NASA's Multi-Million Dollar Search for Other Earths

Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets. NASA has laid on several
multi-million dollar missions to look for them. Why? Could the
answer be physics? Could the law of entorpy be the reason?

Catch the show!

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"Kevin Smith" wrote ...
Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets. NASA has laid on several
multi-million dollar missions to look for them. Why? Could the
answer be physics? Could the law of entorpy be the reason?

Catch the show!

http://kevinsmithshow.com

Just for once I agree. Go click this link immediately to confirm that it
actually does say "law of entorpy" (sic.)

It appears from your Biographical Brief that English is your native
language (well as much as it is for any American) so I guess we
should be free to make fun of the confused nature of your quote.

In article ,
(Kevin Smith) wrote:

Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets.

The Drake Equation is utter garbage.

NASA has laid on several
multi-million dollar missions to look for them. Why? Could the
answer be physics? Could the law of entorpy be the reason?

The answer is astronomy. Despite the Drake Equation being pure bunk,
the search for extrasolar planets is a valid and useful branch of
astronomy, and astronomy is among the things that NASA does.

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"Joe Strout" wrote ...
In article ,
(Kevin Smith) wrote:

Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets.

The Drake Equation is utter garbage.

It's just typical stone soup.

http://spanky.triumf.ca/www/fractint/stone_soup.html

Joe Strout writes:

In article ,
(Kevin Smith) wrote:

Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets.

The Drake Equation is utter garbage.

There's nothing wrong with the Drake equation - it's just the data is missing.
The controversial parts a
percentage of stars with intelligent civilizations =
(percentage of stars with suitable planets) x
(percentage of suitable planets that develop life) x
(percentage of life bearing planets that generate intelligent life).

This seems very hard to argue with, but data is sparse.

It used to be that the pessismists would assign 10^(-12) to all 3 factors, and the
optimists 1, so the answers differed by about 36 orders of magnitude.

We are now getting a handle on the frequency of planets, reducing the uncertainty
somewhat to only 24 orders of magnitude.

If we find life, any life, on Mars, Titan, etc. then we would have some scientific
evidence that the second term is closer to 1 than 0. Then we would have only 12
orders of magnitude uncertainty.

And perhaps a better understanding of evolution can help with the third term (or
of course one of the SETI searches could succeed).

Anyway, the equation itself is fine. The data is lacking, but the equation tells
interested parties where to focus their research towards narrowing the uncertainties.
That alone is a useful property.

Lou Scheffer

In article ,
Louis Scheffer wrote:

Joe Strout writes:

In article ,
(Kevin Smith) wrote:

Based on the Drake Equation, scientists say our galaxy holds as many
as 30 billion other earth-like planets.

The Drake Equation is utter garbage.

There's nothing wrong with the Drake equation - it's just the data is
missing.

No. The whole premise is faulty.

The controversial parts a
percentage of stars with intelligent civilizations =
(percentage of stars with suitable planets) x
(percentage of suitable planets that develop life) x
(percentage of life bearing planets that generate intelligent life).

This seems very hard to argue with, but data is sparse.

It's not hard to argue with at all. I'll demonstrate: this equation
assumes a static galaxy, where civilizations exist on a star system and
never venture out of it. It completely ignores the fact that travel
between star systems is possible. In reality, such travel IS possible
and so it's almost certain (by basic biological principles which apply
to all living things) that the first civilization to arise will in
fairly short order colonize the whole galaxy. (Where "fairly short
order" means "within a few hundred million years" -- we've only been
around as a civilization for a few tens of thousands.)

Drake was an astronomer, and perhaps a competent one, but his ignorance
of the most basic principles of biology led him to throw together this
utterly worthless combination of terms. It does not describe any
universe which we are likely to find ourselves in.

Or maybe it wasn't ignorance, but some sort of faith-based
irrationality. SETI proponents seem to be unreasonably attracted to the
idea of civilizations arising and going about their business for
millions of years without ever leaving their home star system,
contenting themselves with sending out faint signals for diligent young
civilizations to detect. But this is rubbish. A civilization is
composed of living things -- and on a different scale, may be considered
itself a living thing -- and such things *always* expand into new
available niches. The rest of the galaxy is composed of available
niches (or was, for the first civilization to arise anyway). There is
no chance that they will go uninhabited for long.

By analogy, suppose you're trying to estimate the number of fish in a
lake that was just created (e.g., by a large dam) five years ago. Would
you go about it with an equation like this?

Number of fish =
Cubic meters of water in the lake
* Probability that a fish occurs in each cubic meter
* Percentage of fish which are dead
etc.?

This is more obviously bunk -- the correct way to go about it is to take
into account how old the lake is, what the initial source of fish was
(perhaps some were released by aquarium owners or whatever), and then
build a population-growth model based on how fast the fish reproduce.
The answer will obviously depend on how long the population has had to
grow (until it reaches a stable state, when the lake is as full of fish
as it can be). The exact same applies to life in the galaxy.

