>> Amy Draves: My name's Amy Draves. And I'm here to welcome Mario
Livio to the Microsoft Research Visiting Speakers Series. Mario is
here today to discuss his book, Brilliant Blunders: From Darwin to
Einstein, Colossal Mistakes by Scientists that Changed Understanding of
Life and the Universe. Thankfully science thrives on error since none
of us has mastered perfection. Mistakes are inevitable and are factors
an essential part of pushing the envelope forward in any field.
Mario Livio is an internationally known astrophysicist at the Space
Telescope Science Institute. He is the author of several books
including The Golden Ratio, which won both the Pino Prize and
international Pythagoras Prize as the best popular book on mathematics.
Please join me in giving him a very warm welcome. [applause]
>> Mario Livio: Thank you. It's my first time here. So it's really
exciting, I must say and I'm not surprised by most people watching
online, this being Microsoft. So this is actually just to let you
know, the book came out yesterday. So one day later, and I'm already
here coming all the way from the East Coast. So let's see what this is
all about. So the book is about five giant scientists all very big
luminaries, and each one of them I've chosen one major blunder that
they have made.
And there is a thread that goes through all of these five and that's
the thread of evolution. Evolution of life. Evolution of the earth
itself, evolution of stars and evolution of the universe as a whole.
So let me start -- now in the presentation here I've only chosen three
and I may even cut it a little bit shorter because I want to finish in
about half an hour and leave some room for questions and so on.
But I have about three here. So let's start with what we know about
life on earth. And the first thing we notice about life on earth is
its diversity. I mean, wherever you look, there is something there.
You know, you go out here. There are plants, there are birds, there
are dogs, there are people, there are this, and plus you take a
teaspoon of dirt, there can be thousands of species inside that alone
and so on. Nobody even actually knows how many species there are on
earth.
The latest estimate is at 8.7 million. But estimates range all the way
from 5 million to 100 million species. So lots of species here of life
on earth. The second thing that we notice about life on earth, which
is remarkable, is adaptation in symbiosis. So adaptation, you know, it
so happens that you know the body of the bee has the size that it
exactly can get into the flower from which it feeds but at the same
time the pollen, you know, gets stuck to the body of the bee and then
it propagates the other plants and so on and so forth. So all of these
things have led people to think that there must be some grand design
behind all of this.
And the example I gave here is this clown fish that lives among the
poisonous tentacles of the sea anemone and live in the perfect Sim bee
owe sis in the sense that the fish protects the anemone and the anemone
protects the fish and the boiled of the fish is covered with this mucus
which protects it against the poison of its own host and all that.
So over the years people say, oh, there must be something really,
really very designful behind this. And this lasted for centuries, then
came this one person here at this old age, Charles Darwin, and in one
blow changed all of that.
This part is of course about the evolution of life. Now, when I
research books, I tend to go to the places where the people that I'm
discussing lived and so on. So in this case I went to Cambridge where
all of Darwin's stuff is. I actually held in my hand the first copy of
the origin of species and which is that and so he really changed the
whole thing.
And what he did is really remarkable. And it is probably the best
nonmathematical theory ever formulated about something. Now, I put
this here only because the design is so pretty. Because actually this
is not very accurate from a biological perspective. So, for example,
it gives you the impression maybe that humans are more advanced than
tigers or things in terms of evolution, when in fact that's not true.
Evolution really behaves more like a bush than like a tree. It's not
that there is something at the top. It's humans evolved in a certain
direction and elephants involved in another direction and so on and so
forth. But it is true those life species over there are more perhaps
advanced the bacteria from which life originated and so on. But it's a
very nice design.
