Randall Munroe: “What If?” | Talks at Google
Articles Blog

Randall Munroe: “What If?” | Talks at Google

August 18, 2019


MALE SPEAKER: Let’s give it
up for Randall, all right. RANDALL MUNROE: Hi. All right, so I wrote a book. It’s full of my
answers to questions that people submitted
through my website. And so one of the questions that
was submitted that I would like to talk about today
is the question that someone asked– what if
you built a periodic table using bricks, where each
brick was made from the corresponding element? And so for– there’s a
bunch of different elements, some of which are easier
or harder to get a hold of. All in all, there are–
of the 118 elements in the periodic table,
there is about 30 of them which you can get
at the local supermarket. You can get samples of aluminum. You can get samples
of– oxygen and nitrogen are not hard to find, either. And then there are
another bunch of elements that you can get if you’re
a little bit more creative. For example, if you need a
radioactive source for a cloud chamber, which is a
science project you can do, you can take apart a smoke
detector, because they’ll have a tiny lump of americium
in the middle of it. And if you– it’s a
very small amount– but if you wanted
to make a brick, you could just buy a whole
bunch of smoke detectors and disassemble them all
and gather all the americium together. And this is an
effective way to A, get a brick-sized
sample of a rare element that’s otherwise
hard to find, and B, get yourself onto a bunch
of government watch lists really quickly. But despite– there are some
dangers to this, for example, a lot of these
elements, in addition to being maybe hard to find
and/or some degree of illegal, some of them are kind
of dangerous to handle. So mercury, depending
on what form it’s in, can cause mercury poisoning,
which is really bad. Even some of the elements up
near the top of the table, like beryllium, is– it’s
not radioactive or anything– but you don’t want to get it on
your hands and into your food. So there is– but
despite this, people try to collect samples of as
many elements as they can. And I totally understand this
sort of collector’s compulsion that people have, because I
played the original Pokemon on Game Boy. And if you look up
what year I was born and the release dates when
“Pokemon Blue” and “Gold” came out, you’ll realize
that I was actually not quite in the–
I was a little older than the demographic that was
supposed to be playing Pokemon. But I played through, and
there’s the appealing idea that there’s– originally– 151,
plus or minus, Pokemon. And the goal is to
collect them all. And so there are 118 elements. So it’s easy to
think of them as sort of radioactive, and sometimes
very short-lived, Pokemon. But people who try
to collect them usually top out somewhere
around 80 to 90, depending on how
comfortable you are with your health and safety,
how much money you have to put into this, and– in
the case of plutonium– how many international laws
you’re willing to violate. And the elements at the
very bottom of the table are the ones that they
typically have a hard time with for reasons which will
become clear in a moment. So we’re going to start
with the top of the table. So what I decided
to do is think, OK, I’m going to build
a periodic table. There’s going to be
trouble near the bottom. But let’s start with the top. So the first row of
the periodic table is just hydrogen and helium. And that would be easy
to build, because you get a bunch of hydrogen,
get a bunch of helium. I think we have a
helium shortage, but you can still buy
it at party stores. And so you if you
made a brick of those, it would be really
anti-climactic. It would just sort of
diffuse and float away, but this would be a
good place to stop. Because we have
seven rows to build– so of these rows, the
first two rows really you can build without
too much trouble. The third row will
burn you with fire. The fourth row will choke
you with toxic smoke. The fifth row will do all of the
things that the first rows did, plus give you a mild
dose of radiation. The sixth row will disintegrate
instantly in a column of steam and extremely toxic dust
and smoke and destroy whatever building
you’re doing this in. And you should not
build the seventh row. But the first two rows are OK. You can build these
without trouble. The second row you
also– if you built this, you’d have some
elements that are solid and some that are gases,
but they would basically float away. The one, though, that I want
to point out here is fluorine. Fluorine is really, I
think, the worst element. It’s the most reactive
element in the periodic table, and I was recently
reading a list of chemists who have been mauled or killed
doing fluorine experiments. So not only is it
super-reactive, there’s a fluorine
compound which, if you have a gas
of this compound, and you place things in
it, almost any substance will spontaneously catch fire
in a fluorine atmosphere, including, for one of
these compounds, ice cubes. So you definitely don’t
want to breathe it in. It would just sort of spread
out across the ground, but you can back away slowly. I do remember seeing
in a data sheet that it will also eat through
many common gas mask materials. So be careful with
your safety equipment. But it really doesn’t
become a scary situation until we get to the third row. So the third row has a
couple of troublemakers. Over on the left is
phosphorus– over on the left is
sodium and magnesium, and those would
probably also– you can see the sodium
actually– I think drew it starting to
tarnish a little bit. Depending on how
moist the air is and what the
conditions are like, those would more or
less rapidly start to oxidize, either
slowly or quickly. But over on the right,
we have phosphorus. And because it’s, I
guess, more fun to draw, I assumed that we were using the
white allotrope of phosphorus, which will spontaneously
ignite when it comes into contact with air. And so we have this lump
of burning phosphorus, and then the things around
it, which might not normally spontaneously
catch fire, will be lit on fire by the phosphorus. And as if the whole situation
were not combustible enough, it’s not just
happening in oxygen, because we’ve got
fluorine from the row before spreading out
over it, and then also we have chlorine that’s just
below the fluorine, which is almost as bad. So at this point, you definitely
don’t want to breathe this in. You want to back away. It’s going to be a lot more
smoky than the previous one. But you could
probably survive this. The fourth row gets trickier. So the fourth row introduces
a bunch of new elements, including the metals– a lot
of the more traditional metals. And also we have a lump–
underneath the phosphorus is a lump of arsenic. And so arsenic is sort of a
really recognizable element, and we have a lot of
associations with it. And I remember
hearing an interview with a spokesperson for a
chemical plant in Texas, I think, where there had been
groundwater contamination downstream from the plant. And the spokesman
said, you know, yeah, they’ve detected
arsenic in the water, but arsenic is
really a scare word. And on one hand,
that is probably not the best public relations,
to say, oh, it’s arsenic, but arsenic is not that bad. But on the other
hand, he has a point, which is that there
are trace amounts of arsenic in just
about everything. So all of our food
has a little bit of arsenic in it– few parts
per million or billion– and that’s OK. And there could be a
little bit more than that, and it’s also OK. It’s not going to be toxic. But on the other
hand, this is a lump of arsenic, one part per lump. And the reason that
we– even though there is a little bit of arsenic in
everything– the reason we have these associations for it is
that in large enough quantities it is toxic to virtually
all forms of life. And this is– a lump about
yea big is definitely a large enough quantity. So the phosphorus has the
burning sulfur– the burning phosphorus and then the
sulfur sitting on top of it. Next to it is the
selenium and the bromine, which are also reacting pretty
vigorously, although probably at this point cloaked
in the smoke that’s bubbling off of the
phosphorus here. And all of this is wrapped in
this smoke that’s boiling off, which is also smoke that’s
full of fluorine compounds, just to make things
more exciting. And so you have all the
burning chunks– arsenic combining with the phosphorus
and making all these compounds that are
