Fermi's Paradox and DNA

[Terry Pilling]

I have an idea that I would like to hear comment on.
I formulated it last night while reading the latest excellent
book by Richard Dawkins called `The Ancestor's Tale'.

Last week I looked at the paper that came out on the
arxiv about Fermi's Paradox. It is the idea that the
galaxy should be filled with extra-terrestrial life just
based on probability. The paradox is: why aren't they here
already?

Anyway, I thought. What if DNA/RNA was seeded throughout
the galaxy by some ancient intelligent organisms? It would
have been designed by them as a teraforming method. So
that 3.5 billion years ago a meteor hits the earth's
atmosphere (composed of nitrogen and carbon-dioxide at
the time) it breaks apart and is spread over 3/4 of the
globe. It rains out into the water/organic hydro-carbon
soup and then starts to do what DNA/RNA does, namely
reproduce itself, mutate and evolve. Then 3.5 billion
years later, the earth is green and blue, oxygen rich
and seething with biomass. Exactly as intended.

I figured that if this were true, then it may be possible
that they had left a message encoded in the DNA so that
intelligence, if it evolved, would be able to decode it.
So for example, if we sequenced the DNA of enough organsims
so as to `triangulate' back and reconstruct the original primordial
DNA sequence from my hypothetical meteor, we may notice large sequences
of exactly conservative and yet useless information. This
`useless' information would be the coded message. So that
the message of the teraformers is encoded inside the biomass
itself.

All of this may be wrong, but it isn't stupid. It is a
hypothesis that makes a prediction. It is testable.
It is potentially important. So it is scientific.

Plus, Suppose we someday get to the point where we can
manipulate our own DNA and create better humans. Suppose we then
travel about the galaxy and find to our dismay that there is
absolutely no life anywhere else and that the evolution of DNA
was just a freak accident occuring only here on earth. Would
we not be tempted to set up machines to send out meteors and seed
the rest of the galaxy? If we did that, it is only a small
leap to admit the possibility of encoding a message for the future
beings evolving from our seeds, wherever and whatever they may be.

I am interested in hearing comments. Especially if you have
any simple reasons why this could not be possible (for example
proof that DNA itself evolved from simpler molecules on earth)
Please be nice though.

--
-Terry

---------------------------------------------------
Terry Pilling
Department of Physics
North Dakota State University
http://www.physics.ndsu.nodak.edu/people/index.html
---------------------------------------------------

[rof@maths.tcd.ie]

terry@nospam.sdf-eu.org (Terry Pilling) writes:

>Anyway, I thought. What if DNA/RNA was seeded throughout
>the galaxy by some ancient intelligent organisms?

>I figured that if this were true, then it may be possible
>that they had left a message encoded in the DNA so that
>intelligence, if it evolved, would be able to decode it.
>So for example, if we sequenced the DNA of enough organsims
>so as to `triangulate' back and reconstruct the original primordial
>DNA sequence from my hypothetical meteor, we may notice large sequences
>of exactly conservative and yet useless information. This
>`useless' information would be the coded message. So that
>the message of the teraformers is encoded inside the biomass
>itself.

I'm afraid that DNA mutates too quickly for any message
to survive inside it for long. If you compare even closely
related species, you find that only functionally important
parts of the DNA sequence are conserved; that is, unless
mutations of that part of the DNA sequence cause the mutant
to fail to produce descendents, then the sequence will mutate
beyond recognition in a few million years.

Reconstructing the nonfunctional sequence of the common ancestor
of all vertebrates, for example, isn't feasible, although we can
be fairly sure that that creature had RNA polymerase and ribosomes
and so on.

>Plus, Suppose we someday get to the point where we can
>manipulate our own DNA and create better humans. Suppose we then
>travel about the galaxy and find to our dismay that there is
>absolutely no life anywhere else and that the evolution of DNA
>was just a freak accident occuring only here on earth. Would
>we not be tempted to set up machines to send out meteors and seed
>the rest of the galaxy? If we did that, it is only a small
>leap to admit the possibility of encoding a message for the future
>beings evolving from our seeds, wherever and whatever they may be.

>I am interested in hearing comments. Especially if you have
>any simple reasons why this could not be possible (for example
>proof that DNA itself evolved from simpler molecules on earth)
>Please be nice though.

This was the theme of one of the episodes of the original Star Trek.

R.

