
A Universe Full of Planets - sew
http://www.nytimes.com/2013/07/26/opinion/global/a-universe-full-of-planets.html?hp&_r=0
======
GuiA
This is one of the topics that I find the most fascinating, and if I die
before we learn more about life in the Universe other than on Earth, I will
probably be very sad that my life span did not coincide with its discovery.

There's an entire body of knowledge that we cannot chart yet because we have
no data to formulate it from. It seems likely and intuitive that if there are
life forms on planets other than Earth, they are subject to evolution; but we
cannot hypothesize much further than that.

Under what conditions does sentient meta-cognizant life evolve? How does it
develop culture, religion, mathematics, art, philosophy, language? (has the
Church-Turing thesis been formulated identically somewhere else than on
Earth?) Which of those are constants amongst such species, and for the ones
who aren't, what leads to their creation? How intertwined are they to biology?
(e.g., death and religion) How frequently does the notion of "gender" happen
in complex living structures? Do principles of cultural development such as
the ones presented in "Guns, germs and steel" hold for non-Earth
civilizations?

And if we find advanced sentient life that is much older than we are, that
will be even more interesting. Are there events that this civilization went
through/constructs that it built that are similar to ours? (various notions of
democracy/freedom/government; mechanical transportation, "computers",
electricity, digital communications, artificially expanding life (i.e.
healthcare), etc.)

"Xenopology" is going to be one fascinating subject[1]. And on a related note,
if any one is aware of serious academic work in that field (it seems pretty
much impossible right now, because we just don't have the data; but you never
know), I'd love to hear recommendations :)

 _[1] With fascinating consequences when it arises, too. We 'll have to
rewrite a lot of the more "meta" Wikipedia articles, for starters (Wikipedia
is terribly anthropo-centered). And then, what will happen with our body of
knowledge? We will merge human mathematics with xenomathematics? (if it's even
possible) If they have a communications construct comparable to the internet,
do we keep the two separate? Do we want them to be able to communicate at all
on an individual level, much like any human on Earth can email any other human
on Earth freely right now? Those are all of course very hypothetic
considerations, but they're probable and fascinating to think about._

~~~
incompatible
It is fascinating. Imagine if we did detect a radio signal from intelligent
life elsewhere. What sort of reply would we send them? I imagine it would be
every sort of reply imaginable, as everybody with access to a radio telescope
gave it their best shot. I expect a lot of new radio telescopes would be
constructed also.

If we don't receive any such signals, then finding life elsewhere is going to
be a long, hard slog. It seems we don't yet have the energy/technology levels
required to get a probe to another star within a reasonable amount of time
(100 years travel time, would perhaps be reasonable? Could any of our
equipment last that long?) Self-replicating space probes that could
exponentially explore the entire galaxy seem to be right out of the question,
at present.

~~~
murtza
If you are interested in exploring this topic more, the fiction book _Contact_
by Carl Sagan is based on the premise of detecting a radio signal from
intelligent life. It is a great book that you will make you wonder what
effects contact from intelligent life elsewhere would have on human behavior.

~~~
dandelany
And if you wonder about the opposite - how human contact would affect the
behavior of intelligent life elsewhere - I highly recommend _The Sparrow_ by
Mary Doria Russell.

------
vidarh
It fascinates me to think about what this will mean to science _fiction_.
There's obviously lots of sci fi that assumes lots of planets out there, but
just like actually going to the moon means sci fi depictions of the moon "had
to" align with what they actually found and it altered depictions of space
ships and suits (and caused endless crappy attempts at trying to capture "low
gravity"), it will increasingly "have" to deal with actual facts about what's
out there.

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marcosscriven
One idea that fascinates me is the possibility of _two_ planets in the same
solar system evolving intelligent/technological life. How amazing would it
have been to have been one of the first astronomers on such a planet, and see
macro-structures like large cities on another planet.

~~~
wikiburner
I often wonder how much more advanced our space program would have been by now
had Mars or Venus been habitable.

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dkural
The universe never does anything just once.. black holes, gamma ray bursts,
supernovae, planets, and yes, life.