arsenic-something-something oxide, arsenic fluoride,
and things that. If you don’t get
away pretty quickly, you will be breathing in a bunch
of stuff that could definitely kill you. So the right thing to do here
is to run away very quickly and not keep
building rows, which is what we’re going to do. This fifth row I think of as
sort of the foreshadowing row, because the fifth row
is the place where we meet our first mildly
radioactive element. And this is one
that I have heard– so I memorized the
periodic table. If you hadn’t gathered
from the Pokemon story, I was not always the best
at being social and finding other people who
shared my interests. So one thing was I learned
the periodic table from books, but did not talk to a
lot of people about it. And so this is an element
where it’s sort of like the aluminum-aluminium thing–
I’ve always pronounced it “tech-net-ium,” but the few
times I have heard someone else pronounce it, which I have–
although, come to think of it, I’m not sure why
I had heard that– but I’ve also heard technetium. And that led me– I was
wondering about that. But then I got distracted
because I decided to look it up on Wikipedia, and then
got diverted into reading the something like 10,000-word
talk page argument over aluminum versus aluminium. And I got into, like,
archive seven of that and then had totally forgotten
what I was originally supposed to be doing. But this element,
whichever one it is, is the first mildly
radioactive one. Now in this scenario,
it would not kill you before the arsenic,
the phosphorus, the smoke, the fluorine, and
then also, again, the left side of the
table here, which is like slightly less
bad, but still bad– the potassium and sodium. Those would all kill you first. The “tech-net-ium” or technetium
is not radioactive enough to kill you. At least, I think you
would have to cradle it to your body for a
day or so, or if you managed to eat a chunk
of it, or wore it as a hat that could
give you a lethal dose. Hopefully they can add
that to the material safety data sheet– do not wear as hat. But the radiation
itself would really not be the biggest problem
you would be facing here. For that, we’re going
to go to the sixth row, because the sixth throw
contains astatine. It contains a lot
of other things too. And I remember when I first
saw this printed in the book I was reading, I was
flipping through, and I hit this article, and
I hit this illustration, and it was like,
oh, hey, I stopped drawing all the smoke and stuff. I wonder why. Was that a mistake? I had the– the
mercury should be flowing just like
the bromine was. How come I just drew them
sort of stationary like that? And then I remembered
that the only chance we will have to see this table
is the snapshot taken right at this moment, because–
so plutonium is radioactive. And we use it– we use
uranium in reactors, where we trigger chain
reactions in the uranium. And those chain reactions–
the uranium undergoes fission, and because I can never
figure out the verb form that I would use there to
say where it fizz– fizzes– fissions– nothing
sounds right, so I’m just avoiding saying that. It undergoes fission. It splits into chunks,
and that releases energy which splits more of
it and splits more of it. But it will also– if you
have plutonium sitting there, it’s radioactively decaying,
and so it emits heat. And that is what
we used to power a bunch of the
long-term space probes. So the Curiosity Rover
has– and I really find this amusing
for some reason– but they have a chunk
of plutonium, which– I think we’ve come very close
to running out at this point and may be buying
it from Russia. So if you’re an
element collector, I know that there’s someone
out there who’s selling it. If you can avoid all of
the federal agents who will try to find you if you
Google– I did Google plutonium prices for this and then started
thinking, like, wait a minute, well, I’m probably on
that watch list already. I think, actually someone
asked me if any of my research got me in trouble, and as
far as I know, all of that googling– like there was
a question I answered where I was writing about the
most expensive thing you could put in a shoe box. And I’ve looked up prices
of a bunch of hard drugs and then realized my
search history is now how much does heroin cost? How much does LSD cost? OK, but, like, on the
street, in the city, how much does it cost? Or what about this city– trying
to get a real practical street price. But really the only
consequence I’ve ever suffered was there was an article I was
writing a couple of months ago, and at one point I wanted to
include a sample of the items in the collection of
the Library of Congress and what kinds of things
they were on the whole. And it was sort of hard
to get broad statistics of the kind I wanted. So I figured, oh, hey,
I’ll just randomly sample their collection and look at 100
items and see how many of them are books and how many
of them are other things. And so I found–
they had a web API and collection items
had one number. And I was like, OK,
the number looks– it’s not too many digits. It’s probably not
too sparse a space. I’ll just start
requesting random IDs. And then I parallelized
that, because that was going too slowly. And then I found it was
really hard to get good data. And so I was ramping up
the number of requests I was making. And then suddenly they
stopped returning anything, and then I found that not
only had the API blocked me, but the entire Library
of Congress website was now redirecting me to a 403. And in fact, everyone
in my building was also redirected to the 403. And I felt like that’s totally
fair, because I was definitely spamming their API
and abusing it, but I also felt
really bad about that, because I have never been
kicked out of a library before. And I felt like that was
a line I had crossed. So I really wanted
to apologize to them, that I just wanted
to tell people about their cool
collection, but sorry. So the thing that really
entertains me about plutonium is that you think of these
sort of complicated reactors, but with plutonium
electric generators, we’re just using the fact that
this thing gets really hot. We just wrap it in things
that will generate electricity from the heat and
from the radiation that’s being put off by this. But then we have the
problem that it’s a big chunk of plutonium, and
it’s hot, and it’s radioactive. And so they put it
out on a long stick and just hold it
away from the Rover. And so you can see
on the Voyager probe they’ve done the same thing. And so they’ve got this
long scaffolding arm. And at the end
there’s a little thing that I always assumed is
a scientific instrument. But no, it’s just a
chunk of plutonium. And the Curiosity rover
has the same thing. And this plutonium
has a half-life on the order of a century,
which means that after a century or so– or whatever the
specific half-life is– 80-something years–
the heat and power output will drop in half. And so they’ve
designed it to keep working until the voltage
drops to a certain point. And so it can keep
running for decades, assuming the other
stuff holds up. But if you wanted to run
something for longer than that, you would need something
with a longer half-life. I did work out, by the way–
the plutonium chunk that they’re using on Curiosity, if
you had a Nintendo Game Cube and a TV hooked up to it,
it would provide enough power for about 130 years
of continuous play. So if you are stuck
on Mars, and you’ve managed to commandeer
the Curiosity Rover, if you have brought nothing
except a Game Cube and a TV– But the half-life of
plutonium is just about right, because if it were
much longer, that also means that it is less
radioactive, because it’s taking longer for half
of it to decay, which means it will be producing
less power and less heat. And so you always try
to find a balance. And this is also why nuclear
contamination sites– when a reactor melts down or
something– the really nasty elements are the ones that
half-lives of about 30 years, because the ones that have
half-lives of a day or two are incredibly
radioactive, but then they all decay,
and they’re done. And so those will be the
things that will give people lethal doses very, very quickly. And then the things that
have really long half-lives– like uranium 238 is on the
order of billions of years– that stuff does not decay often
enough to emit much energy. So the really bad
stuff is the stuff that is like a 30
year half-life, so it will contaminate the