[Andreas Most]

Terry Pilling wrote:
> I have an idea that I would like to hear comment on.
> I formulated it last night while reading the latest excellent
> book by Richard Dawkins called `The Ancestor's Tale'.
>
> Last week I looked at the paper that came out on the
> arxiv about Fermi's Paradox. It is the idea that the
> galaxy should be filled with extra-terrestrial life just
> based on probability. The paradox is: why aren't they here
> already?
>
> Anyway, I thought. What if DNA/RNA was seeded throughout
> the galaxy by some ancient intelligent organisms? It would
> have been designed by them as a teraforming method. So
> that 3.5 billion years ago a meteor hits the earth's
> atmosphere (composed of nitrogen and carbon-dioxide at
> the time) it breaks apart and is spread over 3/4 of the
> globe. It rains out into the water/organic hydro-carbon
> soup and then starts to do what DNA/RNA does, namely
> reproduce itself, mutate and evolve. Then 3.5 billion
> years later, the earth is green and blue, oxygen rich
> and seething with biomass. Exactly as intended.
>
> I figured that if this were true, then it may be possible
> that they had left a message encoded in the DNA so that
> intelligence, if it evolved, would be able to decode it.
> So for example, if we sequenced the DNA of enough organsims
> so as to `triangulate' back and reconstruct the original primordial
> DNA sequence from my hypothetical meteor, we may notice large sequences
> of exactly conservative and yet useless information. This
> `useless' information would be the coded message. So that
> the message of the teraformers is encoded inside the biomass
> itself.
>
> All of this may be wrong, but it isn't stupid. It is a
> hypothesis that makes a prediction. It is testable.
> It is potentially important. So it is scientific.
>
> Plus, Suppose we someday get to the point where we can
> manipulate our own DNA and create better humans. Suppose we then
> travel about the galaxy and find to our dismay that there is
> absolutely no life anywhere else and that the evolution of DNA
> was just a freak accident occuring only here on earth. Would
> we not be tempted to set up machines to send out meteors and seed
> the rest of the galaxy? If we did that, it is only a small
> leap to admit the possibility of encoding a message for the future
> beings evolving from our seeds, wherever and whatever they may be.
>
> I am interested in hearing comments. Especially if you have
> any simple reasons why this could not be possible (for example
> proof that DNA itself evolved from simpler molecules on earth)
> Please be nice though.
>

The idea is not new, at least as it concerns Sci-Fi:
In one of the Star Trek Voyager (I think) series they had
to collect the DNA from 7 different races to retrieve a
message encoded in the DNA by an ancient alien race.

Andreas.

[AndyCav]

"Terry Pilling" <terry@nospam.sdf-eu.org> wrote in message
news:dqj5n9$5v8$1@chessie.cirr.com...
>I have an idea that I would like to hear comment on.
> I formulated it last night while reading the latest excellent
> book by Richard Dawkins called `The Ancestor's Tale'.
>
> Last week I looked at the paper that came out on the
> arxiv about Fermi's Paradox. It is the idea that the
> galaxy should be filled with extra-terrestrial life just
> based on probability. The paradox is: why aren't they here
> already?
>
> Anyway, I thought. What if DNA/RNA was seeded throughout
> the galaxy by some ancient intelligent organisms? It would
> have been designed by them as a teraforming method. So
> that 3.5 billion years ago a meteor hits the earth's
> atmosphere (composed of nitrogen and carbon-dioxide at
> the time) it breaks apart and is spread over 3/4 of the
> globe. It rains out into the water/organic hydro-carbon
> soup and then starts to do what DNA/RNA does, namely
> reproduce itself, mutate and evolve. Then 3.5 billion
> years later, the earth is green and blue, oxygen rich
> and seething with biomass. Exactly as intended.
>
> I figured that if this were true, then it may be possible
> that they had left a message encoded in the DNA so that
> intelligence, if it evolved, would be able to decode it.
> So for example, if we sequenced the DNA of enough organsims
> so as to `triangulate' back and reconstruct the original primordial
> DNA sequence from my hypothetical meteor, we may notice large sequences
> of exactly conservative and yet useless information. This
> `useless' information would be the coded message. So that
> the message of the teraformers is encoded inside the biomass
> itself.
>
> All of this may be wrong, but it isn't stupid. It is a
> hypothesis that makes a prediction. It is testable.
> It is potentially important. So it is scientific.
>
> Plus, Suppose we someday get to the point where we can
> manipulate our own DNA and create better humans. Suppose we then
> travel about the galaxy and find to our dismay that there is
> absolutely no life anywhere else and that the evolution of DNA
> was just a freak accident occuring only here on earth. Would
> we not be tempted to set up machines to send out meteors and seed
> the rest of the galaxy? If we did that, it is only a small
> leap to admit the possibility of encoding a message for the future
> beings evolving from our seeds, wherever and whatever they may be.
>
> I am interested in hearing comments. Especially if you have
> any simple reasons why this could not be possible (for example
> proof that DNA itself evolved from simpler molecules on earth)
> Please be nice though.
>
> --
> -Terry
>
> ---------------------------------------------------
> Terry Pilling
> Department of Physics
> North Dakota State University
> http://www.physics.ndsu.nodak.edu/people/index.html
> ---------------------------------------------------
>