In any case, the theory that Darwin developed, the theory of
evolution -- why is this not -- Darwin almost never -- well, he never
actually published genealogy trees like this. He didn't publish a
single one. However, in his own personal notes he did sometimes draw
them for himself to guide his thinking and this one which I also saw
directly, see it's an interesting one because he has primates here and
he has man right there at the top. And he drew these for himself but
he never published these such things. Now, his theory was a theory
that relied on four main pillars, and those four main pillars are
supported by one mechanism. And so I took this Hindu mythological
drawing because it shows four pillars on which everything rests and all
of that is standing on supported by one mechanism. And I'm sure you
know this. There is a story that people always tell about Bertrand
Russell which almost certainly never happened. But it is such a good
story that you cannot not tell it, which is that he showed something
like this and then some lady asked him and what does that giant turtle
stand on. He said on another giant turtle and that giant turtle stands
on yet another giant turtle and on that -- he said lady, I'm afraid
from there it's turtles all the way down.
So probably never say that, but the phrase remained. So these are four
pillars, evolution, gradualism and speciation. What do I mean by every
one of them. First there's the concept of evolution itself.
Before Darwin people were saying that species were immutable, that the
way they are now they always were. Species always existed and so on.
Darwin said absolutely not. The species that are now actually did not
exist, there were other species that existed and it became extinct and
from them came other species and from them came other species until we
got what we got today. It's not that what is now was what was always
has been. Second is gradualism. He borrowed this from the geologist.
Geologist basically said we see changes in the earth but there are
extraordinarily slow. In fact, they're so slow that for all practical
purposes we actually don't see a beginning and don't see an end. At
the same rate that things are happening now, they happened before and
they happened before that and they happened before that and so on.
So Darwin borrowed that and said, look, the changes in this evolution
that you're going to see are extremely slow. They take hundreds of
thousands of generations. So don't expect to see one species turning
into another and so on. Then there's common decent. Common decent is
the idea that everything started from a few or even one life form
basically. So it's a bit like a tree where you have one trunk, then
you have these branches and then you have the twigs and so on.
So common decent, everything started from one thing. And finally
there's speciation. Namely he had to address this question of how come
there are so many species today and he said, well, the reason you have
so many is because you have branching. So at every node you basically
doubled the number of species because you get more and more and more.
And this is the only drawing that actually made it into on the origin
of species which is how you get this branching and nodes and, by the
way, notice here he said at the top I think. So he was a very modest
person in terms of -- this is all supported by one mechanism. And what
is that mechanism? It's natural selection, of course. So natural
selection is -- philosopher Daniel Bennett, who I think was in Seattle
two days ago or something, if I'm not mistaken, because I'm speaking at
town hall tonight and I think I saw that he was at town hall two or
three nights ago, said that natural selection, he thought, was the
single best idea that anybody has ever had. And I kind of tend to
agree with that, because it's an amazing idea. And the idea is that
what Darwin said was you have a certain characteristic. If a certain
characteristic give you a little bit of an advantage, and if that
characteristic is also inheritable, then what happens is that over time
this characteristic will see more and more of it and so on. So you
first needed to give it an advantage, but also you had to be able to
transfer it to the offspring and so on.
And here I just put in a few examples. This is a very nice example.
There was this peppered moth in England that in the 19th century, there
were lots of it. And it is light colored like this and so on. But
then in 1848 started the industrial revolution, and they were burning
lots of coal and stuff. So all the trees and things became dark and so
this became the target of massive predation because it lost its
camouflage ability. And they almost became extinct. And instead the
melanic, the dark species of that type of moth actually started
thriving in those conditions. But then what happened is that they
started to adopt somewhat cleaner practices.
And as they adopted greener practices, the light colored moth came back
and did not become extinct. This shows a rat snake and the way it in
different environments it developed different colors and so on and
this. And of course the best example we see are with bacteria, where
it now has become almost a disaster in that there are bacteria now that
are resistant to essentially all antibiotics and there will be more and
more of this. And we have not discovered new antibiotics for at least
15 years or so. So it's going to become a problem.
And of course the reason that we see this same bacteria is that, first
of all, the population is enormous of bacteria. And second that they
might be crazy every 20 minutes and so on they multiply and so what
happens you get the whole of evolution, natural selection compressed.
And you get that. Now, so all of this is great and Darwin did all of
this in a fantastic way, but where is his blunder? So here is the
blunder.