area for a couple of decades, but also be short
enough that it’s emitting a lot of radiation. And plutonium is,
again, about a century. So it emits all of that
heat in about a century. So astatine, in its
most stable form, has a half-life of
eight hours, which means that all of
the energy emitted by the plutonium
powering the Curiosity Rover over the course
of the next century, if it keeps running, is being
limited by our lump of astatine in an afternoon. This is why no one has
ever collected enough of a sample of astatine
to really look at it, because any sample large
enough to see with a naked eye would also melt the naked
eye and vaporize itself from its own heat. This actually leads to a
really funny situation. My favorite thing about
looking up these elements is, if you look
under astatine, there are all these great
chemistry data tables, like “CRC Handbook
of Chemistry” that list all of the elements and
every conceivable property you could want. And actually during the
street drug research, I remember I was
trying to figure out cocaine density, or
something like that, and found that they actually
have a whole bunch of data on a bunch of these, but
for some of the drugs they have mysteriously
missing chunks. I didn’t know if those were
removed for some reason– if that’s sensitive information,
or if it’s just no one else has really tried to figure out the
physics of a shoe box of LSD. In the handbooks, if
you look up astatine, you’ll find all its
density and stuff and its various properties. But if you look at–
surface appearance is a field that they’ll have
where they’ll say is it shiny? Is it reddish? Is it matte? Does it have a luster? Is it black? And astatine will just
have a question mark, because there is no way–
if you have a sample that is large enough
to reflect light, the light that the
astatine is emitting will be brighter
than whatever it is you’re trying to
illuminate it with. And so no one has
ever– I think that I’ve read that the best guess is
that it is probably black if you were able to illuminate
it brightly enough to see. But it’s also possible
that it’s shiny and kind of metallic-looking. And that will probably
be a mystery forever, because those are
chunks of astatine that are a collection of a bunch
of molecules in one place. This would be a chunk
of about a liter, which is more astatine than
has ever been made or exists in the world. And this lump of
astatine would promptly turn into a column
superheated steam by that heat that it’s pouring out. But this column of
superheated steam will continue pouring
out that heat steadily for the next eight
hours, and then the next day for less
than that, and less than. And this is– so if
someone were actually trying to do this
table following these instructions,
first of all, there’s a legal disclaimer
at the front of my book. They said, you can make
this kind of a joke, but definitely do put this in
about not doing this at home. And this is one
where if somehow you were a bunch of people
with both the resources to get a hold of some
of these elements and an environment
that was fostering really weird experiments
in the building where you might be able to
get away with doing something like that, the
amount of astatine that you would be using here
is a quantity that maximizes the amount of paperwork
you’re going to have to face, because if it were
smaller– a liter is enough that it will probably demolish
the building that you’re doing this in. And there are going to be a
lot of people asking questions. For example, whoever
owns the building, or whoever was paying
you to do something else when instead you
were doing this. Do you still have
20 percent time? Is that? Well, I guess you’ve
already seen all the Google searches I’ve done for
plutonium suppliers. You can find that out. But if you did this,
there would be no way– if it were a smaller
amount of energy coming from the astatine, you might
be able to cover it up. You could just– if it was
a well-built room and sealed away, and then you’d
have charred walls, a lot of radioactivity, but you
could in your 20 percent time discretely work
to clean that up, and maybe the news
of what happened would not reach your
immediate superiors. If it were a substantially
larger chunk of astatine, then there would be no one
left to submit paperwork to. And that is what would
happen with the seventh row. And so the seventh
row– we’re getting down into the elements that
just have numbers, and they have not
settled on names yet. When I was a kid and
learning the periodic table– and playing Pokemon and
being really totally well-adjusted and very,
very popular and social, but also memorizing the
periodic table– I found there were a whole bunch
of elements that got you up to 100– you could get
up to 105 or so, or 110. Some of the books I
had went up to 110. But then they stopped, and all
of those didn’t have names. They would just be like
“unun-something-ium” that was like this
naming convention. And they’ve start
assigning names recently. They’ve started finishing it up. But we’re also at a really
interesting situation, which is that they have
synthesized elements, as of a couple of
years ago, they finally synthesized element number
118 in a particle accelerator, which means that
they’ve squared off the bottom of the
periodic table, because they finished out a row,
which is not something– which has not been the case for a
very, very, very long time. And when I saw that, because
all the periodic tables I learned as a little kid had
an extra line that ended halfway across. And I don’t know if it’s
a typographic thing, but I feel like it’s
very, very satisfying have the nice, square,
rounded-off shape. And it gives me this weird urge
to sabotage particle physics experiments, so they don’t
synthesize element 119 and ruin the really
nice justification. But the reason that the elements
are only being filled in right now is that they’re
very hard to produce, and they are very short-lived. And so astatine, the reason
it decays so violently and destroys the
building you’re in, is that its half-life
is only eight hours. So it dumps all
of that stored up radioactive energy
in eight hours. Some of the elements at the
bottom of the periodic table will decay– they have
half-lives– some of them are measured in seconds and a
couple of them in milliseconds. So all of the energy
that’s released by your column of
heated astatine rising into the stratosphere over
the course of an afternoon will be released by these
elements now, right away. It would be sort of like
a nuclear chain reaction, only it’s not one
part triggering– it’s not one of them decays,
and that triggers the other ones to decay. It’s not a chain in that sense. It’s just a reaction. It all happens it once. However, there is sort
of a chain element, because the elements that are up
way far on the periodic table, some of them will emit a couple
of protons and neutrons, which now makes– element 118
has 118 protons– it decays immediately, releases some
protons, and becomes element– maybe it drops down two spaces–
it becomes element 116, which is also extremely radioactive
and has a very short half-life. And so you get
these decay chains, all of them pouring out a
whole bunch more and more and more energy all at once. And the energy
released– so if you were able to watch this whole
scenario from very, very, very far away, on one of
the mountains– which way are the
prevailing winds here? They come in from the ocean,
so I guess from the west, out over the east, so maybe
to the south in the mountains, southwest– anyway you
would first see this, because the energy released
in the first few seconds would be on the order of that
from a medium-sized nuclear weapon. But because of
these decay chains, these things just continue and
continue decaying and decaying. So it’s like a nuclear bomb
which just keeps exploding. And what happens is you’ve
got your wall, which existed for– if it’s made
out of one liter blocks, I guess it’ll be a
couple of metres wide. It will take light in the
neighborhood of 10 nanoseconds to cross from one side
of the wall to the other. So you have that
much time to enjoy it before the radiation
vaporizes it. But it vaporizes
it, but you’ve still got this plasma of these
radioactive nuclei, which are continuing to decay. So your mushroom
cloud is now pouring out all these radioactive
products and elements, and it’s continuing to become
super-hot the winds carry it away from you, cover
everything downwind, and it’s only– I
