From Andrea Milani <>

Dear Benny,

this is my contibution to the debate on planetary defense. However, to
avoid dangerous misunderstandings, please post it with this short notice:
it is not an anticipation from some secret paper of mine, it is not about
the war (or is it?), but it is just a work of fiction, namely an excerpt
from my Science Fiction Novel 'The Dinosaurs' Bequest" which I have
written in 1996, revised and translated in English recently (Chapter 17,
as you can easily figure out, is a recent upgrade...).

Yours Andrea Milani

Andrea Milani
Dipartimento di Matematica
Via Buonarroti 2

tel. +39-050-844254 fax +39-050-844224

Chapter 16. Spaceguard

The villa Carletti perched on a cliff over the sea; I do not know if
it had been built that way, or if it had been a house on the hill
which then had found itself to be a seaside house. Anyway, at the time
of our visit, it was accessible only from a private pier. The old man
was waiting for us on the terrace, seated in his wheelchair.


--And how might an old man like me be of help? --he asked.

--You are old, and that's why you still have ideas and knowledge which
  are all but forgotten. --Giusti as usual did not hesitate, and went
  straight to the point --What we would like you to talk about are
  some of the arguments which were at the origin of the Spaceguard

--I had the impression you were studying dinosaurs.

--That's right --said the prof-- Alberto, show him the video about
  the asteroid.

I turned on my notebook computer and showed him the dinosaur spaceship
appearing from behind the asteroid.

--What is the age of the layer where the fossil CD has been found? I
  mean --said the old man --is the layer near or far from the boundary
  clay, separating the Cretaceous from the Tertiary?

--Just below, very close, --I answered --it looks as though the age of
  the technologically evolved dinosaurs occurred just before the

--Then there is good reason to think that this asteroid has something
  to do with the one that dug the Chicxulub crater?

--It's possible, but that's precisely what we don't understand:
  --Giusti presented the main problem with her usual lucidity --if the
  dinosaurs were capable of getting to an asteroid with a spaceship,
  and even had space stations indicating a space technology superior
  to our own, why couldn't they deflect the Chicxulub asteroid from
  its deadly course?

The old man thought for a while, before answering, and then began
his explanation from basics.

--As a matter of fact, the theory of the deflection of asteroid and
  comets was one of the first subjects of debate at the beginning of
  the Spaceguard Survey. If you search the sky with telescopes, to
  discover objects which might be on a collision course with the
  Earth, you run into a contradiction. If you don't know what to do
  if one is indeed found, one big enough to destroy most of the
  life on our planet, then what's the purpose of your search? To know
  in advance we are doomed?

Giusti assented, but she asked the old man to explain the problem
better, because I was too young to have ever heard this argument.

--You see, Doctor Nieri --was the old man's explanation --from the
  point of view of your generation, the Spaceguard Survey is a
  research project which was completed when you were children. So you
  take for granted that neither an asteroid nor a comet with short
  period will hit the Earth in the next 200 years, apart from objects
  smaller than 200 meters, which cannot generate a global catastrophe,
  but only local damage.

The old man looked towards the sea, as if the wide horizon helped him
remember the ways of thinking of the olden days, and went on:

--On the contrary, when we began to set up the network of telescopes
  and computers intended to achieve the result you take for granted,
  we had to convince the scientific and political authorities that it
  was worthwhile to make an effort to achieve it. To obtain the
  support we needed, the money for the hardware and for the salaries
  of the researchers, it was not enough to present the threat of a
  possible repetition of a Chicxulub-style catastrophe. Such a
  possibility at that time could not be excluded, given the current
  knowledge at the end of the last century. However, it was useless to
  be prophets of misfortune, especially since the catastrophe was only
  a possibility, by no means certain; that is, unless there was some
  possibility of defense against such misfortune. We needed to
  convince the public and the political leaders that our search for
  potentially hazardous asteroids and comets was effective in
  decreasing the risk of impact with our planet. Thus we had to
  present at least an hypothesis on how to deflect an asteroid/comet
  heading our way, in case our Survey were to discover it.

--But then what exactly was the Spaceguard Survey? --I was confused.