Hi Terry. This is an old idea though isn't it... that the so called 'junk
DNA' may contain a message from some intelligent being that created it.

To me the idea passes as a scientific idea in that it's a testable
hypothesis but I can also see why no one so far has bothered to test it;
because it 'smells' too much of searching for meaning in life, trying to
replace God...

If I found out that we were created by another being, appart from being very
excited by alien life, I would have a drink to them and then go about my
business! And if they returned demanding that we pay the debt I'd fight
them! Freeeeeedom!

Cough.... but seriously, I'm sure someone will write some software to
download soon enough, just like SETI @ home, to search through the genome
for patterns.

AndyCav

[Terry Pilling]

AndyCav <a.m.ciavarella@durham.ac.uk> wrote:
> Hi Terry. This is an old idea though isn't it... that the so called 'junk
> DNA' may contain a message from some intelligent being that created it.

> To me the idea passes as a scientific idea in that it's a testable
> hypothesis but I can also see why no one so far has bothered to test it;
> because it 'smells' too much of searching for meaning in life, trying to
> replace God...

Well.. replacing a non-existent creator by a scientific hypothesis
seems like a good trade. But I do know what you are saying. I am
certainly not asking for some higher meaning for our existence.

However, there is a large amount of time and money being spent around
the world right now on the search for extra-solar planets and in
particular for signs of life elsewhere. If there is life elsewhere
it seems there are only two choices: 1. it is based on DNA or RNA or
2. it is not. If it is based on DNA or RNA then either 1) DNA is easy
to evolve, or 2) it is difficult to evolve and so was possibly seeded
by the very rare instances where it did evolve.

So forgetting about the hidden messages (I am convinced that this couldn't
happen now by the argument of `R' in a previous post: that DNA mutates too
fast for any coherent message to remain.) I still find it hard to imagine
how the first life could have appeared on earth so soon after the crust
had solidified (as if I or anyone else has any idea what a `reasonable'
estimate is for how quickly this could occur). However if, rather than a
billion years, the process had 12 or so billion years to occur on countless
planets it would be that much more likely.
This would be the case if life had happened to evolve somewhere
else at some point in the past and was subsquently seeded elsewhere
in some fashion.

> Cough.... but seriously, I'm sure someone will write some software to
> download soon enough, just like SETI @ home, to search through the genome
> for patterns.

Waste of time (considering the mutation arguement above).

However I would be interested in a distributed simulation modelling
the early conditions on earth to see if somehow self replicating organsims
could be formed and thus determining what the timescale would have to be.

If such a simulation could be written (I doubt if this is possible in
the near future) and it could show a 2 or 300 million year time scale
for the emergence of DNA from the primordial soup, then I would happily
give up the hypothesis of extraterrestrial origins.

However, what does Fermi's Paradox imply about the time scale?
Perhaps Fermi's Paradox implies that the probability is very low for
the formation of D/RNA. Which may suggest we could end up being the
terraformers rather than the terraformees in this scenerio.

--
-Terry

---------------------------------------------------
Terry Pilling
Department of Physics
North Dakota State University
http://www.physics.ndsu.nodak.edu/people/index.html
---------------------------------------------------

[ianparker2@gmail.com]

[ Mod. note: Please try to stay on topic, the physics of the problem, in
the follow-ups. Otherwise the discussion should be taken elsewhere.
-ik ]

>However, what does Fermi's Paradox imply about the time scale?
>Perhaps Fermi's Paradox implies that the probability is very low for
>the formation of D/RNA. Which may suggest we could end up being the
>terraformers rather than the terraformees in this scenerio.

There is low probability. Another possibility is a race. Once
interstellar travel of any sort becomes possible the evolution of
intelligent life other than that of the first travellers ceases. If we
are indeed in a race this has consequences for how we view interstellar
travel. If we are rare we don't have to do it. If we are racing,
interstellar travel is vital for our survival.