only realized very, very recently that when
you have a mushroom cloud, and you have all the heavy
dust and stuff with the uranium dust on it that is in
the mushroom cloud, but it’s heavier than
air– so as it cools, it falls down from the cloud
on to the ground, which is actually why it
is called fallout, because it falls out
of the mushroom cloud. And I guess that’s sort
obvious in retrospect, but it had never occurred
to me until just now. So this cloud is full of this
stuff, which falls out of it and covers land. And this stuff is
rapidly decaying. All of these elements
way down the table are decaying until
they reach something so stable as astatine, and
then they take a break. And that is a much
more calm situation, because then it’s just
superheated plasma and not quite as superheated
exotic particle mess. So this whole mushroom
cloud will continue spilling out this stuff as
it goes downwind, rendering more and more
areas uninhabitable for long periods of time. And from a nuclear
cleanup point of view, it’s sort of hard to figure out
what to model this on, because of the way that the
steam is superheated, and it’s all mixed
in this cloud. And you’ve got a lot
of heat, and then a lot of cold environments, and a lot
of high pressure environments, and then low pressure
environments. And you have samples of
literally every single element in this– at least
at first– you have all of chemistry
happening at once. Every different pair of atoms
that can run into each other will be running into each other
here somewhere in your cloud. And they were doing it
under every different kind of condition. So every product that could
happen from a reaction that you’re like, oh,
this is hard to clean up, will be happening in this cloud. So in addition to all
of the radioactivity and all of everything, if you
just flip through a chemistry book, and you can
point like anything, you will have that
problem to deal with too. And also at this
point, it’s definitely the least your problems,
but all I can think is also there’s a liter
of fluorine in there too. And I’ll just have
my gas mask, and I’d be thinking about that too. So this, if nothing
else, definitely helped me come to
terms with my sort of Pokemon-inspired frustration
that you can only buy 85 or 90 of the 118 elements, because
this has really driven home that the most important
thing an element collecting is that you
do not catch them all. But I got this– I had
come up with the scenario. And I have physics background. And in doing what– I’ve
gotten a lot more into geology. I was learning about
the way continents break apart as you do various
horrible things to them– that’s been a lot of fun. And I’ve also learned a
lot more biology lately, but I feel like chemistry
has always been something that I’ve had a
harder time with, maybe just because there
are a lot of things that– this atom is more
electronegative than this atom. But we don’t have a real
life– it’s sort of harder to connect that to real life. And you know quantum mechanics
can be hard in the same way. And I really like
stuff where it’s easy to think about intuitively,
like mass and speed and force, because you can think
about this is an object. This is an apple. This weighs this much. This is what a kilogram means. This is what a ton means. And so I feel like I had a
harder time with chemistry. And so after I
finished this article I got, because I was
writing this for my book and had a little bit more
luxury– I could have a longer deadline– I got in touch
with a professional chemist, because I wanted
to run it by him. And I said here are all these
reactions that I’ve worked out that I think will happen, but
I wanted you to look over it. And let me know what you think. And this guy was really helpful. I talked to Derek Lowe, who’s
a chemist who also writes the drug industry blog
“In the Pipeline,” which I had read for a while. And so he went
through my article. And actually his
first question was, if you’re going to build this,
this would definitely not be a good idea. He said, so what form
is the carbon in? Do I get to specify? Do I get to be a giant
chunk of diamond? And I said, I don’t know. And he said, well,
because diamond, it will actually burn if
you get it hot enough. But that’s pretty difficult. And you’d have sort of the
problem– the same thing that happened with some of the
Cold War-era projects, which is if you have an
explosion like this, that’s this violent, the question is
will it fling the thing away before it delivers enough
energy to disintegrate it? So he said there’s a
decent chance that– when you have this radioactive
nuclear bomb going off– that it’s possible that
the diamond will not be incinerated. So back in the early
days when we were still doing nuclear weapons tests,
there was this series of tests underground. One of them was
Operation Plumbbob, where they had a
nuclear weapon going off in an underground
chamber with a shaft connecting to the surface. And the shaft had a
cement plug and an iron– some kind of heavy steel– cap
on it blocking the top of it. And some of them had been
doing some calculations about when you have the
incredibly high pressures in this, they have nowhere
to go except up the shaft. They’re going to hit this plug. And they think the
plug will not actually be disintegrated by this,
but it might be hurled away. And there was an interview
with one of them, where he talked about
it they weren’t sure how fast it was– they thought
it was going to be flung / and they were coming up with
some sort of high numbers for the speed. And so they what did is they
trained a high-speed camera about a quarter mile away
on the mouth of the shaft, just to catch anything
that happened. And so they detonated
the bomb and they had this high-speed
camera– I think they said it was running
around 300 frames a second– the plug that was
over the top of the shaft appears in the air in one frame. So they can put a lower bound
on how fast it was going, but they do not
have an upper one. The lower bound is a– I tried
to run through the calculations myself using the field
of view of the camera. It’s a little bit
tricky calculate– but it is a double digit number
of kilometers per second. One of them– one [INAUDIBLE]
was about 65 kilometers per second. And that’s interesting
because you’ll see sometimes the Helios 2 probes that we sent
around the sun are often listed as the fastest human
objects– the fastest thing we’ve ever made. And frame of
reference questions, it’s hard to figure
out how to define that. But with reference to the sun,
the thing it was going around, they dropped so close, they
whipped around it really fast, and at the bottom
of that they got up to about around 60 or 70
kilometers per second. Depending on exactly how
fast this manhole cover that was on top of this
thing was going, it is possible that
for a moment this was the fastest
object ever built. And there was some
thought that this might have– if it was going
at 60 kilometers a second, the escape velocity from
the surface of the earth is less than 10
kilometers per second. And in fact, the escape velocity
from the whole solar system from where we are is only
about 40 kilometers per second. And so this manhole cover,
which was never found, may have left– it’s
possible, given its speed, it made out of the atmosphere. And I actually started doing
a bunch of calculations to figure out if it
was going forward from the Earth– like in
the direction of the Earth’s motion. If they were pointed toward the
direction the Earth was going, you get to add on the
Earth’s 30 kilometers a second speed around
the sun, when you’re trying to get up to
the escape velocity. And so this thing could be going
over 100 kilometers a second, which would send it straight
out of the solar system. And it would be going
way, way faster, even after it had lost
all its speed there than the Voyager probes
at their fastest. And so that would now be our
first representative heading for the stars, which is
a really appealing idea. And I think I came
up with– I was digging through these files
trying to find what time of day did this happen, so which
way would the shaft have been pointed? And I think that the
Earth’s speed came out as kind of a wash. But it’s also sort
of a moot point, because further calculations
show that probably the metal cover, because it was
not quite large enough, probably did not survive the
impact with the atmosphere. So it would have been sort of
the only– maybe the only time in Earth’s history that we’ve