Darwin didn't know any genetics, and that's not surprising because
nobody knew genetics at the time. So we cannot blame him for that. So
the theory of heredity that existed at the time was that characteristic
get mixed like the mixing of paints. And Darwin, because there was
nothing better, he believed that is the case. You take what the mother
gives, what the father give you, mix them like you would mix paint.
So the fact that he took that is not a mistake. That's all he knew.
The mistake is that he didn't realize that if this were truly the
theory of inheritance, then natural selection could never have worked.
And I want to explain this a little bit why it could never work like
this. So let's look for a second. Imagine you have a certain -- I
write this in terms of genes here but of course there's no genes in
blending heredity but imagine that there's a quality that A is black
and big A is black and small A is white. And what happens in blending?
You get one thing from this, one little A from that. You combine them.
They blend like a color. They become gray but they blend. So there is
no really individual A and A. Let's call it A-1 the thing that you
get. So basically what happened is that once you take two of this, you
get something that already the color black has disappeared, actually.
Even after just one or two generations, you don't see black anymore.
Now, in Mendelian heredity, Mendelian heredity says no it's not like
mixing of paints, it's more like mixing two decks of cards where if you
have a jack, the jack retains its identity, no matter how much you
shuffle the decks of the card the jack remains a jack and you will
always, if jack gives you an advantage, then you can find the jack
sometime down the line. Okay? So here is what would happen in
Mendelian inheritance. This thing would come together and they would
do a gray. But this gray would give one black and one white and the
same for that one. And when this combines, when this A will combine
with that A, it will give black. We combine like this they'll give
gray and otherwise it will give white. So you still have a black in
there. So, of course, this is a completely different thing, and Darwin
somehow failed to understand this that no matter how, let's suppose
that black gives you an advantage, well, guess what, in blending
heredity there's no black after two generations there is no black
anymore. Now, once it was pointed out by an engineer named Flemming
Jenkins, Darwin did get the idea that maybe there was something wrong.
And at some point he actually wrote things that, you know, show that he
almost thought the correct way. For example, in 1857, even before the
mistake was pointed out, he said that propagation by true fertilization
will turn out to be some sort of mixing and not fusion. And then in
1866 he noted something that was so, seemingly so trivial but only then
it hit him that every female in the world is producing distinct male
and female offspring and not some mixture hermaphrodite. So it must be
that there's something that is not quite like mixing of paints. So he
got that.
Now some people suggested that maybe he got that from actually reading
Darwin's -- I already explained what is here, from reading Darwin's
paper. Now, basically what is explained here is that if I have a black
cat and a population of a thousand white cats, then in blending
heredity, after a few generations, I'll just get barely a shade of gray
and that will be it. While if you do Mendelian heredity the black
never disappears and if indeed it gives an advantage it could
eventually turn the entire population black. Now, no fewer than four
books suggested that maybe Darwin read at one point Mendel's paper. So
I decided to look into this. And before me somebody named Andres
Fetter looked into that from the Darwin Project. And so basically let
me tell you what the story is. First of all, in Darwin's possession it
didn't have any copy of Mendel's paper. Mendel's paper was published
in an obscure journal and Darwin didn't have it. What is true is that
there was a book in Darwin's possession in which Mendel's work has been
mentioned. And this book was by this gentleman here, Dillon Ormus
Fokey [phonetic], a German biologist and I held that book in my hand
and actually had a picture of that book taken. You know why? Because
do you know where Mendel's work is mentioned in this book? It's in
those uncut pages here, in the book that was in Darwin's possession.
Darwin never read that book. Plus, had he even read that book, it
would have taught him nothing, because this guy, Fokey himself, did not
understand the meaning of Mendel's work.
So Darwin didn't know of Mendel's work. The next person I'm discussing
here, not in the book, in the book I go to Lord Calvin. Here I'm going
to Linus Pauling. Linus Pauling, I'm going to be in Portland tomorrow
and he came from Portland. I gave a talk once in his house in
Portland. Of course, he spent most of his career at Cal Tech, but he
was originally from Portland.
