged, brand new asteroids, new to our awareness.This one was discovered, they calculated its orbit and we found out that the orbit wouldcome dangerously close to earth. And the uncertainty in the orbit was such that it's nexttime around it might even hit earth. And if it hit earth at the center point of the uncertainorbits, so in other words you run the computer model and there is a range of orbits itcould have based on your data. When you get better data then that range get narrower andnarrower and narrower. But based on the data available at the time there is a range oforbits within there, there was a tinier range of orbits, where if it threaded that key hole, itwould hit us 7 years after that. Why didn't you read about it when that happened? By theway it would hit if it went through the center of the key hole it would hit the PacificOcean 500 kilometers west of Santa Monica. I will describe the tidal wave it would makein just a moment, the tsunami that would be.Why didn't you hear about it? Because the week it was discovered was the week of theIndonesian Tsunami. And so the odd thing though is that, right, do you know it is not a -it's not to duly grab the headlines, but if this asteroid hits it would create a tsunamibeyond measure. No, we can actually measure it, but beyond anything you would everseen that would make the Indonesian Tsunami look like a the tides just rolling in. Andso we keep monitoring the orbit trying to get attuned and so here are the facts. On Fridaythe 13th of April in the year 2029, this asteroid named Apophis, That's the Egyptian Godof Death and Darkness. We didn't name that one Bambi, okay.It obviously got named after we saw where it was headed. So and I am not ignoring youguys over there, I am just trying to bring them into the conversation over here, the rightside of the room. So Apophis is the size of the Rose Bowl. Imagine the Rose Bowl werelike an egg cup and then you get an egg to fit in it, that's the size of this asteroid. OnApril 13th the year 2029 it will come close enough to Earth to dip below our orbitingcommunication satellites. It will be the biggest closest thing ever to come to Earth in ourrecorded history. Recorded meaning, when we took records of events and things. Now theuncertainty in that orbit includes what, I am saying, is called the keyhole, a narrow regionwithin these uncertainties.If it threads that keyhole it will hit us seven years later once again on April 13th, althoughthis time not a Friday. It would be a Thursday at that time, I am pretty sure I looked it up.Thursday the 13th you know that would create a whole new legend of movies, you know,Thursday the 13th you know. So what you want to do is make sure it doesn't go throughthe keyhole. Now you got some people out there just blow the sucker out of the sky, youknow. These are the men who wield nukes, because they, you know, they can justify yournuclear arsenal. But that's that's not a good idea, because you blow the thing tosmithereens, now all the smithereens are headed towards you. And what would have hit itone spot now takes out half the world. So plus you don't know where it's going to go.Bombs are uncontrolled releases of energy, that's why they are bombs, okay. So you wantto be able to control what this thing does and one of the one of the things to do is todeflect it from harms way. So we have got top people working on deflection scenarios.When you deflect it, you have got to be careful, because it is still there and you got tolook over your back next time its around, you got to keep looking at it, okay. You havegot the power to deflect, you now have the power do not greet the same fate that thedinosaurs did 65 million years ago when an asteroid came and took them out leavingthem extinct, because I don't want to be the laughing stock of the galaxy when they findout that a species that had a space program and the intelligence to stop an asteroid impactjust simply went extinct.That'd just be embarrassing. I don't want, you know, its okay for the dinosaurs. They hadthat pea brain and they didn't have opposable thumbs, they were not going to build aspaceship. So it's called Apophis. I would think of it as a coming attraction in a continent near you.Let me just end quickly, it plunges into the Pacific, it will go by three miles down beforeit then explodes. Cavitating the Pacific in a three-mile wide hole. So you now have a holethree miles wide and three miles deep. Water does not like having holes in it. So the actof having made the hole sent the pulse of water to the shores all around. Then the waterfills in the hole with such ferocity that the water rises back up high into the atmosphere,falls back down, cavitates another hole. There goes another pulse and this will continuefor dozens of times. It will go to the shoreline, the wave will go to the whole entire North,North American Coastline and the wave will go in maybe about a quarter of a mile. Thenit will get pulled back out to get ready for the next wave. It's not one of this one waymarching tsunamis like the one in Indonesia. This one goes in and comes out. Now if youhad a home here, the home comes out, gets taken out, but now the wave comes back in, incomes your home again, but it doesn't have the shape that it had before. It's now debrisand so the debris becomes this mulching machine, this sand blasting machine. This thingthat ablates the entire coastline wiping it clean of all traces of civilization.So have a nice day. Thank you for your -