[AndyCav]

[ Mod. note: Please try to stay on topic, the physics of the problem, in
the follow-ups. Otherwise the discussion should be taken elsewhere.
-ik ]

"Terry Pilling" <terry@blah.sdf-eu.blah.org> wrote in message
news:dqudu8$j5l$1@chessie.cirr.com...
> AndyCav <a.m.ciavarella@durham.ac.uk> wrote:
>> Hi Terry. This is an old idea though isn't it... that the so called
>> 'junk
>> DNA' may contain a message from some intelligent being that created it.
>
>> To me the idea passes as a scientific idea in that it's a testable
>> hypothesis but I can also see why no one so far has bothered to test it;
>> because it 'smells' too much of searching for meaning in life, trying to
>> replace God...
>
> Well.. replacing a non-existent creator by a scientific hypothesis
> seems like a good trade.But I do know what you are saying. I am
> certainly not asking for some higher meaning for our existence.
>
> However, there is a large amount of time and money being spent around
> the world right now on the search for extra-solar planets and in
> particular for signs of life elsewhere. If there is life elsewhere
> it seems there are only two choices: 1. it is based on DNA or RNA or
> 2. it is not. If it is based on DNA or RNA then either 1) DNA is easy
> to evolve, or 2) it is difficult to evolve and so was possibly seeded
> by the very rare instances where it did evolve.
>
> So forgetting about the hidden messages (I am convinced that this couldn't
> happen now by the argument of `R' in a previous post: that DNA mutates too
> fast for any coherent message to remain.)

Yes I agree - that's a pretty solid answer (assuming it's right of course,
which I will here!)

>I still find it hard to imagine
> how the first life could have appeared on earth so soon after the crust
> had solidified (as if I or anyone else has any idea what a `reasonable'
> estimate is for how quickly this could occur). However if, rather than a
> billion years, the process had 12 or so billion years to occur on
> countless
> planets it would be that much more likely.
> This would be the case if life had happened to evolve somewhere
> else at some point in the past and was subsquently seeded elsewhere
> in some fashion.
>

Yeah, actually this is the most interesting point isn't it: life appeared
VERY quickly on Earth (so we are told). Problem being that we have only one
example of life occurring and so can not really infer odds of such
occurrences based on this occurrece alone - maybe we owe our existence to
the fact that life on this planet has had such an adnormally long time to
evolve! I think that's a very irritating problem.

>> Cough.... but seriously, I'm sure someone will write some software to
>> download soon enough, just like SETI @ home, to search through the genome
>> for patterns.
>
> Waste of time (considering the mutation arguement above).
>

Agreed! Dissappointed I didn't suggest this mutation issue myself.... :(

> However I would be interested in a distributed simulation modelling
> the early conditions on earth to see if somehow self replicating organsims
> could be formed and thus determining what the timescale would have to be.
>
> If such a simulation could be written (I doubt if this is possible in
> the near future) and it could show a 2 or 300 million year time scale
> for the emergence of DNA from the primordial soup, then I would happily
> give up the hypothesis of extraterrestrial origins.
>
> However, what does Fermi's Paradox imply about the time scale?
> Perhaps Fermi's Paradox implies that the probability is very low for
> the formation of D/RNA. Which may suggest we could end up being the
> terraformers rather than the terraformees in this scenerio.
>
> --
> -Terry
>
> ---------------------------------------------------
> Terry Pilling
> Department of Physics
> North Dakota State University
> http://www.physics.ndsu.nodak.edu/people/index.html
> ---------------------------------------------------
>

I think that Fermi's paradox suggests a low formation rate for intelligent
life only with a certain assumpion: that intelligent life would be
*obvious*. I mean, would intelligent aliens necessarily visit us? What if
life is *so* common that they can't be bothered - they've seen our type a
million times before?! And would an alien race be so energetically
ineffiecient that they could be detected from lightyears away?

And there's something which I think NEVER gets enough attention: what if
faster than light travel just ISN'T possible?! Civilisations would spread
out in galactically, relatively very small bubbles of civilisation - which
may not be anywhere near us! What's a hundred or so light years, or a
thousand, compared to the length scale of the galaxy?! - 10,000s of
lightyears!!!

Andyav

[Ralph Hartley]

Terry Pilling wrote:
> I figured that if this were true, then it may be possible
> that they had left a message encoded in the DNA so that
> intelligence, if it evolved, would be able to decode it.
> So for example, if we sequenced the DNA of enough organsims
> so as to `triangulate' back and reconstruct the original primordial
> DNA sequence from my hypothetical meteor, we may notice large sequences
> of exactly conservative and yet useless information. This
> `useless' information would be the coded message.