So Linus Pauling was perhaps the greatest chemist ever. Certainly the
greatest chemist of his generation. He's the only person ever to have
gotten two Nobel Prizes by himself without sharing them with anybody.
Well, one was for peace. But he didn't share that one either. So he
got two Nobel Prizes without sharing. And Linus Pauling had first an
incredibly successful model of proteins, that is his model. This is
when he was very young and this is the same man when he was older still
with a same model of proteins. And what did he actually do? Pauling
turned around the whole thing of thinking about structure of molecules
and in particular proteins in this case and so on. What other people
were doing is that they were doing x-ray diffraction experiments of the
molecules. Namely they were shining x-rays on to the molecule seeing
how the x-rays are scattered and using Bragg's Law to try to determine
the structure of the molecule. Pauling decided to go the other way
around. He said I'm going to use structure chemistry, namely I'm going
to use everything I know about chemistry, the sizes of the sub
molecules here and so on. I'm going to try to construct something, and
then test it against the x-ray diffraction images.
So basically 1948, when he was sick at Oxford, he, on a piece of paper,
he started doing these models for certain proteins. And at first he
decided that the carbon atom and the atoms that connect to it have to
be in a single plane. And then he started folding this paper. You can
actually see here the signs of the faults that he started to do. And
eventually came up with a structure that was called the alpha helix,
which is this structure for the main structure of many proteins. And
this was an incredible structure and it explained almost everything
that was seen, except that it had 5.4-angstrom between the rungs here
while the x-ray diffraction thing showed 5.1-angstrom. You might have
thought, well, so what and so on. But he was very disturbed by this.
And he actually set on this model for almost 13 years. And testing
every possible thing, you know. He asked Robert Cory, who was his
assistant to test the structure of the individual building blocks and
everything and so on and after 13 years he convinced himself that his
model must be right and maybe the 5.1-angstrom signature comes from
something else. And he published it and he turned out that he was
correct. And this indeed came from just from the fact that there were
two spirals, one wrapped around the other and so on. So this was a
huge success. But it was almost too big a success in the sense that it
actually was bad for him when he went to try to discuss the structure
of DNA. So already in 1948, long before the structure of DNA was
discovered, he wrote the following. He said that if the structure -see in DNA you need to have something that manages to replicate itself.
You say the best way to have something that replicates itself is if
it's made of two parts that precisely complement one another. If it's
made of two parts that complement one another, if you have half of it,
you can immediately do the other half, because if this one has
something sticking here, the other one has a hole and so on, if you
have the hole you know there's something sticking and so on. So this
is work in '48.
Then there were the Chargoff rules, a chemist Irwin Chargoff who
discovered. See DNA is made of phosphates, sugars and bases, these are
the bases and they come of two kinds. They either have a single ring
or two rings to them. And they're called, they have these names. I'll
call them for short AT C and G. Irwin Chargoff discovered that any
piece of DNA he could take the number of As is equal to the number of
Ts, the number of Cs equal to the number of Gs.
This also sort of hinted at something that two fold type structure.
knew this. [inaudible] knew this. And yet he came up with a crazy
model that had three strands in it and --
He
>>: Failed to predict the structure of DNA. The problem with his
triple helix model is that the phosphates form helical core, with a
basis pointing out wards. This would be impossible under normal
cellular conditions. Each phosphate group is negatively charged. And
so many negative charges forced together would repel each other,
literally driving the structure apart.
>> Mario Livio: So Pauling came with a model that was built literally
inside out, had three strands instead of two, and could not have been
stable because the negative phosphates would have pushed the thing
apart. And he tried to hold it together with hydrogen bonds, but if
hydrogen was supposed to hold the structure together, then this thing
would not have been an acid, because an acid is when you put it in
water it releases hydrogen. That's what an acid is. And this could
not release hydrogen because hydrogen was kept to hold the structure.
So it was something horrible. So one of the things I do in the book
for every one of the scientists, I try to do a little bit of amateur
psychology. Now, this is only amateur psychology because number one
I'm not a psychologist.