--To be precise, a research project with the goal of discovering all
  potentially dangerous objects, with a long lead time with respect to
  the possible impact: we had to discover a possible killer asteroid
  decades before it could hit. In this way, if indeed such an object
  was discovered, there would have been time to deflect it. The lead
  time is the key factor, because the change in speed necessary to
  deflect the asteroid is as smaller as longer is the time to the
  collision. Moreover, given many years of time it might even be
  possible to develop the necessary technology.

--All this is very interesting, from the point of view of the history
  of science and of human thinking, but what has this got to do with
  the dinosaurs? If they had done their version of the Spaceguard
  Survey, something they certainly had the technology to do, they
  could have done exactly the same thing you were planning for
  mankind. --Perhaps my interruption indicated impatience,  out of
  respect for old age I should have been more polite.

--The fact is, they did not do it, otherwise we still would be mice
  --pointed out Giusti --or at least the domination of the intelligent
  dinosaurs might have lasted much longer, and their extinction would
  not have occurred near the layer with the asteroid impact fallout.

--Indeed... they did not do it. --continued the old professor, little
  impressed by our counter-arguments --Of course they could have been
  unlucky, they could have started to search the sky too late, they
  could have discovered the Chicxulub asteroid only a few months
  before impact, when it was too late to deflect it. This danger of a
  late detection was precisely the argument used by followers of a
  theory opposing ours, namely that while we were proceeding on the
  search for asteroids on orbits crossing that of the Earth, we
  should simultaneously develop the defense system. The technology
  needed to deflect an asteroid, even with only a few years of impact
  warning, could have been based upon thermonuclear bombs of great
  power, tens or even hundreds of Megatons, to be exploded beside the

--To blow it up into a thousand pieces, like in some second-rate
  science fiction movies?

--Not at all! If an asteroid on a collision course with the Earth is
  blown to bits, how many of those pieces end up hitting our planet?
  This could even increase the damage, since the same energy would be
  distributed over a larger portion of the Earth's surface. The thing
  to do is to leave the asteroid as much as possible in one piece,
  while pushing it in a well-chosen direction. This can be obtained
  with an explosion not onto the asteroid itself, but above the
  surface: a layer of the surface then vaporizes, creating a rocket
  effect of sorts.

--And man has developed this technology?

--No, because this hasn't been necessary, and fortunately we were able
  to convince the political leaders that it was not a good idea to
  develop this technology as a preventive measure. You must remember
  something you should have studied on your history textbook, which
  took place around the turn of the century, in the same years in
  which we were proposing our Spaceguard Survey. At that time the
  process of nuclear disarmament was at a critical stage, and as you
  know it progressed with great difficulty, and even some setbacks.
  We did not want the threat of the asteroids to be exploited in order
  to step back from nuclear disarmament agreements: indeed some
  nuclear powers used the anti-asteroid defense as an excuse to refuse
  some decisive clause in the nuclear treaties.

--They refused to dismantle some nuclear weapons in order to have them
  ready to be used against an asteroid? --I didn't really remember
  this story; on the other hand, my high-school studies of modern
  history had been somewhat less than perfect.

--They even wanted to go on testing new weapons, using this as an
  excuse: indeed it was an excuse, since the same governments did not
  support the Spaceguard Survey at all; that is they did not really
  care to establish whether this threat was real. This is why our
  position was that priority should be given to the astronomical
  search for Earth crossing objects, while the deflection technology
  should have been made available only after we had discovered
  something dangerous. One of the arguments used in that discussion
  might be exactly what you have been looking for.

At this point I was confused indeed: I didn't understand how this
discussion about old scientific policy and nuclear weapons had to do
with the dinosaurs. The old man saw my perplexity, smiled at me, and
signaled to help him by pushing the wheelchair.

--Come with me, young Nieri. I have a book which might explain exactly
  what you need to know. You're not accustomed to using books printed
  on paper anymore, are you?

--As you know, the University of Pisa/Calci does not have a library
  any more. The books, I mean the copies on paper, were abandoned when
  the dam gave way.

--Not exactly. The University abandoned the books, but each faculty
  member was authorized to take away all the books he could carry with
  his own hands. And at that time my hands were still strong... here,
  push me into that room, my library.