Evolution does not *do* "exactly conservative and yet useless
information". Such a message, unless its preservation was essential for
survival, would be quickly lost, and even more quickly corrupted.

A non-functional message wouldn't last a million years.

Even if the message were functional, it would have to be very resistant
to change. Even a small change would need to be completely lethal.
Otherwise selection would optimize it for changing conditions, which
would eventually destroy any message.

There *is* a small set of data that is fairly arbitrary, but almost
absolutely resistant to change.

The assignment of amino acids to three base DNA/RNA codes comes to mind.

The coding is arbitrary (more or less, there may be some constraints),
it is determined by transfer RNAs. One part of the tRNA contains the 3
letter code, and a *different* part controls which amino acid gets loaded.

It is also *very* strongly conserved, all life on earth uses the same
encoding. Presumably, this is because it is basically the machine
language in which a complicated operating system is written. If you
changed the function of just one code, you would have to also change
every gene that *uses* that code. Even in the simplest organism that
would mean hundreds, if not thousands, of simultaneous changes.

The message would have to be rather brief though. There is at most room
for about 120 bits. "(C) Genesis Inc" might fit, but not much more.

Ralph Hartley

[ianparker2@gmail.com]

>What if life is *so* common that they can't be bothered - they've seen
>our type a million times before?! And would an alien race be so
>energetically ineffiecient that they could be detected from lightyears
>away?

A civilization is likely to be extravagent in its use of energy until
it reaches Dyson status. If all the energy of a star is NOT being
intercepted then our civilization will simply intercept some more.

Are there Dyson civilizations? What do they look like? A Dyson C is an
Infra Red star with no spectrum. There are basically 2 types f IR star.

1) Proto stars condensing from a nebula.
2) Old giants which have evolved off the Main Sequence and have large
envelopes of tenuous gas.

I would have imagined that a "giant" could be identified quickly by
means of an interference filter operating on rotational and vibrational
lines.

Needless to add all IR stars seen to date are gaseous, there are no
solid Dysons. around.

I think we must accept that intelligent life is rare.

[Terry Pilling]

AndyCav <a.m.ciavarella@durham.ac.uk> wrote:

> I think that Fermi's paradox suggests a low formation rate for intelligent
> life only with a certain assumpion: that intelligent life would be
> *obvious*. I mean, would intelligent aliens necessarily visit us? What if
> life is *so* common that they can't be bothered - they've seen our type a
> million times before?! And would an alien race be so energetically
> ineffiecient that they could be detected from lightyears away?

This is very true. I have wondered about this also. Carl Sagan's Seti
program was based on the idea that intelligent life would be deliberately
transmitting messages in focussed beams. So Perhaps the reason Fermi
didn't see his aliens everywhere is simply that they are like us,
passive transmitters. In which case the signal would be far too weak
to detect except for the very closest stars.

<begin aside>
Aside about Sagan: Probably you know that Sagan designed a famous
plaque which was carried on the two Pioneer spacecraft and are now
headed out into the galaxy like a ``galactic message in a bottle''.
Well, on the plaque are some interesting and informative things,
in particular, a distance scale is set by the hydrogen atom, which
also sets a time duration scale in terms of the number of hyperfine
transitions of the hydrogen atom. A time duration which we know to
be 7.04024183647 x 10^-10 seconds and we can assume any other intelligence
would also know this. With this time scale Sagan listed a bunch of
pulsars along with their distance and periods of pulsation. For example,
the 7th pulsar listed is PSR 0531 in the crab nebula (M1)
[see: http://chandra.harvard.edu/photo/2002/0052/movies.html for
something I consider to be very cool! I even put a question on an
electrodynamics midterm exam last semester about the magnetic fields
generated by this thing.] Its rate is given on Sagan's plaque as
47057538 hyperfine transition periods. This is 33.1 ms. However, the pulsar
is slowing down at a rate of 10^-8 seconds per day! This means that since
the launch in 1972 the pulsars rate has slowed down and is now only 33.3 ms.
So any aliens getting our message (especially in a few million years!)
will have great difficulty triangulating our position (all of the pulsars
on the list are slowing down over time). In addition to this, the
pulsars are all moving through space! So by the time an alien
civilization gets the message the pulsars will all be in completely
different relative positions to the earth, making the message useless!