Number two, because all these people are dead, and I cannot really
analyze them in any way, but I tried to sort of get into their minds
and see what led them to this thing.
So very quickly I thought, first of all, do you know how long it took
him to publish this model? One month. So why did he rush so much?
How did he forget about his own statement about this complementarity in
the Chargoff rules and so on, what about basic chemistry. This wasn't
an acid, this was the world's greatest chemist, how could he have
missed that.
So very briefly, why did he rush? Not because of Watson And Creek. He
hardly even knew them. He didn't know they were working on this. But
he did fear that Brag or some of the London people actually who he knew
had better x-ray images than he had could come up before him with a
model. Forgetfulness, it's funny, but one of the reasons may have been
that he didn't like Chargoff very much. He met Chargoff -- they were
on a trip together to Europe on a boat, and Chargoff was this very
intense individual who kept nagging. They ran into each other. He
kept nagging him about his rules and things and Pauling just couldn't
run away faster and so on.
So he probably didn't want to remember much about this. What about
chemistry? Almost certainly fell victim to his own success. And what
he learned from the proteins example is that his initial model was
correct. And that once he has the basic model correct, even things he
thinks are problems at the end find the solution.
So he thought that the same will work again here you know he can work
the magic again one more time. Yeah, it wasn't exactly an acid. It
didn't exactly hold together, but the structure kind of looked nice and
so on and so maybe it is so.
That was that and this is why
structure was found by Watson
inside, As connect to T, C to
number, they exactly have the
about and all that.
it didn't work. Of course, the correct
and Krigg, the basis is really in the
G and this is why they're equal in
complementarity that Pauling was talking
So of course once they did this, that
correct model, they went to the Eagle
Eagle Pub. There's this plaque there
Krigg stood up and said we discovered
announced that.
same day when they found the
Club, I took this picture at the
which says this is where Francis
the secret of life in the pub he
So and I showed you how they looked when they were young. So just to
show you also how they looked when they were old. Since then, of
course, Krigg has died. Jim Watson is still alive.
So I think I'll stop here because it's a good place to stop. So I only
did two of my people. But I think you get the flavor of what it is. I
do have a third person here, but since you can get the book you can
read all about this. There are any how three more and so on. I'll
stop here and perhaps take questions. Thank you. [applause].
Any questions?
>>: How did you come up with the idea of the book, what was ->> Mario Livio: Why did I come up with the
there were a number of reasons actually and
were. One was that I think it's comforting
who are in the sciences, to know that match
also made major blunders.
idea for this book. So
I can tell you what they
to all of us, especially
greater scientists than us
So I think it's a good feeling. Even these giants -- the other two, by
the way, so I talked here about two of them. There are Lord Kelvin I
said, Fred Hoyle and Albert Einstein. All of these are giants.
The second reason is that I think that too much more of the general
public, I'm not talking about people who work in research and so on,
got this idea that science is a kind of a success story that goes from
A to B in a straight line.
And that nothing could be further from the truth. That's not how
science progresses. Science really progresses in the zigzag path with
lots of blind alleys and lots of things so on. And blunders I call
them brilliant blunders because, number one, they were made by
brilliant people but also in one way or another these blunders actually
led eventually to breakthroughs.
So sometimes breakthroughs require blunders. There are things I'm sure
you know this, I mean there are things that are inaccessible by
incremental science. You need to think outside the mainstream to
actually really get to a real breakthrough.
And thinking outside the mainstream often encounters blunders. That's
how it works. So that's the other reason that I wanted to do, plus
these are people that I like at some level. And I also chose them, I
said, because they were connected by this revolution.
>>: Have you had any blunders yourself and have you met any of these
contemporary, at least the contemporary people that you write about?
>> Mario Livio: First of all, I made lots of blunders by myself. I
don't know that any of them has been a brilliant blunder. But also I
don't pretend for a second to have worked on problems that are as
fundamental as the people who I describe in the book.
So, yes, I made a good number of blunders, and I also benefited from
some blunders. I'll give you an example, because I'm an
astrophysicist. I'm a theoretical astrophysicist. So I don't do
observations myself.