seen a meteor going directly upward, burning up
in a plasma trail. And so probably that
manhole cover was destroyed, but it’s possible it is
still out there somewhere. So when I talked to the
chemist his first question was, hey, that
chunk of diamond– it’s possible that’s just
going to be flung free from this explosion,
and have landed OK. And then at the
very least, I would like to go and pick
it up and then use it to pay for all of the
damage that I did the labs, and to the city, and
all the rebuilding. And then he thought
for a second. He was like, I would definitely
wipe it off first, though. What was really fun is he also
got to– he said you, yeah, these reactions that
you’ve talked about, they would definitely–
they would happen. But there are a lot
of really bad ones too that you didn’t
even get to, you know? And he said– he pointed
out that the selenium and the bromine would
react vigorously. He said the fluorine–
he said you’re right that fluorine is where
this whole scheme goes to hell. That the fluorine, he said,
it would be OK with the neon, and it would observe
sort of an “armed truce” with the chlorine,
but everything else– his exact words were “but
everything else, sheesh.” But you get further
down the table, and he got to throw in
all these fun tidbits. He said that you’re right. That this would be really
toxic, but also the selenium would be burning,
and burning selenium is the worst thing
that he’d ever smelled. And he said it’s
like– he said it makes sulfur smell like Chanel. So the selenium
and the tellurium and would both be really,
really awful smelling. And he listening
then, this would produce all these chemicals. And this would produce
all these chemicals. And this one I’ve never
worked, and this is why. You know? And I found this really,
really satisfying, because when I answer
these questions, people say that I write
all these articles, and how come I destroy
the earth so often? And how come the
articles always end with everyone
dying or something? And it’s really because
that’s the questions that people ask me. That would really
be the consequence of the scenario
you’re talking about. But I’m trying to not make them
more dramatic than they are. I’m trying to tell the real
story of what would happen in as fun a way as possible. But especially with the
chemistry things like this, I liked going to
experts to find out– make sure I’m not
overselling this. Like, is this
really– the science that I’m talking about– really
this weird and this horrifying, or it is it more
complicated than that? And it’s really nice to
learn that, in fact, reality is way more horrifying
than I was able to imagine. And I think that’s
been the most fun thing about doing all of
this, is getting to discover all this really crazy and
exciting and fun and uplifting and sometimes really terrifying
stuff that the science can show us. And so we also–
we have some time. I think we’re running into–
we have some time for Q&A, if anyone wants to
do any questions. We’ve got a
microphone back here. So you can just– if anyone
wants to ask any questions, you can come up there. AUDIENCE: Hi, I’m Alex Weisen. I’m the tech lead
manager for Google Voice. And you’ve made a few
comic strips on “xkcd” that mentioned Google Voice. And so I just wondered,
is there anything we can do for you, anything
we can help you with? RANDALL MUNROE: Which ones? Sometimes I’ll
have people come up and say, oh, I really
liked in comic 446. Can you say, is that
from experience? And then they
pause for a minute. And I have a moment
where I’m like, oh god, they think that
I know them all by heart. Do they know them all by heart? It’s weird. And so when people both cite
them by number I don’t know, but also now I’m trying
to think, what have I said about Google? Was it nice? AUDIENCE: Yeah, it
was pretty nice. You just made funny jokes. It’s cool. RANDALL MUNROE: I’ve had some
fun transcripts delivered to my phone. I really enjoy the sort of
the word play aspect of it. Like, here is how the transcript
rendered my dad talking. Now it’s like a
crossword puzzle, figuring out what
did he actually say? But I assume that a
huge amount of that is the quality of the
connection and everything. But I am kind of
enjoying that part. So I would say keep that up. No, I’ve been really enjoying
the rate at which the voice recognition has been improving. Especially recently,
to where we’re finally getting to the
point where do not have to mode switch five times
to get voice commands up, to then say, OK,
now I want to search for this in a clear, loud
voice projecting to everyone. I’m really looking
forward to the future where you can just
kind of discretely be like, oh, what’s
the weather right now? OK, it’s this. So I’m enjoying that. And keep up the
progress on that. Yeah, thank you. AUDIENCE: Hi. It’s great to have you here. I missed your last talk,
as I wasn’t at Google yet, and I’ve been waiting–
waiting for this day we finally get to see Randall Munroe. RANDALL MUNROE:
That’s satisfying. AUDIENCE: In all of the
submissions that you received for “What If,” were there
ever any that intrigued you, but that were just
too frightening. You weren’t going to touch
them with a 10-foot pole? RANDALL MUNROE: Yeah, there have
been a number of weird things. I had one person
who in their job may have conceivably– they
asked a question about– a fun earth science question
involving nuclear weapons. And their from address, the
TLD that it was coming from, and the title that was
after their signature, and then some of what they
described in the letter suggested that perhaps
this was a person who had access to nuclear weapons. And that was a little worrying. I have also gotten
ones from– I had one that I think came from
a doctor that was like, suppose that a toxin blocks
the effect of so and so on a patient’s so
and so receptors, and it was delivered
at this dose, what would be the effect
of this toxin? And that’s not sort of the vibe
of the usual “What If” question I get. And it gave me the sense
that somewhere there’s a doctor who’s in a
hospital at a computer, and there’s a nurse coming in
who’s like, Doctor, Doctor! Asking her, we have
a patient so and so. What is your decision? What are you going to do? They have this talk, and
the doctor’s like, hang on. There’s an internet
cartoonist who I really think we should ask about this. And they’re waiting
for– like, we have to wait for
this week’s article. But hopefully you’ll
tackle this for us. And so that’s definitely
sort of worrying. I also get a lot of questions
that are very transparent attempts to get me to
do people’s homework. Like, what if you had a ball
was on an inclined plane at this many degrees that was
this many centimeters long, and you let it go? Like, how many
seconds do you think it would take to hit the bottom? It’s like, nice try. And then I think, actually,
the most worrying ones are– there are a
bunch where they’re totally reasonable, legitimate,
answerable questions that I still just refuse to tackle. Which are like– one of them
was someone asked would it be possible to chill your
teeth to such a low temperature that drinking a cup of hot
coffee would cause them to shatter? And I included this
question, and I have never been able to get beyond
the end of that sentence without just cringing,
because I imagine it. And so I have never– I
don’t have the stomach to do the research to
answer that question. And so there are a
couple like that, where it’s like this
is just pushing it. But other than that, there’s
a huge number of what if Superhero X
fought Superhero Y. And I feel like that’s
A, sort of hard to answer scientifically, because the
powers of the superheros sort of change depending
on who’s writing them, and it will often be the ones
who are sort of infinitely powerful, where it’s
not really well-defined what the limits of
their powers are. But I’ve gotten to learn
a great list of all of the near-infinite
power superheroes, because people really like to
pit them against each other. And part way I don’t
answer that is that, in addition to being hard
to tackle with science, it’s– from what I understand–
that’s basically the kind of question that superhero
comics exist to try to answer in the first place. It’s like, what if we took
Hero X from mythology X and had crossover with
someone from mythology y. And I was thinking that this–
but this interest in asking about infinity is
a common trend, and it’s not limited
to just superheroes, because before that it’s