As soon as my eyes adapted to the shadow, I saw that the room was
completely filled with shelves, and the shelves were full of books,
paper books. Most of the books were in very poor shape, damaged by
humidity, the acid paper used at the end of the last century
dissolving, crumbling as soon as touched; over all this, an incredible
layer of dust. I knew, however, that it had not been possible, due to
lack of time, to scan all the books of all the libraries of the
University of Pisa, so those moldy tomes contained some knowledge not
to be found in our current digital library, although it might have
been possible to locate it at some other site in cyberspace. On the
wall, yellowed with age, hung a copy of the Evacuation Decree, which I
had studied as a freshman; and indeed I half-remembered that it said
something about taking away as many books as they could.

The old man asked me to push him along until we were right below a
shelf, and with some effort stretched to be able to rummage among the
books. He took down a book, raising a cloud of dust which made me
cough: the cover was falling to pieces, and only one word could still
be read of the title: ``Hazards''. The book lost shreds of paper every
time the old man turned a page, but Giusti looked at me with a warning
look, so I tried not to show my distaste.

--Here it is, this is what I was looking for... you know, we old men
  have a strange memory, sometimes we remember perfectly something we
  read forty years ago, but not what happened yesterday. The paper is
  by Harris, Canavan, Sagan, and Ostro. The subject is ``Use and abuse
  of the technologies to avoid the risk of interplanetary

--Abuse? --The old man had caught even Giusti by surprise, and
  she knew practically everything.

--Abuse... in this paper the point is made that, if mankind develops
  the technology to deflect an asteroid away from a collision course
  with the Earth, then exactly the same technology can be used to
  deflect an asteroid in such a way that it hits the Earth. It also
  says that the opportunities for this destructive use of this
  technology are much more frequent than the opportunities to use it
  for defense.

--This is a form of that classic argument which claims that no weapon
  is only defensive --commented Giusti,

--True, but here there is a quantitative argument, an explicit
  computation on how often an asteroid could be found, which is
  suitable for use as a weapon... look here, this figure. It shows
  which change in velocity one would need to give to some asteroid, to
  have an opportunity for a deliberate impact on Earth, as a function
  of the size of the asteroid.  To tell the truth, the case we are
  interested in, the asteroid of the Chicxulub class, about ten
  kilometers in diameter, is out of scale in this graph. To have an
  opportunity on average every year, to deflect an asteroid of the
  Chicxulub class onto the Earth, one would need to impart a velocity
  change of one kilometer per second to such a large mass.

--This requires a technology far superior to ours  --said Giusti.

--Not true --retorted the old man --because as a byproduct of the
  arguments surrounding the Spaceguard Survey, a method was invented
  to deflect a large asteroid, even without the use of nuclear weapons.

--How is this possible? To deflect a monster weighing millions of
  millions of tons, traveling towards Earth at a speed of several
  kilometers per second, and even without nuclear energy?

--Exactly: the method is based upon the use of another asteroid, or
  better a comet, to be flung against the asteroid on a collision
  course with the Earth. The kinetic energy released upon impact is
  proportional to the square of the difference in velocity... I don't
  know if you are familiar enough with celestial mechanics to
  appreciate the details. Anyway I can find another book where the
  method is described clearly... there, please give me that big volume
  up there, with ``Idaho National Engineering Laboratory'' written on
  the cover.

I had the unpleasant job of pulling down another heap of dust and mold
and passed it to Carletti; in a few minutes he found a figure which
more or less explained the principle. A rather conventional propulsion
system was used to push some mass removed from a comet on a collision
course with an asteroid which had to be deflected. In extreme cases,
that is in order to deflect a rather large asteroid, an entire comet
was deflected to collide with the asteroid. It was even considered a
multi-stage system, deflecting a small asteroid to impact a
medium-sized comet, in such a way that the latter would hit and
deflect a huge asteroid.

--This is space billiards! I can't believe this could really
  be done; that's only an abstract theory --maybe Giusti's comment was
  too harsh, but it was a bit difficult to believe.

--But the space technology of the dinosaurs may have been superior
  to the one we have now --retorted professor Carletti.