But when I was just towards the end of my Ph.D., there was a French
astronomer who will remain unknown who looked at -- there are these
things called planetary nebulae, things that happen in the late life of
a star when it ejects outer layers and hot core illuminates everything
and creates these beautiful shapes.
Until then, everybody thought that the central stars of planetary
nebulae are single stars. It's just the core of one star. That person
published six planetary nebulae, I don't mind saying it was a she, that
she observed. And she claimed that they were all closed binary nuclei,
that there were two stars in the middle.
Before that, nobody really claimed that. As it turns out, with the
years that have passed, none of those six objects that she pointed out
turned out to be a closed binary no close. Not one. However because
of her work lots of astronomers started looking more carefully at this
and lots of close binary nuclei were discovered.
And I actually did quite a bit of theoretical work of how you formed
the shapes of planetary nebulae with binary nuclei and so on.
So I benefited from a blunder, but the whole of astronomy benefited
from that blunder. Was there something else you asked?
>>: Have you met any of these?
>> Mario Livio: Have I met? No. I spoke on the phone with Jim
Watson. I have met Fred Hoyle once. But I didn't know him. I spoke
with his son at some length and I spoke with people who worked with him
and post-docs and so on in this.
Einstein is one of them. I clearly have not met Einstein. But my
Einstein number compared to the Erdoesh number who wrote a paper is
two, which is the smallest you can have today because I wrote a paper
with Nathan Rosen from the Einstein [inaudible] Rosen paper. So that's
about as close as you can get to Einstein.
>>: Einstein left when I came in.
>> Mario Livio: Yes. So, no, I've not met them.
course, I could not have met.
But, yes, Darwin, of
>>: Of course.
>>: I have a question from online. Saying lots of these blunders
occurred many years ago. Any recent blunders the last quarter century
that you think as brilliant.
>> Mario Livio: I don't know about brilliant but there have been
certainly blunders and serious blunders even in recent years that at
some level have opened areas. And I can mention some.
For example, the very first announcement of planets around the pulsar
turned out to be wrong. These were the very first extra solar planets
discovered in 1991 that turned out to be wrong. But in the same year
somebody else discovered planets around the pulsar that were real. And
that is now a known class of objects. Many of you I'm sure have heard
very recently actually just a couple of years ago of this announcement
of arsenic-based life that there was, that there were these bacteria
having their DNA arsenic instead of phosphorous.
This turned out to be wrong. But you know the announcement of that and
all the research work that went around proving that this was wrong
actually opened some interesting avenues and it got people thinking
about, I mean, really could you have maybe, arsenic is somewhat similar
to phosphorous in its properties, you know, and so on.
So these were not brilliant blunders in the sense of the blunders in
the book, but because they were in very interesting areas, they did
stimulate other interesting research.
>>: Did Newton blunder ->> Mario Livio: Newton I decided, by the way, consciously decided not
to go as far back as that. I specifically went only far -- because you
see if you go far enough back, then clearly even the greatest geniuses,
I mean Aristotle, almost everything he said in physics is wrong, yes,
yet he was a genius, it's just because he worked at a completely
different time.
So I decided not to go too far back. And I did look into Newton. I
know I didn't want to do him, but I still look at it and Newton was one
of these annoying people who almost makes no mistakes.
Of course, he did one crazy thing in he actually dealt a lot in
alchemy. And so that entire branch of his work was crazy. But in the
more serious work he did in physics, you know you can look a lot and
you will not find any mistakes.
Einstein, by the way, they did many mistakes. I mean, I chose one
blunder to concentrate on. But he did many mistakes. Pauling, some of
you may know that late in life he became he became obsessed with
vitamin C and so on. And Fred Hoyle was one of my people that I talk
about steady state but he had things about life that were very wrong.
So most people make more than one serious blunder and so on.
was very annoying in that respect. Any other questions?
>>: Obscure question I'll try to frame it right.
referenced four elements.
>> Mario Livio:
One of my recent blogs.