So I have an idea for an update of the plaque: We should list, in
addition to the pulsation periods, the decelerations of the pulsation
periods. The decelerations would allow them to find the pulsars (assuming
the decelerations are also constant) and the period data themselves will
allow them to figure out the travel time of the spacecraft since launch,
These will allow them to back trace the original positions of the
pulsars at time of launch (assuming they know the relative motions of
at least 4 pulsars) and thus finally triangulate our position at
time of launch. Then forward track our local motion to find our
position at the time of their discovery of the spacecraft!
Whew! Sounds complicated I know, but the original plaque, without
the deceleration data is impossible. As it stands now, the best
way for an alien to find the earth from a discovery of the pioneer
is to back track the spacecraft itself and forget the plaque altogether!
<end aside>

> And there's something which I think NEVER gets enough attention: what if
> faster than light travel just ISN'T possible?! Civilisations would spread
> out in galactically, relatively very small bubbles of civilisation - which
> may not be anywhere near us! What's a hundred or so light years, or a
> thousand, compared to the length scale of the galaxy?! - 10,000s of
> lightyears!!!

I am convinced that faster than light travel is, in fact, not
possible. This comes from special relativity and causality and I have
not heard of any reasonable ideas, using normal physics and normal
matter, which could allow FTL without closed timelike loops,
causality violations, and/or unitarity violations in QFT. On the
other hand, great distances can be traversed in the galaxy within
a human beings lifetime (their `proper' lifetime that is) as long
as they don't mind the fact that thousands of years will have
passed by back at home while they travel.
In fact, I think the first obstacle to interstellar travel
that the human race will overcome is our too short lifespan.
We will soon overcome this and vastly increase our lifespan and
thus enable us to make long journeys in the galaxy.
This would indicate that other space-travelling civilizations in the
galaxy will have long lifespans as well and thus we return again
to Fermi's paradox: why haven't they travelled here?

Is it because there are more than 200 billion stars in the milky way
and far fewer civilizations, so that in effect they just haven't got
to us yet?


--
-Terry

---------------------------------------------------
Terry Pilling
Department of Physics
North Dakota State University

terry[at]member.ams.org
http://www.physics.ndsu.nodak.edu/people/index.html
---------------------------------------------------

[markwh04@yahoo.com]

Terry Pilling wrote:
> Last week I looked at the paper that came out on the
> arxiv about Fermi's Paradox. It is the idea that the
> galaxy should be filled with extra-terrestrial life just
> based on probability. The paradox is: why [sic] aren't they here
> already?

We don't know if there are, nor even if any are or have visited Earth
or continue to do so on a regular basis. That question needs to be
firmly resolved first before one can even begin to ask the question
"why not", for otherwise you're begging the question by even posing the
"paradox".

Indeed, the notion that some UFO's are extraterrestial almost falls out
of the "Fermi Paradox" by reductio ad absurdum. Either some are, or
none are, and in the latter case you *really do* have some explaining
to do, a' la Fermi, since it's almost a consequence of Drake's equation
(with the parameters fed into it) that at least *some* kind of
visitation in person or by probes should be present!

It's worthy of note that, despite popular perception, the constraints
imposed by Relativity do *not* impede the prospect of space travel, but
(if anything) reduce it from being an absolute impossibility to a bare
possibility.

You see, the one thing that almost every discussion on distant travel
fails to account for is the Law of Inertia. Just from that condition
alone, travel times to the fringe of the solar system become a major
impediment, for even if you are able to push out a constant 1G
acceleration, it would STILL take you the better part of a month to
reach Pluto!

That's regardless of whether you do this computation by Newtonian
Physics or Relativistic Physics! In fact, the travel times don't
differer in any substantial way to the edge of the solar system.

But here's where the picture gets interesting and where the notion
advanced by some of the more speculative Physicists (e.g. Dyson) get
completely blown out of the water. The amount of time it takes to get
to the nearest star at a constant 1G is about 4 years, slightly more(!)
going by Newtonian physics (time dilatation).

Anyone who even so much has that ability virtually already has the
ability to get to the opposite side of the universe. For the amount of
(proper) time spent at 1G to get to the edge of the galaxy is around a
decade or so; to the next galaxy, not much more. To a place billions of
light years away, around 20, 30 or 40 years. Within a span of 50 years,
at a steady 1 G you can get anywhere IF (and that's the important point
... IF) you can even so much as get to the nearest star by some means
at 1G, because it's around the same order of magnitude (and also:
around the same level of impossibility by ordinary means).