--If the space station we have found orbiting as asteroid 2031 XAX2
  was indeed built by dinosaurs, then they were much superior to us as
  far as spaceships go: 2031 XAX2 has a diameter of almost two
  kilometers --was my comment, which implied that I was beginning to
  be convinced by the arguments of the old scientist.

--Then they certainly had the capability of moving asteroids with a
  comparable mass, and they could use the ``space billiard'' method to
  deflect an even larger asteroid, such as that one of the Chicxulub
  impact --concluded Carletti.

--And this implies that they could have not only deflected it away
  from the Earth, but also against the Earth.  So the question is:
  why? Why should they do something so terrible?  --It was the first
  time I had heard Giusti speak in a trembling voice, as if she was on
  the verge of tears. Was she becoming emotional? Really unexpected.

--Maybe Colonel Jones is right --I proposed --the only motivations of
  the dinosaurs that we can understand are those of war. Maybe the
  quest for destruction of the enemy is a universal sentiment,
  independent of the species, and dinosaurs were well endowed with
  it, being relatives of Tyrannosaurus Rex.

--Don' t be silly --the Prof was angry now --the Waukarlysaurs were
  relatives of the Tyrannosaurs as much as we are relatives of the


--Maybe; but [....] there is a limit to the desire for destruction. I
  don't think that man could do something like that, at least not on
  purpose. Our hate has some limits; we always acknowledge that even
  our worst enemy is a human being.

--This wasn't always the case, in the history of mankind. Take for
  example slavery, religious wars, the last world wars. Anyway
  I thank you, Professor Carletti. You gave us a precious lead, at
  least we can work on this hypothesis. --Giusti signaled me that
  we had to go, and we took our leave.

On the return trip, Giusti was silent for a while. When I tried
to start up some conversation, she answered only absently: her mind
was far away, thinking about the unthinkable hatred of the
dinosaurs. Indeed, I was pensive too: are men really any better? I
took her directly home, and went back to my house, I mean
Terry's; not stopping at San Cataldo was not our style, but we didn't
feel like checking our e-mail.

Chapter 17. How many times

The next morning I was tired from the boat ride to Carletti's house,
or maybe from my mind's ride, and I slept a little longer than
usual. I was awakened by the music Terry had put on; it was one of my
favorite classical rock records:

The answer, my friend
is blowin' in the wind...

but at the moment I woke up, I could neither hear clearly nor remember
what the question was. In Terry's attic, there was no bedroom in the
traditional sense, but only a platform hanging from the roof with a
large bed, and little else. We'd had good times up there, many times;
but that morning she hadn't made any effort to wake me, and she just
climbed down the steep ladder for morning coffee and music. I looked
at her from above, spying on her through the screen of canes enclosing
the bed platform, as she walked pensively among her own paintings
leaning, stacked and propped throughout the studio. I have to talk to
her, I thought; she knows there's something wrong, something I'm
hiding from her. But of course I was in a rush to have breakfast and
go to San Cataldo, as usual.

That same morning, when I logged on my computer, I found a message
waiting for me since yesterday: it was indeed exceptional for me not
to check my e-mail in the evening. It was a job opening. The
Australian government had decided to create a new research center,
dedicated to the understanding of the dinosaurs' civilization, at the
very site of the fossil CD-ROM dig: they were looking for a specialist
in the subject, to serve as director of the research center and of the


So I sent in an application form straightaway, with my CV and list of
publications, including the first version of my monumental
``Waukarlysaurus pseudodictionary''. On the form they asked for the
names of qualified experts as references, and I could only list Giusti
and Marchi. Maybe I should have warned her I was sending the
application? After some thought, I decided to do the formally correct
thing: I sent her a copy of my application. This could also serve to
stir her up a little.