exactly the same impulse that leads people to ask the
old question of could God make a rock so heavy
that he can’t lift it? And this question–
you’ve defined this person as infinitely powerful. How powerful are they really? Goku from “Dragon Ball Z”
I gather, at some point becomes nearly
infinitely powerful, because people keep asking
questions about what if he fought the
Hulk or Superman? And so I think this is
sort of a common trend, although I was thinking
that I don’t think anyone has– this has been a common
trend throughout history– but I don’t know if they
necessarily always combine them with the sort of pitting
rivals, because I don’t think anyone
who’s ever asked in. What if Goku “Dragon
Ball Z” fought the God of the Old Testament? And I don’t know what science
has to say about that, but if anyone does
discover if they’ve done a crossover comic of
that, please let me know. I would read that. AUDIENCE: Thanks for coming. Hope you’ll be back soon. RANDALL MUNROE: Yeah. Thank you. AUDIENCE: Hi, thanks for coming. You mentioned how
you’ve been learning a lot about different
subjects that are sort of out of your
original realm of study, in terms of chemistry and
biology and these things. How do you go about learning
enough in this new domain to be able to produce
a meaningful answer to these kinds of complex
questions in a complex world? RANDALL MUNROE: I
think one sort of skill that I have gained that I didn’t
really have before this, was I have learned to read– skim–
a whole lot of research that does not turn out to be
relevant really fast. Like download 40
PDFs on some subject, skim each one looking
for, does this have the equation
that I’m looking for? Does this have something
that I’m looking for– and discard them really quickly,
like doing blind– going down blind avenues or dead ends. I haven’t learned to avoid
doing dead end research, but I’ve learned to do it
as quickly as possible. But the other thing is
people are– whenever I write about one of these–
I’ll write about some space thing, and someone will say, oh,
yeah, I don’t know about that. I didn’t– I know
you worked at NASA. So you know about what
happens when the moon collides with something or something. And it’s like my
formal education. I was working in a
robotics lab at NASA. And I’ve worked on some
virtual reality stuff. But the physics of the moon
running into things stuff was like if we were hanging
out at lunch talking about it. But I think more
than anything, just there hits a point
in the night where I stop getting anything
productive done. And if I have
Wikipedia tabs open, I’ll just start
reading from there, and it will never be
anything useful for what I’m doing right
then, but often I’ll learn all about something
that two weeks later is the answer to a
question that comes up. So just a lot of totally
unfocused reading of Wikipedia or
weird papers ends up coming in handy later on. AUDIENCE: And lots of Googling? RANDALL MUNROE: Hm? AUDIENCE: And lots of Googling? RANDALL MUNROE: Yes,
I’ve actually found– so everyone’s like, oh,
yeah, do spend a lot of time on ResearchGate, JSTOR– how
do you pronounce– A-R-X-I-V? That’s another I’ve never heard. Is it just archive? Yeah, but I found that– and
even Google Scholar and stuff– and I use all of
those, but I have found that if you’re looking for
weird research that maybe isn’t the easiest to find–
maybe it was a government study in the Cold War that
has been declassified, but not really they haven’t
published [INAUDIBLE]. I have a lot more luck just
googling for the search terms that I would been looking for
and adding “PDF” to the end. In terms of does this
get me a paper that answers the question
I’m looking for, that has a higher hit rate
than any of the specialized services. So I appreciate that. AUDIENCE: Cool, thank you. RANDALL MUNROE: Thank you. AUDIENCE: Hi, so you had
a lot of fans show up. And that’s just
to hear you talk. You must get a bunch of
requests on the email address that you use for us
to ask you questions. I was wondering how many
of those do you get, and how do you
whittle them down? And really what I
would like to know is how do I ask you
the perfect question that you end up answering? RANDALL MUNROE: I don’t know. So it’s really nice to that
so many of you came out here. Although I feel
like that’s easier to do when it’s appearing at a
workplace, because it’s like, so do I work on
the thing that I’m supposed to do
this evening, or go hang out of the
talk about comics? I’m flattered, but I figure– But there are definitely a
lot of questions submitted, and I will admit to doing–
there’s some sort of filters that I put on the inbox. So after a little bit
I started filtering out the names of all of the
invulnerable superheroes, because they were just too
many questions about them that were never ones that I was
going to be able to answer. I also filtered out the word
“woodchuck” after week one. Because the first time
someone submitted “hey, how much would could a
woodchuck really chuck if a woodchuck
could chuck wood?” I laughed. I was like that’s
funny, and then the second time I was like,
oh, yeah, hey, someone else thought of that joke. And then in the first week it
was like 70 or 80 emails that were just the same
woodchuck joke, and then by then I was like,
OK, I now hate that rhyme, and I refuse to
answer any questions about woodchucks on principle. But other than that,
I actually find some of my favorite questions
come from little kids, because adults will sort of try
to be really clever about it and come up with a
question that suggests all these horrible
consequences, and they’ve set up a scenario that’s going
to result in a mushroom cloud engulfing wherever it
is you’re doing this. Whereas little kids will ask
extremely straightforward questions like, I want to
build a billion-story building. Can I do that? And then answering
takes you in a bunch of unexpected directions. So my advice to people who
are submitting questions is mostly ask little
kids for questions, because they have
some of the best ones. AUDIENCE: Cool, thank you. RANDALL MUNROE: Yeah, thank you. AUDIENCE: I guess I am the last
one here, so I want to ask you something I asked Vin
Diesel, because you have a lot in common with him. RANDALL MUNROE: OK, wait. Hang on. Before you ask your
question, which parts? AUDIENCE: I think
both of you have a real passion for geeky things. RANDALL MUNROE: Yeah, he was
a role playing guy, wasn’t he? AUDIENCE: Yeah,
so I was wondering if you’d want to join us
for Dungeons and Dragons? RANDALL MUNROE: Sure, so here’s
the qualifier– the thing for this– possibly. Coming back to this theme again,
the more social geeky pursuits, I didn’t really get into
until I went away to college. And then eventually got a job
working with more geeky people. So when I was a kid, I knew
about Dungeons and Dragons but never actually
played it with people. So what I did is I got a bunch
of– my closest exposure to it was the single player NetHack
and derivatives, Angband and stuff, which
I played through for several years every day. So all of my Dungeons
and Dragons knowledge is secondhand from that. The one time I did play Dungeons
and Dragons, the DM was like, OK, your character. You’ve at this point
picked up a weapon, which only you can pick it up. It’s magically enchanted. If anyone else– it’s a
10-pound ax– or something, and if anyone else picks it
up, it weighs 1,000 pounds. If anyone else touches it, in
fact, it weighs 1,000 pounds. And I was immediately
like, OK, wait a minute. Is there a water
wheel in this town? Can I get someone else from the
party or a peasant or someone? I want to strap the
ax to the water wheel, and have the handle sticking
out, like my hand on one side and their hand on
the other side. And we’ll get it spinning. And then we’ll have it weighted. So it’s really heavy, but then
it comes around to my side, and I touch it, and
suddenly it’s light, and the it starts spinning
faster and faster. And then we get it spinning
up to the speed that’s the maximum speed that the
water wheel can handle. And then we pull the axles
out so it drops to the ground. And then we’ve got
this giant heavy water wheel spinning at
a fantastic rate. It’ll go tearing across the
landscape toward the enemies who we’re trying to fight. There was this very
nice woman in college who invited me to play that one
time and then didn’t invite me back. My D&D experience is limited,
but I would love to try it out. AUDIENCE: Thank you very much. RANDALL MUNROE: And thank you.