By Newtonian physics, the times go more like in the range 10,000 to
100,000 years -- despite the ability to reach arbitrarily high speeds.
The absence of time dilatation, coupled with the serious drag provided
by the Law of Inertia, puts a real damper on the ability to go anywhere
at all. So, in a way, Relativity comes to the rescue, with the
existence of a speed limit ironically being the very thing that enables
travel to distant places (theoretically) in a reasonable time.

The Dyson picture of civilizations advancing in stages, island-hopping
from point to point, is thereby completely wrong. Any civilization even
so much as able to get to the next depot can just as immediately spread
everywhere in that same single step.

There is no island-hopping: it's all at once, everywhere, or never at
all.

The alternative scenarios of travel by new and heretofore unexplored
Physics (wormholes and time travel) only buttress the conclusion of the
"all at once, everywhere, or nowhere at all", since by the very
assumption, such alternate means provide what's required to directly
skip the intervening space between two given points.

This, in turn, only serves to make all the more poignant the question
of who (if anyone) is already visiting here and (if nobody), why not --
which, in turn, puts the spotlight even more heavily on UFO's. For
anyone here, in person (so to say) can literally be coming from
anywhere else in the entire Universe, not just the nearest stars.

The question of what, if anything, off-worldly UFO's might represent
has actually been a topic of some mainstream science seminars in the
last year or so. There has been a push to get a better understanding on
what anomalies might be hidden in these phenomena, whether it be
atmospheric (e.g. sprites), or otherwise.

It also bears pointing out that all the constraints mentioned on
travel, themselves, are completely blown out of the water when it comes
to the issue of remote probes or even von Neumann probes. Unlike humans
or other lifeforms of a similar nature, there is no time constraint on
how long a probe may be in transit, since there's no life aboard to
support. With the case of von Neumann probes (which, in fact, is what
the monoliths in the 2001 trilogy were), they would even replicate by
drawing off whatever resources are found on celestial bodies along the
way, so that the issue of numbers comes into play -- a kind of
artificial panspermia.

This, in turn, further draws the issue to what -- if anything -- lies
behind the large numbers of UFO's sighted all around the world.

> I am interested in hearing comments. Especially if you have
> any simple reasons why this could not be possible (for example
> proof that DNA itself evolved from simpler molecules on earth)
> Please be nice though.

There was a recent article posted in a peer-reviewed science journal
earlier this month which boldly raises the possibility that the red
rain phenomenon that occurred recently in India (which laid out a large
amount of cellular structures similar to blood cells in form) may have
actually be extraterrestial in origin.

You can find more information (including an article reference and PDF)
doing a Web search on "Red Rain"and "India".

The question of what it takes to evolve DNA, itself, may be little more
than a distraction. One of the more recent accomplishments amongst
biologists has been the ability to synthesize chemical processes that
embody many of the features associated with life (e.g. replication, the
spontaneous formation of cellular structures). Not only are we getting
closer to that vaunted Frankenstein Moment, but in the process are
finding out that there may be a lot more ways to get there than just by
the route selected on Earth through DNA.

This, too, serves to make all the more poignant the Fermi "paradox".

[Aaron Denney]

On 2006-01-24, Ralph Hartley <hartley@aic.nrl.navy.mil> wrote:
> The assignment of amino acids to three base DNA/RNA codes comes to mind.
>
> The coding is arbitrary (more or less, there may be some constraints),
> it is determined by transfer RNAs. One part of the tRNA contains the 3
> letter code, and a *different* part controls which amino acid gets loaded.
>
> It is also *very* strongly conserved, all life on earth uses the same
> encoding.

This is almost, but not quite true. There are some species that use a
slightly different variants -- the extremophiles that live near the thermal
vents on the ocean floor are one example, mitochondria are another.

http://en.wikipedia.org/wiki/Genetic_code#Variations

--
Aaron Denney
-><-

[Dirk Bruere at Neopax]

Terry Pilling wrote:

> AndyCav <a.m.ciavarella@durham.ac.uk> wrote:
>
>
>>I think that Fermi's paradox suggests a low formation rate for intelligent
>>life only with a certain assumpion: that intelligent life would be
>>*obvious*. I mean, would intelligent aliens necessarily visit us? What if
>>life is *so* common that they can't be bothered - they've seen our type a
>>million times before?! And would an alien race be so energetically
>>ineffiecient that they could be detected from lightyears away?
>
>
> This is very true. I have wondered about this also. Carl Sagan's Seti
> program was based on the idea that intelligent life would be deliberately
> transmitting messages in focussed beams. So Perhaps the reason Fermi
> didn't see his aliens everywhere is simply that they are like us,
> passive transmitters. In which case the signal would be far too weak
> to detect except for the very closest stars.