------
Zikes
I think this link will bypass the paywall:
[http://www.nytimes.com/2013/07/26/opinion/global/a-universe-...](http://www.nytimes.com/2013/07/26/opinion/global/a-universe-
full-of-planets.html?pagewanted=all)

~~~
baddox
Still a paywall.

~~~
ludwig
Use Chrome's incognito mode.

------
cletus
Like many here I find the subject of finding life on other planets fascinating
and consider it inevitable. What's interesting is that the estimate of planet
incidence is seemingly much higher than originally postulated by the Drake
Equation [1].

A factor in the development of life, especially sentient life, is metallicity
[2]. Almost all of the first 100 elements naturally occur on Earth. This is
pretty amazing. Nuclear fusion in stars naturally produces elements up to iron
[3]. S-capture is thought to produce elements up to Bismuth (atomic number
83). Elements higher than this are thought to be produced only in supernovae
or other cataclysmic events.

It's amazing to think that enough time has gone by in the Universe to take the
abundant hydrogen and helium, form stars, have those stars run out of fuel and
enough of them explode to scatter their elements to form heavy planets around
later stars.

While heavy elements may not be required for life it seems less likely that
starfaring sentience can form without them. Semiconductors for example require
an odd mix of heavy elements.

It seems amazing that even we exist given that you need metals, a long-lived
and stable star, likely billions of years of evolution, a sufficiently stable
(and probably geologically active) planet with an atmosphere that has water in
liquid form (a pretty narrow temperature band even taking into account
different atmospheric pressures) and no cataclysmic events to happen in all
that time (it seems to have been ~65 million years since the last big one).

It may just be that sentient life is fleeting. We've had "civilization" for
X0,000 years, which is the blink of an eye. It's entirely possible we'll wipe
ourselves out due to war or simply lack of (sufficiently cheap) resources in
another blink. The problem isn't lack of resources. They are plentiful in
space. The problem is the cost of getting them if energy is anything other
than free.

Additionally interstellar distances seem almost unconquerably large that one
has to wonder if we'll ever meet another sentient life form face to face
(assuming they have faces).

Even if we do, one wonder what evolved elsewhere for facilitate communication.
Will they see? Will the wavelengths of light they see cross over ours at all?
These are questions we can only really speculate about.

It's also been suggested (by Hawking among others) that we really don't want
to meet a much more advanced species as it will probably be bad for us,
perhaps even an Outside Context Problem [4] and it seems unlikely given the
rate of change we're experiencing that another civilization will be at the
same point as us.

We could of course be "first". I mean someone has to be right? It does seem
unlikely however. But I suspect there were many "firsts" (in the sense that
they evolved independently and without any contact or evidence of other
species).

The seeming lack of self-replicating robots, something we'll almost certainly
be able to build and start filling the galaxy with within a thousand years I'm
sure, is also somewhat puzzling.

Personally I just hope we find evidence of extraterrestial life sometime soon
as it will settle [5] a whole bunch of issues about us being "special" (in the
typically religious sense).

[1]:
[http://en.wikipedia.org/wiki/Drake_equation](http://en.wikipedia.org/wiki/Drake_equation)

[2]:
[https://en.wikipedia.org/wiki/Metallicity](https://en.wikipedia.org/wiki/Metallicity)

[3]: [http://hyperphysics.phy-
astr.gsu.edu/hbase/astro/nucsyn.html...](http://hyperphysics.phy-
astr.gsu.edu/hbase/astro/nucsyn.html#c1)

[4]:
[http://en.wikipedia.org/wiki/Excession#Outside_Context_Probl...](http://en.wikipedia.org/wiki/Excession#Outside_Context_Problem)

[5]: [http://xkcd.com/1235/](http://xkcd.com/1235/)

~~~
prawn
"What's interesting is that the estimate of planet incidence is seemingly much
higher than originally postulated by the Drake Equation."

I always assumed that the estimates there were purposefully low to show "Hey,
even with all these low estimates, we should still find something, right?"

------
RickyShaww
Don't we know this in high school. Of course the universe is full of planets.

~~~
vidarh
Unless you left high school within the last few years, no we didn't. We might
have assumed, but the evidence is quite new.