Only registered users can comment.

  1. Randall, you are my favorite person, ive read every comic, alt text, and explain page (for fun) and every what if, and i click every note or alt text in the images on them, but watching you speak in front of an audience physically hurts me.

  2. The last situation he describes with the waterwheel got me thinking about the "immovable rod" from DnD. Here is the description of it from roll 20:
    "This flat iron rod has a button on one end. You can use an action to press the button, which causes the rod to become magically fixed in place. Until you or another creature uses an action to push the button again, the rod doesn't move, even if it is defying gravity. The rod can hold up to 8,000 pounds of weight. More weight causes the rod to deactivate and fall. A creature can use an action to make a DC 30 Strength check, moving the fixed rod up to 10 feet on a success"
    When I was presented with this rod at the last session of my groups DnD, I started wondering: The rod becomes magically fixed in place. But relating to what??? If it is in relation to the user, it could be used as a bag holder, with bags on a string, or dragging a carriage, hauling up to 8000 pounds. If it is magically fixed in place relating to earth (which is the actual game mechanic) it can be used to, for instance, be used to hold people, dragons, etc down. If it is fixed relating to the galaxy, it would instantly, when activated achieve a staggering 1000 km/second, and would rip through anything which would have a piercing threshold of 8000 pounds per square inch (yeah I'm assuming that the rod is a cylinder shape with an inch in its lenght axis) which would, I assume smash through dirt, buildings and people who would be in the opposite direction of where our galaxy is headed , which is the "the Great attractor", a region in space which is pulling our galaxy (along with the local group of galaxies near us). This Great Attractor, having a mass 100 quadrillion times greater than our sun and span of 500 million light-years, is made of both the visible matter that we can see along with the so-called dark matter that we cannot see. Uh… where were we? oh right.. DnD..