And even we are slowly ceasing to be that.
Most comms are being moved to either uwave beams or fibre optics.
The days of high power TV and radio are probably coming to an end. So that only
leaves radar pulses that contain very little info.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

[Terry Pilling]

> Terry Pilling wrote:

> Aside about Sagan: Probably you know that Sagan designed a famous
> plaque which was carried on the two Pioneer spacecraft and are now
> headed out into the galaxy like a ``galactic message in a bottle''.
> Well, on the plaque are some interesting and informative things,
> in particular, a distance scale is set by the hydrogen atom, which
> also sets a time duration scale in terms of the number of hyperfine
> transitions of the hydrogen atom. A time duration which we know to
> be 7.04024183647 x 10^-10 seconds and we can assume any other intelligence
> would also know this. With this time scale Sagan listed a bunch of
> pulsars along with their distance and periods of pulsation. For example,
> the 7th pulsar listed is PSR 0531 in the crab nebula (M1)
> [see: http://chandra.harvard.edu/photo/2002/0052/movies.html for
> something I consider to be very cool! I even put a question on an
> electrodynamics midterm exam last semester about the magnetic fields
> generated by this thing.] Its rate is given on Sagan's plaque as
> 47057538 hyperfine transition periods. This is 33.1 ms. However, the pulsar
> is slowing down at a rate of 10^-8 seconds per day! This means that since
> the launch in 1972 the pulsars rate has slowed down and is now only 33.3 ms.
> So any aliens getting our message (especially in a few million years!)
> will have great difficulty triangulating our position (all of the pulsars
> on the list are slowing down over time). In addition to this, the
> pulsars are all moving through space! So by the time an alien
> civilization gets the message the pulsars will all be in completely
> different relative positions to the earth, making the message useless!
>
> So I have an idea for an update of the plaque: We should list, in
> addition to the pulsation periods, the decelerations of the pulsation
> periods. The decelerations would allow them to find the pulsars (assuming
> the decelerations are also constant) and the period data themselves will
> allow them to figure out the travel time of the spacecraft since launch,
> These will allow them to back trace the original positions of the
> pulsars at time of launch (assuming they know the relative motions of
> at least 4 pulsars) and thus finally triangulate our position at
> time of launch. Then forward track our local motion to find our
> position at the time of their discovery of the spacecraft!
> Whew! Sounds complicated I know, but the original plaque, without
> the deceleration data is impossible. As it stands now, the best
> way for an alien to find the earth from a discovery of the pioneer
> is to back track the spacecraft itself and forget the plaque altogether!

In the above, I say that one needs at least 4 pulsars to triangulate
the position of the earth. I read that somewhere but now I am not so sure.
Why can't one do it with fewer pulsar positions?
So on the plaque (http://en.wikipedia.org/wiki/Pioneer_plaque) there
is the distances to the pulsars from the earth and on my revised
version there would also be the deceleration data along with the
period data of the pulsars. So the problem is this:

----------
Problem:

Given the distances to the pulsars _today_, the periods, and the
decelerations of the periods, and assuming you can experimental
determine the trajectories through space of the pulsars, what is
the minimum number of pulsars needed at any time in the future so
that a triangulation of the earth's future position can be made?
----------

The way I was thinking about it is that you would need 4, first
determine the travel time of the probe since launch based on
the current periods of the pulsars given the decelerations. Then
track the pulsars back to their positions on the date of probe
launch. Then draw spheres centered on each pulsar with radius
equal to the distances given on the plaque. If there is a unique
point of intersection of these spheres, then you have found the
earth. In fact, even if there is a _discrete_ but finite number
of intersection points, or even a finite one-dimensional line of
intersection points (like a circle of relatively small radius),
then enterprizing aliens could find us. So the problem could be
restated (I think!) as `how many spheres does one need in 3
space so that their intersection is a `findable' set?' where
by `findable' I mean finite discrete set of points, or a
compact 1-dimensional manifold of points.

Anybody know how to solve this and what conditions are
necessary to guarantee a solution?


--
-Terry

---------------------------------------------------
Terry Pilling
Department of Physics
North Dakota State University

terry[at]member.ams.org
http://www.physics.ndsu.nodak.edu/people/index.html
---------------------------------------------------