------
Zigurd
Why haven't they called?

If planets are abundant, that puts the kibosh on the "rare Earth" theory, as
shaky as that was to begin with. The other explanations are less optimistic:
Maybe they all nuke themselves or turn to grey goo before they can muster the
technology and energy to build a starship. Or they are roasted by random
blasts of radiation before they become space-faring.

It's either something universal about civilizations, or something is wrong
with the Drake equation or the underlying cosmology.

~~~
Balgair
There are many reasons: Here are a few:

A) The universe is very large. The nearest star is 4 and some change
lightyears (ly) away. That means any message take over 8 years to get,
process, and transmit to the nearest star. All other stars are further than
that. Since we have been weakly radio broadcasting for about 100 years, the
number of stars we have been able to speak with is at best 1600
([http://wiki.answers.com/Q/How_many_stars_within_50_light_yea...](http://wiki.answers.com/Q/How_many_stars_within_50_light_years_from_earth)).

B)Messages get lost in noise. We assume that we are heard out in the universe.
But it is very very difficult to hear a mosquito at a rock concert 100 miles
from you. The reverse is true for us. Also, you have to know to look. The
concert has been going on for 100 years but the venue, so to speak, is 4
billion years old. Also, you might be on the other side of the galaxy, or in
another one entirely.

C)Messages aren't understood as such. Do you know the protocol for USB to
serial conversion? (If so I have many questions for you) We may think an
actual message is just noise. Or, that noise is a message. We cannot possibly
tell. Yes hopefully the other side will start out easy on us but define 'easy'
to an alien.

D)Lets assume that they have spotted us and are pre-sending signals. In what
medium? We haven't even figured out the basic laws of the universe yet. Heck
Dark matter is ~25% of the mass-energy of the universe. The other ~75% is some
crazy stuff we just labeled Dark Energy. We have no clue what is going on
there. They may already be blasting us with data, but we just haven't got the
interstellar radio invented yet.

E) They simply don't give a shit. What do we have that they want? Lets assume
they are about 10,000 years older in tech than we are. Geologically speaking,
thats nada, thats the last ice age. People were around then. And look now we
have radios and iPads and ISS's and stuff. 10,000 years is a lot of time to
think and make stuff. What could we do in that much more time? Well, make a
computer that'll calculate just about anything, probably. And if your
civilization is all entertained, why bother looking at the stars? Why bother
with a,likely, giant telescope array that beams out gibberish for a thousand
years. What stuff on Earth over 1000 years old? Not all that much but piles of
rocks and some windows. The engineering of a giant thingy is very hard. And
all for what? Some algae that you hope turns into a little curious squid or
something?

F) They dont give a shit. Not because they are hedonistic but because they
live under an ice-sheet the planet wide. Or they are at the bottom of a giant
cloud where pressure is just right. Or they are frozen periodically in ammonia
ice for 700 years. Or they have no idea of math and science because they don't
have nerves that work like that. Or because they don't have cells at all. Or
because they have no photoreceptors and can't even begin to imagine light. Or
because they think that thing we call matter is just a rounding error. Or
because they already migrated into dark energy beings and are just waiting to
see us.

G) We are just plain jane alone.

~~~
drhodes
Information theory can discriminate between noise and language,
([http://www.peterrussell.com/Dolphin/DolphinLang.php](http://www.peterrussell.com/Dolphin/DolphinLang.php)),
Zipf's law
([http://en.wikipedia.org/wiki/Zipf's_law](http://en.wikipedia.org/wiki/Zipf's_law)),

~~~
phreeza
Once you start applying compression to your signals, as we do with many of our
radio signals nowadays, that possibility goes away.

~~~
Balgair
Why so? The compression should..... wait, yes, yes it will go away. And their
'signal' may be compressed naturally, much as we say 1984 as 'nineteen eighty
four' but in Spanish they say 'mil novecientos ochenta y curato' (thousand
nine hundred eighty and four). Not a great example but I think it fits. Apply
this over thousands of years with creatures that have hydraulic pumps not
muscles (or something) and you get the idea.