  3. Maybe you could find the color of astatine by plating a sphere of lead with a thin layer? I don't need a brick of it, I need a layer just thick enough to be opaque.

  4. 35:00 I already know this story. Orbit. Specifically interplanetary orbit or maybe even an interstellar trajectory.

  5. One of my favourite what-ifs is the extremely cataclysmic outcome of the question "what if the Earth was made entirely of protons, and the Moon was made entirely of electrons?". Essentially you get the obliteration of anything that could be considered local reality, spreading outwards at relativistic speeds with no clear limit on the effect radius…

  6. Some notes on Technetium and the like:
    * As far as I'm aware, from working in a field that uses it on a daily basis, pronounced Tek-neesh-ium. But once or twice did hear people who Should Know What They're Talking About say Tek-net-ium also…

    * He probably heard it being mentioned due to his wife's illness, sadly enough; it's commonly used as a tracer isotope in nuclear medicine scans, one of the main varieties of which is for cancer staging, particularly osteosarcomas.

    * On which front, it shows us that half-life isn't the be all and end all of radioactive output. The energy of each emission is also important. The main radioactive isotope of Technetium (as it also comes in a wholly stable, radiologically inert form) is known as "metastable" with an atomic weight of 99… or Tc99m for short. The metastable one indicating that its decay path isn't to a different element as is usually the case with radioactive decay (and indeed, what forms Tc99m in the first place, as part of a decay chain via Rubidium), but just to a less energetic form of the same element (namely, stable Tc99). I can't remember if it's simply "born" with heavily excited electrons, or happens to lose a neutron or something, but the upshot is that it doesn't really emit any particle type radiation, simple a relatively soft (ie low energy) gamma ray, which makes it extremely valuable for functional imaging with gamma cameras.

    It also means its 6.2 hour half life – note, somewhat shorter than Astatine – doesn't result in a huge nuclear meltdown or explosion if you concentrate a large amount of the stuff into a small volume, despite its high activity, and nor is it particularly threatening to life. Simply keeping a respectful distance is enough to shield you from the worst of its effects, and a lead-lined apron takes care of the rest when you need to get up a bit closer and more personal. But you can spend years working with it on a 40-hours-a-week basis, or have several scans in the space of a year where the stuff is directly injected to your bloodstream, and come away without anything close to what would be considered a harmful dose. On the other hand, something like Uranium-235 or Plutonium has a much longer half-life, and thus much lower specific activity, but a similar amount of it can be much more damaging than the Technetium, because they undergo genuine nuclear fission and decay to various different child elements, releasing both ray and particle radiation in the process, each of which are much higher energy than Tc99m's ~140keV gamma (which barely even rates classification as gamma, rather than X-ray), so it can do you some serious damage despite having a lower apparent activity.

    Astatine in this case could swing either way; it has a slightly lower specific activity than Technetium, but the effect of that hinges on what its actual radioactive output is like for each decay. Obviously a higher energy disintegration, at a set number of them per second, delivers more energy per second… The amount coming out of Tc99m is so low that you need a very sensitive, scintillator-plus-photomultiplier rig to pick up on it, despite common medical activity levels being in the hundreds of kBq (1000s of decays/sec) to a few dozen MBq. But if each decay released, say, 100x as much energy, you'd have to be far more careful around activities of even ~100kBq… and if they were up more towards Row 7 energies, you've got a serious problem on your hands.

  7. "…will catch fire, even ice cubes" Good ol' ClF3. ls rapidly hypergolic with no measurable ignition delay with concrete, asbestos, and scientists.

  8. I read his book and the images that stuck the most is the ultra fast baseball causing a nuclear explosion and the planet made of moles!

Leave a Reply

Your email address will not be published. Required fields are marked *