If you really want to estimate how many inhabited star systems are out
there, you need a dynamic model that takes growth into account. This is
harder to do, but it's possible -- I've attempted it, and in my model,
it seems that the first 2 or 3 civilizations to arise in a galaxy may
find themselves in relatively empty space. Those are the early risers,
the extreme outliers of the time-to-civilization distribution. Everyone
else -- i.e., 98% of the civilizations to arise -- will find themselves
in a galaxy long ago populated by the early ones.

Now, there are a zillion unknowns in this model too, but at least it's
taking the right approach. You cannot understand or estimate ANYTHING
about the distribution of life in the galaxy without taking growth
dynamics into account. This is why the Drake equation is garbage.

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In article ,
"Paul Blay" wrote:

The Drake Equation is utter garbage.

It's just typical stone soup.

http://spanky.triumf.ca/www/fractint/stone_soup.html

I don't get the analogy. Can you elaborate?

- Joe

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"Paul Blay" wrote

The Drake Equation is utter garbage.

It's just typical stone soup.

I'm not sure that Drake really meant it to be more than stone soup:
a way to get discussions started, an attempt to provide a non-
unique framework for thinking about the problem. Stone soup
can be very tasty as long as people cooperate by putting chickens
and cabbages and seasonings into the pot.

In article ,
(Allen Thomson) wrote:

"Paul Blay" wrote

The Drake Equation is utter garbage.

It's just typical stone soup.

I'm not sure that Drake really meant it to be more than stone soup:
a way to get discussions started, an attempt to provide a non-
unique framework for thinking about the problem.

Ah, now I see the analogy. No, from what I've read, that was not the
intent; Drake (and others, most famously Carl Sagan) actually took this
bit of nonsense seriously.

Stone soup can be very tasty as long as people cooperate by putting
chickens and cabbages and seasonings into the pot.

Granted, because stones are fairly innocuous. But what we have here is
pure, stinking garbage -- it's going to ruin the soup no matter how much
good stuff you try to add in. Getting anything satisfying out of this
will require throwing that garbage out completely and starting over.

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In article ,
Andi Kleen wrote:

Joe Strout writes:

[...description of growth model snipped...]
dynamics into account. This is why the Drake equation is garbage.

It seems to me that the Drake Equation just gives the starting point
for your growth model.

That's not how it's generally used. However, I agree that something
like it could be used to estimate the number of planets on which a
civilization could arise.

Growth models would assume that interstellar travel by lifeforms and
colonization of new planets (possible terraforming) is possible and
practical (not overly expensive).

Not really -- it only needs to assume that it's possible, which isn't
assuming much, since we can already envision a variety of ways to do it
that are consistent with our understanding of physics (and we've only
been around for a few tens of millenia).

If it's possible at all, then some elements of a civilization will do
it, sooner or later. This is pretty much inevitable due to selection
pressure -- those groups or individuals which expand and multiply very
quickly outnumber those that don't.

Also it would require an expansive civilization at the right time.

I don't know what you mean by this. The right time is the time at which
the civilization develops the technology for interstellar travel
(however slow that travel may be -- no need to assume FTL here).

It is quite possible that a very advanced civilization capable of
colonizing other star systems is already static and in decline and
not interested in such adventures anymore.

Possible in the sense of "not violating any laws of physics," but not
possible as in "even remotely likely." A civilization that fills a
solar system is almost certainly going to be composed of diverse and
varied individuals, and even if the civilization itself is in decline,
there will be some individuals with the will and means to slink on off
to the next star over. They and their descendants (and those of other
groups like them, which will be continuously spawned by the declining
civilization) will fill the galaxy.

Sure, you can contrive various scenarios where it takes much longer, or
a civilization fails entirely. But so what? The time scales involved
here make such shenanigans irrelevant. The universe is over 13
*billion* years old. Our planet is 4.5 billion. Compare this to the
entire history of human civilization, which is about 40 thousand years.
There is a gross difference in the number of zeros here. There is
plenty of time for false starts, without making any difference in the
grand scheme of things.

Do you have a probability for these factors too? If any of them is 0
there will be never growth above a single planet.

None of them are 0; they are in fact quite close to 1.

At least for the Drake Equation we have proof that the result is = 1.
For a growth model there is no proof at all so far. I'm not saying
that it is impossible, but that data is certainly thin, much thiner
than even for Drake.

You've missed the point completely. It makes no sense to talk about
what the "data" are for the Drake equation, because the equation itself
is meaningless. There are NO numbers which could be inserted by an
omniscient god and make the equation make sense. It is, in short,
complete crap.

A growth model, on the other hand, describes living things (which
civilizations certainly are). With the right numbers, it would describe
the evolution and distribution of life in the galaxy over time. Feel
free to haggle over what the various numbers might be (though when you
actually run the numbers, you discover that they don't make much
difference to the important conclusions about SETI).

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