Newton
On your blog you
>>: One of your recent blog posts. Reminded me of a book called
Science since Pavlon, old Yale lectures. There was an argument that
western science because it came from four elements and four was
significant where five elementary in the east set them off in a
different way, because you kind of jump around from so many different
fields like Pythagorean theorem, is that something you think about in
terms of four versus five elements.
>> Mario Livio: No, not a lot of time however I will say, I think I
mentioned this in the blog, that even when the ancient Greeks talked
about four elements, they actually did add a fifth. I mean the
quintessence, the fifth element, which Plato and Aristotle actually
talk about which was supposed to kind of more represent the universe as
a whole.
So they also talked about five in some way. I mean, there were the
four basic elements that formed everything kind of we see but then
there was this fifth element which was for Aristotle it was the ether.
And so on.
>> Amy Draves: I know that he's not at the same scale, but what sort
of blunders do you think are going to come from this new science like
mathematical -- or that sort of ->> Mario Livio:
Did you mention Wolfrom did you say?
>>: Yes.
>> Mario Livio: So I imagine what you refer to is this idea that
everything is some sort of cellular automata and you should do it in
those terms.
I think this is a very interesting thing. I mean, basically what he
would say, look, instead of going along the path that took us from
geometry and number theory through differential equations and whatnot,
we could have gone through a path that would start with some very
simple rules, like you have some pebbles. If you put the white pebble,
put a black pebble next to it and I don't know what, basically small
computer programs you would call them today, and you could develop all
mathematics based on that. I think that's a basic idea. And there are
people -- I imagine there are people here who work with cellular
automaton and so on. I don't know any scientist that as a result of
Wolfrom's thing sort of stopped solving differential equations and
started doing cellular automata. But you can argue that this could
have happened, and you know if there is life somewhere else, maybe they
would have gone that path. I mean, I believe that we have gone the
path of geometry in number theory because of our particular perception
system. Namely we are extremely good at seeing what is a straight line
and what is not a straight line, for example.
seeing edges of things.
Or we're very good at
So this really helped us develop number theory and geometry. But if
there is some other species that I don't know sees mostly in the
infrared or I don't know what, maybe they would come up with something
that's different.
So it's certainly not a blunder.
think it's interesting. Yeah.
I mean, it's a different path and I
>>: I had a question from online I'm going to ask you one of them which
is as an astrophysicist, what do you think about the ->> Mario Livio:
What do I think about Pluto?
[laughter].
>> Mario Livio: This I expect to hear at a talk in kindergarten not at
Microsoft. [laughter].
They are very emotionally attached. I think the entire discussion is
absolute nonsense to be honest, because Pluto has not changed what it
was. It remained the same thing. It is just that at one time we
didn't know about the Kipper belt. We didn't know that Pluto was just
one object out of thousands and thousands that are in this hyper belt
that's around our solar system, and it just is closer and it's one of
the biggest.
It's perhaps not the biggest but one of the biggest. So it was
discovered, and you know classified as a planet. Since then we know of
these hyperbelt. We know there are all these billions of objects in
it. And we know of at least one that is bigger than Pluto, probably.
Although they are pretty close and so on.
So then the question came about, well, wait a second what should we do,
what, we'll call all these millions of objects planets or shall we just
recognize that Pluto was one of the hyperbelt and demoted from a plant
to be a dwarf planet. But it hasn't changed what Pluto is and so on.
So should we have changed the name or not? Well, it depends on taste,
I guess. If you think, well, for historical reasons it was always
called a planet, let's continue to call it a planet, who cares. Or you
say, well, I want really to be more accurate from a physics perspective
and blah I demote it from being called a planet because I define planet
by a certain number of criteria and it doesn't meet all of this.
That's all there is to it. To feel emotionally attached with this
business is a bit strange to me.
It's somehow the planet that all Americans love the most for some
reason.
>> Amy Draves: Thank you so much.
anyone's interested.
There are more $10 books if
>> Mario Livio: And I'll be happy to sign all of them. [applause]