After that pause for long-term projects, I went back to my current
job. I had to test the hypothesis put forward by Carletti of an
intentional deflection of an asteroid against the Earth. The only
place where I could look for some confirmation was in that section of
the CD where the asteroid was shown. The text illustrating the video
had been pseudotranslated, but this didn't mean it had been
understood. I used my own method, consisting of the use of semantic
markers with uneven weighing, to identify the most important section
of the text. After several hours of hard work, I had decided the key
phrase was:

[others; bad ones, monsters] [use, exploit; build]
[celestial body; asteroid, comet; rock] [non] [harmonizing, resonant;
timely, synchronized] [again; return, coming back; known]
[for; to; towards] [evil; death, severe illness; aggression, war]

The phrase was indeed obscure, but it pointed to some strange maneuver
made with an asteroid/comet, resulting in great evil. And the subject
of the phrase could mean ``the bad guys'', the enemy, whatever they
were. Resonant, synchronized, could be terms having to do with
celestial mechanics, that is with some strange theory of the motion of
these bodies. I was stuck, and for the usual reason: because I didn't
understand the technical terms of some other discipline, I had no idea
of the context, and thus could not understand the true meaning. Time
to get some help. Giusti might know what these words meant, and then
she might not. Better to resort to a true expert: I had to contact

Fabrizio, however, was away for a meeting, and according to Anna he
would be back in the evening. Taking advantage of my friendship with
Anna, I invited myself to their place for dinner. In the afternoon, I
ran across Giusti in the corridor near our offices, and warned her
that I was following some interesting leads on the dinosaur-asteroid
connection. She nodded absently, as if she wasn't too keen on knowing
the answer to the questions raised by yesterday's visit to Carletti.


When Fabrizio arrived, we had dinner, and I was very cautious about
avoiding the issue that had made Anna furious. I went straight to my
own purpose for the visit. Immediately after dinner, I showed
Fabrizio the pseudotranslation of the key sentence of the text about
the asteroid. He was stricken by some of the possible translations I

--Timely, resonant; coming back, return. Could be `resonant return'?

--These words are preceded by a word, whose meaning is not ambiguous at
  all: negation --I corrected.

--Then `non-resonant return'?

--Could be.

Fabrizio went pale. Anna forgot their grudge and asked him whether he
was all right.

--I'm fine, but what's this about? --He did not look at all well.

--As far as I can tell, this is the explanation of what a dinosaurs'
  spaceship is doing around the asteroid, as depicted in the video
  --My explanation did not seem to reassure Fabrizio, who asked for a
  drink. After he had gulped down a whisky, he started to give me some
  background information.

--Non-resonant return is a theory extensively studied in connection
  with the safe control of a process of deflection of an asteroid. In
  the 10's a task force of top level scientists was set up to
  understand in depth the mechanics of asteroid deflection, in case
  this might prove to be necessary. It was then discovered that
  deflection could be dangerous, because to push an asteroid away from
  an orbit undergoing a very close approach at one encounter could
  result in the increased likelihood of an impact at a later encounter.

--Then it's better not to deflect?

--Of course not, if an asteroid had been discovered on a collision
  course with the Earth we would have had no choice but
  deflection. However, the process would need to be very carefully
  controlled to ensure that the deflection would not result in another
  impact later on.

--Then why are these words `non resonant return' so frightening for

--According to a well-known theory developed at the time, a
  non-resonant return is a mechanism which might result in an
  unexpected new impact as a result of a wrong maneuver to avoid
  another one. The term refers to a second close approach
  typically occurring 18 months after the first one.

It was my turn to go pale. After I had in turn fortified myself with a
whisky, I proposed my translation of the key sentence:

--Then the meaning should be: they, the bad guys, use, are building,
  an asteroid non-resonant return for aggression, war.

Fabrizio assented, unable to speak, and poured more drinks for all
three of us before going on.

--A non-resonant return might result from a wrong maneuver, but it
  could also be obtained on purpose. A small change in the asteroid's
  velocity during the first close approach could be used to insert it
  into a collision course for a year and a half later.

--Then the dinosaurs, I mean all the dinosaurs, would know that this
  second, deadly encounter would take place?

--Yes, they all would know --concluded Fabrizio --and it would be too
  late to do anything with an asteroid of the size of the Chicxulub

--This perfectly explains the haste to close down Mammal Park, as well
  as any other research project, and to deposit the records of its
  results underground --Anna had totally forgotten her personal
  problems,  for tonight.

The evening ended on a sober tone. While going back home in my boat, I
all of a sudden remembered what the song I had heard in the morning
was all about.

Copyright 1999, Andrea Milani

CCCMENU CCC for 1999